Evaluation Criteria for Comparing

Domestic and Foreign Material

Specifications

U S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Measurement Laboratory

Metallurgy Division

Washington, DC 20234

March 1 983

Final Report

Issued May 1 983

i for States Coast Guard

ment of Transportation

gton, DC 20590

r .Research Information Center

^National Bureau of Standards

Gaithersburg, Maryland 20899

NBSIR 83-2692

EVALUATION CRITERIA FOR COMPARING

DOMESTIC AND FOREIGN MATERIAL

SPECIFICATIONS

Qc/od

ao. 22 -5

J. G. Early

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Measurement Laboratory

Metallurgy Division

Washington, DC 20234

March 1983

Final Report

Issued May 1 983

Prepared for United Coast Guard

Department of Transportation

Washington, DC 20590

U.S. DEPARTMENT OF COMMERCE, Malcolm Baldrige, Secretary

NAilONAL BUREAU OF STANDARDS, Ernest Ambler, Director

TABLE OF CONTENTS

Page

ABSTRACT 1

GLOSSARY 2

.INTRODUCTION 3

COMPARATIVE ASSESSMENT 4

GUIDELINES AND EVALUATION CRITERIA 5

Specification Philosophy 7

Composition Effects 10

Metallurgical Effects 11

Product Form Effects 14

Tensile Test 15

Bend Test 17

Impact Test 19

Wedge Tension Test 20

Flare Test 21

Test Acceptance Criteria 21

Flattening Test 22

Hydrostatic Test 23

SUMMARY 23

ACKNOWLEDGMENTS 24

REFERENCES 25

APPENDICES

A Selected Quality Descriptor Terms 28

B Strain Analysis of Bending Test ......... 32

C Strain Analysis of Flattening Test 33

D Checklist of Typical Tests and Requirements from Domestic

Product and Application Specifications 35

i
Page

TABLES

I. List of Specifications Compared 37

II. Standard Tensile Test Specimens for Wrought Products 38

FIGURES

1. Classification of Metals Specifications 39

2. Examples of Text Similarity Between Specifications 40

3. Schematic of Rimmed Steel Ingot 41

4. Microstructure of Hot-Rolled Steel Plate 42

5. Effect of Cooling Rate on Mechanical Properties 43

6 . Effect of Casting Size on Tensile Properties 44

7. Effect of Mechanical Working on Tensile Ductility Anisotropy . .45

8 . Test Specimen Orientation in Rolled Products 46

9. Strain Analysis of Bend Test Specimen 47
ABSTRACT

Consistent decisions on the degree of equivalency between metal specifications of different national origins cannot be made only on the basis of

chemical composition and direct comparison of mechanical property numbers.

There are numerous additional factors, including metallurgical effects,

product form effects, test acceptance criteria, and differences in specification philosophy which, if present, may influence the determination of

equivalency -because of their effect on property requirements. In order to

remove the uncertainty in this decision-making process, these additional

factors must be evaluated for each comparison.

Excerpts from actual comparisons have been used to illustrate the

methodology based on the principles discussed in this report. The specific

evaluation criteria identified are not meant to be totally inclusive, but

rather represent those most often encountered. Some material specifications,

especially application specifications, may include special requirements

dictated by the application. Finally, material specifications are dynamic

documents because revisions of test methods and test requirements are part of

the specification writing process. Care must always be exercised to insure

that the appropriate versions of specifications are being compared.

1
GLOSSARY

capped steel

coupon

ductility

heat-affected

zone (HAZ)

killed steel

martensi te

necking

pearl ite

rimmed steel

upper shelf or upper shelf

energy level

A classification of steel based on the amount of gas evolved

during solidification as a result of steelmaking deoxidation

practice. In capped steels, the normal oxygen-carbon reaction

during solidification is stopped at a particular point by

placing a mechanical cap over the ingot mold. A capped steel

will have the low carbon rim typical of rimmed steels but will

have greater uniformity of composition and mechanical properties

like a killed steel.

A piece of metal from which a test specimen can be prepared.

Often an extra part of a casting or a forging.

The ability of a material to deform plastically without

fracturing.

The portion of the base metal not melted during brazing or welding but whose microstructure and properties are changed

by the heat from the molten metal. The region separates the

unaffected base metal from the weld or molten metal zone.

A classification of steel based on the amount of gas evolved

during solidification as a result of steelmaking deoxidation

practice. Killed steels are produced by adding deoxidation

agents, e.g., silicon and aluminum, to the ladle before pouring

into the ingot mold. This reduces the oxygen content to such a low level that there is little or no oxygen-carbon reaction

during solidification. Killed steel ingots typically have a large shrinkage cavity and relatively uniform chemical composition

and mechanical properties throughout the ingot.

In steel, a metastable phase of iron and carbon formed by the

diffusionless transformation of a high temperature phase.

A supersaturated solid solution of carbon in iron characterized

by high strength and low ductility.

Reducing the cross-sectional area of a tensile specimen in a localized area as a result of nonuniform deformation. Occurs

after the attainment of maximum load during a tension test.

In steel, a lamellar mixture of low carbon iron and iron carbide

formed by a diffusion-controlled transformation of a high

temperature phase.

A classification of steel based on the amount of gas evolved

during solidification as a result of the steelmaking deoxidation

practice. Rimmed steels are poured into ingot molds without

deoxidation by silicon or aluminum. Oxygen and carbon react

continuously during solidification. This continuous reaction

causes the region near the ingot surface to be lower in carbon,

sulfur, and phosphorus than the average ingot composition.

Rimmed steel ingots are less likely to have a large shrinkage

cavity while chemical composition and mechanical properties

vary widely throughout the ingot.

The average value for all impact test specimens whose test

temperature is above the upper end of the ducti 1 e-to-bri ttle

temperature transition region.

2
INTRODUCTION

The Office of Merchant Marine Safety, United States Coast Guard, Department of Transportation, has primary responsibil ity for enforcing safety

regulations applicable to all commercial shipping, both domestic and foreign,

operating within United States territorial waters. For U.S. flag vessels

manufactured in foreign countries or manufactured domestically with foreign

produced materials, the Coast Guard is required (Title 46 Section 366 of the

U.S. Code) to make a determination as to whether materials of construction

produced under foreign specifications for specific components, such as pressure

vessels, piping, fasteners, flanges, are acceptable substitutes for materials

produced under approved United States specifications. Currently, Coast Guard

rules are taken primarily from standards and specifications issued by United

States standards writing organizations, e.g., American Society for Testing and

Materials (ASTM) and American Society of Mechanical Engineers (ASME).

In recent years, a number of organizations have attempted to facilitate

this process of comparing material specifications from different countries by

using various approaches based primarily on matching chemical composition. As

a result, a limited number of compilations of foreign and domestic material

specifications have been developed. (1-5)* These lists of apparently equivalent

specifications are of limited use, however, because of the emphasis on only

chemistry and specific mechanical properties. The absence of a more com- prehensive technical analysis of the equivalency or lack thereof between

individual foreign and domestic specifications has often resulted in a caseby-case determination of equivalence or acceptability.

In the review of foreign material specifications, an inspector or approving

official is responsible for evaluating the foreign materials and certifying

that these materials can be substituted for U.S. approved materials. Materials

produced under approved U.S. specifications have been proven suitable for

their intended service, and since they also have been incorporated into various

industry standards, any limitations or service restrictions on their use are

known. Current procedures for evaluating the equivalence of foreign and U.S.

approved materials are not always uniform and consistent because equivalency

has taken on various meanings, depending upon the inspector or approving

official. This often leads to uncertainty as to whether materials produced

under foreign specifications will be accepted.

Some approving officials consider materials equivalent if only the

chemical compositions are the same; thus a pipe specification could be con- sidered equivalent to a forging specification if they had identical chemical

requirements. Other approving officials consider both chemical and mechanical

property requirements , while others take into account additional requirements,

such as heat treatment, product form, and non-destructive tests. In addition

to the different choices of requirements to be satisfied for equivalency, the

weight given to specific requirements is not always the same. Some approving

*The numbers in parentheses refer to references identified at the end of the

report.

3
officials believe in absolute numerical equivalency without regard to

end-use, and thus similar but not identical materials may be rejected

or restrictions placed on the material to make it equivalent. Specification

writers prefer to use whole numbers and thus rejection can occur even when

minor differences in numerical values are not physically real but may be

due to the conversion of numbers from one type of units to another, as between

English and metric units. Other approving officials may take into account

the end-use, e.g. a material used in an air line filter will not require

the same degree of agreement between properties as would be required

for pipe in a cargo piping system. In a similar manner, the design factor of

safety for the component may be considered, that is, the greater the factor of

safety, the less weight the approving official may give to small differences

in the material specifications. Lastly, the amount of metallurgical knowledge

and background possessed by the inspector or approving official will significantly

affect the evaluation process.

In order to establish the level of equivalence between material specifications, comparisons must be based on a set of identified criteria

characterizing the essential properties and behavior of the material. These

criteria include specification writing philosophy, metallurgical and processing

parameters, and quality control parameters. Systematic procedures or guidelines are necessary to achieve consistent and reproducible comparisons for

determining the level of equivalence.

COMPARATIVE ASSESSMENT

To meet the short term problem of case-by-case determinations of the

equivalence between material specifications, detailed metallurgical evaluations of selected specifications were carried out to develop a manual that

specifies: (a) those foreign specifications or alloy grades within a specification that are acceptable substitutes or equivalent to domestic

specifications; (b) those foreign specifications or alloy grades that are not

acceptable substitutes; and (c) those foreign alloy grades that would be

acceptable substitutes if certain additional criteria were satisfied.

Approximately sixty material specifications, twenty domestic and forty

foreign, were chosen representing the materials most widely specified for

critical ships components, (see Table I) Comparisons were made between

Japanese Industrial Standards ( J IS) , Deutsche Institut fur Normung (DIN)

Standards, and American Society for Testing and Materials (ASTM) specifications. Each comparison was carried out between two specifications: the

domestic ASTM document and the relevant J I S or DIN document, and an extensive

report was prepared containing the metallurgical analyses and conclusions

about the degree of equivalence for each pair of specifications. (6) In all

cases, the ASTM specification was the Coast Guard approved benchmark to which

the foreign specification was compared.

The process of determining whether one material specification is

equivalent to another can be complex and is dependent on the evaluation of a variety of factors. Decisions must be made as to the relative importance of

these factors. A finding that two material specifications are equivalent

implies that these materials will be interchangeable in any application,

4
that is, they will perform in a known and like manner even though the specification documents are not performance standards.

The process of comparing foreign specifications to domestic specifications

is further complicated by differences in specification philosophy, not only

for foreign versus domestic, but even among specifications of the same national origin. Some specifications are highly specific in listing typical

applications or end-uses, i.e. application specifications, while others are highly specific in listing end-uses for which the specification does not apply

either because of inappropriateness or because another specification covers

the application. Other specifications are limited to product forms including

plate, pipe, castings, etc., i.e. product specifications, while some are true

material specifications not limited to product form or applications. Some

specifications contain hints about the rationale for specific requirements or limits while others offer no guidance. Some specifications state the en- vironment of the application, i.e., temperature and/or pressure conditions,

without specifying properties for these conditions, while others specify

additional requirements for these conditions. The final evaluation of

specifications cannot be carried out without knowledge of the specific end-use

of the material and its operating environment. Thus, there will be situations

where the ultimate determination of equivalence between material specifications

will depend on the actual application of the material in a component or structure and the design operating parameters for that structure.

Design engineers, however, still make material selection decisions based

on specified material properties and these property requirements can be

compared and a generalized determination of equivalence or suitability made on this basis. However, it is not sufficient to simply compare lists of numbers

representing chemical and mechanical characteristics and conclude equivalence

or lack thereof.

This report generalizes the approach followed in carrying out the specification comparisons. Evaluation criteria are identified and discussed in

terms of their role in the determination of equivalence. These criteria are presented as a guideline for conducting comparisons of foreign and domestic

material specifications. Portions of actual comparisons will be used to

illustrate the methodology followed.

GUIDELINES AND EVALUATION CRITERIA

Consistent decisions on the degree of equivalency between metal specifications of different national origins cannot be made only on the basis of

chemical composition and direct comparison of mechanical property numbers.

There are additional factors which, if present, may influence the determination of equivalency because of their effect on property requirements.

The factors may be broadly grouped in the following categories:

5
1) Specification Philosophy

2) Composition Effects

3) Metallurgical Effects

4) Product Form Effects

5) Test Acceptance Criteria

In order to remove the uncertainty in this decision-making process, the role

of each category must be evaluated for each comparison.

The starting point is always to determine whether or not the two specifications being compared contain a common basis for comparison, i.e. are they describing the same subject? The determination is usually based on an examination of the section of each document which contains information about

the specification philosophy being followed. (This is usually the "Scope

section in U.S. specifications.) This step insures against comparing un- related specifications, e.g. a casting specification against a forging

specification. The philosophies illustrated by the foreign and domestic

specifications reviewed for the Coast Guard are reviewed in this report with

respect to their influence on the comparison and evaluation criteria.

Evaluation of chemical composition is the next step in comparing specifications. Such evaluations generally cannot stand alone, however, and

must be interpreted along with other considerations such as: the methods of

primary metal production and their effect on chemistry; subsequent thermo/

mechanical processing and the interrelationship between chemistry, mechanical

properties, fabrication requirements, corrosion resistance, and such qualitative requirements as weldability. In some specifications, chemical

composition requirements are not directly controlling but are, in fact,

determined from the desired mechanical property requirements and the allowed

methods of primary metal production.

Mechanical properties such as strength and ductility are typically

referred to directly in specifications and thus are major comparison

criteria. Measured mechanical properties depend not only on such obvious

factors as chemistry and thermo/mechanical processing, but can be strongly

influenced by more subtle factors such as: location within the material from

which test specimens are taken, changes in structure and properties due to

cooling rate differences, or metallurgical effects; and the geometry (size

and shape) of test specimens and its effect on measured parameters, the

orientation of test specimens with respect to processing directions, or product form effects. In addition, there are situations where each specification may require the same qualitative test but use a different

acceptance criterion to determine what constitutes passing the test. Thus,

an evaluation of the acceptance criteria must be made to determine if the

difference is significant. Caution must be exercised when direct comparisons are made between mechanical property numbers to insure that both

numbers are a measure of the same phenomena normalized for differences in

test conditions and test specimens.

6
Specification Phi 1 osophy

The general format and scope of the ASTM, J IS and DIN metals specifications reflect different characteristics that play a role in any

comparison procedure. These differing characteristics can be used to

classify specifications into broad categories or types. For metals, the

classifying variables of composition, form or method of production, and use

or application provide a basis for distinguishing between, respectively

material specifications, product specifications, and application specifications.

Sometimes the specification does not fall neatly into one type but rather is

a combination of two types. For example, in the United States, the dominant

systems for identifying carbon and alloy steels are those developed by the

American Iron and Steel Institute (AISI) and the Society of Automotive

Engineers (SAE). These systems are based only on chemical composition and

thus according to the approach outlined above, the published AISI /SAE

designated alloys are true material specifications. ASTM, on the other

hand, has developed a number of product/application specifications which

frequently reference AISI/SAE alloys. For example, American Iron and Steel

Institute (AISI) type 304 stainless steel with one set of chemical requirements is specified within 31 different ASTM specifications: 6 specifications

are for fabricated products, e.g. nuts, bolts, flanges, for general, high or low temperature service; 16 specifications are for mill products for general

service, e.g. plate, sheet, strip, pipe; and 9 specifications are for mill

products for specific applications, e.g. boilers and other pressure vessels,

sanitary tubing.

The typical ASTM metal specification is written as a product/application specification, that is, other than chemical limits, the mandatory

test requirements are frequently tailored for a particular product and

application. The J IS specifications are also usually product/application

specifications, while the DIN documents are often substantially different in

format and content than either the ASTM or J IS specifications. Some of the

DIN specifications resemble material specifications, that is, they contain a large generic class of alloys, e.g. quenched and tempered steels, stainless

steels, used in many diverse applications. These specifications, however,

also contain detailed information on all product forms available, e.g.

plate, sheet, bar, pipe, wire, forgings, the heat treatment conditions

available, e.g. normalized annealed, quenched and tempered, and the specific

properties guaranteed for particular products forms and heat treatment. A

classification of foreign and domestic metals specifications by specification

type is shown in Figure 1.

Often the ASTM document is organized into two parts. The first part is

divided into sections which contain all of the descriptive and mandatory

requirements for the specific alloys covered by the specification. These

sections cover topics such as: scope; applicable documents and general

requirements for delivery; basis for purchase or ordering information;

manufacturing process, including heat treatment; chemical requirements;

mechanical requirements, including test specimen and methods of test;

7
number of tests and retest rules; marking and packaging; and basis for

rejection. The second part, not present in all metal specifications,

contains supplementary or optional requirements which may be requested by

the material purchaser and agreed to by the seller. Typically, these

suppl ementary requirements include additional numbers of tests and/or

different types of tests than the mandatory tests.

In some ASTM ferrous mill product specifications, the alloy will be

described as representing a specific "quality." The term quality as used by

the metals industry does not mean that the product is better or worse than

other mill products but, rather that the product has characteristics that

are particularly important for specific applications or subsequent fabrication

processes. Over the years, a group of terms or "quality descriptors" have

been developed by the metals industry to enhance communication between

producers and users of metals products. Detailed descriptions of many of

these terms can be found in the appropriate parts of the AISI Steel Products

Manual. A few examples are given below with the accompanying descriptions

located in Appendix A.

Carbon Steel Quality Descriptors

Carbon Steel Plates

Regular Quality

Structural Quality

Forging Quality

Pressure Vessel Quality

etc.

Hot Rol 1 ed Carbon Steel Bars

Merchant Quality

Special Quality

etc.

Steel Specialty Tubular Products

Pressure Tubing (Quality)

Mechanical Tubing (Quality)

etc.

There are additional mandatory requirements for most of the ASTM alloy

specifications that are not contained within the specific alloy document or

its supplementary requirement section. These additional requirements are found in other specifications, often called general requirements for delivery.

These general requirement specifications must also be satisfied unless

otherwise stated in the individual document. Thus, the individual alloy

specifications may contain those requirements that are different or not

included in the general requirements for delivery.

The mechanical property requirements in ASTM specifications are almost

always specified only for room temperature even for alloys designated for

other than room temperature service. Data and other information on the

typical or expected mechanical properties for the alloy at other temperatures

are not provided in the specification, but are left to other standards or code writing organizations to specify.

8
The J IS metal specifications closely resemble the ASTM specifications,

occasionally using almost identical language, as illustrated in Figure 2.

The document format is somewhat different, however, because the J IS specifications do not contain a section on supplementary or optional requirements

.

Some of the ASTM supplementary requirements are mandatory in the JIS documents while others are omitted. Many JIS metal specifications also must

satisfy requirements which are not found within the specification document.

These requirements are found in specifications of general rules for inspection, somewhat analagous to the ASTM general requirements for delivery.

However, the JIS general rules for inspection primarily contain requirements

for the location of various types of test specimens as well as the number of

tests to be carried out. Comparisons between individual ASTM and JIS

specifications have shown that overall the same types of tests are required

in both documents even though the test details, e.g. specimen type, location,

and acceptable test value may be different. As in the case of the ASTM

specifications, the JIS documents do not include elevated temperature re- quirements for the alloys specified for elevated temperature service. Only

room temperaature properties are specified.

The DIN documents, both material specifications and product specifications, tend to be more complete because a larger number of property

requirements are included, e.g. mandatory requirements on notched bar impact

strength, steel hardenabi 1 ity behavior, magnetic properties. Further, those

DIN specifications for alloys in elevated temperature service contain tensile

strength requirements, typically yield strength, over the applicable temperature range. Often, reference or advisory data on such properties as creeprupture strength and ultimate tensile strength, working pressures for piping,

temperature dependence of modulus of elasticity, thermal expansion and

thermal conductivity, and hot working temperatures are included to assist in

materials selection for specific applications. When ASTM product specifications are compared to these DIN specifications, care must be exercised

to insure the correct comparison.

Many of the DIN product specifications, e.g. for welded steel pipe,

contain different sets of requirements for various quality levels associated

with different end-use applications. These quality levels are usually

identified by a particular code, e.g. Sheet 2 quality, Sheet 3 quality.

Although the alloy grades common to more than one quality level have the

same chemical composition limits and the same tensile property requirements,

each quality level requires either different additional tests or different

acceptable property values for the same test. Thus, only one of the DIN

quality levels may satisfy the domestic requirements

.

As an example, ASTM A312, Seamless and Welded Austenitic Stainless

Steel Pipe, describes a mill product, pipe, in either the hot or cold

finished condition and contains requirements for numerous grades of austenitic

stainless steel pipe in standard nominal diameters for high temperature and

general corrosion service. Further, a foreign specification comparable to

ASTM A312 is assumed to be DIN 17440, Stainless Steels. The appropriate

versions to be compared are the 1977 edition of A312, designated A312-77,

and the 1972 edition of DIN 17440, designated DIN 17440-72.

9
Specification DIN 17440-72 resembles a material specification because

it includes almost all alloy steel grades generically called stainless

steels, including ferritic and martensitic grades in addition to the austenitic

grades. Futher, DIN 17440-72 covers most of the mill products in the hot or cold finished conditions, except castings, including sheet, strip, bars,

wire, seamless and welded tubes (pipes), and forgings. On the basis of the

scope of each specification, it can be concluded that the mill product

described in ASTM A312-77 is one part of DIN 17440-72, thus leading to the

next level of comparison.

It is necessary to identify within DIN 17440 those requirements applicable

to welded and seamless pipe, including chemistry, thermo/mechanical treatments,

and mechanical properties. Since a material specification covers many types

of mill products, not all of the specified characteri sties and tests are applicable and each section must be reviewed to sort out only the requirements for the product form and/or application covered by the product or application specification. In this example, there is little ambiguity

because: almost without exception the various product forms in DIN 17440

have identical chemical requi rements ; the DIN austenitic grades have heat

treatment requirements independent of product; and the DIN mechanical

property requirements are based only on alloy composition and heat treatment,

again, independent of product. Obviously, mechanical property requirements

and special tests applicable only to pipe, e.g. flattening, hydrostatic,

must also be evaluated by additional criteria at a later stage in the comparison.

The content of some material specifications, however, is much more

complicated because of the metallurgical behavior of the class of materials.

Specification DIN 17200, Quenched and Tempered Steels, is an example of a material specification which includes almost all of the mill products except

castings, including wire, bars, plate, sheet, strip, seamless tubes (pipe),

and forgings, where the individual alloys are supplied according to the

processing treatment received. As a result, DIN 17200 contains separate

requirements for alloys in a number of thermo/mechanical conditions, including quenched and tempered, normalized, soft annealed, and heat treated

for either specific strength or improved workability. Thus, in this example,

only the properties and requirements of the appropriate thermo/mechanical

condition can be used as the basis for comparison.

Composition Effects

Chemical composition requirements are the starting point for the technical comparison procedure because of the dominant role chemistry has in

controlling metal properties, not only specified mechanical properties, but

also such often unspecified properties as steel weldability or corrosion

resistance. Chemical requirements can be expressed as maximum or minimum

values, or as a range of acceptable values. Generally, a determination of

chemical equivalence is straightforward since a direct absolute comparison

or numbers can be carried out without ambiguity. Most chemical requirements

10
are specified on the basis of ladle or heat analyses of molten samples

taken from the refining furnace, representing the homogeneous alloy

composition. If the product form covered by the specification is subject

to a significant non-uniform distribution of alloying elements or chemical

segregation e.g. resulting from steel deoxidation practice, then a product analysis may be permitted in which the product is sampled and

wider chemical limits allowed to compensate for the segregation effect.

The critical factor in making comparisons of chemical composition limits

is to distinguish between differences in alloying element concentration

that strongly affect properties, e.g. corrosion resistance and weldability,

and those that do not. This evaluation becomes particularly difficult

when the affected properties are not directly addressed by the specifications.

Weldability requirements are typically not explicitly stated and it is

necessary to evaluate the influence of the differing chemical composition

limits between the two alloys based on some weldability criterion so that if the foreign material is less weldable, additional controls on the welding procedures may be necessary.

One widely used measure of weldability for ferrous materials is the

carbon equivalent (CE) of the alloy; the lower the carbon equivalent the

greater the ease of welding for a given material thickness. The CE is

determined by the chemical composition and is equal to the sum of the

contributions from the alloying elements; each alloying element has a different "weighting" factor in the sum. A number of empirical arithmetic

relationships have been developed to fit the behavior of different

classes of ferrous alloys.* For carbon and low alloy steels, the carbon

equivalent can be represented by:

CE = % carbon + % manganese/6

For example, ASTM A1 05-77, Carbon Steel Forgings, has maximum carbon and

manganese limits of 0.35% and 1.05%, respectively, while DIN 17200-69,

Quenched and Tempered Steels, specifies maximum carbon and manganese

limits of 0.39% and 0.8%, respectively , for Grade C35. The CE for these

two alloys is the same, 0.52, and thus, based on this criterion, have

the same level of weldability in spite of differences in chemical composition

1 i mi ts

.

Metal 1 urgical Effects

Most of the typically measured mechanical properties, e.g. ultimate

tensile strength, yield strength, percent elongation, percent reductionin-area, and impact resistance can be affected by metallurgical factors

such as chemical segregation and microstructure, even for identical

chemical compositions.

The thickness effect on properties in many wrought products is an important example of a metallurgical effect. As-cast steel ingots typically

exhibit chemical segregation zones because of the very slow cooling rates

from the molten state. The extent of the chemical segregation is strongly

dependent on the deoxidation practice used and is least for fully deoxidized

or killed steels and greatest for rimmed steels. (7) There is substantial

variation in chemical composition in rinrned steel ingots compared to killed

steel ingots, and this can result in a limitation in maximum thickness for

certain rimmed steel products. The degree of segregation for a riirmed

*Examples of these relationships can be found in International Series on Materials Science and Technology, Volume 33, Pergamon Press, 1980.

11
carbon steel is schematically shown in Figure 3. In addition, steel ingots

usually contain an undesirable columnar or coarse dendritic cast microstructure which often exhibits reduced strength and poor ductility. As the

ingots are reduced in size by mechanical working, the cast microstructure is

broken up, the grain structure refined, and the chemical heterogeneity

reduced. If the ingot reduction is not sufficient, the influence of the

non-uniform chemical composition and coarse grained cast microstructure may

cause unacceptable variability in the mechanical properties of the end

product. When high thickness reductions occur from ingot to final product,

the microstructural and chemical variations found in the as-cast ingot are reduced. For example, ASTM A36-77a, Structural Steel, does not permit

rimmed or capped steel for plates and bars over 13 mm (0.5 inch) thick

because of the adverse effect of greater chemical heterogeneity in rimmed or capped steels on both mechanical properties and weldability. The DIN specification

for structural steel, DIN 17100-66, however, permits six of its alloy grades

to be produced as either rimmed or killed steels without restriction on thickness for plates and bars. Thus, additional limitations on steelmaking

practice, must be applied to these DIN grades for thicknesses over 13 mm

(0.5 inch) in order to satisfy the A36 requirement.

However, as shown in Figure 4, a killed carbon steel which has undergone

substantial thickness reduction still exhibits a lamellar or banded microstructure at the mid-thickness originating from chemical segregation. (8)

Thick products tend to retain more of the chemical and microstructural inhomogeneities from the ingot than thin products and thus can retain measurable

property variations through the thickness of the product. When comparisons

are made between specifications for products in a wide range of sizes, two common approaches can be followed. First, for products below a certain

thickness, a specification may require ful 1 - thi ckness test specimens so that

the effects of inhomogeneities are averaged out. Data should then be com- pared between full-thickness specimens. Second, where product thickness

allows test specimens less than full-product thickness, the locations within

the material from which specimens are taken may be specified to minimize the

effects of chemical and structural inhomogeneities. In such cases, care must be exercised to ensure that numerical comparisons are made between

specimens representative of a similar microstructure.

Product thickness also results in variations in cooling rate which

affects mechanical properties independent of chemical composition effects.

For example, thick hot-rolled steel products will typically exhibit lower

strength and higher ductility than thin products because, after mechanical

working, the differences in cooling rates through the transformation temperature produce different microstructures with different properties. (9) As

shown in Figure 5, the change in pearl ite spacing due to changes in cooling

rate have a strong influence on strength properties. Specifications deal

with this problem in a number of ways. In one approach, followed in DIN

17100, Structural Steel, and DIN 17155, Boiler Plates, the chemical com- position limits of the major alloying elements are held reasonably constant

and the mechanical property requirements adjusted based on product size or

12
thickness to compensate for the cooling rate effect. In another method, used

in ASTM A36, Structural Steel, and ASTM A515, Pressure Vessel Plates, the

mechanical property requirements are held reasonably constant and the

chemistry, primarily carbon and manganese levels for steels, adjusted to

maintain the same mechanical properties as the size or thickness changes.

One result of comparing specifications based on each approach, e.g. DIN

17100 vs ASTM A36 and DIN 17155 vs ASTM A515, is the observation that as the

product thickness increases, a single DIN grade is less likely to satisfy

the strength requirements of a single ASTM grade. Different thickness

ranges for a DIN grade may satisfy the requirements of different ASTM

grades, e.g.- grade HIV plate from DIN 17155-59 satisfies ASTM A515-78 Grade

65 strength requirements up to 130 mm thick but satisfies ASTM A515-78 Grade

70 strength requirements only up to 95 mm thick.

A similar influence of cooling rate on microstructure is observed for

both ferrous and nonferrous castings because the casting section thickness

usually controls the resulting as-cast mechanical properties. Thick-section

castings have a lower strength and lower ductility than thin-section castings.

(10-12) The determination of mechanical properties of castings requires

careful control over the preparation of the test specimen. The solidification

behavior is very important because the cooling rate strongly affects the

resultant casting grain size; the type and amount of the metallurgical

phases present; and the extent and location of chemical segregation, shrinkage, and porosity. These factors dominate the final mechanical properties of

the casting in the absence of further heat treatment. Not only are mechanical

properties often dependent on the casting size or section thickness, but

separately cast test bars can have markedly different mechanical properties

than the component casting poured at the same time from the same heat of

metal due to exaggerated differences in size, as shown in Figure 6. Typically

in copper alloy castings, the permitted test bars or test coupons have

essentially the same dimensions, independent of the casting section thickness.

In the case of gray cast iron, an attempt has been made to respond to

this problem by adjusting, over a limited range, the test bar dimensions

based on the controlling or critical section thickness of the casting. Most

castings have critical areas where the resultant mechanical properties

control the subsequent behavior of the component. ASTM A48 and J IS G5501

for gray cast iron provide for a series of separately cast test piece sizes

allowing selection of a test piece which approximates the cooling rate in

the critical section of the casting in an effort to reduce the effect of the

cooling rate on mechanical properties. A48 recognizes as-cast specimen

diameters of 22.4 mm (0.88 inch), 30.5 mm (1.20 inch), and 50.8 mm (2.00

inch) for a critical section thickness range of 6 mm (0.25 inch) to 50 mm (2

inch) while G5501 requires specimen diameters of 20 mm, 30 mm, and 45 mm for

a critical section thickness range of 8 mm to 50 mm. Thus, these specimen

diameters are almost the same or are within 10% while the critical thickness

ranges for each test piece closely overlap and so the requirements based on these specimens can be directly compared.

13
For steel castings, test specimens may be taken from coupons cast as part of the casting, from separately cast coupons, or from specified areas

of the casting itself. For example, DIN 17245-67, Ferritic Steel Castings,

generally requires test specimens machined from coupons cast as part of the

casting although separately cast test specimens are permitted when the

former is not possible. ASTM A216, Carbon Steel Castings, (by reference to

ASTM A703) also allows the test specimens to be taken from casting coupons

or separately cast test specimens. Although the ASTM test bar, whether from

a casting coupon or a separately cast piece, has an initial diameter of

about 31 inn (1.25 inch) and a final diameter of about 13 mm (0.5 inch), the

dimensions of the DIN test bars are not defined. Therefore, the DIN properties

must be evaluated on the basis of a similarly sized test specimen. In all

situations, however, mechanical property comparisons should be carried out

on the basis of similarly sized test bars without regard to the correlation

between test bar properties and casting properties.

Product Form Effects

The value of testing is measured by the degree to which the performance

of a material in service can be predicted from information obtained from

tests. Mechanical properties are not uniquely determined; rather, indications of these properties are obtained from samples of the material tested

under certain sets of circumstances. A test is significant if: (a) it

measures a sufficiently fundamental property such that test data can be used

in design, or (b) it can discriminate between suitable and unsuitable

materials based on experience in service. (13)

After fabrication, many wrought metal products exhibit mechanical

properties that depend on the orientation of the test specimen within the

product. This non-uniformity or anisotropy of properties (14) arises

generally from one of two sources, crystal 1 ography or microstructural

features. Athough the individual grains in a commercial alloy are anisotropic

in strength properties because of their crystal! ographic nature, a reasonably

random orientation of the grains will result in similar properties in all

directions due to the averaging of the orientation anisotropy. Severe cold

work, however, can produce a preferred or non-random orientation of the

grains which causes anisotropic behavior in the commercial alloy similar to

that observed in the individual grains. The yield strength of nonferrous

alloys, for example, can be increased or decreased in the direction of the

principal deformation depending on the type of preferred orientation which

is produced.

Ferrous alloys are more likely to develop anisotropic mechanical

properties due to the preferred alignment of microstructural features, e.g.

inclusions, chemical segregation, in the principal deformation direction.

This alignment is often observed in forgings and rolled products. This

preferred alignment, or banding in the case of chemical segregation, relates

14
to the three principal deformation directions in these products. The longitudinal direction is the principal direction of working and longitudinal

specimens have their axes aligned parallel to this direction. The shorttransverse direction is the direction of minimum product dimension, e.g. the

plate thickness. Often, properties in this direction cannot easily be

measured because of insufficient material for a specimen. The long-transverse

.direction (often just called transverse direction) is perpendicular to both

the longitudinal and short- transverse directions. For plate products,

longitudinal properties are typically specified, while for tubular products,

transverse properties are also often specified.

a. Tensile Test

Although little difference between ultimate tensile strength and yield

strength values of longitudinal and transverse specimens have been found for

forgings and plate products, substantial variations in the tensile ductility

parameters and notched impact toughness properties occur. Higher values for

percent elongation and reduction-in-area of from 10% to 50%, respectively

,

have been observed in longitudinal specimens compared to transverse specimens. (15-17) For steel forgings, the anisotropy effect is illustrated in

Figure 7. The strong decrease in transverse ductility is primarily a result

of the drawing out of the non-metal! ic inclusions into long stringers. The

relationship between impact toughness properties and test specimen orientation

is more complex, however, because of the larger number of specimen configurations that can be specified (Figure 8a). The effect of specimen orientation

on impact toughness as measured by energy absorption in an impact test is

significant (Figure 8b), particularly in the region of the upper energy

plateau or upper shelf. (18) For some applications, properties in certain

directions assume special importance. For example, in piping and cylindrical

pressure vessels which are internally pressurized, the transverse properties

are important because the largest principal stress, or hoop stress, acts in

the transverse direction. Generally, when specifications do not identify

specimen orientation, the longitudinal orientation is assumed. In any

event, requirements for the same orientation should be compared.

For over a century, investigators have reported size and shape effects

on material strength properties. A recent review (19) of this phenomena

reveals the considerable controversy in the literature on specimen size and

shape effects on static strength and ductility properties. Although a com- prehensive theory or model is lacking, a number of studies (20-24) have

indicated that the size and shape of test specimens, including round and

rectangular specimens, had no effect on either the measured ultimate tensile

strength or yield strength. A tension test, therefore, can give strength

properties that, when modified by a suitable factor of safety, can be used

as allowable working stresses. Further, the results of these and other

studies (25, 26) demonstrated that for round specimens, the tensile ductility

parameter percent reduction-in-area is practically independent of specimen

diameter as long as the ratio of gage length to diameter, L/D was greater

than about 2, whereas a larger effect of size was observed for rectangular

15
specimens. During the test, local nonuniform deformation occurs over a distance of about 2 to 3 times the diameter so that for L/D less than 2, the

specimen shoulders act as a lateral restraint against necking and thus the

reduction-in-area becomes geometry dependent. (13) Similarly, the interpretation

of the rectangular specimen results focuses on the role of restraint by the

specimen shoulders on the strain behavior in the reduced section. (26)

However, the overall evidence supports the conclusion that the measured ultimate

tensile strength, yield strength, and the ductility parameter percent reductionin-area are relatively independent of specimen size and shape for limited

ranges of geometry, assuming metallurgical factors like microstructure are

size independent.

A different situation exists for the tensile ductility parameter, percent elongation. Numerous studies (19,20,22-26) have demonstrated the

strong effect of specimen size and shape on percent elongation. Percent

elongation has significance only when it can be correlated with the performance

of the material during fabrication or in service. It is not a design parameter

but rather a measure of the relative response of the material to plastic deformation. Historical ly , the total elongation measured in a tensile test

has been divided into a uniform strain component proportional to the specimen

gage length and a local nonuniform strain component (necking) that is proportional to the square root of the cross-sectional area. (27,28) A number

of empirical relationships between percent elongation, specimen gage and

specimen cross-sectional area have been formalized into the following widely

used equation combining the uniform and nonuniform components of the total

elongation: (29)

e = a (^) a

[1]

L

where e is percent elongation, L is the specimen gage length, A is the

specimen cross-sectional area, and a and a are the constants. For round

specimens, /A can be replaced by the specimen diamenter, D. For many types

of carbon and alloy steels in several heat-treated conditions, the value

a = 0.4 has been found to give reasonable conversions between different

specimen sizes and shapes while a = 0.127 can be used for annealed austenitic

stainless steels. (30) For copper and brass, a value of a = 0.2 has been

reported. (29)

This equation is used by ASTM to normalize percent elongation between

retangular and round standard test specimens (30) for all wrought products

except tubular products. The ASTM round specimen has a constant ratio of

L/D of 4 or an equivalent L//A of 4.51 while the rectangular specimens have

a variable L//A ratio because the specimen thickness is generally the fullthickness of the material. In a similar fashion, foreign standards-wri ting

organization like Deutsches Institut fur Normung (DIN) and the Japanese

Industrial Standards ( J IS ) Committee have identified standard test specimens.

The DIN standard specimens for wrought products, whether round or rectangular,

16
generally have a constant ratio of L/D of 5 or the equivalent value of 5.65

for L//A. The J IS standard specimens for wrought products include types with

L//A ratios of 4 to 9 (L/D ratios of 3.54 to 8) as well as specimens with

variable L//A ratios. A summary of the specimen types is shown in Table II.

Elongation values can be converted between specimens of different sizes

and shapes by re-writing equation [1] for specimens X and Y:

[ 2 ]

Comparisons of elongation requirements from different specifications must be

made on the basis of equivalent geometry. The approach discussed above can also be used for situations which involve more than test specimens with

different fixed geometries. For example, ASTM A53-78, Steel Pipe, and DIN

1626-65, Welded Steel Pipe, contain differing approaches to tensile ductility

as measured by percent elongation. ASTM A53 calculates, the minimum percent

elongation for a 50 mm (2 inch) gage length from the ultimate tensile strength

and the specimen cross-sectional area. Thus, the L//A ratio varies for each

specimen and the minimum percent elongation for each grade of pipe is different and depends on the type of test specimen and pipe wall thickness. In

DIN 1626, a minimum percent elongation is specified for each grade of pipe

based on ultimate tensile strength but independent of pipe wall thickness and

specimen cross-sectional area, or a constant L//A ratio of 5.65 for all

specimens. Thus, a direct comparison between the elongation requirements

between A53 and DIN 1626 cannot easily be made. However, since for all DIN

specimens, L//A is 5.65, it is possible using Table X7 from ASTM A53-78 to

calculate the specimen area for constant L = 50 mm at the same L//A and then

compare for any ASTM specimen the resulting expected percent elongation.

Assuming the correlation between gage length and specimen area does not

change over the range of pipe wall thicknesses in ASTM A53, then the con- clusion can be drawn that if requirements of both specifications are satisfied

at the same L//A ratio, then the requirements will be satisfied as the

specimen dimensions change.

b. Bend Test

Bend tests are a simple, widely used means of obtaining an index of the

materials ductility. For flat products, e.g. plates and flats, the test

establishes a measure of a materials ability to undergo plastic deformation

without cracking, and thus represents a qualitative forming limit. In the case of welded products, e.g. pipe, bend tests can characterize the overall

weld ductility by assessing the behavior of the weld, the fusion line, the

heat-affected zone (HAZ), and the base metal for various directions of

stressing. Bend tests can also be used as a screening test to monitor the

17
bending ductility for particular types of service or to detect a loss of

ductility as a result of processing or other thermo/mechanical treatments.

For example, transverse bend tests on el ectric-resistance welded pipe can detect the undesirable, brittle martensitic structure that sometimes develops

in some steel alloys as a result of this high cooling rate welding technique.

Typically, the bend test is a go/no go type of test in which a prepared

specimen is bent about a radius of curvature. The material passes the test

if a crack does not develop on the specimen tensile surface after being bent

through a specified angle, and fails if a crack or cracks develop. In some cases, the tensile surface elongation is measured and used as a ductility

index. Generally, the elongation of the tensile surface is directly proportional to the specimen thickness and inversely proportional to the radius

of curvature. (See Appendix B) Thus, in order to maintain approximately the same levels of tensile surface strain, specimens of different thickness are bent around different radii of curvature. This analysis only approximates

the actual test because it does not account for the observation that the

actual maximum tensile strain experienced in bending tests substantially

exceeds the calculated value. (31) This observation is not relevant

to this report because the bend test criteria normally do not contain any

quantitative requirements based on the analysis given in Appendix B. The

test itself, however, is considerably more complex than the go/no go

criterion indicates because of the strong role that specimen dimensions have

on the severity of the test.

In simple bending of a rectangular specimen, shown in Figure 9a, the

strain tangent to the bend radius, e , or circumferential strain is assumed

to vary only in the thickness direction of the specimen and has its maximum

tensile value at the outer specimen surface. The actual circumferent i a

1

strain distribution across the specimen width is fairly uniform except at the

edges, where it is somewhat higher. However, the strain distribution in the

specimen width direction, eT

, is very nonuniform, with a maximum compressive

strain at the specimen edges that decreases with distance from the edges, and

has a greater effect as the specimen width decreases. Thus, both the specimen

width and thickness affect the in-plane or biaxial strain distribution within

the specimen. The ability of the bend specimen to undergo plastic deformation,

defined as its ductility, is a function of the stress state in the outer

tensile surface of the specimen. A biaxial tensile stress state reduces the

ductility of the material and so specimens with a low width to thickness

ratio (w/t) require a high bending strain to produce fracture because the

transverse strain is compressive and must be overcome before a tensile

biaxial stress state can be produced. As the width to thickness ratio

increases, the effect of the transverse compressive strain decreases and

therefore the strain to produce fracture decreases until it reaches its

saturation or minimum value at about w/t = 8, as illustrated in Figure 9b.

For specimens with a w/t < 8, the specimen dimensions strongly affect the

minimum bend radius below which the material will crack on the outer tensile

surface. In evaluating the relative severity of bend test requirements from

different specifications, the specimen geometry must be considered in addition

to the bending radius. For example, both ASTM A285-78, Pressure Vessel

18
Plates, and DIN 17155-59, Boiler Plates, require bend tests on transverseoriented specimens. Each test requires the specimen to be bent 180° around a mandrel of fixed diameter without developing a crack on the tensile surface.

The ASTM specification reduces the mandrel diameter/specimen thickness ratio

as the specimen thickness increases in order to maintain similar degrees of

test severity while DIN 17155 sets a constant ratio independent of thickness

for each grade of steel. These requirements are illustrated as follows:

Mandrel Diameter

Specimen Thickness

Specimen

Thickness

ASTM A-285-78

(ASTM A20-78)

DIN

Grade HI

17155-59

Grade HII Grade Hill

£ 25 mm 1-1/2 1/2 2 2-1/2

>25 to < 38 mm 2-1/2 1/2 2 2-1/2

>38 mm to 50 mm 3 1/2 2 2-1/2

Specimen Width 32 - 41 mm 30 - 50 mm

The somewhat wider specimen allowed by DIN 17155 means that for a given

specimen thickness, the DIN test is generally more severe than the ASTM test.

Based on the the mandrel diameter/thickness ratio: the DIN test for grade HI

is more severe than the ASTM test for all specimen thicknesses; the DIN test

for grade HII is less severe than the ASTM test for all specimens 25 mm (1

inch) or less in thickness and more severe than the ASTM test for specimens

greater than 25 mm (1 inch) thick; the DIN test for grade H III is less severe than the ASTM test for specimens 25 mm (1 inch) or less in thickness,

of equal severity to the ASTM test for specimens greater than 25 mm (1 inch)

thick and 38 mm (1-1/2 inch) or less thick, and more severe than the ASTM

test for specimens greater than 38 mm (1-1/2 inch) thick and 50 mm (2 inch) or less thick.

c. Impact Test

Historically, the tendency for normally ductile steels to catastrophical ly

fail in a brittle manner under certain conditions led to the increased usage

of notched-bar impact tests to evaluate the susceptibility of a material to

brittle fracture. The notched-bar impact test satisfies the important criteria

contributing to brittle fracture, namely, a triaxial stress state and a high

strain rate. The notch provides a localized stress concentration and limits

local deformation, while impact loading creates the high strain rate resulting

in the impact energy being absorbed in a localized volume at the root of the

notch. The notch contributes the triaxial stress state in the same way that

the specimen width contributes a biaxial stress state in a bend specimen.

Static tests, e.g. tension tests, are not sensitive to this type of brittle

behavior. Materials that exhibit similar ductility in tension tests or even unnotched impact tests can have large differences in notch sensitivity.

19
Notched-bar impact tests measure the amount of energy absorbed during

the fracture of small standardized specimens. The test results do not directly

predict the ductile-brittle behavior of a component in a structure and thus

the test values cannot be used in design. The test results have significance

only when they are correlated with the behavior of the material in service.

In some service environments, the probability of failure greatly increases

when the energy absorption values fall below a given value and so the test

can be used to screen out materials unsuitable for specific applications.

Although a number of different notched-bar test specimens have been

employed in investigating the ductile-to-brittle behavior in metals, two

broad types of specimens have been standardized: center notched Charpy-type

specimen supported as a beam in 3-point loading and the asymetrical notched

Izod-type specimen clamped at one end. The Charpy-type specimen has become

dominant in the United States and is now widely used throughout the world.

Standard sized specimens must be used because the relative magnitudes of the

three principal stresses at the notch root depend critically on the test bar

dimensions and the notch configuration. Reducing the width or depth dimensions

has two effects. First, it decreases the volume of metal and so tends to

lower the energy necessary to break the specimen. However, reducing the size

can increase the energy necessary to fracture the specimen because the

restraint at the notch root is decreased, reducing the chance of brittle

fracture. (32) Although the energy absorbed by the specimen is not strongly

influenced by the notch angle unless it exceeds 60 degrees, the sharpness of

the notch root definitely affects the energy absorbed in breaking the specimen,

especially for less ductile materials. The fracture energy decreases as the

root radius decreases because of an increase in the stress concentration.

(33) Finally, there are two options for reporting the energy absorption

values measured by the notched-bar impact test. Generally, domestic specifications specify the minimum energy absorption directly in energy units,

foot-pounds or joules, because there is only one standard Charpy-type specimen.

In many foreign specifications, additional standard specimens are permitted

in which the notch depth or specimen dimensions are different and so the « minimum energy absorption is specified in energy per unit area units, J/cm.

Comparisons of notched-bar impact test requirements must be made on the basis

of geometry, size, specimen type, and equivalent energy absorption units.

However, it is not correct to directly compare results from different size

specimens on the basis of normalized absorbed energy, i.e. energy absorbed/unit

area, because the strong effect of notch restraint on the specimen fracture

mode.

d. Wedge Tension Test

The wedge tension test is a widely used test applied to bolting materials for the quantitative determination of ultimate tensile strength and the

qualitative measure of bolt head ductility. This test together with

hardness measurements are used as an acceptable alternative to the standard

tension test, especially for bolts too short to be made into tensile

20
specimens. The bolt head is subjected to eccentric loading through use of a wedge to simulate misalignment of the bolt in service. The test requires

fracture of the bolt to occur in the body or threaded section, and thus does

not allow brittle fracture at the head-body junction. The angle of the wedge

determines the severity of the eccentric loading or bending: the larger the

angle the more severe the test. The general ASTM test requirement for wedge

angle is based on yield strength, with heat-treated high yield strength bolts

tested with a smaller wedge angle than lower strength bolts because of the

normally reduced ductility of the higher strength material. Other specifications, e-.g. DIN, specify wedge angles based on bolt diameter, bolt

length, and the percent elongation requirement. Bolts with the lowest ex- pected ductility are tested with the smallest wedge angles, as in the case of

the ASTM test. When comparing wedge tension test requirements, the wedge

angle specified in the foreign test should be equal to or greater than the

domestic requirement to insure at least an equally severe ductility test.

e. Flare Test

Expansion, flare, or drift tests of tubes, both seamless and welded

tubes, provide qualitative information about the tube ductility and, when

applicable, the weld strength. These tests are widely used for tubes with a wall thickness that is too thin for standard tension test specimens. In the

test itself, a solid cone of fixed included angle slowly expands the end of

the tube to a predetermined change in diameter without rupturing or developing cracks. If the tube is welded, the tube may be expanded until rupture

occurs. If failure occurs outside the weld zone, then the weld possesses

sufficient strength and ductility. (34) There are two major test variables

that affect the severity of the test: the amount or percent of diameter

expansion and the included angle of the cone. When comparing test requirements based on diameter expansion only, a larger required diameter expansion

means a more severe test for a constant cone angle. When comparing test

requirements based only on cone angle, a larger cone angle means a more

severe test, even for the same diameter expansion, because the strain developed in the transition between the deformed and undeformed portions of the

tube is greater. A cone with a 60 degree included angle. results in about a 10 percent increase in the angle between the deformed and undeformed portions

of the tube than a cone with a 45 degree angle. Comparisons between two

specifications must account for any differences in both the required percent

diameter expansion and the included angle of the cone.

Test Acceptance Criteria

There are some required tests common to specifications of different

national origins that, although identical, contain different specific values

for parameters which determine acceptable or unacceptable behavior. The

hydrostatic test and flattening test, often required in ferrous and nonferrous

specifications for both seamless and welded tubular products, are examples of

such tests.

21
a. Flattening Test

This test is used as a qualitative measure of the transverse ductility

of the pipe including weld and base metal. In particular, the test is used

to identify external and internal defects, e.g. lap seams, cracks, laminations

which can affect the integrity of the pipe. The transverse ductility is

particularly important in piping because the hoop stress or transverse stress

in the pipe wall of an internally pressurized pipe is substantially greater

than the longitudinal or axial wall stress. Most ASTM, JIS, and DIN ferrous

specifications for seamless and centrifugal ly cast pipe and some welded pipe

specifications require the pipe specimen to be flattened without cracking to

a height that is a function of the geometry of the pipe and a constant parameter

whose value depends on the particular ferrous alloy type. The relationship

used in these specifications is as follows:

h = (1 + e)t where H = distance between flattening plates

(e + t/D ) [3] D = pipe outside diameter

t = pipe wall thickness

e = constant for a given grade

This analysis only approximates the actual test because it does not account

for the experimental observation that the actual maximum tensile strain

experienced in pipe flattening substantially exceeds the calculated value,

similarly to that observed in the bend test. This effect does not affect the

comparisons because all three national standards groups base their acceptance

criterion on equation [3]. In ASTM specifications, the constant "e" is

defined as deformation per unit length. In JIS and DIN specifications, "e"

is defined only as a constant that varies according to the grade of pipe.

The actual value of this constant for a particular alloy type, however,' is

not always the same in the ASTM, JIS, and DTN specifications. In order to

evaluate the significance of different values of this constant, it is nec- essary to have some physical understanding of the constant. Based on the

work of Thomas et al. (35), equation [3] can be developed from a simple

curved beam bending equation, shown in Appendix C. This analysis defines the

constant M e" used in these specifications as the maximum tensile circumferential

strain in the pipe. Thus, as the value of "e" increases, the pipe must

sustain a greater circumferential strain without cracking in order to pass

the test. In both ASTM A53-78, Steel Pipe, and JIS G3454, Carbon Steel Pipe,

each alloy grade must undergo a flattening test based on fixed values of the

maximum tensile circumferential strain, "e." The maximum strain required is

identical (e = 0.07) for A53 Grade B and JIS G3454 class 3 pipe. However,

for Grade A, A53 requires a maximum surface strain of 0.09 compared to 0.08

required for JIS G3454 class 2. The JIS test, therefore, permits the class 2 pipe to experience about 12% less strain (less flattening) than A53 Grade A

pipe and thus the JIS requirement for class 2 pipe is less severe than the

ASTM requirement. Although the JIS acceptance criterion in this example is

less severe, this criterion could be adequate for specific service applications.

However, any further analysis of the difference in acceptance criterion must

include both the designed service environment and a determination that some important aspect of component behavior in service is measured by this test.

22
b. Hydrostatic Test

The hydrostatic test as applied to welded and seamless pipe and tubing

is typically used as either a mill quality control or inspection test,

especially for welded pipe, or as a proof test to indicate the ability of the

pipe to operate at design pressures without leaking. As a quality control

test, the test pressures are not intended as a basis of design requirements

and may not be related to the intended operating pressures. As a proof test,

the test pressure will exceed the specified operating pressure by some minimum

amount. The analysis used in all specifications, however, is based on the same equation for the hoop or circumferential stress in an internally pressurized, thin-walled cylinder:

2St

P = . . . [4] where P = internal pressure

D S = hoop stress

D = outside diameter

t = thickness

Most specifications set the internal pressure by requiring the hoop stress,

S, to be some fraction of the minimum material yield strength and upper limit

on the test pressure. Occasionally, a specification may fix the internal

pressure at a constant value for a variety of pipe diameters and wall thicknesses thus causing the hoop stress to be a variable function of the minimum

material yield strength. Therefore, comparisons must be made based on equivalent values on the hoop stress rather than internal pressure test values.

SUMMARY

Consistent decisions on the degree of equivalency between metal specifications of different national origins cannot be made only on the basis of

chemical composition and direct comparison of mechanical property numbers.

There are numerous additional factors, including metallurgical effects,

product form effects, test acceptance criteria, and differences in specification philosophy which, if present, may influence the determination of

equivalency because of their effect on property requirements . In order to

remove the uncertainty in this decision-making process, these additional

factors must be evaluated for each comparison.

Excerpts from actual comparisons have been used to illustrate the

methodology to be followed based on the principles discussed in this report.

The specific evaluation criteria identified are not meant to be totally

inclusive, but rather represent those most often encountered. Some material

specifications, especially application specifications, may include special

requirements dictated by the application. A checklist of typical requirements

and tests found in product and application specifications has been compiled

to aid in making comparisons between foreign and domestic material specifications. This list (Appendix D) is based on the results of the metallurgical

evaluation of a selected group of domestic materials specifications. (6) No

23
attempt has been made to evaluate the appropriateness of specific tests and

requirements for specific applications or end-uses. Finally, material specifications are dynamic documents because revisions of test methods and test

requirements are part of the specification writing process. Care must always

be exercised to insure that the appropriate versions of specifications are being compared.

ACKNOWLEDGMENTS

The author wishes to express his appreciation to Mr. Howard Hime, United

States Coast Goard, for his support and advice throughout the entire program.

Special thanks to Dr. John Smith, National Bureau of Standards, whose insight

into codes and standards philosophy was most valuable during the present

phase of work. Appreciation to Mrs. Mary Wykes for her outstanding help in

the preparation of this report. Special thanks to Mrs. June Toms for her

extraordinary assistance in preparing the final version of this report.

24
REFERENCES

(1) Handbook of Comparative World Steel Standards, Vol . 6, Steel,

International Technical Information Institute, Tokyo, Japan, 1980.

(2) Stahlschlussel , 10 Auflage 1974, Yerlag Stahlschlussel Wegst KG.,

West Germany.

(3) Worldwide Guide to Equivalent Irons and Steels, American Society

for Metals, 1979.

(4) Worldwide Guide to Equivalent Nonferrous Metals and Alloys,

American Society for Metals, 1980.

(5) Alloy Cross Index, Mechanical Properties Data Center, Belfour

Stulen, Inc., Traverse City, Michigan, 1977.

(6) Early, J.G. and Ballard, L.D., "Analysis of Foreign and Domestic

Material Specifications for Ships Components", Report No. MBS I

82-2481, National Bureau of Standards, Washington, D.C., February

1982.

(7) Bashforth, G.R., "The Manufacture of Iron and Steel," Volume 2,

Steel Production, Chapman & Hall, London, 1959, pp. 298-303.

(8) Early, J.G., "A Metallurgical Investigation of a Full-Scale

Insulated Rail Tank Car Filled with LPG Subjected to a Fire

Environment," Federal Railroad Administration Report, FRA OR & D 75-52, 1975, NTIS PB 250587.

(9) Brick, R.M. and Phillips, A., "Structure and Properties of Alloys,"

McGraw-Hill, 1949, p. 297.

(10) Metals Handbook, Vol 1, "Properties and Selection of Metals,"

American Society for Metals, 8th Edition, 1961, p. 977.

(11) Steel Castings Handbook, Steel Founders Society of America, 1950

Edition, pp. 247-249.

(12) Campbell, H.L., "Relation of Properties of Cast Iron to Thickness

of Castings," Proc. ASTM, Vol. 37, Part II., 1937.

(13) Davis, H.E., Troxell , G.E., and Hauck, G.F.W., "The Testing of

Engineering Materials," 4th Ed., McGraw-Hill, 1982, pp. 9-10.

(14) Dieter, G.E., Mechanical Metallurgy," McGraw-Hill, 1961, pp. 269-272.

(15) Wells, C. and Mehl , R.F., "Transverse Mechanical Properties in

Heat Treated Wrought Steel Products," Trans. ASM, Vol. 41, 1949,

pp. 715-818.

25
(16) Interrante, C.G. , Early, J.G., and Hicho, G.E., "Analysis of Four

Tank-Car Accident Reports," Federal Railroad Administration Report,

FRA OR&D 75-50, 1975, NTIS PB 251097.

(17) Early, J.G., "Elevated-Temperature Mechanical Behavior of a Carbon-Manganese Pressure Vessel Steel," Jour. Engr. Matls. and

Tech., Vol . 99, 1977, pp. 359-365.

(18) Interrante, C.G., "Impact Properties of Steels Taken from Four

Failed Tank Cars," Federal Railroad Administration Report, FRA OR&D

75-51 , 1976, NTIS PB 255854.

(19) Harter, H.S. "A Survey of the Literature on the Size Effect on Material Strength," Technical Report AFFDL-TR-77- 11 , Air Force

Systems Command, Wright-Patterson AFB.

(20) Templin, R.L., "Effects of Size and Shape of Test Specimen on the

Tensile Properties of Sheet Metals," Proc. ASTM, Vol. 26, 1926,

pp. 378-403.

(21) Zlochevskii, A.B., "Relation Between Deformation Kinetics and Size

Effect," Problemy Prochnosti , No. 9, 1971, pp. 19-22.

(22) Lyse, I. and Keyser, C.C., "Effect of Size and Shape of Test

Specimen Upon the Observed Physical Properties of Structural

Steel," Proc. ASTM, Vol. 34, 1934, pp. 202-215.

(23) Bach, C. , "Elastizitat und Festigkeit, Springer, Berlin, 1905.

(24) Moore, H.F., "Tension Tests of Steel with Test Specimens of Various

Size and Form," Proc. ASTM, Vol. 18, 1918, p. 403.

(25) Miklowitz, J., "Influence of the Dimensional Factors on Mode of

Yielding and Fracture in Medium-Carbon Steel-II," J.A.P., Vol. 17,

1950, pp. 159-168.

(26) Miklowitz, J., "The Influence of the Dimensional Factors on the Mode

Of Yielding and Fracture in Medium-Carbon Steel -I," J.A.P.,

Vol. 15, 1948, pp. 274-287.

(27) Martens, A., "Handbook for Testing Materials", Translated by G.C.

Henning, 1st Ed., John Wiley & Sons, New York, N.Y., 1899.

(28) Unwin, W.C., "Tensile Tests of Mild Steel and the Relation of

Elongation to the Size of the Test Bar," Proc. Inst. Civil

Engineers, Vol. 155, 1903, pp. 170-292.

(29) Oliver, D.A., "Proposed New Criteria of Ductility from a New Law

Connecting the Percentage Elongation With Size of Test-Piece,"

Proc. Instn. Mech. Engrs., Vol. 2, 1928, pp. 827-864.

26
(30) "Standard Methods and Definitions for Mechanical Testing of Steel

Products - A370-73," American Society for Testing and Materials,

Philadelphia, PA, Annual Book of Standards, Part 10, 1974.

(31) Dieter, G.E., "Mechanical Metallurgy," McGraw-Hill, 1961, pp. 557-562.

(32) Habart, H. and Herge, W.J., "Sub-size Charpy Relationships at

Sub-zero Temperatures," Proc. ASTM, Vol. 39, Part II, 1939, pp. 649-658.

(33) Davis, H.E., Troxell, G.E. and Hauck, G.F.W., "The Testing of Engineering

Materials," 4th Ed., McGraw-Hill, 1982, pp. 221-241.

(34) Simons, E.N., "Testing of Metals," Great Albion Books, New York, N.Y.,

1972, pp. 108-110.

(35) Thomas, W.H., Wilder, A.B., and Clinedinst, W.O., "Development of

Requirements for Transverse Ductility of Welded Pipe," Paper SS 2-2,

American Petroleum Institute Symposium on Mechanical Properties of Pipe,

1967 Midyear Standardization Conference, San Francisco, CA, June 1967.

27
Appendix A

A summary of selected quality descriptors as defined in appropriate

parts of the American Iron and Steel Institute Steel Products Manual.

CARBON STEEL PLATE QUALITIES^

Regular Quality

A common designation for carbon steel plates having a maximum of

0.33 per cent carbon by ladle analysis. Plates of this quality

do not have the high degree of uniformity in chemical composition,

internal soundness or freedom from nonmetal lie inclusions and

surface imperfections that are associated with other plate steel

qualities. Plates of this quality are not customarily produced to

mechanical property, cold bend, or ductility requirements. Such

plates are not intended for deep drawing, severe cold forming or for pressure vessels or any applications requiring specified

minimum mechanical properties. Tension and bend tests are not

appropriate for such plates.

Structural Quality

Plates are intended for application in structures such as bridges,

buildings, structural steel for locomotives, railroad cars and

other mobile equipment. Two longitudinal tension and two longitudinal

bend tests taken at random are commonly required from each he$t.

Forging Quality

Plates are intended for forging, heat treating or similar purposes

or when uniformity of commposition and freedom from injurious

defects are essential. Plates of this quality are produced by a killed steel practice and rolled from slabs or ingots conditioned

to eliminate injurious surface defects. Forging quality is ordinarily furnished with the phosphorus content up to 0.035 per cent

and the sulphur content up to 0.040 per cent by ladle analysis.

Plates of this quality can be produced to chemical ranges and

limits and mechanical properties. When mechanical properties are specified, two tension and two bend tests from each heat are made.

Where the steel from one heat differs 3/8 in. or more in thickness,

one tension and one bend test are made from the thickest and

thinnest plate rolled, regardless of the weight represented. All

test specimens are taken in a longitudinal directions.

(a) Steel Products Manual "Plates and Rolled Floor Plates," American Iron

and Steel Institute, January 1979.

28
CARBON STEEL PLATE QUALITIES (CONT)

Pressure Vessel Quality

Steel plates are intended for application in pressure vessels.

Except for quenched and tempered plates, a minimum of one trans- verse tension and one transverse bend test representing each plate

as-rolled are required as described in ASTM A 20. For quenched and

tempered plates ordered to ASTM or ASME specifications, two transverse tension and one transverse bend test are required from each

plate as heat treated. Plates of this quality may be supplied to

ultrasonic testing requirements.

HOT ROLLED CARBON STEEL BARS^

Merchant Quality

Merchant quality is the lowest quality for carbon steel bars.

Merchant quality bars are produced to specified sizes, with appropriate control of the chemical limits or mechanical properties for

non-critical uses. Bars of this quality are usually rolled from

unconditioned billets. The size ranges are limited and the type of

steel applied is at the producers option, i.e. , rimmed, capped,

semi-kiled or killed steel. Merchant quality steel bars are produced for a wide range of uses, such as structual and similar

miscellaneous aplications involving mild cold bending, mild hot

forming, punching and welding as used in the production of non- critical parts of bridges, buildings, ships, agricultural implements,

road building equipment, railway equipment and general machinery.

Mild cold bending refers to bending using a generous bend radius

with the axis of the bend at right angles to the direction of

rolling. This quality is not suitable for applications which

involve forging, heat treating, cold drawing, or other operations

where internal soundness or relative freedom from detrimental

surface imperfections is of prime importance. Merchant quality

steel bars should be free from visible pipe; however, they may

contain pronounced chemical segregation and for this reason product

analysis tolerances are not appropriate. Internal porosity,

surface seams, and other surface irregularities may be present and are generally to be expected in this quality. Steel bars of this

quality are commonly produced to chemical composition (cast or heat

analysis only), within the limits of 0.50 percent maximum carbon,

0.60 per cent maximum manganese, and 0.04 per cent maximum phosphorus.

This quality is produced in nonresul phurized steels only within the

limit of 0.05 per cent maximum. Merchant quality steel bars are not produced to any specified silicon content, grain size, or other

(b) Steel Products Manual, "Alloy, Carbon and High Strength Low Alloy Steels,"

American Iron and Steel Institute, August 1977.

29
HOT ROLLED CARBON STEEL BARS (CONT)

Merchant Quality (Cont)

requirements which would dictate the type of steel produced.

Merchant quality steel bars do not require the chemical ranges

typical of standard steels. They are produced to wider carbon and

manganese ranges and are designated by the prefix, "M". Merchant

quality bars are also produced to compatible mechanical properties

as previously described in this Part.

Special Quality

The basic or standard quality for carbon steel bars. Special

quality steel bars can be produced using a rimmed, capped, semiki 11 ed or killed type of deoxidation practice. The appropriate

type is dependent upon chemical composition, quality and customer's

specification. Killed steels can be produced to coarse or fine

austenitic grain size. Steel bars of this quality are produced to

be free from visible pipe and excessive chemical segregation.

Also, they are rolled from billets which have been inspected and

conditioned, as necessary, to minimize surface imperfections. The

frequency and degree of surface imperfections are influenced by the

type of steel, chemical composition and bar size. Resulphurized

grades, certain low carbon killed steels and boron treated steels

are most susceptible to surface imperfections. Special quality

steel bars can be produced to chemical requirements. Bars of this

quality are produced to tolerances for product analysis. Also,

they can be produced to mechanical property requirements. Special

quality steel bars are used when the application, method of , fabrication or subsequent processing treatment requires quality

characteristics not available in merchant quality. Typical applications involve hot forging, heat treating, cold drawing, machining

and many structural applications.

STEEL SPECIALTY TUBULAR PRODUCTS^

Pressure Tubing

Pressure tubes, as distinguished from pressure piping, are used to

convey fluids at elevated temperatures or pressures or both and are suitable to be subjected to heat application. Pressure tubes are also used at low temperatures. Pressure tubes are produced to

actual outside diameter and minimum or average wall thickness (as

specified by the purchases) and may be hot finished or cold finished,

as specified. Wall thickness is commonly specified in decimal

parts of an inch rather than by gage numbers. Specifications for

(c) Steel Products Manual, "Steel Specialty Tubular Products," American

Iron and Steel Institute, October 1980.

30
STEEL SPECIALTY TUBULAR PRODUCTS (CONT)

Pressure Tubing (Cont)

pressure tubes are written by such bodies as American Society for

Testing and Materials and American Society of Mechanical Engineers.

These specifications should be consulted for the grades and chemical

compositions involved.

Mechanical Tubing

Mechanical tubing derives its name from its end use. It is employed

for a variety of mechanical purposes and is generally produced to

meet specific end use requirements. Mechanical tubing can be

produced to a wide variety of finishes and mechanical properties.

It is made in sizes up to and including 12-3/4 inches in outside

diameter. Tubing produced by hot rolling processes has surfaces

similar to the surface regularly produced on hot rolled steel and,

in general, the dimensional tolerances cannot be held so closely as

in the case of tubing produced by cold finishing. Cold finished

mechanical tubing can be produced by cold working or by means of

surface removal. By cold working is meant the cold reducing to

effect changes in cross-sectional dimensions. Surface removal

includes turning, polishing, grinding or machining. Cold working

can also be used to produce tubes having cross-sectional shapes

other than round. Requirements involving additional testing are sometimes specified, such as restrictions in chemical compositions,

mechanical properties, qualifications for macroetch, fracture,

hardenability, and nonmetallic ratings. Mechanical tubing is

commonly specified to outside diameter and wall thickness. If

inside diameter is the more important dimension, cold worked tubing

is specified to inside diameter and wall thickness or outside

diameter and inside diameter.

31
APPENDIX B

Strain analysis in bending test

General Strain Equation

where: ev

is strain parallel to the

y neutral axis (N.A,) at a distance y from the N.A.

r-i radius of curvature at N.A.

1 before bending

r 9 radius of curvature at N.A.

L after bending

y distance from N.A.

Assume

:

(a) N.A. does not move during bending

(b) N.A. lies midway between specimen surfaces

e y =

1

r l

y

r± + y

l

t

i_l

BEFORE

substituting for r 2

and y in the general strain equation.

i r

—

1

I

1 CNl

r* —

1

2R + t r-j_ 2 1

j

' ri_

then,

substituting for r^

1

1

32
APPENDIX C

Strain analysis in pipe flattening test

General Strain Equation for Curved Section

where: e

y

is strain parallel to the

neutral axis ( N . A , ) at a distance y from the N.A,

r^ radius of curvature at N.A,

before bending

r2radius of curvature at N.A.

after bending

y distance from N.A.

For the case of a pipe of original outside diameter D flattened to

a distance H, the maximum circumferential tensile strain at the 90°

position occurs at the outer surface fiber parallel to the N.A. and

is determined as follows:

Assume:

(a) N.A. does not move during bending

(b) N.A. lies midway between pipe surfaces

(c) Semi-circular pipe shape at 90° position

is maintained during bending

ey1

r

l

ny

rj+.y

33
AFTER

D t

r

11 2 2

H t

2 "

2 2

t

y = -

2

substituting into the general strain equation.

H

1 —D

e y ~ or rearranging.

H D

1

D t

H -

( 1 + e)t

e + -

D

wnere e:e

y = maximum

circumferential

strain at surface

34
Appendix D

Checklist of typical tests and requirements found in a selected group

of domestic material product and application specifications.

Structural Products (including plate, strip, shapes, rods, bars)

Typical Requirements

Chemistry

Ultimate Tensile Strength and Yield Strength

Percent Elongation

Supplemental Requirements

Bend Tests

Impact Tests

Nondestructive Evaluation (NDE) Tests

Wrought Tubular Products (including pipe and tubes)

Typical Requirements

Chemistry

Ultimate Tensile Strength and Yield Strength

Percent Elongation

Bend Tests

Flattening Tests

Hydrostatic Tests

Flare Tests (Nonferrous alloys)

Corrosion Tests (Nonferrous alloys)

NDE Tests

Hardness

Cast Products

Typical Requirements

Chemistry

Ultimate Tensile Strength and Yield Strength

Percent Elongation

Percent Reduction-i n-Area

Supplement Requirements

Bend Tests

NDE Tests

Bolting and Fastener Products

Typical Requirements

Chemistry

Ultimate Tensile Strength and Yield Strength

Percent Elongation

Wedge Tension Test

Hardness

35
Supplemental Requirements

Impact Tests

NDE Tests

Forging Products

Typical Requirements

Chemistry

Ultimate Tensile Strength and Yield Strength

Percent Elongation

Percent Reducti on-in-Area

Hardness

Supplemental Requirements

NDE Tests
o

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37
STANDARD

TENSILE

TEST

SPECIMENS

WROUGHT

PRODUCTS

(EXCEPT

TUBULAR ) £

LA LA LA lA

Ot a: lO lO v-D lO < < • • • • _1 > > LA la LA lA i o CO • • • • • «o at Ctt O' O' 1 X LD z < < < < < 1 H z z > > > > > 1

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38
Classification

of

Metals

Specifications

39
FIGURE 2. EXAMPLE OF TEXT SIMILARITY BETWEEN AS TM AND JIS

SPECIFICATIONS

AS 1 M A515 CARBON STEEL PRESSURE VESSEL PLATES

SECTION 5.1 "PLATES 2 IN. (50.8 MM) AND UNDER IN THICKNESS

ARE NORMALLY SUPPLIED IN THE AS-ROLLED

CONDITION."

SECTION 5.2 "PLATES OVER 2 IN. IN THICKNESS SHALL BE NORMALIZED,

JIS G3103

SECTION 3.1.1 "THE STEEL PLATE OF 50 MM AND UNDER IN

THICKNESS . . . SHALL BE AS-ROLLED."

SECTION 3.1.2 "THE STEEL PLATE OVER 50 MM IN THICKNESS

. . . SHALL BE NORMALIZED."

40
+

4. REGIONS WITH

' HIGHER THAN AVERAGE

+ ¥ LEVELS OF CARBON,

SULFUR, AND

4-4- PHOSPHORUS

REGIONS WITH

LOWER THAN AVERAGE

-

- - LEVELS OF CARBON,

I'l SULFUR, AND

~ - - PHOSPHORUS

REGION A HAS VERY LOW

CARBON CONCENTRATION

FIGURE 3 . SCHEMATIC OF RIMMED STEEL INGOT SHOWING SEGREGATION

REGIONS C 7 )

41
OUTSIDE SURFACE

INSIDE SURFACE

FIGURE 4. REPRESENTATIVE MICROSTRUCTURE OF A HOT-ROLLED

CARBON-MANGANESE STEEL PLATE (8)

42
FIGURE

5.

EFFECT

OF

COOLING

RATE

ON

ME

CFIAN

I

CAL

PROPERTIES

OF

EUTECTO

I

D

STEEL

(9)

43
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cz

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44
FIGURE 7

M 3«l 5‘! 7*1

FORGING RATIO

EFFECT OF

DUCTILITY

MECHANICAL

ANISOTROPY

WORKING

( 15 )

ON TENSILE

FORGING RATIO = RATIO OF AREA BEFORE S AFTER

Long. = longitudinal specimens

Trans. = transverse specimens

FORGING

45
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m oH c

C * 43 o

0 E-> XI •A 4) 4J # AJ .G * -O u O ij HI O

43 c U >i V) -A u

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AJC —1 U S 4> A) LU o X O 4) AJ > c 1

|

4) O' <U .C H <0 A< •A VU AJ O' c ki W O’ o c r$ 4J 0 • O C 0 Q U 3 .C 00 0 C A3 H A in C o

43 -A U UJ £ 43 AJ 43 a x: o >aj >3 E- CO 0^ U AJ 43 4)

4) U U o O.IM —

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JOULES

120 90 60 30

(8i-id) NOiidyesaa A3y3N3

46

-220.0

-120.0

-20.0

80.0

180.0

280.0

TEST

TEMPERATURE

(F)
£ c = CIRCUMFERENTIAL STRAIN, NORMAL TO RADIUS OF CURVATURE

£ t

sr TRANSVERSE STRAIN

(a)

Gc = CIRCUMFERENTIAL STRESS

-TRANSVERSE STRESS

(b)

FIGURE 9. STRAIN ANALYSIS OF BEND TEST SPECIMEN (31)

47

A BS-) 14A [REV. 2-80

U.S. DEPT. OF COMM. 1 . BIBLIOGRAPHIC DATA

SHEET (See instructions)

PUBLICATION OR

REPORT NO.

NBSIR 83-2692

2. Performing Organ. Report NoJ 3. Publication Date

May 1983

4. TITLE AND SUBTITLE

Evaluation Criteria for Comparing Domestic and Foreign Material Specifications

5. AUTHOR(S)

J. Early

6. PERFORMING ORGANIZATION (If joint or other than NSS, see instructions) 7. Contract/Grant No. NATIONAL BUREAU OF STANDARDS Z70099-2-02055

DEPARTMENT OF COMMERCE S. Type of Report & Period Covered

WASHINGTON, D.C. 20234

FINAL

9. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street. City. State. ZIP)

Commandant

U.S. Coast Guard

Washington, DC 20593

LO. SUPPLEMENTARY NOTES

| | Document describes a computer program; SF-185, FIPS Software Summary, is attached.

LI. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bibliography or literature survey, mention it here)

Consistent decisions on the degree of equivalency between metal specifications

of different national origins cannot be made only on the basis of chemical composition

and direct comparison of mechanical property numbers. There are numerous additional

factors, including metallurgical effects, product form effects, test acceptance

criteria, and differences in specification philosophy, which if present, may influence

the determination of equivalency because of their effect on property requirements. In

order to remove the uncertainty in this decision-making process, these additional

factors must be evaluated for each comparison.

Excerpts from actual comparisons have been used to illustrate the methodology

followed which is based on the principles discussed in this report. The specific

evaluation criteria identified are not meant to be totally inclusive, but rather represent those most often encountered. Some material specifications, especially application

specifications, may include special requirements dictated by the application. Finally,

material specifications are dynamic documents because revisions of test methods and

test requirements are part of the specification writing process. Care must always be

exercised to insure that the appropriate versions of specifications are being compared.

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolons)

ASTM, comparison methodology, DIN, foreign specifications, JIS, metal

tests

L3. AVAILABILITY

| X| Unlimited

| | For Official Distribution. Do Not Release to NTIS

f' 1 Order From Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402.

Order From National Technical Information Service (NTIS), Springfield, VA. 22161

specifications,

14. NO. OF

PRINTED PAGES

51

15. Price

$ 10.00

USCOMM-DC 6043-P80
)

)

I

'

Ij

I