J

NBSIR 74-48300

Progress Report on the Corrosion and Stress

Corrosion Behavior of Selected Stainless

Steels in Soil Environments

Part I. General Corrosion Behavior

W. F. Gerhold, W. P. Iverson, E. Escalante, B. T. Sanderson

Corrosion and Electrodeposition Section

Metallurgy Division

Institute for Materials Research

National Bureau of Standards

Washington, D. C. 20234

May 1974

Progress Report

Prepared for Committee of Stainless Steel Producers

American iron and Steel Institute

150 East 42nd Street New York, New York 10017

NBSIR 74-483

PROGRESS REPORT ON THE CORROSION AND STRESS

CORROSION BEHAVIOR OF SELECTED STAINLESS

STEELS IN SOIL ENVIRONMENTS

PART I. GENERAL CORROSION BEHAVIOR

W. F. Gerhold, W. P. Iverson, E. Escalante, B. T. Sanderson

Corrosion and Electrodeposition Section

Metallurgy Division

Institute for Materials Research

National Bureau of Standards

Washington, D. C. 20234

May 1974

Progress Report

Prepared for Committee of Stainless Steel Producers

American Iron and Steel Institute 150 East 42nd Street New York, New York 10017

U. S. DEPARTMENT OF COMMERCE, Frederick B. Dent. Secretary

NATIONAL BUREAU OF STANDARDS, Richard W. Roberts. Director

Progress Report on The Corrosion and Stress Corrosion

Behavior of Selected Stainless Steel

Alloys in Soil Environments

Part I General Corrosion Behavior

by

W. F. Gerhold, W. P. Iverson,

E. Escalante, and B. T. Sanderson

A. Introduction

Stainless steels have, within the past several years, successfully

been used in increasing amounts for pipe clamps for joining and repairing

cast iron sewer lines. Other applications in use or under test include

ground rods, transformer cases, submerged switches, underground

residential distribution equipment (connector sheaths, housings, clamps,

and bails), gas lines (1,2), water lines, buried caskets, culverts,

residential sewage disposal, etc.

Corrosion data available pertaining to the suitability of stainless

steels for underground uses are reported in NBS Circular 579 (3) and the

reports by Branch (1) and Steinmetz and Hoxie (2). The NBS tests, con- ducted for 14 years in various soils of the United States showed that

Type 304 and Type 316 were highly resistant to both pitting and general

attack. In certain highly aggressive soils Type 304 showed some scattered

pitting. Type 316 with its almost negligible pitting attack was found

to be the best alloy tested. Type 302 was tested in only a few soils.

Types 410 (12% chromium) and 430 (17% chromium) were found to be fully

resistant to attack in only 1/3 of those NBS tests sites where exposed.

The stainless steel specimens used in these tests were flat, annealed,

unstressed coupons.

In a two-year exposure to various soils in and around Baltimore,

Maryland, Type 304 service gas lines (50 for a total length of 1 mile)

were reported to have suffered no corrosion effects (2).

Stress corrosion cracking also has not been reported to be a problem

with Types 304 or 316 in actual underground applications (1).

In order to more fully evaluate the corrosion and stress corrosion

behavior of some of the alloys proposed for soil environments, NBS in

cooperation with the American Iron and Steel Institute initiated in

1970 a soil burial program in representative corrosive soils utilizing

nine stainless steel alloys in both the annealed and cold worked

conditions with various treatments.
These treatments incorporated welds, crevices, galvanic couples,

stresses, and/or sensitization by heat treatment to induce carbide

precipitation. In 1971 and in 1972 the program was expanded to include

other stainless steels. This report is based upon the one-and two-year

burial results of the 1970 and 19 71 program and the one-year burial

results of the 1972 program. Results on the stressed stainless steel

specimens are given in Part II,

B. Experimental Procedure

1. Soils at NBS Test Sites . Following are detailed descriptions of

the soils at these test sites, which have been selected by NBS as the

most representative of 128 test sites previously used:

Sagemoor sandy loam (Site A) is a well-drained alkaline soil,

typical of that found in vast areas of eastern Washington and Oregon.

The site is located on the Yakima Indian Reservation near Toppenish,

Washington. The soil is consistent in composition to a depth of at

least 7 feet and supports abundant growth of sagebrush.

Hagerstown loam (Site B) is a well-drained soil representative

of the majority of well-developed soils found in the eastern part of

the United States. The site is located at the Loch Raven Reservoir

of the Baltimore Water Department. The soil consists of a brown loam

about 1 foot deep, underlain by a reddish-brown clay that extends 5

feet or more to underlying rock. Practically all the materials that

have been investigated in the extensive NBS soil corrosion tests since

1922 have been exposed at this site, which, therefore, serves as a reference site in the correlation of data obtained for specimens in the

present program with data obtained from the earlier tests.

Clay soil (Site C ) is located in a large clay pit on level land

at Cape May, New Jersey, which floods during heavy rains. The soil

consists of a plastic gray clay to a depth of 6 inches underlain by

gray clay mixed with patches of brown clay to a depth of 12 inches.

This is underlain by a poorly drained very heavy plastic clay.

Lakewood sand (Site D ) is a white, loose sand with some black

streaks occurring in places which supports the growth of beach grasses

abundantly. The site is located in a well-drained rolling area at

Wildwood, New Jersey, which is not subject to overflow from the ocean

except under unusualy flood conditions.

Coastal sand (Site E) is a typical white, coastal beach sand, with

a high content of black sand that occurs in streaks. This sand is

similar to Lakewood sand except that at this site, which is located on Two-Mile Beach at Wildwood, New Jersey, the sand is constantly damp and

occasionally flooded with seawater.
Tidal marsh (Site G) Is a soil charged with hydrogen sulfide

typical of the poorly drained marsh soils that are found along the

Atlantic and Gulf coasts. The site Is located along a creek (Pine

Hill Run) that empties Into the Chesapeake Bay at Lexington Park,

Maryland.

Some of the properties of the soils at these sites are given in

Table I. The corroslvity of these soils on plain carbon steels is

shown in Figure 1.

2. Materials, Treatment, and Preparation

In order to simulate some of the conditions that may occur on components fabricated from stainless steel alloys, materials for these

soil corrosion studies included unstressed flat sheet specimens with

and without welds, welded tubing specimens and coated specimens.

Descriptions of the alloy systems burled at each test site and

the alloy treatments and preparation are presented in Table II. Only

Systems 1-19 and 50-66 are covered in this report; Systems Nos . 20-42

and 67-92 are covered in Part II. The chemical analyses and mechanical

properties of each alloy used in Systems Nos. 1-19 and 50-66 are presented in Tables III and IV respectively.

Upon receipt of the specimens from the stainless steel companies

the specimens were first stamped with identification numbers using

chromium plated steel dies.

All flat sheet materials (approximately 0.06" thick) were supplied

with sheared edges which had been deburred. In some instances further

deburring was necessary. Following the passivation procedure (described

in Table II) , all specimens were scrubbed with a fiber brush,

thoroughly rinsed with water, and air dried.

Half of the coated (coal tar epoxy, 16 mils per side) specimens

(System No. 61) were scored diagonally from the corners, twice on one

surface, by cutting through the coating to the base material with a sharp pointed Instrument. The other half of the specimens were

exposed in the "as-coated" condition.

Type 304 tubing was prepared according to ASTM Specification A-249.

Type 409 tubing was tested in the "as-welded" condition. All proprietary

alloys wer ^ tested as supplied by the producers, except for cleaning and

passivatlng.

The ends of the tube (welded) specimens were plugged with rubber

stoppers and plastic or rubber caps were placed on each end. All of

the specimens with the exception of the coated specimens were weighed

prior to exposure for weight loss determinations.

- 3 -
3. Exposure

At each test site the specimens were buried in trenches approximately

2-1/2 feet deep and 2 feet wide. The specimens were placed about one

foot apart. The 8"xl2" sheets were placed in a vertical position (along

the long dimension) . Sufficient specimens were buried at each of the

six test sites to permit recovery of a complete set at specified

intervals (1, 2, 4, and 8 years) and the final set to be removed at

a date to be determined. For the 8"xl2" flat sheet specimens and for

the welded tube specimens each set consisted of four specimens.

The burial order for each test site is shown in Figure 2a, b,

and c. There are 1,054 specimens buried at each test site for a total

of 6,324 specimens at the six test sites. This report covers 36

of the 73 systems described in Table II.

'4. Examination of Specimens After Exposure

Upon removal, all of the specimens were rinsed thoroughly in tap

water to remove the adhering soil. All the specimens, except the coated

ones (System No. 61) and the composites (Systems Nos . 14, 15, and 16), were cleaned ultrasonically for 20-30 minutes using a 10% nitric acid

solution at 120° to 130°F. Specimens from System Nos. 14 and 16 were

ultrasonically cleaned using an aqueous 10% ammonium citrate solution

heated to 175° to 185°F. The time for cleaning these specimens varied

and was dependent upon the tenacity of the corrosion scale. The

specimens from System No. 15 were ultrasonically cleaned for

approximately 30 minutes using an aqueous 10% ammonium chloride solution

at 175° to 185°F. After cleaning, the specimens were rinsed in

distilled water and then air dried. The sheet specimens (8"xl2") were

then weighed twice and the weightless was determined. The average loss

in weight of similar unexposed (control) specimens given the identical

cleaning processes was subtracted from the weight loss of the exposed

specimens

.

Pit depth measurements and visual observations were made on all the

specimens.

C. Results

All specimens were examined visually in order to determine the nature

and extent of the degradation after exposure up to two years in the

various soil environments. Table V summarizes the results obtained from

visual examination of the non-welded, coated and uncoated 8"xl2" sheet

specimens. The results obtained from visual examination of the weldments

(8"xl2" sheet and tubing specimens) are summarized in Table VI. Results

obtained from pit-depth and loss in weight determinations are given

in Table VII.

- 4 -
The data given for each ally system is a compilation of the results

obtained from four specimens. Therefore, the weight loss for a given

alloy system exposed in the soil environment may appear to be extremely

small in comparison to the observed corrosion. This occurs because the

corrosion of stainless steels in this type of environment can often be

localized and confined to a very small area. Similarly, one specimen

may have only one corrosion pit which caused perforation of the specimen,

while there was little or no corrosion observed on the other three

specimens exposed in the same environment.

Corrosion of stainless steel alloys is generally attributed to a breakdown of the passive film on the surface of the alloy at localized

or selective areas. If corrosion occurs, it may often be influenced by

one or more of the following:

1. Inhoraogeneities at the surface of the metal.

2. Concentration cell effects due to adhering soil particles or crevices where stagnant conditions may exist.

3. Presence of chlorides in the soil.

4. Sulfate reducing bacteria.

5. Abrasion of the metal surface by soil particles or foreign debris.

A break in the passive film at the localized area results in a small anodic site. The larger surrounding area is the cathode. The

electrolytic cell formed could result in localized pitting corrosion,

which can rapidly penetrate the thickness of the alloy. Similarily,

concentration cells formed at stagnant areas beneath soil deposits or

at crevices can also result in localized corrosion with subsequent

perforation of the alloy. Tunneling is an unusual form of pitting

corrosion normally associated with edges, which can be increased by

gravity flow of corrosion products. All flat specimens were buried

vertically, thus increasing the propensity for tunneling.

AISI 200 Series

There was little or no apparent corrosion on the austenitic Type

201 and 202 (annealed) stainless steel specimens buried in the soils

for two years at Sites A, B, and D. Some rust staining was observed

on two of the four Type 202 specimens exposed at Site B. Pitting

corrosion was noted at the edge on one of the Type 201 specimens

exposed at Site D. Pitting and tunneling corrosion occurred generally

in areas at or adjacent to the edges of both Types 201 and 202 specimens

exposed at Site C. The Type 202 specimens were perforated by corrosion

at these areas. There were pin-point perforations of specimens of

both stainless steels exposed at Site E as a result of pitting and

tunneling corrosion at face and edge areas of the specimens. One of the

- 5 -
Type 201 specimens exposed at Site G was severely attacked by corrosion

at the edge. On this and other specimens of both alloys, pitting

corrosion was also observed.

MS I 300 Series

In general the corrosion behavior of the austenitic 300 series alloys

exposed for two years at Sites A, B, and D was similar to that noted for

the 200 series alloys. With a few exceptions, corrosion, where observed

on specimens exposed at these sites, was generally superficial. Small

"blister-like" eruptions on the surface were noted on one of each of

the Type 301 (sensitized) and Type 304 (sensitized) specimens. These

appeared to be very small corrosion pits. Tunneling corrosion was also

observed at the edge on the Type 304 (sensitized) specimen.

Of the specimens exposed at Site C, corrosion of Type 316 (annealed) was superficial. Pitting corrosion with subsequent perforation of

the specimens was noted in areas at or adjacent to the edges of the

Type 301 (annealed) , Type 304 (annealed) , and Type 304 (sensitized)

specimens. Tunneling corrosion was found at the edge on one of the

Type 316 (sensitized) specimens. Pitting corrosion was noted in areas

at and adjacent to the weld seam, and in areas adjacent to and under

the caps of Type 304 tubing specimens. Similarly, pitting corrosion was observed at areas adjacent to the weld bead on the cross-bead welded

Type 301 alloy specimens.

At Site E, annealed Types 301, 304, and 316, sensitized Type 304,

and the cross-bead welded Type 301 specimens exhibited pitting and

tunneling corrosion and subsequent perforation of the specimen. Pitting

corrosion and severe etching or attack due to corrosion was observed

on sensitized Types 301 and 316 and on the heliarc welded Type 304

specimens

.

Corrosion of Types 301 and 304 exposed at Site G generally involved

severe etching accompanied by pitting corrosion. In addition, the

sensitized Types 301 and 304 and annealed Type 304 specimens were

perforated by corrosion at scattered localized areas. Tunneling corrosion

was also found on one of the annealed Type 301 specimens. Superficial

pitting corrosion was observed on the annealed and sensitized Type 316

specimens exposed at this site.

AISI 400 Series

Stainless steels in this series include the martensitic Type 410

and the ferritic Types 409, 430, and 434.

With a few exceptions, there was little or no apparent corrosion on

any of the 400 series specimens buried in the soils for two years at

Sites A and B. Pitting and/or tunneling corrosion was found on the Type

410 specimens exposed at Site A.

- 6 -
Non-welded specimens exposed at Sites C, E, and G were perforated

by corrosion. Localized corrosion wasnoted on Type 430 and Type 434

specimens exposed at Site D. Type 410 specimens at this site were perforated by corrosion at localized areas.

There were a few scattered corrosion pits on the heliarc welded

Type 409 specimens exposed at Site D, although no corrosion pits were

observed at or adjacent to the weld areas on these specimens. The

high frequency welded Typed 409 specimens exposed at this site were

perforated by corrosion at weld areas. Of the welded Type 409 specimens

exposed at Sites C, E, and G, all were perforated by corrosion at

localized areas. However, of the weldments exposed at these sites,

only the high frequency welded Type 409 specimens exposed at Site E

were perforated by corrosion at weld areas.

The coated (coal-tar epoxy) Type 409 specimens were unaffected

by corrosion in any of the soil environments. However, on the coated

specimens that were scored prior to exposure in the soils, there was

some superficial rust staining at the scored areas of those exposed

at Sites B, C, and D. Corrosion pits were noted at the scored

areas on specimens buried for two years in the soils at Sites E and

G, and the paint coating was blistered and brittle at the

scored areas.

Specialty and Developmental Alloys

Stainless steels in this classification include proprietary and

composite materials. The proprietary stainless steels may be grouped

as follows according to major alloying constituents:

1. Cr Stainless Steels

26 Cr-1 Mo

18 Cr-2 Mo

18 Cr-2 Mo (Nb)

18 Cr (Ti)

2. Cr-Ni Stainless Steels

26 Cr-6.5 Ni

20 Cr-24 Ni-6.5 Mo

18 Cr-8 Ni (N)

The results obtained from visual examination of these specimens

exposed for one and two years are summarized in Table V.

Cr Stainless Steels

Alloy 26 Cr-1 Mo (System No. 1) specimens were relatively unaffected

by corrosion after burial in the soil environments for up to two years.

- 7 -
There was little or no apparent corrosion of the Alloy 18 Cr-2 Mo

(System No. 6) specimens buried at Sites A, B, C, and D for two years.

Similar specimens exhibited scattered pitting corrosion with perforation

of the specimen after exposure for two years at Sites E and G.

Of the Alloy 18 Cr-2 Mo (Nb) (Systems Nos . 7, 11, and 12) specimens

buried for one year, those in the annealed condition (System No. 7) were

also relatively unaffected by corrosion. There was little or no apparent

corrosion on specimens with the cross-bead weld (System No. 11) or heliarc

weld (System No. 12) specimens in five of the six soils. Pitting

corrosion at and adjacent to the weld was observed on specimens of System

No. 11 exposed at Site E. One specimen was perforated by corrosion at

the weld area. Crevice corrosion with perforation of the specimen was noted at localized areas under the cap on the heliarc welded specimens.

The annealed (System No. 2) , cross-bead welded (System No. 3) and

heliarc welded (System No. 18) Alloy 18 Cr (Ti) specimens were similarly,

relatively unaffected by corrosion after burial in the soils for two

years at Sites A, B, C, and D. Tunneling corrosion at edge areas was observed on the annealed and cross-bead welded specimens exposed at Site

E. Localized corrosion was noted at crevice areas under the cap on two

of the heliarc welded specimens exposed at this site. There was no apparent corrosion on the other two specimens. The annealed Alloy 18

Cr (Ti) specimens buried for two years at Site G were perforated by

pitting corrosion. Pitting and tunneling corrosion was observed at non- weld metal areas on the cross-bead welded specimens of this alloy buried

for two years at Site G. The heliarc welded specimens buried at this

site were perforated by pitting corrosion observed at non-weld metal

areas

,

Pitting and tunneling corrosion, particularly in areas at and

adjacent to the edge of the specimens, was observed on the Alloy 26 Cr6.5 Ni (System No. 10) specimens buried at Sites C, E, and G for two

years. Similar specimens of this alloy exposed at Sites A, B, and D were relatively unaffected by corrosion.

Cr-Ni Stainless Steels

The annealed (System No. 8) and cross-bead welded (System No. 9)

Alloy 18 Cr-8 Ni (Ti) specimens buried for two years at Sites A, B,

C, and D exhibited little or no corrosion. Pitting corrosion was noted

at the edge on two of the four annealed specimens exposed at Site E.

Tunneling corrosion with subsequent perforation was observed on one of

the annealed specimens exposed at Site G. Other specimens of System No.

8 exposed at these sites were relatively unaffected by corrosion. Pitting

and tunneling corrosion was found at and/or adjacent to the weld on the

cross-bead welded specimens (System No. 9) exposed at Site E. For similar

specimens exposed at Site G, pitting corrosion was noted at weld areas.

- 8 -
There was little or no apparent corrosion noted on the annealed

(System No. 4), sensitized (System No. 5), or heliarc-welded (System

No. 19) Alloy 20 Cr-24 Ni-6.5 Mo specimens buried in the six soil

environments. Where corrosion was observed, it was superficial.

Composite Materials

The composite systems are essentially sandwich materials wherein

the outer layers of carbon steel are metallurgically bonded to a thin

core of stainless steel (total thickness approximately 0.120").

Composites A and B (Systems Nos . 14 and 15) were fabricated with a Type

430 stainless steel, while Composite C (System 16) utilizes a Type

304 stainless steel as the core material. In addition, Composite B

specimens were hot-dip zinc coated (galvanized, 4.5 to 5 oz/ft Zn) . This was a thicker coating than would normally be used on carbon steel

products

In general there was very little difference in the corrosion

behavior of Systems Nos. 14 and 16 buried in the same soil environment

for two years. The carbon steel outer layers were severely attacked by

corrosion at Site A. Pitting corrosion of the carbon steel was noted on specimens buried at Site B. Corrosion of the carbon steel on specimens

buried at Sites C, D, and E appeared to be relatively uniform. However,

the carbon steel appeared to be blistered (raised) at one area on one of

each of the System Nos. 14 and 16 specimens buried at Site C. Examination

of sections machined from these areas did not reveal any corrosion. The

blisters appeared to be due to a metallurgical defect in the carbon

steel outer layer. Severe corrosion attack was observed on the specimens

of both systems exposed at Site G, particularly at the edges where the

attack was sufficient to expose the core material. The carbon

steel layers were completely corroded away at large areas adjacent

to the edge on one of each of the Systems Nos. 14 and 16 specimens

exposing the stainless steel core. There did not appear to be any

significant corrosion other than discoloration of the stainless steel

alloy core on any of the specimens.

The hot-dip zinc coating on the specimens of System No. 15 provided

protection to the underlying carbon steel and the stainless steel core

in all of the soil environments. While the percent dissipation of the

zinc varied in the various environments, there was some zinc remaining

on all of the specimens after exposure for two years in the six soil

environments

D, Summary

1. AISI 200 and 300 Series

Of the austenitic stainless steel (200 and 300 series) alloys

included in this soil corrosion program, all exhibited good corrosion

resistance after exposure for two years in the alkaline soil (Site A),

Hagerstown loam (Site B) , and Lakewood sand (Site D) . In general.

- 9 -
these alloys were susceptible to corrosion in the acid clay (Site C)

,

costal sand (Site E) , and tidal marsh (Site G) . Type 316 appeared to

be the least susceptible to corrosion in the six soils investigated.

Corrosion of the 200 and 300 series stainless steels was generally

characterized as pitting and/or tunneling corrosion with subsequent

perforation of the specimen at scattered localized areas. For

similar specimens of these alloys exposed at Site G, corrosion occurred

at large areas and was characterized as severe etching or general

corrosion of the metal surfaces. Sensitization, by heat treatment, of

Types 301, 304, and 316 generally resulted in increased susceptibility

to corrosion in all of the soil environments. Similarly, areas at or adjacent to weld beads on sheet specimens or weld seams on the heliarc

welded Type 304 tubing specimens were more susceptible to corrosion

attack on specimens exposed at Sites C, E, and G. Type 304 exposed at

these sites was also susceptible to crevice corrosion.

2. MS I 400 Series

The martensitic Type 410 and the ferritic Types 409, 430, and 434

stainless steels included in this investigation were in general susceptible

to pitting and/or tunneling corrosion at Sites C, D, and E, and to severe etching or general corrosion attack at Site G. Except for Types 430 and

434 exposed at Site D, all 400 series stainless steels exposed at these

sites were perforated. Similar specimens buried in the soils at Sites

A and B for up to two years were relatively unaffected by corrosion.

Areas at or adjacent to the weld seams on the heliarc welded Type 409

tubing specimens did not appear to be susceptible to corrosion at Sites

A, B, and D, Similar specimens buried at Site G for two years were

perforated by corrosion. The high-frequency welded Type 409 tubing

specimens exposed at Sites C, D, E, and G were perforated by corrosion

in areas at or adjacent to the weld seam. Similar specimens exposed at

Sites A and B were relatively unaffected by corrosion at these areas. Type 409 was susceptible to crevice corrosion at Sites C, E, and G. The

coal-tar epoxy coating applied to the Type 409 specimens appeared to be

effective in providing protection from corrosion at all of the test sites.

However, on specimens where the paint coating had been scored to bare

metal, the specimens at these bare (uncoated) areas were susceptible to

pitting corrosion at Sites E and G.

3. Proprietary Stainless Steels

All of the proprietary materials were relatively unaffected by

corrosion after exposure up to two years in the soils at Sites A and B.

With a few exceptions, particularly at weld or crevice areas of specimens

buried at Sites C, E, and G, the Alloy 18 Cr-2 Mo (Nb) (buried for one year), the Alloys 26 Cr-1 Mo and 20 Cr-24 Ni-6.5 Mo (burled for two

years) appeared to be the most corrosion resistant in all of the soil

environments. Alloys 18 Cr (Ti) , 18 Cr-2 Mo, and the 26 Cr-6,5 Ni

were found to be the more susceptible to corrosion at Sites E and G

after two years. Degradation of the alloys at these sites was generally

- 10 -
due to pitting and tunneling corrosion at localized areas with

subsequent perforation of the specimen,

4. Stainless Steel Core Composites

There was no apparent corrosion of Type 304 or Type 430 stainless

steel core alloy on any of the composite materials buried for two

years in the soil environments. There was little difference in the cor- rosion behavior of the carbon steel alloy layers of Composite A and C

when buried in the same soil environments. The zinc coating on the

Composite B specimens provided protection to the carbon steel base

metal in all of the soil environments.

- 11 -
References

1. Branch, H. C. , Corrosion Resistant Materials for URD Equipment,

Materials Protection and Performance , 12 . (3), 9-14 (1973),

2. Steinmetz, G. F. and Hoxie, E. C, A Field Test of Type 304

Stainless Steel for Gas Service, Materials Protection and

Performance , 12, (9) 41-44 (1973).

3. Romanoff, M. , Underground Corrosion (NBS Circular 579), U.S.

Dept. of Commerce Clearinghouse, PB 168 350 (1957) April.

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Table II. Stainless Steel Systems in Underground Corrosion Tests^^^

System

Burial Year Stainless

Steel Spec. Confiq. & Size* Passivation"

Trea tment"*" Procedure

Spec. Stressed* Coupled To

12.34

, 56

78

910n

1214

1516

17

18

19

20

2122

2324

25

26

27

'28 30

33

34

35

36

37

3842

.50

5152

53

54

55

565758

5960

6162

63

64

65

66

6768

69

70 . 7172

73 - 74

7576

77

78

7980

81828384

85

86

8788

89

90

9192

1971 26 Cr-1 Mo

18 Cr (Ti)

" 20 Cr-24 Ni-6.5 Mo

It It 18 Cr-2 Mo 1972 18 Cr-2 Mo (Nb)

1971 18 Cr-8

26 Cr-6.5 Ni 1972 18 Cr-2 Mo (Nb)

1971 Composite A

" Composite B

" Composite C

" 26 Cr-1 Mo

18 Cr (Ti)

" 20 Cr-24 Ni-6.5 Mo

" 26 Cr-1 Mo

II II

" . 20 Cr-24 Ni-6.5 Mo

18Cr-2Mo

18 Cr-8^ Ni(N)

26 Cr-6.5 Ni 26 Cr-1 Mo

26 Cr-6.5 Ni

Sheet (8"xl2"

Tube (2" 00x12") Sheet (8"xl2")

Tube (2" 00x12")

(1 1/8" 0Dxl2")

(7/8" 00x12") Sheet (l"xl2")

1970 201 202

301

304

316

409

410

430

434

301

304

II

II

II 316

434

301

II

304

409

Sheet (8"xl2"

Tube (2" 00x12") Sheet (8"xl2")

Tube (1-1/8" 0Dxl2") Tube (7/8" 00x12") Sheet (8"xl2")

Sheet (l"xl2")

XBW

S

XBW

XBW

HU

HW

HW

HW

SXBW

SHW(b)

CHW HFW

HHHH HH+S

FH

FH

HH

HH

S

HHHH

HH

FH

FHFH

II

(g)

(g)

(g)

(g)

(g)

(uu)

u (UU)

u uu

(UU)

u (uu)

u

uu

u

u

uu

u

u (UU)

uu

u (UU)

u (UU)

u (UU) UU

u (UU) UU

u (UU)

uu

u

u

u

u

uu

u

ZnMg

Fe

ZnMg

FeCu

ZnMg

FeZn

Mg

Fe

ZnMg

Fe

CuCu

* All sheet and tube specimens 0.064" thick.

+ All specimens in the annealed condition unless noted otherwise.

Ca) Systems 1-19, 50-66, covered in this report.

(b) Welded with a full finish per ASTM Specification A249.
Table II. (Cont'd)

Key: S - Sensitized (by heating at 1200°F for 2 hours, followed by air cooling and descaling in sodium hydroxide);

XBW - Cross bead weld (specified to be done in accordance with Welding Research Council recommendations. On half

of these specimens, the welds were cleaned prior to exposure. The other half of the specimens were to be exposed "as welded.

HW - Heliarc weld,

HFW - HFW High frequency weld;

C - Coated;

HH - Half hard;

FH - Full hard.

°Key: — = Unstressed;

U = Single U-bend specimen;

UU = Double U-bend specimen, no spot weld;

(UU) = Double U-bend specimen joined by spot weld.

"Passivation procedure:

I. 20 to m by volume of 67% nitric acid at 120-160°F for 20-30 minutes.

II. 20% by volume of 67% nitric acid plus 2-6% sodium dichromate at 110-140°F for 20-30 minutes.

III. 20 to 40% by volume of 67% nitric acid at 110-140°F for 20-30 minutes,

(g) Minimum specified concentration of acid, temperature and time for sensitized materials.
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Table V, Summary of results^ obtained from visual examination of stainless steel sheet specimens buried in the soils at the NBS soil corrosion test sites. Specimens

of Svstem No. 7 were buried for approximately two years.

System Stai nless

Steel Specimen Type

and Treatment

(b)

Test

Site

(c)

Results of Visual Examination

of Specimens

(d)

Years Exposed

Exposed in 1970

50 Type 201 Sheet, annealed

51 Type 202 Sheet, annealed

52 Type 301 Sheet, annealed

53 Type 301 Sheet, sensitized

55 Type 304 Sheet

56 Type 304 Sheet, sensitized

58 Type 316 Sheet, annealed

59 Type 316 Sheet, sensitized

60 Type 409 Sheet, annealed

61 Type 409 Sheet, painted

61 Type 409 Sheet, painted

and scored

A N B N C T,P,H

D IP

E H,P,T

G A,P,IP,Et(sli)

A N B N C T,P,H

D IP

E H,T(E),P,IP

G P. IP

A N B IP

C T,P,IP

D IP

E H G P,T(E),IP

A IP,Et

B IP{E)

C P,Et

D IP(E)

E A(E),P(E,AE),IP,Et

G Et(mod and sev),P,IP

A N

B N C H,T,IP

D IF

E H,P,IP

G H(E),P,IP,Et(sev)

A EtrE(sli)],IP

B Et(sli),IP

C H,T(E),P

D IF

E H.P.IP

G H(E),P,IP

A N B N C Et,IP

D N E A and T(E),P(F,E)

G IP

A IP{E)

B N C P{E,F),H{E)

D IP

E P(E)

G P(E)

A IP

B N C P,H(E),Et(sev)

D IF,RS

E H,T(E,F),P

G H,Et(sev),P,IP

A N

B N C N D N

E N G N

A RS{s)

B RS(s)

C RS(s,c)

D c,RS(s)

E c,RS{s)

G RS(s)

NRSP(F,E) ,T,IP P,IP H,T,P,IP,Et(sli)

H(E) ,P,A(sev) ,IP

IPRSH,P(F,E),T,IP

DSH,P,T,IP,IF

P,IP

IPRSP(F,E),IP

IPH,P,T,IP T,P,A and Et(sev),IP

E(E),P,IP

P(sli),IP

Et(sev),P(F,E),IP

P.Bl ,IP Et{sev),Bl,A(E),P,IP

H,A and Et(sev),P,IP

IPRST.P.IP

NH,T,P,IP

A(sev) ,P,IP

P(sli),IP

NH,P(E,AE),T,A(E),IP

T,P(AE,E),IP,B1 H,T,P,IP H,A,P,IP,Et(sev)

IP

NIP

NH,T,P,IP P(F,AE),IP

P(sli),IP

DSA and P(E) ,T,Et(sli

)

Nf',A(E),Et(sli)

P,IP,Et(sli

)

NP(sli)

H,P,Et(sev),T,IP

P.T H,T(AE,F),P,IP,Et{sli)

H,P,A(sev),Et,IP

N

N

N

N

NN

NRS(s) RS[s(sli)],U

RS[s(sli)]

P and RS(s),U,Bl

P and RS(s),U,Bl
Table V . (cont'd)

System Stainless

Steel Specimen Type

and Treatment

(b)

Test

Site

(c)

Results of Visual Examination

of Specimens

(d)

Years Exposed

Exposed in 1970 (cont'd)

64 Type 410 Sheet, annealed A P and IP(E,F) T,P,A(E)

B IP H

C H,P,IP H,P,Et(sev),A,IP

D H,P,T,IP H,T,P,A(E),Et(sev),IP

E H(E),T H,T,P,IP

G Et(sev),H,P,IP H,A and Et(sev),P,IP

65 Type 430 Sheet, annealed A

B Et(sli),IP

N

IP

N

C H(E) H,P,T,Et

D IF T(F)

E H,T,IP H,T,P,IP

G H,Et(sev),P,IP H,P,A and Et(sev),IP

66 Type 434 Sheet, annealed A N IP

RD IP N c H(E) H,P,T,IP

D N P(F).IP(E)

E H,P,IP H,T,P,IP

G H(E),P,IP H,P,A and Et(sev),IP

Exposed in 1971

1 26Cr-lMo Sheet, annealed A P(sli)IP N

B N RS

C P(AE),T,IP(E) IP.RS

D IP Et(sli)

E P(E,AE),IP N G P(E,F),Et,IP N

18Cr(Ti) Sheet, annealed A P(sli),IP N B N Et(sli),RS

C H,P,Et,IP Et,P(E.F),IP,RS

D P(AE),T,IP N

- E H,P,T H,P(E.AE,F),T

G H.P.A and Et(sev),IP H,P(E,AE,F),Et,IP

4 20Cr-24Ni- Sheet, annealed A IP N 6.5MO B N Et(sli),RS

C IP(E) N

D N Et(sli),RS

E N N G N N

5 20Cr-24Ni- Sheet, sensitized A IP N 6.5MO B N N

C IP Et(sli),IP,RS

D IP Et(sli)

E A(E) Et(sli)

G P(E),Et(sli),IP Et(sli)

6 18Cr-2Mo Sheet, annealed A P(sli) ,IP N B IP N C T,P(E,F) ,IP RS

D P(F) Et(sli)

E H,P,IP H,P(AE,E,F),RS

G H,T,A,P,IP H,P(AE,E,F)Et

8 18Cr-rfUi(N) Sheet, annealed A IP N

B N RS

C IP P,IP,RS

D N Et(sli

)

E P(E) P(E)

G P(E,F),IP H,P,T(E,AE),Et,IP

10

' 26Cr-6.5Ni Sheet, annealed A P(sli) ,IP P(sli AE)

B N RS

C H,T,P,IP H,T(E),P,IP

D N IP

E HP IP H,P,T(AE,E,F)IP

G h'.pIa and Et(sev) ,IP H,P,T(E,AE),IP
Table V . (cont'd)

System Stainless

Steel Specimen Type

and Treatment

(b)

Test

Site

(c)

Results of Visual Examination

of Specimens

(d)

1

Years Exposed

2

Exposed in 1971 (cont'd)

14 Composite A Sheet, hot rolled

and pickled

A

B

CD

EG

Et(sev),P

Et(sev),P,IP

Et(sev) ,P Et(sev),P

Et[F,E(sev)]

Et(sev),Bl ,P(AE)

P,Et[(sev)F,AE]

P,Et[(sev)F,AEj,A(E)

P,Et(F,AE),A(E)

P,Et(F,AE)

P,Et(F,AE)

P,Et(F,AE),A(E)

15 Composite B Sheet, hot-dip zinc coated (4.5 oz/sq ftZn )

A

BCD

EG

N

N

N

NA[F(sli)]

P(F),F1(AE,E)

N,c

NN

N

NP[sli(F)]

16 Composite C Sheet, hot-rolled

and pickled

A

BC

D

EG

Et(sev),P(F,AE)

Et(sev),P

Et(sev),P

Et(sev),P

Et(sev) ,P Et{sev),P

P,Et(F,AE)

P,Et(F,AE),A(E)

P,Et(F,AE)

P,Et(F,AE)

P,Et(F,AE)

P,Et(F,AE),A(E)

Exposed in 1972

7 18Cr-2Mo(Nb) Sheet, annealed A

B

CD

EG

NN

N

NP,IP

N

(a)

(b)

(c)

(d)

Results given for each system exposed at each of the six soil test sites are a summary tabulation for four indi- vioual specimens.

Specimen dimensions and treatment for each system are given in Table II.

Properties of the soils for each of the test sites are given in Table I.

Abbreviations used:

A - metal attack IF - irri descent film AE - adjacent to edge IP - incipient pitting

81 - blisters mod - moderate

BS - black stain N - no apparent attack

c - coating chipped P - pitting

DS - dark stain RS - rust stain

E - edge s - scored area

Et - etched sev - severe

F - face sli - slight

Fl - coating flaked T - tunneling

H - perforation U - undercutting
Table VI. Summary of results'^' obtained from visual examination of welded stainless steel slieet and tube specimens buried in the soils at six NBS soil corrosion test sites. Specimens of System fto.'s 11 and 12 were buried for approximately one year while all of the other

specimens were buried approximately two years.

System Stainless Material Test

Exposed 1 Year Exposed 2 Years ""^

TrP^Jmcnt ^(r'l "ody Cap End Weld Adjacent Body Cap End Weld ^Jf""* Treatment (c) y^,^ or to Weld

^ ' Face Edge Face Edge

Exposed in 1970

54 Type 301

Type 304

Type 409

Type 409

Exposed in 1971

3 18Cr-0.5Ni(Ti)

l£iCr-liili(i>l)

18Cr(Ti)

2CCr-24Ni-5.5Mo

Exposed in 1972

11 18Cr-2Mo{Nb)

18r.r-2Mo(.<b)

Sheet with A N N/A N N N cross-bead B N N/A N N N weld C N N/A P N P

D IP N/A N U N

E H N/A N N N G P N/A P P P

Tube with A Et(sli

)

N N N N heliarc welded B Et(sli) N N N N seam (2-in 00) C Et(5li) N N N N 0 Et(sli) N N N N

E Et(mod to sev) N N N N

G Et(mod),P,IP N N N N

Tube with A P,IP P&IP(UC) N P,1P N heliarc welded 6 N N N N N seam (1-1/8 in C H N N N N OD) D N N N N N

E H,P N N N H

G H,Et&A(sev),P,IP N N N N

Tube with A Et,P IP(AC) N IP N high-frequency B N N N N N welded seam C P N N N N (7/8-in 00) 0 N N N H H,P

E H.P.IP N N N N G H,A(sev) ,P,lP,Et P(AC) N N N

Sheet with A IP.Et N/A N N N cross-bead B N N/A N N N weld C P,T,IP N/A P.T P P D P N/A N P P

E H,P,IP N/A H,P P P G H.P.IP N/A H,P P P

Sheet with A IP N/A N Et IP cross-bead B RS N/A N Et M wel d C A,P N/A N Et.P IP D N N/A N Et IP

E P,T,Et N/A N P H,P

G P.Et.IP N/A P P,Et IP

Tube with A N N N N N heliarc welded B N N N N N seam (2-in 00) C N N N N N

D N N N N N

E N P(UC) N N N G _P RS(AC) N N N

Tube with A N N N N N

-•eliarc welded B N N N seam(l-l/8 in C P.IP.Et H5P(AC) N P P OD) D N N N N N

E P,IP H(AC) N N N G H,P,Et,IP N N H,P H,P

Tube with A N N N M N

hel iarc wel ded B N N N N N seam (7/8-inOO) C RS N N N N 0 RS \i N N N E N N N N N G N N N N N

Sheet with A N N/A N N N cross-bead B N N/A N N N wel d C Et(=li) N/A N P,Et{sli),IP Et(sli).

D N N/A N N N

E P W/A N P P G N N/A N N N

Tube with A N N N N N heliarc welded B N N N N N seam (2-1n OD) C N N N N N

0 N N N N N E H PCuc) N N N G N N

' N N N

IP

IP

pN H,T,P,IP P,Et(sev),IP

Et Et(sli)

P Et(sll) Et(sev),P,IP

P,Et(sli),IP

Et(sli).IP

P,IP H,P,Et,IP P,ET(sl1),lP H,P,Et(sli),IP

H,P,A(sev),Et,IP

IP P,IP H,P,Et,IP H,P,Et(sli),IP

H,T,P,IP H,P,A(sev),Et,IP

N/A P(AE) N P N/A N RS RS N/A P P P N/A N N P N/A P N P N/A P P,A(se») P,A(sev)

N N N N Et(UC) N N N P(UC,AC),A(UC) N P P

N N N N P(AC,UC) N N N P{AC,IJC) N P N

N N N IP

N N N N H&P(AC,UC) N P N

N N N N HSP(AC,UC) N P N H&P(AC,UC) N H,P H,P

N P N IP

N N IP IP H(AC) N H,P P N N H,P H,P H6P(AC.UC) N H,P H,P H8P(AC) N H,P H,P

P N/A N N N N N/A N N N Et(sli),IP

N N/A P P N N/A N N N H,P,Et,IP N/A P(AE,E) P N P,Et,T M/A P(AE,E) K N

N N/A N N N RS N/A N RS N Et-IP N/A Et(AE) P P,Et(sev)

Et(sli) N/A N N N Et(sli) N/A N P P

P N/A P(AE,E) Et.P Et,P

N N N N N

N N N N N

N P(AC,UC),RS(UC) N N N N N N H N

N PSEt(UC) •A N N

P P(UC) N N N

N N N N ;i N N N H N

P H8P{AC) N P P N N N N N

N P(UC) N N N H,P,Et H,PSEt(AC) N N N

N N N N N

RS l< N N N RS N H N N

N N N N N

N N N N N

N RS(AC) N N N

(a) Results given for each system exposed at the six soil test sites are a summary tabulation for four individual

spec i mens

.

(b) Specimen dimensions and treatment for each system are given in Table II.

(c) Properties of the soils and treatment for each system are given in Table I. (d) Abbreviations used:

N - no apparent attack

N/A - not appl icable

P - pitting

RS - rust stain

sev - severe

sli - slight

IP - incipient pitting T - tunneling

mod - moderate UC - under cap

AE

metal attack adjacent to cap adjacent to edge edge etched perforation

incipient pitting moderate
S = §SSSa = ££^Sg=' si's '5 0 = ^ = 5=^1='

odoodododdddod od__-^d,-;d--:^ , d dddddd . , d , dddddddd~9;---oj^ d ^

. . . r c jrc I-S l"^ II

SS~SSS3S3SS8g£S= 5oSaS22S2::22SSSS 5 5S5S SSSSSSSSSSS^,--.-,/,^ S SS dddddddddddddddddddddddddddddddd d , dddd . ddodddddddddddddd d . . .dd

.|,,e:^^.^i=:,S|.^,,:;,,|,^||ig,^,.

S 5 S5

. = , , I

,

SSSSSSSSSSSSSS 5 SSSS = S2S2S~2S2 S SSoSS 5 55 S3SSo~^^^-. 6S6ocicSS^66S6a6 .d . . oo^o6o<£o6ooSaa d .ddddd .d ,do . ,dddd_:-^_:_:. 5 S

i 2l,

5 S

5 oSo SSo

,o .=oo .ooo

i S 5

P ... If II

K ?!

r iii feiii-i

Jl-ii

Jsifli

I L I

!i ii i ii HI

i!il.„ Jill

aiiJii

IS

g s 2 ^ S S S S S S § § § I I I S S i I I

2 5 ; I _ I 1 I

S : — g _^ ! |i|

i II III I II II s 11 II ^ i III Ji u I j

11 i y . II

mm

2 S £ S S 2 2

Figure 1. Relative Corrosion Effects of the Soils at the Six

NBS Test Sites on Ferrous r.etals.
Figure 2a. order of burial of specimens at test sites (1970)

First Removal Second Removal Third Removal Fourth Removal Fifth Removal

(1 Yr) (2 Yr) (4 Yr) (8 Yr) (X Yr)

DUxUl JUXU J 50x05 50x0 7 50x09 50x11 50x13 50x15 50x17 50x19

51 51 51 51 51 51 51 51 51 51

52 52 32 52 52 52 52 52 52 52

53 53 53 53 53 53 53 53 53 53

54 54 54 54 54 54 54 54 54 54

55 55 55 55 55 55 55 55 55 55

56 56 56 56 56 56 56 56 56 56

57 57 57 57 57 57 57 57 57 57

58 58 58 58 58 58 58 58 58 58

59 59 59 59 59 59 59 59 59 59

60 60 60 60 60 60 60 60 60 60

61 61 61 61 61 61 61 61 61 61

62 62 62 62 62 62 62 62 62 62 63 63 63 63 63 63 53 63 63 63

64 54 64 64 54 64 64 64 64 64

65 65 65 65 55 65 65 65 65 65 66x01 66x03 66x05 66x07 65x09 56x11 65x13 65x15 66x17 66x19

50x02 50x04 50x06 50x08 50x10 50x12 50x14 50x16 50x18 50x20

51 51 51 51 51 51 51 51 51 51

52 52 52 52 52 52 52 52 52 52

53 53 53 53 53 53 53 53 53 53

54 54 r 54 54 54 54 54 54 54 54

55 55 '

• 55 55 55 55 55 55 55 55

56 56 56 56 55 56 56 56 56 56

57 57 57 57 57 57 57 57 57 57 58 58 58 58 58 58 58 58 58 58

59 59 59 59 59 59 59 59 59 59

60 60 60 60 60 60 60 60 60 60

61 61 61 61 61 61 61 61 61 61

62 62 62 62 52 62 62 62 62 62 63 63 63 63 53 63 63 53 63 63

64 64 64 64 54 64 64 54 64 64

65 65 " "" '• 65 65 55 65 65 65 65 65 66x02 66x04 66x06 66x08 66x10 66x12 66x14 66x16 66x18 66x20

57x02 67x04 67x06 67x08

68 68 68 68

69 69 69 69

70 70 70 70

71 71 71 ' 71

72 72 - 72 72 73 73 73 , 73

74 74 74 74

75 75 75 75

75 75 76 76

77 77 77 77 78 78 78 78

79 79 79 79 80 80 80 80

81 81 81 81

82 82 82 82 83 83 83 83

84 84 84 84

85 85 , -,85,; .. ... 85

85 86 86 86

87 87 87 87 88 88 88 88

89 89 89 89 90 90 90 90 91 91 91 91 92x02 92x04 92x06 92x08 m

72x10

68x12

6971

73

74

75

7678

7981x12

-67x12

70x12

t

r

72x12

77x12 80x12

82x12

83x12

84x12. 85x12

86x12

II

tl 87x12 88x12—1

89x12

90x12

fl 91x12 92x12-

67x14 67x16

68 68

69 69

70 70

71 71

72 72

73 73

74 74

75 75

76 76

77 77 78 78

79 79 80 80

81 81 91 91 92x14 92x16

92x18

58x20

59

71

73

74

75

7678

7981x20

-57x20 70x20

t

t 72x20 77x20- <—80x20

I 91x20

ti 92x20

4"x4" Post

Wire terminal to Dost for electrical measurements

Wire terminals (galvanic couple) to post for electrical measurements.
Figure 2b. ORDER OF BURIAL OF SPECIMENS AT TEST SITES (1971)

First Removal Second Removal Third Removal Fourth Removal Fifth Removal

(1 yr) (2 yr) (4 yr) (8 yr) (X yr)

1x01 1x03 1x05 1x07 1x09 1x11 1x13 1x15 1x17 1x19

2x 2x 2x 2x 2x 2x 2x 2x 2x 2x

3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 4x 4x 4x 4x 4x 4x 4x 4x 4x 4x

bx 5x 5x 5x 5x 5x 5x 5x 5x 5x 6x 5x 6x 6x 6x 6x 6x 6x 6x 6x

8x 8x 8x 8x 8x 8x 8x 8x 8x 8x

9x 9x 9x 9x 9x 9x 9x 9x 9x 9x lOx lOx lOx lOx lOx lOx lOx lOx lOx lOx 14x 14x 14x 14x 14x 14x 14x 14x 14x 14x

15x 15x 15x 15x ISx 15x 15x 15x 15x 15x 16x 16x 16x 16x 16x 16x 16x 16x 16x 16x

17x 17x 17x 17x 17x 17x 17x 17x 17x 17x

18x 18x 18x 18x 18x 18x 18x 18x IBx 18x

19x01 19x03 19x05 19x07 19x09 19x11 19x13 19x15 19x17 19x19

1x02 1x04 1x06 1x08 1x10 1x12 1x14 1x16 IxlB 1x20

2x 2x 2x 2x 2x 2x 2x 2x 2x 2x

3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 4x 4x 4x 4x 4x 4x 4x 4x 4x 4x

5x 5x 5x 5x 5x 5x 5x 5x 5x 5x 6x 6x 6x 6x 6x 6x 6x 5x 6x 6x

8x 8x 8x 8x 8x Bx 8x 8x 8x Bx

9x 9x 9x 9x 9x 9x 9x 9x 9x 9x lOx lOx lOx lOx lOx lOx lOx lOx lOx lOx 14x 14x 14x 14x 14x 14x 14x 14x 14x 14x

15x 15x 15x 15x 15x 15x 15x 15x 15x 15x

16x 16x 16x 16x 16x 16x 16x 15x 16x 16x

17x 17x 17x 17x 17x 17x 17x 17x 17x 17x

IBx 18x 18x 18x 18x 18x 18x 18x 18x IBx 19x02 19x04 19x06 19x08 19x10 19x12 19x14 19x16 19x18 19x20

20x02 20x04 20x06 20x08

21x 21x 21x 21x 22x 22x 22x 22x

23x 23x 23x 23x 24x 24x 24x 24x

25x 25x 25x 25x

26x 26x 26x 26x

27x 27x 27x 27x

28x 28x 28x 28x

30x 30x 30x 30x 33x 33x 33x 33x 34x 34x 24x 34x 35x 35x 35x 35x 36x 36x 36 x 36x 37x 37x 37x 37x

38x 3Bx 38 X 38x 42x 42x 42x 42x

20x10 20x12 22x 22x

24x 24x

25x 25x 27x 27x

21 x r2lx

23x10 23x12

I

t 26x10

28x —

I

t 26x12

28x —

|-30x r30x

33x10 33x12

+1 Urn*-

It

II

34x10

II 34x12

35x — 35x —

p36x r-36x 37x 37x

tl 1 ^^ If It 38x10 38x12

42x — 42x —

20x14

21x

22x

23x

24x

25x

26x

27x 28x

30x 42x

43x 44x

45x14

20x16

21x

22x

23x

24x 25x

26x 27x

28x

30x 42x

43x 44x 45x16

20x18 20x20

22x 22x

24x 24x 25x 25x

27x 27x r2lx r21x

23xlB 23x20

\ 1

26xlB 25x20

28x —i 28x —J

30x r30x

42x18 42x20

4"x4" post

»- Wire terminal to post for elect, cal measurements B Wire terminals (galvanic couple) to post for electrical measurements.
Figure 2c. Order of Burial of Specimens at Test Sites (1972).

First Removal Second Removal Third Removal Fourth Removal Fifth Removal

(1 Yr) (2 Yr) (4 Yr) (8 Yr) (X Yr)

7x01 7x03 7x05 7x07 7x09 7x11 7x13 7x15 7x17 7x19

11 11 11 11 11 n 11 11 11 11 12 12 12 12 12 12 12 12 12 12

7x02 7x04 7x06 7x08 7x10 7x12 7x14 7x16 7x18 7x20

11 11 11 11 11 11 11 11 11 11 12 12 12 12 12 12 12 12 12 12

- 4"x4" post
U.J c. - : BIBLIOGRAPHIC Data

SHf'.T

I 'M.H A 1 I'K HI- I'OK 1 NBSIR 74-483

2. I. lOV '[ Aci c- S S I HI) No.

3. Ki ripicnt's Ac (. L- s uin .\ ).

4. 1 i 11. 1 i< I n 1.; The Corrosion and Stress Corrosion Befiavior of Selected

Stainless Steels in Soil Environments. Part I. General

Corrosion Benavior.

5. Pub! ic.u ion O.it I May, 1974

6. I'of torminp Ur>;a(i i zai ion Code

7. AL' riiou.^i W. F. G 3rhold, W. P. Iverson, E. E scalant e.

9. Hl.l^l^.'K.^;..^^.. i.M;o.v\i/A i iiA N.wti-. .\NH AiiPi^i:.-.-^ NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

8. HirU^rmine Ur^.m. Krpi>r[ No. erSHfl^^^

i'roicct r.i>k V...rk i a;i \o.

3120362

11. Co ntract Orant No.

12. >p^'n-oro'.- i."*-^- .in I,- .It u n .N.in-.i- .inj l^on-rii-tt- AJ.in-.ss fSfreef. City, St^ite, ZIP)

Coir.ni ttee of Stainless Steel Producers

American Iron and Steel Institute

150 East 42nd Street

i^ew Yor k, .New York 10017

13. lypc ot Rcp.ut X Hcrio- Covered Two-Year

Progress Report

14. Sponsoring Agency Code

15. >Li'HLi;.\li;N l AK-i" NOl h

16. A!*>1R.A< 1 'A J''()-uorJ or /e.s.s tactual surrmary oi mo.-.t si^tdc^nt in (ormo tion. II document includes a signiticont

bibliodrjphy or litc-rJture :iurvey, mention it here.) Corrosion data is presented for selected stainless steels exposed for up to tv/o years

in various soil environr^.ents . Test materials included coated and uncoated sheet

specimens in the annealed and sensitized condition and uncoated welded tubing

specimens. Systems studied were standard austinitic (200 and 300 series) alloys,

ferritic and martensitic (400 series alloys, proprietary alloys (Cr and Cr-Ni)

and composite (sandwich materials with outer layers of carbon steel metal 1 urgi ca I ly

bonded to a stainless steel core (Type 304 or Type 430).

17. KKV ftOKO'^ f,si\ to f.ie/vf entries, alphabetical order; capitalize only the tirst letter o( the first key viord unless a proper

n<ime; separated by semic olons ) Stainless steels; corrosion behavior; soil environments; field tests; coati ngs.

18. .AVAILAIULITY 1 I'niimited 19. SHCURITV CLASS

(THIS REPORT)

21. NO. OF P.ICES

'Of Oiticial Distribution. Do Not Release to NTIS

UNCL .VSSIFIED 32

( Order From

* a shin^ton

Slip, of Doc.. U.S. Government Hrinrinf; Office

U.c;. 20 i02. .-^D <".if. N.>. <1 i 20. SI'CL'KITY CLASS

(THIS P.\GE)

22, Price

! Order 1 ron

.^pr m>;t ulJ

N'.iMonal TcchniC.il Intormation ."^crvicc (NTIS)

'viri;:nia2JI''l UNCLASSiriLD

uscoMM.oc ;.;4i-f74