/ til- A.z*

EA-6010-27

Dist. Category UC-90C

MATERIALS RESEARCH FOR THE CLEAN UTILIZATION OF COAL

Quarterly Progress Report

January - March 1981

S. J. Schneider

Project Manager

Center for Materials Science

National Bureau of Standards

U. S. Department of Commerce

Washington, D. C. 20234

PREPARED FOR THE UNITED STATES DEPARTMENT OF ENERGY

. Office of Advanced Research and Technology

Under Contract No. EA-77-A-01-6010

"This report was prepared as an account of work sponsored by the United

States Government. Neither the United States nor the United States

Department of Energy, nor any of their employees, nor any of their

contractors, subcontractors, or their employees, makes any warranty,

expressed or implied, or assumes any legal liability or responsibility

for the accuracy, completeness, or usefulness of any information,

apparatus, product or process disclosed, or represents that its use would not infringe privately owned rights."

TABLE OF CONTENTS

PAGE

I. SUMMARY OF PROGRESS TO DATE 1

II. DETAILED DESCRIPTION OF TECHNICAL PROGRESS 2

1. Materials Performance and Properties 2

2. Creep and Related Properties of Refractories 15

i

I. SUMMARY OF PROGRESS TO DATE

Brief Summary

1. Materials Performance and Properties

Data Center personnel have received training in the use of the new Data

Base Management System (DBMS). The Failure Information Data Base has been

transferred to the new DBMS and is now operative on it. The normal activities

of the Data Center have proceeded, especially with regard to production of the

book of data for materials for coal gasification.

2. Creep and Related Properties of Refractories

This report describes the twelve station creep facility and presents

data obtained on fused-cast-alumina and hot-pressed silicon carbide.

1
II. DETAILED DESCRIPTION OF TECHNICAL PROGRESS 1.

Materials Performance and Properties (H. M. Ondik, B. W. Christ,

A. Perloff, W. A. Willard)

Progress : Since the last quarterly report for this project the Data Center

personnel have received training in the use of the vendor's computer.

This training included:

1. Classes providing instruction in the capabilities of the vendor's

installation and the services offered (including a tour of the

facilities), the sign-on procedures to gain access to the computer,

and the control language for use of the vendor's time-sharing system.

2. Classes teaching the user how to access and query the specific Data

Base Management System (DBMS) to be utilized by NBS. This training

included hands-on practice in on-line querying of a sample data

base using computer terminals in the classroom.

3. Several consultation sessions with the systems analysts assigned

to NBS in the design and establishment of the data base.

The Failure Information Data Base (to be designated in the future as the

Materials and Components Plant Performance Data Base) has been completely

transferred to the new DBMS. The vendor company did the programming needed

to take the magnetic tape copy of the data base as it was structured in

the old DBMS on another computer and read it into their computer, transforming the structure to fit the new DBMS. Pre-programmed statements, known

as macros, for querying this data file were also prepared by the systems

analysts. In spite of the large effort expended by the vendor. Data

Center personnel, upon review of the entire new data base and the macro

queries had to spend an appreciable amount of time and effort in correcting

a fair number of data errors and in changing the macro queries to fit

the desired NBS pattern. The Failure File containing Plant Performance

information is now fully operative on the new system.

During the last six months (since the last quarterly report) the Data

Center has received eleven reports of failures and failure analyses. These

reports have been abstracted and entered into the current Data Base. The

Center also received twenty-two requests for information and in response

to these requests has provided a total of 3436 computer abstracts of failure events and analyses, sixty statistical tables, and fourteen hard copy

reports. Summary statistics for the current file of failure events in

pilot plants included in the Data Base are given in Tables 1 through 4.

The Materials Properties Data Base has gone through various design changes

during the lengthy procurement period preceding the awarding of the computer

services contract. These changes have been with regard to structure and

definition within the computer, however, and not with respect to either the

number or identify of the data items or the relationships between them. The

currently planned design takes advantage of certain characteristics of the

DBMS which reduce the need for storage of repetitive data but do not affect

the ease of searching for data. Although the data will appear to the user to

2
be contained in one data base there will, in reality, be several data bases, one for references, one for materials, and one for properties. The DBMS

is known as a "user friendly" system and permits queries structured so that

multiple data bases are searched as if they were actually one data base. At

this time a fourth data base is under consideration, one for test conditions.

The current arrangement of the data includes the test conditions in the properties data base but the use of the fourth base would reduce the amount of

keyboarding of data required and also reduce the amount of computer storage

needed. Tests of the data base structure are being conducted and a small

amount of information has been entered for test purposes.

Work on the book "Construction Materials for Coal Gasification--Performance

and Properties Data" has progressed well. Over 400 pages are complete to

date of the 600 pages projected for the first issue of the looseleaf format

book. A full outline of the book was given in an earlier quarterly report

of this series and, although there have been a few revisions to the outline,

the major divisions of the book are the same. These divisions are:

Section A. Materials Considerations and Performance Data

Section B. Materials Tests Results

Section C. Properties of Candidate Materials

Section D. Properties of Experimental Materials

Section E. References

Section F. Index

The first issue of the book will contain information in Sections A, B, E,

and F. The materials in Section A is subdivided by component area: Coal

Handling and Preparation Equipment which will include sections on conveying

equipment, grinding and crushing equipment, drying equipment, fines control

equipment such as cyclones, wet scrubbers, and bag houses, heating equipment; Vessels (including reactors, devolatilizers, lockhoppers, etc.)

which will include sections on pressure-containing shells, refractory linings

and components for both dry-bottom and slagging vessels, and metal internal

components; Gas Clean Up Equipment including solids separation equipment

(scrubbers and cyclones), cooling-down systems (quench systems and heat

exchangers), and gas removal systems; Water-Gas Shift Equipment;

Methanation Equipment; Compressors; Piping for gas, solids transfer, slurry,

and liquids; Pumps for gas, liquids, and slurry; Valves for gas, liquids,

slurry and solids.

The information in each component area section will be organized in the

following way:

Operating Requirements (a brief discussion of the major problem(s)

of that component area)

Performance Data

Plant Experience (summary tables and brief discussion of the

pertinent data in the NBS/DOE Failure Data Base)

3
Component Test and Development (data obtained by testing

prototypes or real components

on test stands, or in constructing

and testing portions of or models

of components--such data are not

available for all component areas)

Materials Evaluation (summaries of pertinent data

tables contained in Section B of

the book with evaluations)

Candidate Materials (discussion of possible materials for

use in the component area based on the information included in the entire

Performance Data section)

Section B is divided into four main headings:

1. Corrosion Effects, Chemical Reactions, and Phase Changes

2. Erosion, Erosion/Corrosion, and Abrasion Effects

3. Mechanical Properties Testing

4. Physical Properties Testing

Each of these categories is divided into sections for alloys, refractories, and,

where such data exist, one for coatings. The main source of the information

in this section is the collection of DOE materials research contractor's reports.

These tables and graphs summarize the data in as condensed a form as possible.

The tests include laboratory experiments as well as the results of exposure

of small test specimens in pilot plants. These data are organized in this

separate section rather than in Section A to avoid the duplication resulting

from the applicability of the same information to more than one component area

of a gasification plant. Sections C and D will contain handbook-type data for

those materials mentioned in Section A as showing some promise for possible

use. Examples of pages from the book are attached in the appendix.

Pljuis: The first issue of the book on materials for coal gasification will be

completed. Keyboarding of data for the Materials Properties Data Base will

proceed. The regular activities of the Data Center will be maintained.

4
TABLE 1

FAILURES IN COAL CONVERSION INDUSTRY

PROCESS NO. OF INCIDENTS PERCENT

BIGAS 18 4.00

BMI 35 7.78

CARBONATE 5 1.11

CLEAN COKE 27 6.00

C0 2 52 11.56

CPC 1 0.22

CRESAP 20 4.44

EXXON 3 0.67

GFETC 3 0.67

H-COAL 1 0.22

HYGAS 48 10.67

LETC 3 0.67

LIGNITE 18 4.00

METC 14 3.11

MISC. 15 3.33

PETC 2 0.44

SRC 22 4.89

SRC-W 17 3.78

SYNTHANE 114 25.33

SYNTHOIL 2 0.44

WESTINGHOUSE 30 6.67

TOTAL NUMBER OF INCIDENTS = 450

5
TABLE 2

FAILURE MODE ANALYSIS

PROCESS FAILURE MODE

CORROSION EROSION/

WEAR

MANUFACT

DEFECT ( 1

)

PROCESS

CONTROLS)

see STRESS/

TEMP ( 3

)

BIGAS 0 3 2 9 4 0

BMI 3 4 6 12 0 2

CARBONATE 1 1 1 0 2 0

CLEAN COKE 3 7 6 4 0 5

C02 20 8 4 7 8 2

CPC 0 0 0 0 0 1 CRESAP 3 9 5 2 1 0

EXXON 2 1 0 0 0 0

GFETC 1 0 1 0 1 0

H-COAL 0 0 0 0 1 0

HYGAS 13 10 3 6 9 5

LETC 0 2 0 1 0 0

LIGNITE 6 1 0 2 6 1 METC 3 6 2 1 0 2

MISC. 7 0 0 1 1 5

PETC 1 0 0 1 0 0

SRC 6 4 2 4 4 1 SRC-W 2 7 4 0 3 1 SYNTHANE 24 33 11 18 7 8

SYNTHOIL 0 1 0 1 0 0

WESTINGHOUSE 5 6 4 3 9 3

100 103 51 72 56 36

(1) INCLUDES FAILURES BY DESIGN, FABRICATION, AND QUALITY CONTROL

(2) INCLUDES FAILURES BY OVERHEATING AND OVERSTRESSING

(3) INCLUDES FAILURES BY CREEP, FATIGUE, AND THERMAL STRESS

l

6
TABLE 3

COMPONENT FAILURES IN COAL CONVERSION INDUSTRY

PROCESS COMPONENT

AUX

EQUIP ( 1

)

COAL

HAND (2)

PIPING PUMPS VALVES VESSELS

(3)

BIGAS 8 0 7 1 1 1 BMI 14 8 4 4 5 0

CARBONATE 1 0 1 0 2 1 CLEAN COKE 5 0 10 6 3 3

C02 2 1 42 0 2 5

CPC 0 0 0 0 0 1 CRESAP 5 0 4 8 1 2

EXXON 0 0 3 0 0 0

GFETC 0 0 1 0 1 1 H-COAL 0 0 1 0 0 0

HYGAS 7 0 33 5 2 1 LETC 0 0 2 0 1 0

LIGNITE 1 1 10 4 1 1 METC 0 0 3 0 9 2

MISC. 2 0 10 0 0 3

PETC 0 0 2 0 0 0

SRC 2 0 4 4 2 10

SRC-W 2 0 0 6 3 6

SYNTHANE 12 4 34 24 24 16

SYNTHOIL 0 0 0 0 2 0

WESTINGHOUSE 8 0 19 0 3 0

69 14 190 62 62 53

(1) INCLUDES COMPRESSORS, CYCLONES, THERMOCOUPLES, AND OTHERS

(2) INCLUDES BA6H0USE, FILTERS, CONVEYORS, ELEVATORS, AND OTHERS

(3) INCLUDES GASIFIERS, REGENERATORS, DISSOLVERS, SEPARATORS, AND OTHERS

7
TABLE 4

COMPONENT VS. FAILURE MODE

COMPONENT FAILURE MODE

CORROSION EROSION/

WEAR

MANUFACT

DEFECT ( 1

)

PROCESS

CONTROLS)

see STRESS

TEMP ( 3

)

AUXILIARY EQUIPMENT 5 4 7 12 0 4

COAL HANDLING 2 1 1 6 0 2

COMPRESSORS 2 3 6 5 0 1

CYCLONES 0 5 0 0 0 0

PIPING 58 32 10 22 46 12

PUMPS 4 29 9 9 0 4

THERMOCOUPLES 7 0 0 1 0 0

VALVES 8 25 11 10 2 1

VESSELS 14 4 7 7 8 12

100 103 51 72 56 36

(1) INCLUDES

(2) INCLUDES

(3) INCLUDES

FAILURES

FAILURES

FAILURES

BY DESIGN, FABRICATION, AND QUALITY CONTROL

BY OVERHEATING AND OVERSTRESSING

BY CREEP, FATIGUE, AND THERMAL STRESS

8
APPENDIX

Samples of data from the book "Construction Materials

for Coal Gasification—Performance and Properties Data"

9
COMPRESSOR IN-SERVICE PERFORMANCE 15]

Material Compressor/

Components

Plant/

Process

Service

Life Atmosphere

Temp.

•F Press. PSIG Failure Mode

Aluminum Process air compressor

K-701 A/B

(wheels and

bearings)

Battelle

,

Columbus

5000 hr Air Ambient N.A. Corrosion and/or erosion

of wheels caused an imbalance which damaged

the bearing.

Cast Iron Recycle make gas booster com- pressorBattelle, ColumbusN.A. Process gas/

cooling water

<32 N.A. Crack occurred between the water jacket and cylinder

bore possibly caused by

freezing of residual cooling water. Cast Iron Duplex recycle compressor (oil injection pump

plungers)

Clean Coke

N.A. Oil N.A. N.A. Plungers on oil pumps failed

on startup after oil injection

pumps were extensively rebuilt

Cast Iron Inert gas com- pressor (valve

disc)

Battelle

,

Columbus

3000 hr Inert gas Ambient N.A. Broken valve disc. Cause

unknown

.

304 S.S. Inconel X-750

Hydrogen com- pressor (helical coil springs from

a two-way pressure

valve)

SRC (Wilsonville)

21 hr Hydrogen/

nitrogen

77-190 N.A. Improper material substitution

(304 S.S. for Inconel X-750) led to eventual failure of

valve springs and a total plant shutdown. 416 S.S. Three stage reciprocating

(valve assembly

leaf springs)

Hygas M2 hr H /CO/CO /

h

2o 75-219 1050 Several springs fractured, others suffered pitting

corrosion. Possible causes

are moisture in the gas, preload on springs too high, stress corrosion cracking. Teflon Steel Inert gas com- pressor (piston

ring, shaft)

Synthane 6 mos Recycle CO /

h

2o

2 N.A. N.A. Teflon piston ring wear

has accelerated possibly

due in part to increased moisture in CO . Most of

shaft wear of 6.008" max. occurred in initial operation

and was due to internal rust

and contamination.

10
SOLIDS PIPING IN-SERVICX PERFORMANCE [51

Material Location Description

(Plant ID) Plant/

Process

Service

Life

C-Mo Steel Pipe welded to

a 1 in 1500 lb sock-o-let in char transfer

line, 1 P2112 E2B

1 in Schedule 80 Synthane N.A.

Incoloy 800 Elbow on fines feed line, C102B

N.A. Westinghouse100 hr

Incoloy 800 Piping in spent

acceptor lift line CD-208

4 in ID x 3/16 in wall thicknessC°2 Acceptor

630 hr

Incoloy 800 Piping in spent acceptor lift

line, CD-208

4 in ID x 3/16 in wall thicknessC°2 AcceptorN.A.

Incoloy 800 Piping in char recycle gas line, Dolomite

diverter

1 in Schedule 40 Westinghouse30 hr

Incoloy 800 Pipe below 4 in

x 1 in reducer

on line C-103B

lin pipe Westinghouse120 hr

Incoloy 800 Spool piece below C-103BN.A. Westinghouse

2 yrs

Incoloy 800 Tee on char feed

line near C-105B

4 in Tee Westinghouse200 hr

Incoloy 800

coated with

nickel aluminide

Transition cones

of slip joint

4 in ID x 3/16 in wall thickness

C0

2 Acceptor

184 hr

Incoloy 800 coated with

Stellite 12

Transition cones

of slip joint

4 in ID x 3/16 in wall thickness

C0

2 Acceptor

835 hr

Incoloy 800

coated with

75% chromium

carbide/25% nichrome

Transition cones

of slip joint

4 in ID x 3/16 in wall thickness

C°

2 Acceptor

110 hr

Tabular

A1 2°3 castable

Refractory lined

spool piece at bottom of riser

leg

5 in -thick liner within

14 in ID pipe

Battelle, Columbus

-v-200 hr

304 S.S. Tee in char

transfer line

P2112

1 in Pipe Synthane 3 mos

310 S.S. Inner liner of outlet from re- generator line

6 in pipe with 0.250 wall thick- ness

C°2 Acceptor850 hr

316 S.S. Elbow from coal feed line, above

nozzle 118

2 in/45” pipe elbow Synthane 9 mos

446 S.S. Pipe in solids N.A. Hygas N.A. transfer line of hydrogasifier

Environment

Temp.

®F Press.

,

PSIG Failure Mode

Char/steam/

coal gases

N.A. 600 A hole occurred at edge

of weld due to erosion/ corrosion

.

Coke breeze/

recycle gas 1200 240 Hole eroded in elbow.

Dolomite/recycle gas1450 150 A hole was eroded in the inner liner close to lower slip joint due to misalignment of the slip joint.

Dolomite/recycle gas 1350 150 Line exploded during

attempt to clear a plug

using forced air. Dolomite/recycle gas 1200 240 Hole eroded in "Y" bran

c

caused by impact of dolomite

Coke breeze/

recycle gas

400 220 Hole eroded in wall by

fines impingement.

Char/recycle

gas

400 220 Pinhole leak and hairlin cracks - possibly stress corrosion cracking. Coke breeze/

recycle gas

500 200 Hole eroded in tee by fines impact.

Dolomite/recycle gas 1450 150 Erosion damage to transition cones.

Dolomite/recycle gas

1450 150 Erosion damage to transition cones.

Dolomite/recycle gas1450 150 Erosion damage to transition cones.

Mulcoa (cal- Ambient

cined bauxite)/

lift gas

N.A. Spool piece refractory

erosion caused by excessive lift gas flow.

Coal char/ 400

steam/coal gas/ C0

2/N2

600 Coal char erosion of

line tee.

Dolomite/flue

gas

1830 150 Inner lining broke off

and fell into vessel. Failed by sulfur corrosion and thermal

cycling.

Coal/oxygen/

steam/coal gas

N.A. 600 Hole eroded in elbow

from coal particle

impingement

.

Process

solids/gas

1500 1500 Circumferential cracking and complete fractures

in welds and parent

metal, possibly caused

by stress corrosion

cracking

.

11
EROSION DATA FOR THE GASIFIER REFRACTORY LINING OF A GASIFICATION PILOT PLANT

c( 18 J

MATERIAL

Sample Location

Erosion3 kg/kg abrasiveDensity

kg/m*

ABRASION-RESISTANT CASTABLE

b

e Control specimen

Control specimen

Bottom-of-bed, east, cold end

hot end Bottom-of-bed, south, hot end Bottom-of-bed, north, hot end Mid-bed, east, hot end Mid-bed, north, cold end hot end

DENSE CALCINED FLINT CLAY CASTABLE^

Control specimen05 Control specimen

Mid-bed, south, cold end

hot end Mid-bed, north, cold end

hot end Mid-bed, north-east, hot end

Mid-bed, west, hot end

1.03 X 10”% 2100.8

9.36 X 10-3 2115 4.49 X io

-3 2112 5.50 X 10- 3 2081.1 6.67 X 10- 1921.1

2.42 X 10- 2079

5.88 X 10-3 1957.9

3.63 X 10-1 1967.7

4.37 X 10- 3 2051

1.07 X 10-I 2043

1.02 X i°1 2035

7.51 X io' 3 1899

6.52 X io'

3 1970.9

4.87 X 10- 3 1980.5 6.18 X io’

3 1925.5

5.98 X io'3 1934 6.71 X 10-3 1934

aErosion samples were 0.5 in x 0.5 in x 0.5 in, cut by diamond sawing and diamond

surface grinding; samples were subjected to erosion by 100 mesh Sic, at 30 psig, ambient temperature, 90° angle of impingement, 400 grams of abrasive per sample.

Lining hot face consisted of a 6-in layer of an abrasion resistant castable

(’'-37% Sic>2 , 57% AI2O3 , 6% CaO; Lo-Abrade, A. P. Green) in the lower "boot" section

of the vessel and the same material was used as vapor stops at several heights; the rest of the vessel had a hot face lining of a dense calcined flint clay castable

('•40% Si02 , 50% A1 2 03 , 10% CaO; KS-4V, A. P. Green).

cConoco Lignite Gasification Pilot Plant, CO2 Acceptor Process, was in operation

about five and one-half years; the time the system operated fully at temperature

(1500-1600°F) and pressure (150 psig) was about 3/4 year; the number of pressure

cycles to which the refractory was subjected was at least 175, the number of temperature

cycles at least 123, the number of runs 72; gaseous environment varied widely from run

to run but steam was one of the major reactants to which the refractory was subjected;

in approximately one half of the runs char was used, in the latter half lignite was used.

dCore samples were drilled with a 2-in, water-cooled diamond core drill which yielded

a core 1-3/4 inches in diameter; samples were from various locations within the portion

of the vessel occupied by the char (lignite) -dolomite fluidized bed; the compass point

designations were a convenient way to keep track of samples; core samples could not be taken from higher levels because of the extreme hardness of the material in the upper

region; hot end designates the portion of a core close to the hot face surface; cold end designates the portion of a core adjacent to the underlying insulating refractory or, in the case of cores taken from vapor stops, adjacent to the metal shell of the vessel.

eControl specimens are laboratory-prepared and fired to 900 °C for 16 hr.

12
STRESS RUPTURE TESTS OF SOME ALLOYS IN AIR AND IN COAL GASIFICATION ATMOSPHEREb[101

Minimum

Environment Temperature Stress Time (hours) to Elong. RA Creep Rate °F

ksi

0.1% El . C 0.5% E1. C

INCOLOY 800Hd -

1.0% El.° Rupture

% % %/hr

Air, 1 atm 1200 31.0 0.1 2.7 26.7 174.9 36.4 43.5 0.030

1200 31.0 0.1 2.0 21.4 184.4 34.9 41.5 0.018

1200 31.0 - - - 176.2 38.4 54.2 0.070

1200 31.0 - - - 77.0 36.9 46.9 0.082

1200 31.0 - - - 95.0 33.6 38.5 0. 165 1200 31.0 - - - 87.0 37.6 45.6 0.152

1200 27.5 0.2 4.9 51 555.9 30.8 36.3 0.018

1200 23.5 0.9 12.7 105 1659.1 24.2 30.2 0.003

CGA

b

, 68 atm 1253 35.5 - - - 6.9 18.7 46.8 1.178

1253 31.0 • - - 2.7 35.1 53.5 8.0

1253 17.5 - - - 173.5 26.

1

63.6 0. 180 1200 15.0 - - - 3780.6 33.2 45.9 - 1200 13.0 - - - 3777.5* 32.

4

e 35.7®

Argon, 68 atm 1200 31.0 - - - 143.0 25.0 42.6 0.390

Air, 1 atm 1500 9.6 0.3 2.3 5.2 155.9 39.1 43.5 0.017

1500 9.6 - - - 82.0 44.7 53.0 0.483

1500 8.2 1.7 20.7 50.9 641.4 26.0 40.6 0.021

1500 6.8 5.5 129 240 1739.8 24.9 35.9 0.005

CGA, 68 atm 1583 8.5 - - - 81.8 25.5 51.4 0.052

1583 6.5 - - - 138.0 24.0 13.1 0.090

1500 5.4 B - - 499.0 33.4 27.5 0.004

Air, l atm 1800 4.85 0.4 15.2 27.5 66.8 30.0 38.5 0.0215

1800 3.5 19.5 260 306 432.9 11.0 21.2 0.001

1800 2.75 269 633 738 1018.9 13.9 18.2 0.0007

1800 2.31 210 1293 1630 2579.0 17.4 16.9 0.0002

1800 1.9 370 5280 6820 9540.

3

£ - - 0.00006

CGA, 68 atm 1800 2.0 - 10 15 37.5 33.0 48.8 0.0938

1800 1.8 - - - 78.1 50.8 50.6 - 1800 1.5 - - 457.9 21.6 32.5 - INCOLOY 800H, Al9

Air, 1 atm 1200 28.5 0.1 0.6 1.5 101.2 53.8 54.5 0.155

1200 25.0 0.2 1.5 4.5 356.4 54.2 56.0 0.0358

1200 23.0 0.3 2.7 6.9 533.7 49.7 59.0 0.0199

CGA, 68 atni 1200 ' 29.4 - - - 63.0 43.0 44.2 0.111

1200 22.5 - 4.0 7.0 178.0 46.8 46.7 0.0794

1200 17.5 - - - 975.0 39.3 40.4 0.00529

Air, 1 atm 1500 8.6 0.1 0.6 . 1.3 102.9 73.0 71.6 0.363

1500 7.6 0.2 2.0 9.5 248.8 74.3 61.6 0.144

1500 6.4 3.1 20.6 41.2 1350.4 52.6 55.6 0.0192

CGA, 68 atm 1500 8.6 - - - 59.2 51.7 55.0 - 1500 7.6 - - - 191.4 38. 1 60.8 0.188

1500 6.5 - - - 524.0 28.7 44.6 -

Air, 1 atm 1800 3.4 7.5 38 58 180.6 13.8 22.5 0.012

1800 2.8 0.3 6.1 13.6 194.6 28. R 27.9 0.0688

1800 2.5 175 585 726 847.9 5.5 7.6 0.00039

CGA, 68 atm 1800 2.5 - 1.75 3.5 23.5 55.2 62.0 0.0741

1800 1.8 - - - 50.8 34.8 35.2 1800 0.8 - - - 94.7 66.3 58.3

(Table Continued)

13
FRACTURE

ENERGY

(joules)

FRACTURE

ENERGY

(joules)

VARIATION OF CHARPY-V IMPACT ENERGY WITH TEMPERATURE AND THICKNESS

a b 135] DEPTH FOR ASTM A543 CLASS 1 STEEL PLATE

TEMPERATURE ( ° F

)

TEMPERATURE (°C)

TEMPERATURE (°F)

TEMPERATURE (°C)

(Data Continued)

14

FRACTURE

ENERGY

(ft

lb)

FRACTURE

ENERGY

(ft

lb)
2. Creep and Related Properties of Refractories (N. J. Tighe, C. L. McDaniel,

S. M. Wiederhorn)

Progress : During this quarter the twelve station creep reep facility was put

into service and used to obtain creep data. Measurements were made on a fused-cast sodium-doped alumina and on a hot-pressed silicon carbide

refractory. The materials evaluation included creep measurements, flexural

strength and x-ray analysis of surface scales. Tests were conducted at

1400 and 1500 °C for one to six week periods.

Experimental Procedure : Creep measurements on the sodium-doped alumina

designated "Monofrax A" were made using cores obtained from Montana State

University. The cores were machined to have a 1/2 in diameter by 1 in

long reduced cross-section in a 2 in long by 3/4 in cylinder. The silicon

carbide samples were made from a hot-pressed material from Norton Co. designated

NC 203. Test bars were 4 x 5 x 50 mm and were cut from billet 4294621198.

This billet was 6x6x1 in and was cut into 390 specimens. The specimens

were numbered according to their position in the billet; the numbers were

randomized and specimens were tested in random order.

The test facility was designed and built in order to carry-out long term

tests under static loads at temperatures up to 1600 °C in air. The

completed facility is shown in figure 1. This facility has 4 furnaces and

each furnace has 3 specimen stations. The furnaces have MoSi 2 heating

elements and alumina-zirconia-silicate insulation, and are capable of

holding temperatures of 1600 °C for extended periods. The heat loss

produced when using all three stations restricts the optimum temperature

somewhat as will be discussed later.

Loads are applied to the specimens through 3/4 in diameter rams attached to

pneumatic cylinders. These details are seen in the photograph in figure 2.

The figure shows the cylinders above the furnace and load cells below the

furnace. The rams, shown in figure 3, are connected to the load cells and

to the load cylinders through water-cooled jackets. The rams, made from

sintered silicon carbide and from sintered alumina, are installed now and rams of other materials, such as fused-cast spinel, are being developed.

The ram material must be compatible with both the test specimen material and

with the temperature and load conditions.

Loads are applied manually to the specimens by varying the air pressure

to the cylinder and reading the load from the load cell. Controls for

applying the load are mounted to the frame of each furnace. Timers to

indicate elapsed time and time of failure, are also mounted on the furnace

frame. Load cells are connected to a 20 station scanner which has a digital load indicator and a printed read-out. The load cells can be

switched to a continuous recorder when such reading is required for

breaking the specimen or for determining yield information. The facility

is capable, therefore, of recording both the static load applied over

the 1000 hour periods and of recording the dynamic load applied over

short time periods.

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Furnace temperature control is achieved with the microprocessor-based

system shown in detail in figure 4. With this system, each furnace is

controlled on an independent time base and the rate of rise, soak time

and rate of cooling can be programmed to suit the individual experiment.

Temperatures can be cycled within the rise and fall capability of the

furnace. For example, a cycle of 1400 °C to 1300 °C to 1400 °C can be

achieved with a rise and fall time of 2 minutes. Various alarm control

devices can be connected to the microprocessor board to further change or monitor the furnace during the test cycle. For example, the furnaces can be shut off when the creep reaches a fixed amount or after all specimens

in a furnace have broken.

For the tests described in the following results section, the furnaces

were brought to the test temperature in one hour, and held for 1/2 hour

to allow for equilibration before applying the load. At the end of the

test period, the specimens were either broken at temperature or cooled

to room temperature under the appropriate cooling rate for the specimen

material

.

Experimental Results : The tests carried out during this quarter provided

both significant deformation data and an assessment of the usefulness of

the facility. The two specimen configurations, cylindrical compression

and 4-pt bend bars, permit compressive creep, flexural creep and stress

rupture data to be obtained.

Fused-cast Na doped Al?0g, "Monofrax A ". This material is being used in

the air-preheater experiment at Montana State University. This material

changes composition during high temperature exposure and fractures readily

under thermal shock conditions. The as-received material is two phase

aAl 2 0 3 and BA1 2 0 3 (NaaO* 1 1A1 203 ) . The Na 2 0 volatizes after heating above

1200 °C and the "(3 phase" is not detected in x-ray patterns taken after

cooling to room temperature.

Compressive yield of the alumina was obtained using a constant displacement

rate of 2 x 10~4 in/min. The cylindrical specimens were used with Si C rams and alumina pads. The results are shown below in Table 1.

Table 1. Na-doped A1 > Compressive Yield

Temperature, °C Yield, ksi Deformation %

1400 13.0 2.9

1500 4.1 1.9

1600 1.8 1.5

The static load applied to the cylindrical specimens in the creep facility

was 250 psi. After 1000 hrs at 1400 °C the average deformation for the 3

specimens was 0.13%. Cycling the temperature from 1400 °C to 1300 °C a't 1/2 hr intervals accelerated the deformation and produced the average

deformation of 0.13% in three specimens after 168 hrs with a stress of

250 psi. These results are significant and further cycling tests will be run to substantiate the data.

16
Silicon Carbide, NC203 . Silicon carbide specimens were tested in the

4-pt. flexure configuration using SiC rams and SiC holders. Test

temperatures of 1200, 1400 and 1500 °C were used. Specimens were placed

with a holding load of approximately 1 lb during the exposure period and

broken at temperature without removing them from the furnace.

The exposure times and flexure strength are presented in Table 2. Silicon

carbide oxidizes readily above 1200 °C forming an amorphous and crystalline

oxide scale identified as tridymite. It is seen in the table that specimens

exposed 1030 hrs are stronger than those exposed 168 hr. This finding is

similar to observations on some of the silicon nitride materials and will

be analyzed further to identify the strengthening mechanism. The table

shows also the decrease in strength observed at 1500 °C. These strength

measurements provide basic information required to determine appropriate

static load for long term creep experiments.

The x-ray diffraction patterns were taken from test bars before and after

the exposures at 1200 and 1400 °C.

Table 2. Silicon Carbide, NC203, Billet 4294621198

Temperature °C Exposure, hr Flexure Strength, MPa X-ray Analysis

25 524 ±111 aSiC, 6H+4H , WC

1200 168 419 ±137

1200 1030 605 ±43 aSiC, 6H+4H, WC

Si

0

2

~ tridymite SS

1400 168 413 ±23 aSiC, 6H+4H, WC

Si0 o -tridymite

1500 168 339 ±14 u

Plans : Thermal cycling data will be obtained using larger temperature

differences. Both materials will be subjected to thermal cycle tests.

Changes in microstructure will be monitored using x-ray diffraction

analysis, optical and scanning electron microscopy. The deflection

monitoring system for creep experiments will be installed at each specimen

station.

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FIGURE CAPTIONS

Figure 1. High temperature test facility showing (A) the four furnace

stations, (B) the furnace programmer-controller, and (C) the

scanner-recorder system.

Figure 2. Single furnace station showing (A) the furnace, (B) air cylinders,

(C) controls for cylinders, (D) load cells.

Figure 3. Interior of furnace showing: (A) alumina creep specimen,

(B) silicon carbide rams.

Figure 4. Facility control panels (A) scanner and recorder for load cells,

(B) process control system for the furnace showing keypad and data

input pad and furance power indicators.

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19

Figure

Figure 2

20

21

A B

Figure 4.

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