ORNL-TM-5781.txt

   
    
  

ORNL/TM-5781

L1 /1074

 

Corrosion of Several Metals in
Supercritical Steam at 538°C

H. E. McCoy
B. McNabb

 

TR R T LW

 

 

 
 

 

 

Printed in the United States of America. Available from
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U.S. Department of Commerce
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Price: Printed Copy $4,50; Microfiche $3.00

 

 

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This report was prepared as an account of work sponsored by the United States
Government. Neither the United States nor the Energy Research and Development
Administration/United States Nuclear Reguiatory Commission, nor any of their
employees, nor any of their contractors, subcontractors, or their employees, makes
any warranty, express 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.

 

 

 
 

"

ORNL/TM~5781
Distribution
Category UC-76

Contract No. W?7405—eng-26
METALS AND CERAMICS DIVISION

CORROSION OF SEVERAL METALS IN SUPERCRITICAL STEAM AT 538°C

H. E. McCoy and B. McNabb

Date Published: May 1977

 

 

NOTICE

was as an u:n:tmllt.ol“Ei -&:
nsored the United States Government.

|5 umaw States mor the United States Energy
Rescarch and Development Administration, mor any of
. { theit employees, mor any of their contiactors,
¥ subcontractors, or theit employees, makes any
warranty, express or implied, or sssumes any legal
Eability or responsibility for the accuracy, completenens
of usefulnes of any information, apparatus, product or
process disclosed, or represonts that its use would mot
. | infringe privately owned rights,

 

 

 

OAK RIDGE NATIONAL LABORATORY
Oak Ridge, Tennessee 37830
‘operated by
UNION CARBIDE CORPORATION

- for the =y | | {MASTER
ENERGY RESEARCH AND DEVELOPMENT ADMINISTRATION .

VISTRIBUTION OF THIS DOCUMENT IS UNLIMITED

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CONTENTS

ABSTRACT . « ¢« &+ ¢ ¢ « o« ¢ o o o
INTRODUCTION . . « & « o o o « &
EXPERIMENTAL DETAILS . . . . . .

Test Facility . . . . . . .

Test Materials . . . . . .
Evaluation . . . . . . . .
Errors . . « ¢« o o ¢ ¢ o &
Experimental Observations .
Low—-Alloy Ferritic Steels .
Hastelloy N . . . . . . . .
Stainless Steels . . . . .

Other Alloys . . . « « . &

Tube Burst Results — Hastelloy N

SUMMARY . . . & ¢« ¢ &+ o & & &

ACKNOWLEDGMENTS . . « « « ¢ ¢ ¢« ¢ o &

REFERENCES . . . « . + « « « « &
APPENDIX . . . . + . . . .

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LY

CORROSION OF SEVERAL METALS IN SU?ERCRITICAL STEAM AT 538°C

H. E. McCoy and B. McNabb

ABSTRACT

The corrosion of several iron- and nickel-base
alloys in supercritical steam at 24.1 MPa (3500 psi)
and 538°C has been measured to 7.92 x 107 sec (22,000 hr).
The experiments were carried out in TVA's Bull Run Steam
‘Plant. Corrosion was measured almost entirely by weight
change and visual appearance; a few samples were evaluated
by more descriptive analytical techniques. The corrosion
rates of low-alloy ferritic steels containing from 1.1 to
8.7%2 Cr and 0.5 to 1.0%Z Mo differed by less than a factor
of 2 in steam. Several modified compositions of
Hastelloy N were evaluated and found to corrode at about
equivalent rates. Of the alloys studied, the lowest
weight gain in 3.6 X 107 sec (10,000 hr) ,vas 0.01 mg/cm®
for Inconel 718 and the highest 10 mg/cm® for the low-
alloy ferritic steels.

 

INTRODUCTION

This study was motivated by the need of the Molten-Salt Reactor
Program for a material for use in steam generators. Hastelloy N has
excellent compatibility with molten fluoride salts, but it failed
prematurely in a simulated superheated steam environment. ' Thus,
our program emphasized Hastelloy N, but included a total of over
80 alloys, mostly iron and nickel base. Because of our program to
modify the chemical composition of Hastelloy N to obtain better
resistance to embrittlement by irradiation and the fission product
tellurium, several alloys with compositions slightly different from
that of standard Hastelloy N were included in the study.

The tests were conducted in TVA's Bull Run Steam Plant in
supercritical steam at 24.1 MPa (3500 psi) and 538°C., One test period
included test times up to 5.4 x 107 sec (15,000 hr) and the data were
reported previously. A second test period covered an additional
2,52 x 107 sec (7000 hr) on many of the same test coupons and extended
the total exposure time to 7.92 X 107 sec (22,000 hr).. Since the

Molten Salt Reactor Program has again been discontinued, the results

of the total steam corrosion will be presented in this report.
Although the discussion will deal only with alloys selected to
illustrate several important characteristics of steam corrosion,
compositions and weight changes of all materials under investigation
will be listed.

 
 

EXPERIMENTAL DETAILS
Test Facility . -

The facility used in this study is located in TVA's Bull Run
Steam Plant.? This is a coal-fired plant with a supercritical steam
cycle and a power generation capability of 980 MW. The facility is
located about 5.49 m (18 ft) upstream from the turbine. The steam
is extremely clean at this location containing less than 1 ppb O2,
less than 5 ppb Cu, less than 3 ppb Na, less than 15 ppb Si02, and
less than 6 ppb Fe. Hydrazine is added to the feed water to scavenge
oxygen, and the pH was controlled at 9.40 to 9.45 with ammonia. The
electrical conductivity of the steam condensate is usually less than
3 x 1077 Qeem l.

Although the stream was generally very pure, during at least one
1.44 x 107 sec (4000 hr) period the level of impurities was significantly
higher. During this period all specimens gained very close to
0.5 mg/cm . Bull Run engineers pointed out that several condenser
tube leaks had occurred in the previous year of operation, whereas
in earlier years, few if any condenser leaks occurred. Since the
cooling water in the condensers is at higher pressure than the
condensing steam, untreated cooling water is introduced into the
steam system hot well when a leak occurs. After replacement of
condenser tubes, most of the specimens lost weight for a brief period.
Perturbations in the weight change data due to this phenomenon will
be pointed out as the data are presented.

- A schematic of the test facility is shown in Fig. 1 and a photo-
graph of the disassembled test assembly is shown in Fig. 2. The steam
entered the 4-in.-diam sched 160 type 316 stainless steel test chamber
at a flow rate of 0.12 to 0.13 kg/sec (16 to 17 1b/min). The initial
sample holder was a cube 50.8 mm (2 in.) on each side and would
accommodate 140 samples. A second sample holder was later added
that would hold 72 specimens. Most of the samples were 12.7 mm wide
X 50.8 mm long X 0.89 mm thick (1/2 in. wide X 2 in. long X 0.035 in.
thick). Alumina washers 0.51 mm (0.020 in.) thick were placed between
the specimens before they were bolted in place. Most of the space
between the holder and the vesgsel was baffled to force flow across
the samples at about 6.10 m/s (20 fps). Ten stressed instrumented
specimens were located at the front of the chamber and four uninstru-
mented stressed specimens were located in the filter basket. The
specimen geometry was chosen so that. the stress was provided by the
force of the steam on the inner wall. The wall thickness of the .
reduced section was varied from 0.25 to 0.75 mm (O. 010 to 0.030 in.) "
to provide stresses of 531 to 193 MPa (77 to 28 x. 103 psi). The
front ten specimens had small capillary tubes that were heated by
the steam when the tube specimen failed. A thermocouple attached to
each capillary was recorded by a multipoint recorder and indicated
when failure occurred. The steam passed through .a metal filter to
 

 

ORNL~DWG 68-3995R2

 

| r— ol
5. STEAM SUPPLY
*— 3500 psig, 1000 °F,
1617 Ibs/min

SAMPLE VESSEL

 

 

 

 

 

 

 

 

 

 

 

 

FILTER-
- Qe MULTIPOINT
i RECORDER
~SAMPLE HOLDER
FLOW RESTRICTER REDUCED WALL
THICKNESS

 

 

 

 

 

 

-CAPILLARY
TUBE

 

 

   
   

 

 

 

CONDENSER

TUBE BURST SPECIMEN (TYP 10)

   

WATER OUT " WATER iN

 

Fig. 1. Sch-emati'c of Test Facility Double~Walled Tube-Burst
Specimen.

~

. - 4% Photo 224475

 

 

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Fig. 2. Photograph of the Steam Corrosion Chamber After 19,000 hr of
Exposure. Features to note are the stressed but uninstrumented specimens
in the filter (foreground), the two groups of unstressed specimens, and
the 10 instrumented stressed specimens. The stressed specimens have an
outside diameter of 25 mm (1 in.) and a length of 76 mm (3 in.).

 
trap scale before it entered the small diameter flow restrictor. The
restrictor reduced the steam pressure to near atmospheric pressure
before reaching the condenser. The condensate was returned to
condensate storage.

Test Materials

Chemical analyses of the test materials are given in Table 1.
The first six alloys were commercial production materials. Alloys
LC, MC, and NC were small melts of 2 1/4 Cr-1 Mo steel with variations
in carbon content, and alloy 72768 is a commercial heat of 2 1/4 Cr-
1 Mo steel. The other alloys down to "Hastelloy N modifications"
were commercial production heats. Heats 185 through 237 were 2-1b
laboratory melts. Hastelloy N heats 21541 through 73008 were small
50- to 100-1b melts that were vacuum melted and fabricated by
commercial vendors. Hastelloy N heats 2477, 5065, 5067, 5085, 5095,
5101, and M1566 were large commercial heats of standard Hastelloy N.

All alloys were rolled to 0.89 m (0.035 in.) thick sheet. The
rolling was done cold with intermediate anneals for softening; the
finish of the exposed sample surface was generally typical of cold-
rolled sheet. Samples were sheared, cleaned in acetone and alcohol,
and annealed in argon for 1 hr at 927°C (the low-alloy ferritic steels),
1 hr at 1038°C (the stainless steels), or 1 hr at 1177°C (all other
alloys). :

Evaluation

Generally only weight change measurements were made. However,
the samples were also examined visually for evidence of spalling,
oxide color, etc. More extensive evaluation was carried out on a
few specimens, including metallography to determine depth of oxide
‘penetration and electron microprobe scans of oxide-metal interfaces
to determine the compositions of the oxide and the metal beneath the
oxide. '

The stressed specimens were removed every 1000 hr for examination.
Measurements were made of the inside diameter of each tube with a
die test gage. In this way several points were obtained on the
strain-time plot for each specimen. Any failed specimens were
replaced before the assembly was returned to Bull Run. Some of the
failed tubes were subjected to metallographic examination. '
 

 

 

 

 

 

 

 

 

)

 

 

 

Table 1. Chemical Analyses of Test Materials
Concentration, wt X
Alloy
Ni ¥o Cr Fe Mn c si P s Cu ’ Co v v Al T B Nb o ir Other
Armco Iron® Bal 0.017 0.012 0.005 0.025
Low=-Alloy Ferritic
1.1 ¢r 0.25 0.49 1.1 Bal 0.42° 0.64 <0.05 <0.02 <0.05 <0.05 <0.02
1.9 cr 0.20 0.5 1.9 Bal 0.46 0.17
2.0 ¢r 0.32 0.8 2.0 Bal 0.40 0.25
4.2 Cr 0.36 0.47 4.2 Bal 0.40 0.35
8.7 ¢r 0.35 0.97 8.7 Bal 0.44 0.50
e 0.05 0.98 2.3 Bal 0.51 0.009 0.58 0.002 0.009
M <0.05 1.14 2.4 Bal 0.38  0.030 0.27 0.019 0.025
§C 0.21 0.91 2.2 Bal 0.44 0.120 0.40 0,010 0.015
72768 0.16 0.95 2.2 Bal 0.44 0.09 0.38 0,011 0.011
12-5-3 Maraging 12.7 2.80 5.1 Bal 06.05 0.10 0.3
Stainless Steels
Type 502° 0.5 5.0 Bal 0.1
17-7 PR 7.10 17.0 Bal 0.07 1.15
Type 201 5.23 16.55  Bal 7.28  0.076 - 0.54 0.3 0.006 0.059 N
Type 304% 8.0 18.0 Bal 0.03
Type 309: 13.5 23.0 Bal 0.2
Type 310 20.5 25.0 Bal 0.25 1.5
Type 316, 13,01 - 2.8 17.0 Bal. L.74 0.027 0.65 0.016 0.017 0,10  0.15
Type 321 10.5 18.0 Bal 0.08 0.4
Type 347% 11.0 18.0 Bal 0.98 . 0.4 0.4 Ta
Type 406 13.0 Bal 0.15 4.0
Type 410% 12.5 Bal 0.15
Type 446% 25.0 Bal 0.20 0.25 N
N1-280 Bal . 0.0002 0.002 0.003 <0.0001 0.3%  0.005 <0,00t 0.00Z <0.000L <0.000L 0.3  <0.0001 <0.0001 <0.0001
Monel™ 60.0 1.5 3.5 0.5 23
Copper 0.02 9949
Inconel 600 78.0 14.5 7.0 0.05
Inconel 601 60.5 23.0 1l4.1 0.5 0.05 0.25 0.007 1.35
Inconel 718 53.0 3.0 18.0 0.05 0.50 1.0 5.0
Incoloy 800 3l1. 20.1 46.2 0.84 0.04 0.38 0.008 0,50 0.24 0.36
Hastelloy B Bal 27.0  <0.2 5.2 0.96 0.3 0.01 0.48 0.2 <0,05 <0.01 <0.05
Hastelloy C Bal 16.0 16.0 5.8 0.75 0.48 0.01 1.2 0.1 5.0 0.2 <0.01 <0.05
Hastelloy S Bal 14.7  14.5 0.90 0.04 0.007 <0.01 0.22 0.2 0.01 B
Hastelloy W 60.0  25.0 5.0 5.5 0.08 1.0 0.30
Hastelloy X 8.6 22.0 19.0 0.64 0.60 0.02 2.0 0.05 0.5 0.2 <0.01 <0,05
Haynes Alloy 25  10.0 0.5  20.0 1.4 1.0 0.1 0.7 0.015 0.01 0.02 Bal <0.02 15.2 0.1 0.02 <0.05
Haynes Alloy 188 22.0 22.0 3.0 1.25 0.15 Bal 15.0
Rene 62 Bal 9.0 15.0 22.0 0.25 0.05 0.25 1.25 2.5 2.25 0.01
Hastelloy N
Modificacions: - .
185 Bal 11.0 5.9 3.8 0.46 0.05 0.10 <0.03 <0.1 <0.05 0.91 <0.1 0.98
186 Bal 10.0 5.4 3.5 0.45 0.05 0.09 <0.03 <0.1 0.8 0.88 <0.1 <0.05
188 Bal 13.0 7.3 4.5 0.49 0.05 0.15 <0.03 <0.1  0.95 <0.02 1.1 <0.05
231 Bal 12.0 7.0 4,2 0.03 0.05 0.12 <0.03 <0.05 <0.02 <0.05 1.3 <0,05 1.2 ¥
232 Bal 13.0 8.0 4.5 ~<0,02 0.05 0,12 <0,03 <0.05 <0,02 <0.05 1.2 <0.05
234 Bal 16.0 7.2 4.0 <0.02 0.05. 0.13 <0.03 <0.05 <0.02 <0.05 <0.1 <0.05
236 Bal 11.0 7.0 4.0 0.5 0,05 0,13 <0.03 1.0 <0,02 <0.05 <0.05 0.5
237 Bal 12.0 6.7 4.3 0.49 0,05 0.13 <0,03 <0.05  0.04 1.03 <0.1 <0.05
2477 Bal 16,2 7.0 4.2 0.055 0.057 0.047 0,008 0,006 ©0.01 0.05  <0.,01 0.03 0.02 0.03 0.0002 <0.0005 <0.001 <0.001
5065 Bal 16,5 7.1 4.0 0.55 0,07 0.58 0.005 0.00&4 0.007 0.05 0,20 0.1 <0.03 <0,01 90.001 <0.05 <0.1 <0.1
5067 Bal 17.2 7.4 4.0 0.48 ~ 0.06  0.43 0,005 0.007 0.01: 0.09 0.30 - 0.6 0.01 001 0.004
5085 Bal 17.0 7.0 1.6 0.64 0.06 . 0.65 0.004 0.003 0.01 0.15 0,20 0.07 0.05 <u.01 0.004 <0.05 <0.002
N1 5095 Bal 16.39 7.2 3.87 ° 0.5 0.07 0.68° 0.001 0.007 0.01 0.15 : 0.02 0.002
N2 5101 Bal 16.39 6.92 3.91 0.44 0.05 0.63 0.001 0.009 0.01 0.09 0.02 0.007
21541 Bal 11.6 7.3 0.04 0.16 0.05 0.017 0.001 0.002 0.01 <0.10 <0.10 1.98 0.03 0.005 0.0007 <0.005
21542 Bal 12.1 7.21 - 0.041 0.16 0.06 0.016 0.001 0.004 0.01 <0.10 <0.10 2.05 <0.10 <0.10 ©0.0005 0.96 <0.005
21543 Bal 12.4 7.31 0.038 0.08 0.05 0.019 <0,001 0.004 0.01 <0.10 <0.10 <0.10 <D.02 <0.003 0.0002 0.70 <0.005
21544 Bal 12.6 7.3 <0.10 0.13 0.06 <0.03 <0.01 0.003 0.01 <0.10 <0.10 <0.10 <0.10 <0.10  0.0005 0.44
21545 Bal 12.0 7.18  0.03% 0.29 0.05 0.015 0.001 <0.002 0.01 <0.10 <010 <0.10 0.02 0.4% - 0.00007 0.01
21546 Bal 12.3 7.29 0.046 0.16 0.05 0.009 0.001 <0.002 0.01 <0.10 <0.10 <0.10 '0.02 0.10  0.0002 0.005
21554 Bal 12.4 7.39  0.097 - 0.16 0.065 0.01 0,004 <0,002 , 0.03 0,003 0.0002 0.35
21555 Bal 12,4 7.18 ©0.065 ©0.16 0.052 0.008 0,003 <0.002 - 0.02  0.003 0.0007 0.05
M1566 Bal 16.0 7.5 5.0 0.5 - 0.06 0.5 . - .
68688 Bal 13.8 7.9 498  0.52 0,079 0.38 0.042 <0.002 0.023 0.08 0.013 0.0002 <0.05 <0.05 = <0.05
68689 Bal 13.7 7.6 4.8 0.47 0.081 0.53 0.01 <0.002 0.02. 0.075 0.36  0.0002 <0.0S <0.05 = <0.05
69344 Bal 13.0 1.4 4.0 0.5 0.109 0.5 0.001 "0.004 0.03 0.06 <0.01 <0.01 0.24 0,77  0.00001 - 1.7 <0.01 0.001
69345 Bal 13.0 7.5 4.0 0.52 0.078 0.5  0.001 0.01 0.02 0.07 <001 0.03 0.27 1.05 0.00006 <0.01 0.92 0.3
69641 Bal 13.9 6.9 0.30  0.35 -0.06 0.02 0.001 0.003 0.01 <0.03 0.02 <0.03 1.30 . 0.0001 <0.05 0.70 0.0t
69648 Bal 12.8 6.9 0.30 0.24  0.06 0.05 0.001 0.003 0.02 <0.03 0.10 <0.05 0,92  0.00008 1.95 0.08 0.02
69714 Bal 12.4 . 8,0 0.10 0.35 0.012 <0.05 0.001 0.006 90.05 ° 0,05 <001  0.01 0.17 0.80 . 0.00001 1.6 - <0.01  <0.01
10727 Bal 1.7 1.5 0.05 0.37 0.04 <0.05 0,004 0.001 <0.01 <0.01 <0.01 0.01 <0.03 2,1 0.00006 <0.1 <0,01  <0.01
70785 Bal 12.2 7.0 0.16 - 0.27 0.057 0.09 0,002 0.004 .0.02 0.03 0.003 0.003 0.14 1,1 0.002 0.097  <0.003 0.01
70786 Bal 12,2 7.2 0.41 - 0.48 0.044 0.08 0,002 0.00 0.02 0.05 0.008 0,003 0.13 0,82 0.0005 0.62 0.003  0.06
70787 Bal 12.5. 7.0 0.18 0.43 0.041 0.09 0.002 0.004 0.02 .0.05 0.003  0.003 0.17 0.9  0.0005 . o.jf 0.77 0.07
70788 Bal 12.5 7.2 0.43  0.43 0.027 0.10 0.002 0.004 - 0.02 <0.02 0.008 0.003 0.18 = 1.36 0.0004 O. 0.30 0.01
10795 Bal 13.0 7.8 0.04 0.63 0.054 0.03 <0.005 0.005 0.003 0.005 0.001 <0.005 0.06 1,49  0.002 0.005 0.42 0.017
70796 Bal 12.4 7.3 . 0.05 0.64 0.043 0.02 <0.005 0.005 0.003 0.005 0.002 <0.005 0,10 -0.04 . 0.0005  0.04 0.75 0.024
70797 Bal 12.5 7.0 0.29 9.38 0.055 0.02 <0.005 0.003 0.003 0.005 0.002 <0.005 0.07 - 0.59 0.0002 0.98 0.75 0.035
70798 Bal 12.8 1.5 0.26 0¢.53 0.038 0.02 0.002 0.005 0.003 0.005 0.003 <0.005 0.07 0.71 ©0.0001 0.9% 0.32 0.011
70835 Bal 12,1 1.8 0.68 - 0.58 - 0.053 0.05 0.00L 0.004 - 0.005 0.10 <0.01 <0.01 0.10 -0.71  0.002 2.6 <0.01  <0.005
71114 ‘Bal 12.% 7.14 0.062 0.02 0.05  0.026 0.002 0.005 0.007. 0,07 0.07 1.75 0.002 <0.03
71583 Bal 12.4 7.35 0.13 0.03 0.05 0.055 0.002 0.004 0.015 .10 0.2 1.44 - <0.03
72118 Bal 11.9 7.03 0.07 0.07 0.091 0.09 0.003 0.002 <0.001 0.72 0.2
72503 Bal 12,9 6.79 0.32 0.01 0.066 0.01 0.0008 0.002 0.1  .1.94 <0.001
72604 Bal  11.5 6.69 0.07 0.07 0.09 0.09 0.003 0.003 <0.001 0.30 0.02
73008 Bal 12.4 7.63 0.18  0.45 0.078 0.06 0.03 . 2.1. <0.003 i

 

gouinal co-poaitién, all others are actual analyses.

 
 

 

Errors

The specimens were weighed on a standard four-place balance with
an accuracy of *0.0001 g. The specimens had surface areas of 12 to
14 cm?, so the uncertainty in weight corresponded to almost 0.01 mg/cm?. . et
This error does not include small pieces of loose material that may
have been adhering to the specimen or small amounts of oxide that may
have been knocked off during disassembly. Efforts were made to minimize
these sources of error, but they are likely still present.

The stresses imposed on the tube burst specimens were affected by

- uncertainties in tube dimensions. The uncertainty in the wall thickness
was about *#0,0127 mm (#0.0005 in.). When the nominal wall thickness
was 0.254 mm (0.010 in.), this uncertainty introduced an error in the
stress of *5%. When the wall thickness was 0.762 mm (0.030 in.), this
uncertainty was about *27.

Experimental Observations

Weight gain results on all materials tested in steam are given in
the Appendix.

Low-Alloy Ferritic Steels

Five alloys containing from 1.1 to 8.7% Cr and 0.5 to 1.0% Mo
(Table 1) were exposed to steam for 14,000 hr at 538°C and these results
were presented previously2 and are shown in Table Al. These specimens
were lost during the one year in which the program was inactive, and
it was necessary to begin testing with a new group of specimens. These
specimens were exposed 7000 hr, and the data for the second series are
shown in Fig. 3 along with the scatterband for the first series. The
extremes of the scatterband for the first series were defined by alloys
containing 1.1% Cr (lowest weight gain) and 1.9% Cr (highest weight
grain). These same alloys are near the extremes for the second series,
and the data from the two series generally agree very well.

The behavior in air was vastly different from that noted in
steam. After only 1000-hr exposure all alloys except the one containing
8.7% Cr had begun to spall, and after 13,000-hr exposure all alloys
had lost weight.2

Two samples from the steam series were examined metallographically
and typical photomicrographs are shown in Fig. 4. The microstructures
of the specimen containing 1.1 and 8.7% Cr were quite similar. The .
oxide, which consists of two distinct layers had a total thickness of
about 50 pm. The microstructure of the metal surface was altered to a
depth of about 10 um. Microprobe scans of these specimens showed that
the oxide layer nearest the metal contained detectable quantities of
 

 

 

ORNL-DWG 76-20796

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

20 '
|11
SECOND
SERIES
| [ | 14" |FIRST |
< 10 =/ — ( series_
€ [ _
S B
E ]
w B
2 5 _oF
: =]
O
- '84 o Aw kfo 36 11
(::; —5’ ' %Cr % Mo
= - o 1.4 0.49
= 2 A 49 0.54 —
B 2.0 0.88
e 4.2 0.47
v 8.7 0.97
. LI |
10> 2 5 10° 2
: TIME (hr) -

Fig. 3. Influence of Chromium Content on the Weight Change of
Annealed Low-Alloy Ferritic Steels in Supercritical Steam at 538°C and
24.1 MPa (3500 psi). .

Fe, Cr, Mo, and Si with Fe and Cr being the predominant constituents.
Only iron was detected in the outermost oxide. The two alloys chosen
for metallographic examination had very similar weight gains and
gained the least weight of the series. Note in Table 1 that these
alloys were the highest in silicon and that silicon was detectable

in the oxide film. In light of these observations and previous work
that showed silicon to reduce the oxidation rate of steel »5 it is
quite likely that the higher silicon content of these two alloys
resulted in their superior corrosion resistance.

The weight changes observed with several heats of 2 1/4 Cr-1 Mo
steel are shown in Fig. 5. The scatterbands from the observations
of steels containing from 1.1 to 8.7% Cr are shown and the data for
the four heats of 2 1/4 Cr-1 Mo steel fall within the scatterbands.
The low carbon heat had the lowest oxidation rate, but we do not
know a basis for attributing this to its low carbon content. These
same alloys were exposed in the 50% cold-worked condition. The data
from these specimens are presented in Fig. 6. A comparison of
Figs. 5 and 6 shows that cold working did not have a detectable
effect on corrosion. (These data are also tabulated in Table A2.)

 
| Y-141199

 

 

 

100 200 Ml‘%%OXNS 600 700
0.005 0.010 INCHES 0.020 0.025

   

.20 40 60 MICRONS 120 140
500 X-
0.001 INCHES 0.005

Fig. 4. Photomicrographs of Low-Alloy Ferritic Steel Exposed to Steam at 538°C and 24,1 MPa
(3500 psi) for 7000 hr. (a) and (b) Alloy containing 1.1% Cr. (c) and (d) Alloy containing 8.7% Cr.
All specimens as polished; however, specimen shown in (c) and (d) was etched slightly by moisture
in the ambient air. "

= »

 
 

 

 

- ORNL-DWG 76-20797
20

FIRST
SERIES

o

— | SEconD
SERIES

oLC
A MC
O NC
® 72768

WEIGHT CHANGE (mg/cm?)
o

N

 

1 — .
10> 2 5 10 2
o | "TIME (hr) |
Fig. 5. Weight Changes of Several Heats of 2 1/4 Cr-1 Mo Steel in
Solution-Annealed Condition Exposed to Supercritical Steam at 538°C and
24.1 MPa (3500 psi).

ORNL-DWG 76-20798

20
FIRST

| ~ SERIES
~ 10
o SECOND
L = ( SERIES
E ~
® 5
<
<
o ot
o V .
= o LC
o A MC
= o NC

o 72768

 

2 5 40t
TIME (hr) |

Fig. 6. Weight Changes of Several Heats of 2 1/4 Cr-1 Mo Steel in
the Cold-Worked Condition Exposed to Steam at 538°C and 24.1 MPa (3500 psi).

2

 
 

iy

10

Photomicrographs of three specimens of the 2 1/4 Cr-1 Mo steel
are shown in Fig. 7. The three specimens examined were (1) standard
alloy (heat 72768), annealed and air cooled, (2) standard alloy, “
cold worked 50%, and (3) normal carbon (NC) alloy, annealed and air '
cooled. The oxides on all three specimens were very similar to each
other and to the alloys shown in Fig. 4. The oxide consisted of
two layers and had an overall thickness of about 50 yum. The specimen
underneath the oxide was affected to a depth of 10 ym or less. Electron
microprobe spectral analysis showed that the oxide on each specimen
nearest the metal contained detectable quantities of Fe, Cr, Mo, and
Si with Fe and Cr being the major constituent. The outermost oxide
layer contained only iron in detectable concentrations.

Hastelloy N

The weight changes of four heats of Hastelloy N exposed in steam
are shown in Fig. 8. The variation among the four heats is about the
same as the variation noted for duplication specimens of heat 5065,
One of the heats, 2477, was vacuum melted, and the other three were
air melted. The vacuum-melted heat was much lower in silicon and
manganese than the air-melted heats, but this had no detectable
effect on the corrosion rate in steam. After the first 4000-hr
exposure, the weight change can be described by an equation of the
form :

AW = K£°-21 (1)

where AW is the weight gain in mg/cmz, t 1s the time in hr, and X is
a constant. The perturbation in rate after 15,000 hr is thought to
be due to the condenser leaks in the plant and the attendant higher
impurity levels in the steam. After the leaks were repaired, the
rate of corrosion decreased.

Some Hastelloy N specimens from heat 5065 were given various
surface treatments before exposure to steam. Six samples were solution
annealed. Two of these were tested in the as-rolled and solution-
treated condition, two others were electropolished, and two were
abraded with 400 grit paper before exposure. Figure 9 shows that
the weight changes were least for the electropolished material, inter-
mediate for the as-rolled samples, and greatest for the abraded
samples. Although the corrosion process may have been affected in
a more complex way, the weight changes are qualitatively proportional
to the "true" surface area. | i
 

© e

   

 

100 200 MICRONS 600 700
4 I oox 1 i L

{
0.005 0010 INCHES 0.020 0.025

Fig. 7. Photomicrographs of 2 1/4
538°C and 24.1 MPa (3500 psi). (a) and
(c) and (d) Heat 72768, cold worked 50%.
As polished.

 

20 40 €0 MICRONS 120 140
500X
0.001 INCHES 0.005

Cr-1 Mo Steel Exposed 7000 hr to Supercritical Steam
(b) Heat 72768, annealed at 927°C and air cooled.

 

 

at

(e) and (f) Heat NC annealed at 927°C and air cooled.

 

 

 

Tt
 

WEIGHT CHANGE (mg/cm2)

12

ORNL-DWG 73-4140R

 

€
(8]
S0.5
E
Ll
(L)
<
[
I
&
T
50.2
L
=
0.1 a
10° 2 5 40 2
' TIME (hr)

Fig. 8. Weight Changes of Several Heats of Annealed Hastelloy N
Exposed to Supercritical Steam at 538°C and 24.1 MPa (3500 psi).

0.5

0.2

0.4

-0.02

0.01

103

 

ORNL -DWG 73-4135R

Fig. 9. Effect of
Surface Finish on the Corro-
sion of Hastelloy N (Heat 5065)
in Steam at 538°C and 24.1 MPa
(3500 psi).

50% COLD ANNEALED
WORKED o ELECTROPOLISHED
A & AS ROLLED
o ABRADED - 400 GRIT

2 5 10? 2
TIME (hr)
 

o

13

One specimen was cold worked 507 and tested with an as-rolled
surface. The corrosion rate of this specimen was very mear that of
the annealed specimen with an as-rolled surface. Thus, cold working
appears to have very little effect on the corrosion of Hastelloy N
in steam. This is in agreement with the results of a prior study in
which nickel-base alloys were noted to be less affected by cold working
than high chromium steels.®

Specimens from small commercial heats of modified Hastelloy N
containing from 0.10 to 2.1%Z Ti were exposed to steam, and the results
are summarized in Fig. 10. Alloys containing 0.1% Ti (21546) and
0.49%Z Ti (21545) gained weight more rapidly than the standard alloy.
However, the slope (weight change per unit time for greater than '
2000 hr) was quite low for both these alloys and about equivalent to
that for the standard alloy at long times. Alloys containing 0.92,
1.30, and 2.1% Ti gained less weight than standard Hastelloy N during
10, 000 hr exposure. However, extrapolations to longer times would
indicate that standard Hastelloy N and the alloys containing 0.10 and
0.50% Ti would gain less weight than the alloys containing more
titanium. One alloy containing 0.7% Nb was also exposed and gained
less weight than most of the titanium-modified alloys. The perturbation
after long exposure times was due to the increased impurity level in
the steam caused by the leaking condenser tubes. After the tubes were
repaired, the specimen lost weight.

ORNL-DOWG 73-4139R2

 

0.5
o
&
£
§§ ,
< 0.2
S
= __
5 21546 (0.10% Ti)
= o4 s 21546 (0.49% Ti)
o 69648 (0.92% Ti)
) 69641 (1.30%Ti)
® 21543 (0.7% Nb)
71583 (1.44% Ti)
0.05 ' . ' , .
S0 2 .. 5 ot 2

TIME (hr)

Fig; 10. Several Alloys of Hastelldy N Modified with Titanium and
Niobium and Exposed to Supercritical Steam at 538°C and 24.1 MPa
(3500 psi).

 
 

 

14

Several laboratory melts of Hastelloy N containing additions of
Ti, Al, Zr, Hf, Y, Ce, and Nb were exposed to steam for 22,000 hr, and
the weight changes are shown in Fig. 11. Maximum and minimum weight
changes in these alloys differed by less than a factor of 2, but only
the alloy containing 1.03% Nb gained less weight than the. standard alloy.
The perturbation after 15,000-hr exposure was due to leaking condenser
tubes, and the specimen lost weight after the tubes were repaired.

Typical photomicrographs of two heats of standard Hastelloy N are
shown in Fig. 12, The oxide was not of uniform thickness, but varied
from a few to about 20 um thick. Electrommicroprobe studies revealed
that both the inner and outer oxides contained Cr, Mo, Ni, and a trace
of Fe.

Four of the modified Hastelloy N specimens were examined metallo-
graphically and typical photomicrographs are shown in Fig. 13. The
oxides on all these alloys appear quite similar in morphology to
those formed on standard Hastelloy N. Electronmicroprobe scans of
these samples revealed iron and nickel in the oxide of alloy 69648
(0.92% Ti), Fe, Ni, Cr, Ti, and Mo in the oxide of alloy 21543 (0.7% Nb),
and nickel plus iron in the oxide of alloy 237 (1.03%Z Nb). The presence
of iron in most of the oxides may have been attributable to the presence
of iron particles in the steam. Since most of the steam circuit at
Bull Run is constructed of low-alloy ferritic steels, large amounts of
particulate iron are entrained in the steam and some deposit on the
test specimens.

ORNL-DWG T3-4136R

 

05
~
€
L
.
g v
< 0.2 ' STANDARD
)
O
=
L
X
o
T 04 .
o 185 (0.91 Ti, 0.98 Zr)
3 186 (0.88 Ti, 0.84 A))
168 (0.95 A, 1.4 HI)
005 231 (L3 HT, 42 Y)
232 (4.2 Hf)
234(0.75Ce)
236 (4.0 Al, 0.47 Z¢)
v 237{1.03Nb)
002 :
10° 2 s wo* 2
TIME (hr)

Fig. 11.  Corrosion of Various Modified Compositions of Hastelloy N
in Steam at 538°C and 24.1 MPa (3500 psi).
 

 

 

        

. & v *, o « 4

§Y-141233

 

 

100 200 - MICRONS 600 700 : 20 40 60 MICRONS 120 140
o Lt 100X—y t — . k-~—L1———L——r—L—-sooxee4r———i—7—-l—-1—{
0.005 o;diof INCHES 0.020 0.025 0.001 INCHES 0.005

Fig. 12, Photomicrographs of Hastelloy N Exposed to Steam at 538°C and 24.1 MPa (3500 psi) for
22,000 hr. (a) and (b) Heat 5065. (c) and (d) Heat 2477. As polished,

ST

 

 
 

 

 

 

 

 

 

 

16

e

LT R

 

 

 

20 40 GOMICRONS 120 140 100 200 MICRONS = €00 700
L. T 500X T _ | 1 100X r ;
0.001 INCHES 0,005 0.005 0.010 INCHES 0020 0.025

 

Fig. 13. Photomicrographs of Modified Hastelloy N Exposed to Super-
Critical Steam at 538°C and 24.1 MPa (3500 psi). (a) and (b) Heat 69648
(0.92% Ti), 21,000 hr. (c) and (d) Heat 71583 (1.44% Ti), 12,000 hr.

(e) and (f) Heat 21543 (0.7% Nb), 16,000 hr. (g) and (h) Heat 237
(1.03% Nb), 21,000 hr. As polished.

 

    
 

 

v

17

Stainless Steels

The data on stainless steels are given in Table A3 and the data
for several selected steels are plotted in Fig. 14. These steels
contain from 5 to 25% Cr, and type 502 stainless steel with 5% Cr has
the highest oxidation rate. Type 17-7 PH steel contains 17% Cr plus
1.157 Al and has the lowest rate of weight change over the test period.
The other four steels have about equal weight changes, but types 406
and 446 seem to be approaching a very low rate of weight gain.

Several of these same alloys were exposed in the cold-worked
condition, and the observed weight changes of several of these alloys
are shown in Fig. 15. Cold working reduced the corrosion rates of most
steels studied by about a factor of 2, but had an even larger effect
on type 201 stainless steel. This reduction of the corrosion rate of
high chromium steels has been observed by other :I.nvest:I.gat:ors.7"'9 The
oxldes on the annealed and cold-worked type 201 stainless steel specimens
were subjected to x-ray diffraction after 6000-hr exposure to steam in
an effort to determine a reason for the different oxidation behavior.
The oxide on the annealed specimen consisted of Fe30y, and 0-~Fez03, and
the oxide on the cold-worked specimen was MnFe;0y and a-Fep03. The most
striking difference in the two specimens was that the matrix lines for
the annealed alloy were those of an fcc cell with a lattice parameter of
3.5975 £ 0.0006 A, and those for the cold-worked specimen were those of
a bec cell having a lattice parameter of 2.875 * 0.002 A plus a fcc cell
having approximately the same lattice parameter as above. The bcc lines
were not present in an as-cold-worked specimen, so the phase likely
formed during exposure to steam at 538°C. This bcc phase is possibly
responsible in some undetermined way for the superior oxidation resistance
of the cold-worked materal. It is also possible that the formation of
MnFe;04 on the cold-worked specimen may have increased its oxidation
resistance. |

ORNL-DWG TE~20790

: . STAINLESS STEELS
05 © 302
“ . : & 17-TPH
o 204
o M6
A 406
® 446

© WEIGHT CHANGE (mg/cm?)

o2

 

o4 _ : :
w2 s w2 s
. TIME (hr) o

Fig. 14; Weight Changes of Solution Annealed Stainless-Steels in

Steam at 538°C and 24.1 MPa (3500 psi).

 
 

 

18

ORNL-=DWG 7€-—20791

STAINLESS STEELS ]
© 502
o 201
® 316
A 406

WEIGHT CHANGE (mg/cm?)

o

 

103 2 5 104 2 5
TIME (hr) '

Fig. 15. Weight Changes of Cold-Worked (507) Stainless Steels in
Steam at 538°C and 24.1 MPa (3500 psi).

Six specimens of the stainless steel series were examined metallo-
grahically and typical photomicrographs are shown in Fig. 16. The 502
- stainless steel with only 5% Cr had an oxide film about 80 um thick.
Electrommicroprobe studies of the oxide on this specimen showed that
the inner oxide contained iron and chromium and that only iron was
detected in the outermost oxide. The oxides on the types 304 and 316
stainless steel specimens were quite similar to each other in morphology
and were about 30 um thick. Electronmicroprobe.analysis showed that
these specimens all had outer oxides in which only iron could be
detected. The inner oxide of type 304 stainless steel contained iron,
chromium, and nickel, and the inner oxide of type 316 stainless steel
contained iron, nickel, chromium, and molybdenum. The photomicrographs
of type 201 stainless steel show the marked effect of cold working on the
rate of oxidation of this material. The oxide layer on the annealed
material was about 40 um thick and that on the cold-worked materials was
hardly detectable. On the annealed specimen the oxide consisted of
two distinct layers with the inner one containing Fe, Mn, Cr, and Ni
and the outer one containing iron and manganese. The oxide layer on
the cold-worked specimen was too thin to analyze by the electronmicroprobe
analytical technique used.
 

 

 

¥-141210

   

100 200 - MICRONS

  
 

 

|_...1.r_|__6_|_.|oox 20 90 EoMicRONs | 130 140
0008 0.010 INCHES 0.020 0025 0.004 INCHES 0.00%

Fig. 16. Photomicrographs of Several Steels Exposed to Steam at 538°C
and 24.1 MPa (3500 psi) for 11,000 hr (Type 304 Exposed 12,000 hr). (a) and
(b) Annealed type 502. (c¢) and (d) As-received type 304. (e) and (f)
Annealed type 316. (g) and (h) Cold-worked type 316. (i) and (j) Annealed
type 201. (k) and (1) Cold-worked type 201. As polished.

 

 

 
 

 

20

- Other Alloys

Several other alloys were exposed to steam and their weight changes .
are shown in Figs. 17 through 20. In Fig. 17 the behavior of Armco iron, .
Monel, Incoloy 800, and several nickel-base alloys is shown. Monel and e
Armco iron gained weight at a very high rate whereas Inconel 718 gained
weight at a very slow rate. Inconel 600 fell at an intermediate level
of weight gain, and Inconel 601 fell at a lower level. Incoloy 800
gained weight at a relatively high rate for the first 2000 hr, but the
rate rapidly decreased to where the rate was proportional to time to
about the one tenth power.

The weight changes of several Hastelloys are shown in Fig. 18 and
the data cover about one-half log cycle. These alloys contain from
0.2% Cr (Hastelloy B) to 22% Cr (Hastelloy X), but the differences in
weight change are not simply inversely proportlonal to the chromium
content. - :

- The weight changes of several alloys in the cold-worked condition are
shown in Fig. 19. By comparison with the annealed data in Figs. 17 and
18, some assessment can be made of the effects of cold working. Cold
working caused Hastelloy B to gain weight at a faster rate and slightly
reduced the weight gain of Incoloy 800. The weight gain of Inconel 718
appeared to be increased slightly by cold working, but the values are
still so low that inaccuracies in weighing make this conclusion rather
tenuous. The weight gained in the first 1000 hr was increased by cold
working for several of the Hastelloys, but the rate slowed to where
weight changes were about equivalent after a few thousand hours for
annealed and cold-worked material.

The weight changes of three alloys in the annealed and cold-worked
conditions are shown in Fig. 20. Haynes Alloy 188 gained weight more
rapidly in the cold-worked condition than in the annealed condition, but
the difference was quite small after 10,000-hr exposure. The weight
changes of all these alloys were quite low.

Three specimens from this series were examined metallographically
and typical photomicrographs are shown in Fig, 21. 1Incoloy 800 had a
very irregular oxide with the thickness in some areas as much as 10 um.
Examination by the electron microprobe showed that the inner oxide
contained iron, nickel, and chromium, and that the outer oxide contained
only iron in detectable quantities. This is in qualitative agreement
with the observations of Tilborg and Linde.!® Inconel 718 in the annealed
condition formed a subsurface reaction product to a depth of about 15 um
during exposure to steam, but this product was not present in the
material cold worked prior to exposure. The oxide was too thin to be
analyzed on the annealed specimen, but analysis of the oxide on the -
cold-worked specimen revealed the presence of iron, nickel, and chromium.
 

 

 

 

21

ORNL-OWG 76-20792

10

 

%
{ .
& B Fig. 17. Weight Changes of
w Several Solution-Annealed Alloys
% os in Steam at 538°C and 24.1 MPa
- (3500 psi).
&
* 0.2
O.1
0.05 ARMCO IRON
MONEL
INCONEL 600
) INCONEL 601
0.02 INCONEL 718
INCOLOY 800
T s 0t 2 s 10°
TIME (hr}
: ORNL-DWG 76~
0

 

£
y o2
2
- e o
E
: é _ © HASTELLOY B
T aps & HASTELLOY C
- o O HASTELLOY S
® HASTELLOY W
& HASTELLOY X
08 2 .8 00t 2 -8

TIME (hr),

~ Fig. 18. Weight Changes of ‘Several Nickel-Base Alloys' in the
Solution~Annealed Condition in Steam at 538°C and 24.1 MPa (3500 psi).

 
 

22

ORNL-DWG T6-~20794

20

%

o ¥

s Fig. 19. Weight Changes of Several
- Alloys in the Cold-Worked Condition in
2 0.5 Steam at 24.1 MPa (3500 psi) and 538°C.
g |

c

© 02

®

0.1

ARMCO IRON

- INCONEL 601

0.05 INCONEL 718
INCOLOY 800
MASTELLOY B

HASTELLOY C
0.02 HASTELLOY X

 

0.01
10°? 2 5 10* 2 s
TIME (hr)

-OWG 76-20795

) fem?)
o o
- N

WEIGHT CHANGE (mg
o
Q
o

0.02

 

0.04

2 5 2 s 1

TIME (hr)

Fig. 20. Weight Changes of Three Alloys in Steam at 24.1 MPa
(3500 psi) and 538°C in the Annealed and Cold-Worked Conditions.
 

          

Y -141225 Y-141226

 

N
W

 

t00. 200 Ml{%%(;(NS A' 600 700 20 40 60 Mé%%o)?ls 120 140
0.005 0.010 |INCHES 0020 0.025 0.0014 INCHES 0.005

Fig. 21. Photomicrographs of Specimens Exposed to Steam at 538°C and 24.1 MPa (3500 psi). (a) and
(b) Annealed Incoloy 800, 19,000 hr. (c) and (d) Annealed Inconel 718, 11,000 hr. {(e) and (f) Cold-
worked Inconel 718, 11,000 hr. As polished.

 
 

24

Tube Burst Results — Hastelloy N

Two heats of standard Hastelloy N tubing (N1 5095 and N2 5101) were
evaluated in the stressed condition from 193 to 531 MPa (28.0 to _
77.0 x 10% psi). The specimens of both heats in the annealed condition
(1 hr at 1177°C) had shorter rupture times in steam than in argon.
Specimens of heat N1 5095 tested in the as-received condition and
stressed below 345 MPa (50.0 X 102 psi) in steam had rupture times
equal to those of specimens tested in argon. Figure 22 shows the
stress-rupture properties of heat N1 5095, Flaws in the specimens may
have contributed to the scatter, but at stresses <345 MPa (<50.0 X 1031psi),
where wall thicknesses are heavier, there appears to be no significant
effect of steam on the rupture time. Two of the specimens stressed at
193 and 280 MPa (28.0 and 40.6 x .103 psi) accumulated 15,000-hr exposure.
to steam at 538°C without rupture and three others at slightly higher
stresses accumulated from 10,000 to 11,000 hr of exposure. Figure 23
shows the stress-rupture properties of heat N2 5101. Specimens in the
annealed condition tested in steam had shorter rupture times than specimens
tested in argon. Specimens in the as-received condition tested in steam
had rupture times equal to or greater than specimens tested in argon. |
The longest rupture time of this heat was 12,000 hr for a specimen
stressed at 336 MPa (48.8 x 10% psi) in steam at 538°C.

ORNL-DWG 75-7202R

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SO T TTI T IO T T T T 1 1T
AS-  ANNEALED {tr
50 . RECEWED ~ ATH77°C |
90 \"'--.‘ ARGON © o
ol STEAM @ .
70 —'o——-———\At—:u—-oc |
- ¢ n o~ o\ o
2 e0 —ou >0
0 ¢ ¢ ¢ o] Tow
w fi‘\.
E 50 : —E
e
a0 o e
30 '
oL A ALIN b POAINE f LTI | iilllfl(, L L1
10° 10! 102 10° 10 10°

RUPTURE TIME {hr)

Fig. 22. Rupture Life of Hastelloy N (Heat N1 5095). Tubes stressed
in argon and steam environments at 538°C.
 

25

ORNL-DWG 75-~T201R

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

90 L ,
CTEH T TTHO 0 T IIHHI [T T
‘ c:) AS- ANNEALED 1{ hr
80 | RECEIVED AT H177°C —
" ~ . o o
s Yo~ | o sA'I?gEa’: . .
iy
70 o S —~Q oo} -
- g"‘-.
- “~o
x n . ...\:- o o.
2 60 - e o .
& - . T .
5 RN
= 5 Sy
50 & O 3
a0 ‘ ] o~
30 UL e b e et
10° 10! 102 : 10° 10 10°

RUPTURE TIME (hr)

Fig. 23. Rupture Life of Hastelloy N (Heat N2 5101). Tubes
stressed in argon and steam environments at 338°C.

The minimum creep rates of both heats of material were plotted as a
function of stress in Fig.. 24. The creep rates were calculated from plots
of diametral strain, AD/D vs time, which were based on measurements of the
internal diameter of the specimens at 1000-hr intervals. There is
considerable scatter in the data because of difficulty in measuring the
internal diameters at the point of maximum strain, but the figure is
useful as an indication of the strain rates expected in this stress
range. Buildup of scale on the inside diameter exposed to steam also
constributes to the inaccuracy of this method since the apparent strain
is reduced as the scale thickens.

ORNL~ DWG 76-T424

 

 

 

 

 

 

 

 

 

 

 

 

 

o I T T T T T
s ,. : /
_ ' d/;
o , /| °
50 — . 7
3 ° |
.";40 ;?
z Y4
2 J/
& 30 7 y
“ / ° HEAT
e N23104 .
20 1 © N1S0SS - T |
10 _ _ _
ol crrtmtorr
o8 10°% 10-4 03

MINIMUM CREEP RATE {%/hr)

Fig. 24, Creep Properties of Hastelloy N at 538°C in Steam
Environment.

 

 
 

 

 

; 26

 

: Four typical fractured specimens are shown in Fig. 25. 1In each '
case the outer protective tube has been machined off. The three short-
: term test specimens (1.65 to 75.3 hr) exhibited relatively ductile
; tearing fracture indicative of a very high strain rate at the moment
| of fracture. The specimen from the 2089-hr test had a lower ductility
failure.

i
;
:
|
;
i
{
¥

 

 

 

 

 

 

 

}
§
i

 

 

 

 

Fig. 25. Photographs of Four Specimens Failed in Steam. See Fig. 1
for a schematic drawing of the assembled specimen. (a) SN 64, 340 MPa
(49,340 psi), rupture at 2088.75 hr. (b) SN 118, 410 MPa (59,500 psi),
rupture at 75.3 hr. (c¢) SN 111, 441 MPa (64,000 psi), rupture at 28.75 hr.
(d) SN 106, 489 MPa (70,940 psi), rupture at 1.65 hr. :
 

27

SUMMARY

The corrosion of several alloys in supercritical steam at 538°C
and 24,1 MPa (3500 psi) was measured for times up to 22,000 hr. Various
post-test examinations were performed, and the following important
observations were made.

1. All the alloys formed tenacious, nonspalling oxides when tested
in steam. ‘

2. The corrosion rates of five ferritic alloys containing from
1.1 to 8.7% Cr and 0.5 to 1.0%Z Mo and four heats of 2 1/4 Cr-1 Mo steel
containing from 0.009 to 0.12%7 C were equal to within a factor of 2.

3. Cold working prior to exposure did not have a detectable effect
on the corrosion of 2 1/4 Cr-1 Mo steel.

4. The oxide layer formed on the ferritic steel was about 50 um thick
and consisted of two distinct layers. The layer next to the metal contained
detectable quantities of Fe, Cr, Mo, and Si, and the outermost oxide
contained only iron.

5. The corrosion rate of Hastelloy N in steam increased with
increasing surface roughness.

6. Although rather large changes were made in the composition of
Hastelloy N, the corrosion rate was altered by no more than a factor of
2 . : '

7. The oxide on Hastelloy N was quite irregular with the thickness
in different locations varying from a few to 20 ym. The surface of the
oxide was quite high in iron, and this was likely due to the deposition
of particulate iron from the steam circuit.

8. The corrosion rates of several steels containing from 5 to 25% Cr
varied by an order of magnitude. The highest corrosion rate was exhibited
- by type 502 with 5% Cr and the least by type 17 — 7 PH with 17Z Cr and

1. 15% Al. '

9. Cold working cause a large reduction in the corrosion rate of
type 201 stainless steel. This reduction was associated with either
the formation of a bcc phase or the spinel MnFe;0, that formed on the
cold-worked material. Cold working has a lesser effect on the other
high—chromium steels, but generally decreased the corrosion rates.

10. Oxides on the stainless steels generally consisted of 2 distinct
layers. The layer closest to the metal contained all principal constituents
of the alloy, and the outer oxide contained only iron in detectable
quantities. -

 
 

28

11. Several iron~ and nickel-base alloys were tested. Inconel 718
had the lowest weight gains, and Incoloy 800 had the lowest corrosion
rate with a dependence on (tlme)

12. The inner oxide on Incoloy 800 contained iron, nickel, and
chromium, and the outer oxide contained only iron in detectable quantities.
The oxide on Inconel 718 contained iron, nickel, and chromium.

13. 1Inconel 718 in the annealed condition formed a subsurface
reaction product to a depth of about 15 ym, but this product was not
present in the cold-worked material.

14, Although some small'difference existed in the behavior of
annealed and cold-worked nickel-base alloys, the effects were reasonably
- small.

15. The stress-rupture properties of Hastelloy N were lower in
steam than in argon at short rupture times, but were equivalent at
long rupture times.

ACKNOWLEDGMENTS

The authors are indebted to TVA for allowing this test facility to
be placed in the Bull Run Steam Plant. P. Wade, C. F. Dye, R. C. Bishop,
and C. S. Voles of TVA were very helpful in the day-to-day operation
of the facility. The metallography in this report was prepared by
W. H. Farmer, the electron microprobe work was performed by R. S. Crouse,
the drawings were prepared by the ORNL Graphic Arts Department, and the
manuscript was prepared by J. L. Bishop of the Metals and Ceramics
Division Reports Office. The authors are grateful to J. P. Hammond,

J. C. Griess, and C. R. Brinkman for their technical review of the
manuscript.

REFERENCES

1. C. N. Spalaris et al., Materials for Nuclear Superheater Applications,
GEAP-3875 (1962).

2. H. E. McCoy and B. McNabb, Corrosion of Several Iron- and Nickel-
Base Alloys in Supercritical Steam at 1000°F, ORNL/TM-4552 (1974).

3. Tennessee Valley Authority, The Bull Run Steam Plant, TVA Technical
Report 38, Knoxville, Tennessee, 1967.

4, W. E. Ruther, R. R. Schlueter, R. H. Lee, and R. K. Hart,'"Corrosion
Behavior of Steels and Nickel Alloys in Superheated Steam,"
Corrosion 22: 147 (1966). . :
 

 

 

10.

29

Par L. Grall, "Les aciers inoxydables et les alliages a base de nickel
Etude de leurs propriéties de resistance a la corrosion dans la vepeur
surchauffée, Bull. Inform. Sei. Tech. 139: 19 (1969).

S. Leistikow, H. V. Berg, and E. Pott, Long-Time Corrosion Studies
on Austenitie Cr-Ni Steel and Nickel-Base Alloys in Superheated

. Steam (620 C, 1 atm), with Special Attention to the Behavior of

Cold-Formed Mhterials Surfaces, Report KFK-1301, Karlsruhe Nuclear
Research Center (February 1971).

Societe d'Etudes, de Recherdhes et d'Applications pour I'Industrie,
Brussels, Studies of Steel Corrosion in High Temperature Water and
Steam, Final Report. No. 1, June 16, 1962—October 31, 1965,

Report EURAEC-1581 (1965).

'W. E. Ruther and U. S. Greenberg, J. Electrochem. Soc. 111l: 1116—

1121 (1964).

J. P. Hammond, P. Patriarca, G. M. Slaughter, and W. A. Maxwell,
"Corrosion of Incoloy 800 and Nickel-Base Alloy Weldments in
Steam," Weld. J. (Miami) 52(6): 268-5—280-s (June 1973).

P. J. van Tilborg, and A. van der Linde, Corrosion of Inconel-625
Hastelloy X280 and Incoloy-800 in 550—750°C Superheated Steam,
Report RCN-109, Reactor Centrum Nederland, Pettern, The Netherlands
(October 1969).

 
 

 

 

 
 

 

 

APPENDIX

Collected Wéight,Change Data for Various Metals and Alloys Exposed
to Supercritical Steam at 24.1 MPa (3500 psi) and 538°C

 
 

 

 

 
 

Table Al. Weight'Change Data for First Set of Specimens of Low-Alloy Ferritic and Maraging Steels

 

Weight Gain, mg/cm?, at Various Times in hr

 

 

n Area
Alloy Specimen (cm?) .
, . ¢ 670 1,000 2,000 2,482 4,000 4,482 6,000 8,000 10,000 13,000 14,000
cr 112 ‘172 ' 13.6924 3.14 3.78 5.12 6.00 6.47 6.80 9,12
173 13.6444 3.21
205 13.6221 . 2.31 | 4.22 4.96 5.37 5.60 6.22 7.74
cr 1.9% 202 13.5654 . 3.97 6.30 7.98
208 13.6392  4.28 7.95 8.53 8.89 8.89 9.78 11.71
© 163 13.6274 4.94
164 13.6355 4.93 5.98 7.57 8.90 9.31 9.81 12.03
cr 2.0% 166 13.6369 - 3.93
167 13.6287 3.40 4.32 5.80 6.93 7.37 7.63 - 9.60
203 . 13.5638  2.90. 4.63 5.91
209 13.5759  2.73 4.51 5.77 6.08 6.53 7.31 8.9
cr 4.2% 204 13.5999  3.76 6.14 7.74 8.07 8.64 9.97 11.88
169 '13.6329 3.98 5.13 | 6.83 7.97 8.48 8.96 10.41
170 13.5955 4.49 6.89
cr 8.7% 175 13.6411 3.77 . | - : -
176 13.6668 . 3.73 4,56 o 5.98 7.03 7.43 7.68 9.71
_ 206 13,6558  2.74 5.81  6.27 6.27 6.57 7.29 8.79
12-5-3P 207 13.5928  3.97 6.61 8.91 9.73 10,22 11.33 13.99
178 13.5173 6.33
179 13.4833 6.16 7.37 9.48  11.04  11.77 12.13 15.48

 

a.Low—alloy ferritic steel annealed 1 hr at 927°C in argon.

b

12-5~3 maraging steel annealed 1 hr at 816°C in argon.

£t

 

 

 
 

 

34

Table A2. Weight Change Data for Second Set of Specimens of
Low~Alloy Ferritic and Maraging Steels

 

 Weight Gain, mg/cm®, at Various Times in hr

 

 

Alloy Condition® Specimen (Ac reza)
m‘ 1100 2000 . 3000 4000 4700 6000 7000
LC A 481 13.9030 2.88 3.40 4.10 4.88 4.98 5.34 5.72
LC A 482 13.8512 2.75 3.42 4.14 4.84 4.99 5.35 5.73
LC B 483 13.9548 2.68 3.39 4.19 4.86 5.04 5.45 5.82
LC B 484 13.8130 2.75 3.53 4,28 4,98 5.14 5.60 6.03
MC A 489 13.6378 '3.20 4,16 4.99 5.73 5.91 6.37. 6.85
MC A 490 13.8373 4,08 5.43 6.15 7.00 7.46 8.35 9.01
MC B 491 13.9548 2.96 3.86 4.64 5.35 5.50 5.96 6.39
MC B 492 13.8650 3.77 5.14 5.91 6.82 7.34 7.90 8.38
NC A 485 13.7092 3.08 3.85 4,52 5.18 5.30 - 5.70 6.12
NC A 486 /13.6301 3.96 5.10 6.02 6.88 7.22 7.21 7.41
NC B 487 13.5783 3.31 4.35 5.22 5.99 6.17 6.67 7.17
NC B 488 13,7993 4.18 5.41 6.15 6.93 7.40 7.88 8.23
72768 A 517 13.6437 2.92 3.59 4.52 5.07 5.32 5.56 5.90
72768 A 518 13.6165 2.96 3.65 4,52 5.10 5.37 5.60 5.95
72768 B 519 13.6956 2.96 3.69 4,64 5.28 5.54 5.80 6.16
72768 B 520 13.7200 2.85 3.59 4,61 5.20 5.45 5.70 6.08
Cr 1.1 A 493 11.0218 3.84 4,81 5.63 6.33 6.47 6.92 6.58
Cr 1.1 A 494 13.7718 3.75 4.97 5.56 6.24 6.70 7.17 6.90
Cr 1.1 B 495 13.4363 2.69 3.45 4.11 4.67 4.79 5.15 5.51
Cr 1.1 B 496 13.6437 3.62 4.74 5.39 5.39 6.47 6.90 7.34
cr 1.9 A 497 13.7611 3.55 4.69 5.55 6.25 6.41 6.88 7.33
Cr 1.9 A 498 13.7337 4.35 5.78 6.60 7.38 7.78 8.32 8.70
Cr 1.9 B 499 13.8159 3.42 4.63 5.57 6.31 6.49 6.99 7.52
Cr 1.9 B - 500 13.9780 4.29 5.74 6.58 7.48 8.00 8.59 8.96
Cr 2.0 A 501 13.7365 3.14 4,20 4.99 5.56 5.70 6.07 6.40
Cr 2.0 A 502 13.6573 .14 5.37 6.20 6.91 7.37 7.89 7.94
Cr 2.0 B 503 13.7092 3.49 4.72 5.63 6.22 6.34 6.74 7.25
Cr 2.0 B 504 13.7092 4,09 5.49 6.37 7.15 7.59 8.10 8.43
Cr 4.2 A 505 13.6845 3.84 4.47 5.61 6.26 6.64 6.85 7.15
Cr 4.2 A 506 13.6301 4.45 5.72 6.58 7.34 7.75 8.18 8.48
Cr 4.2 B 507 13.7337 4.30 5.65 6.49 7.36 7.83 8.47 8.93
Cr 4.2 B 508 13.5130 3.35 4,13 5.30 5.97 6.37 6.70 7.10
Cr 8.7 A 509 13.7092 3.03 3.67 4.14 4,79 5.08 5.41 5.65
Cr 8.7 A 510 13.5621 3.05 3.70 4,17 4.82 5.12 5.45 5.72
Cr 8.7 B 511 13.7092 2.63 3.26 4,15 4,73 5.05 5.33 5.70
Cr 8.7 B 512 13.7611 2.58 3.21 " 4.04 4.61 4.91 5.18 5.55
12-5-3 A 513 13.6546 6.14 7.60 9.40 10.7 11.3 12.0 12.7
12-5-3 A 514 13,7993 5.97 7.31 9.26 10.5 11.1 11.8 -12.5
12-.5-3 c 515 13.5016 3.63 4.87 6.65 7.86 8.39 9.04 9.79
12-5-3 c 516 13.6325 3.43 4.64 6.39 7.66 8.18 8.80 "9.56

 
 

Table A3. Weight Change Data for Specimens of Stainless Steels

 

 

 

 

Stainless ) a Area : . Weight Gain, mg/cmz, at Various Times in hr
Steel Specimen Condition (cm?) - :
Type 1,000 2,000 3,000 4,000 . 5,100 6,000 7,000 8,000 8,700 10,000 11,000 12,000
502 372 Annealed 13,7092 3.7 4,77 5.43 6.05 6.84 7.52 8.20 9.75 9.90 10.28 10.61
502 373 Annealed 13,0605 3.29 4,23 4,95 5.49 6.19 6.64 7.09 B.26 8.56 8.94 9.48
502 . 405  Cold Worked 502 13.8650 2.91 4.05 5.14 5.74 6.51 7.11 7.17 8.65 7.02 7.46 7.65
17-7 PH 374 " Annealed - 13.9202 . 0.50 0.66 0.83 0.98 1.19 1.32 1.44 1.75 1.65 1.65 1.69
17-7 PH 375 Annealed . 13.8598 0.33 .51 0.67 0.84 1.08 1.23 1.41 1.65 1.60 1.61  1.67
201 352  Annealed 13.5782 0.71 1.16 1.81 2,20 ° 2,70 3.02 3.39 3.77 3.96 4.16 4,34
201 353 Annealed 13.5727 0.81 1.35 2.08  2.49 2.98 3.29 3.75 3.97 4.10 4.35 4.55
201 354 Cold Worked 50% 13,6137 0.04 0.04 0.07 . 0.04 0.05 0.14 0.21 0.24 0.18 0.11 0.13
201 355 Cold Worked 502 13.7611 0.03 0.03 6.05  0.03 0.07 0.15 0.27 0.32 0.02 0.02 0.03
304 349 As-Received  13.6554 0.79 1.11 1.25 1.47 1.64 1.83 2,05 2,24 2.60b 2.54°¢ 2.45 2.50
309 359 Annealed ©13.7911 1.60 2.05 2.53 2,72 2.95 3.09 3.23 3.45 .46 3.34 3.37
309 360 Annealed 13.4095 1.69 2,06 2.48 2,67 2.90 3.01 3.17 3.43 3.39 3.29 3.1
310 361 Annealed . 13.5377 0.57 0.91 1.10 1.20 1.31 1.43 1.56 1.74 1.60 1.51 1.49
310 362 ~ Annealed 13.53717 0.83 1.10 1.29 1.40 1.50 1.58 1.71 1.84 1.73 1.70 1.69
316 363 Annealed 13.5893 1,34 1.71 2.07 2.39 2.79 3.06 3.35 3.75 3.89 4,07 4.25
316 364 Annealed 13.1245 1.44 1,87 . 2,27 2.61 2.96 3.20 3.49 3.80 3.97 4.15 4.37
316 365 Cold Worked 50% ~ 13.5512 0.52 0.66  0.85 1.00 1.14 1.23 1.34 1.56 1.55 1.51 1.54
321 366 Annealed 13.4699 0.75 1.05 - 1.39 1.69 2.09 2,31 2.61 3.13 3.33 3.56 3.82
321 367 Annealed o 13,4320 0.67 0.93 1.22 . 1.47 1.84 2.03 2,29 -2.76 2.91 3.05 3.28
347 334  Annealed © 13.2688 0.67 1.05 - 1.17 1.33 1.42 1.52  1.61 1.73 1.94 1.71 1.70 1.71
347 335 Annealed 13.3337 0.55 0.78 0.92 1.09 1.19 1.25 1.37 1.55 1.81 1.45 1.44 1.46
406 368 Annealed 13.7580 1.56 1.92 2.28 2.51 2.85 3.02  3.17 3.42 3.48 3.53  3.61
406 369 Annealed 13.6301 1.25 1.54 1.86 2.09 2.45 2.62 2.80 3.07 3.16 3.16 3.24
406 406 Cold Worked 50X 13.5830 0.73 0.96 1,20 1.40 1.58 1.97 1.86 1.97 2.03 2.00 2.02
410 336 Annealed 927°Cc 13.7768 2.39 2.80 3.03 3.48 3.80 4.11 4,37 4.77 5.23 5.27 5.44 5.69
410 337 Annealed 927°C 13.5450 2.53 3.03 3.22 - 3.68 4,02 4.36 4.61 5.02 5.46 5.51 5.70 5.98
446 370 Annealed 12.8269 1.03 1.30 1.58 1.77 2.00 2.09 2.18 2,50 2,49 2.39 2.43
446 in Annealed 14,0554 1.52 1.82 2.03 2.16 2.38 2.56 2.72 2.97 2.87 2.78 2.79
®Annealed 1 hr in argon at 1038°C unless otherwise specified.
b : |
9000 hr.

€9700 hr.

 

 

cE
 

 

36

Table A4. Weight Change Data for Specimens of Nickel 280
Annealed 1 hr in Argon at 800°C '

 

Weight Gain, mg/cmz, at

 

 

Area
Specimen (cm?)
400 hr 1518 hr
266 13.8262 444 54,43
267 ~ 13.8262 3.33 77.11
268 13.9680 4.30 72.95

269 - 13.7880 5.25 75.29

 
         

Table A5. Weight Change Data for Specimens of Various Metals and Alloys

 

” 2
Area Weight Gain, mg/cm’, at Various Times in hr

 

 

Material Specimen Condition® -
. : 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 8,700 10,000 11,000 12,000 13,000 13,700 15,000 16,000
Armco Iron 356  Annealed 927°C 13.6683  4.44 5.52 7.06 8.06 9.17  9.59 10.19 10.97 11.39 - 11.90  12.30
357  Annealed 927°C 13.6241  4.33  5.37  6.88 7.87 9.06 9.62 10.25 11.08 11.51 11.94  12.43
358 Cold Worked 502 13,7063  4.66 5.68 7.22  8.24  9.38  9.97 10.57 11.47 11.89 12.45 12,97
Monel 332 Annealed 800°C 13.6301  0.62 2.81  7.89 12.96 17.28 b . 4
333 Annealed B00°C . 13.6301 © 1.19  4.59 9.50 14.42 18.56 23.33° 27.38  30.52 35.08° 38.22% 4221 as.79
Copper 466  Annealed B0O®C 13.5783  0.3%4 -0.13 —0.9% -—1.61 -2.72 -3.71 —5.45: —5.45 —7.65°
467  Annealed BOO*C 13.555% 0,22 -0.18 —-1.17 -1.80 -2.60 —3.68 —4.46% —4.46 —6.23° ] w
Inconel 600 388 Annealed 1176°C  13.5130  0.26 ©0.30 0.41 0.46 0.52 0.58 0.69 0.87 0.80 0.78  0.77 ~
389 Annealed 1176°C  13.5265  0.24 0.27 0.37 0.43 0.49 0.62 0.87 0.8 0.85 0.7h-  0.74
Inconel 601 316  Annealed 1176°C  13.7337  0.06 0.1  0.17 0.17  0.19  0.25 0.36° ©0.425 0.50 0.5 0.73 . 0.5 0.52  0.57
317  Annealed 1176°C  13.7611  0.07 ©0.12 0,20 0.22 0.24  0.31 0.40° 0.45%° 0,51 0.59 0.7 0.60 0.55  0.59
468  Cold Worked 50X 13.7546  0.21 © 0.31  0.46 0.55 0.54 0.55 0.48  0.50
Inconel 718 390  Annealed 1176°C-  13.5644  0.05 0.02 0.00 0.02 ©0.03 0,10 0.30 0.29 ©0.25 0.10  0.10
391 = Annealed 1176°C  13.7195  0.05 0.02 -0.02 0.00 0.04 0.10 0.28 0.25 0.22 0.10  0.10
412 Cold Worked 50  13.395%  0.12 0.13 0.15 0.18 0.2 0.42 0.5 0.49 0.40 0.32 0.3 °

 

fannesled 1 hr in argon at the indicated temperature.
b6,100 hr.

9,000 hr.

96,700 he.

10,100 he.

 

 
 

Table A6. Weight Change Data for Specimens of Incoloy 800 and Hastelloys B and C

 

Weight Gain, mg/cm?, at Various Times in hr

 

 

 

a Area
Alloy Specimen Condition (cmz)
1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 8,700 10,000 11,000 13,000 14,000 15,000 16,000 17,000 17,700 19,000
Incoloy. 800 198 Annealed 1037°C 13.6339 O.Sdb 0.80° 0.95
199 Annealed 1037°C 13.6200 0.41 0.71 0.82 0.82 0.84 0.90 0.92 0.95 1.03 1.15 1.43 1.11 1.00
200 Annealed 1037°C 13.6350 0.42 0.68 0.81 0.71 0.71 0.75 0.80 0.86 0.92 1.03 1.24 1.01 0.89
201 Annealed 1037°C 13,5310 0.51 0.81 d
469 . Cold Worked 50% 13.8543 0.17 0.17 0.65 0.35 0.36 0.35 0.19° 0.24
Hastelloy B i76 Annealed 1176°C 12,6206 ~  0.10 0.11 0.16 0.19 0.27 0.34 0.36 0.47 0.42 0.38 0.40
377 Annealed 1176°C 13.6480 0.12 0.16 0.21 0.25 0.30 0.34 0.40 0.56 0.50 0.43 0.43
407 Cold Worked 50% 13.3631 0.16 0.29 0.49 0.62 0.76 0.94 1.16 1.26 1.32 1.25 1.29
Hastelley C 378 Annealed 1176°C 13.5241 0.06 0.08 0.10 0.13 0.16 0.23 0.30 0.44 0.35 0.26 0.24
379 Annealed 1176°C 13,5621 0.04 0.06 0.07 0.08 0.14 0.25 0.32 0.51 0.35 0.26 0.22
408 Cold Worked 50% 13.6220 0.15 0.17 0.21 0.21 0.25 0.32 0.40 0.43 0.41 0.32 0.35
BAnnealed 1 hr in argon at the indicated temperature.
bs70 hr.
©2,482 hr.
46,700 Hr.
.
- .
& o ) - 4 . *

8¢

 
Table A7. Weight Change Data for Specimens of Various Superalloys

 

Weight Gain, mg/cm?, at Various Times in hr

 

 

Alloy Specimen Condition® af%%
_ mJ 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000 11,000
Hastelloy S 417 Anmnealed . 13.7229. 0.09 0.14 0.15 0.20 | 0.27 0.44 0.55 0.50: 0.34
418 Annealed 13,7229  0.09 0.12 0.15 0.19 0.27 0.46 0.47 0.46 0.32
Hastelloy W 380 Annealed “12.8533w 0.04 0.05 0.09 0.10 0.15 0.21 0.31 0.20 0.22° 0.22 0.2
381 Annealed 13,2794 0.04 0.06 0.09 0.07 0.12 © 0.17 0.23 0.38 0.23¢ 0.21 0.2
409 Cold Worked‘SOZ 13.3134 0.11 0.16 0.20 0.23° 0.30 0.38 0.49 0.59 0.62° 0.60 0.6
Hastelloy X 382 Annealed 13.8476 0.06 0.06 0.09 0.11 0.15 0.17 0.22 0.33 0.23¢ 0.20 0.2
383 Annealed 13.7953 0.04 0.04 0.05 0.05 0.15 0.18 0.22 0.33 0.25° 0.21 0.2
410 Cold Worked 50% 13.7063 0.12 0.14 0.17 0.21 0.24 0.35 0.38 0.47 0.46° 0.35 0.3
Haynes 25 384 Annealed 13.4209 0.03 0.01 0.10 0.16 0.28 0.34  0.40 0.58 0.49¢ 0.46 0.4
385 . Annealed 13.5889 0.07 0.08 0.18 0.23 0.37 0.41 0.50 0.66 0.60% 0.54 0.5
Haynes 188 - 386 ' Annealed 13.2926 0.03 0.01 0.05 0.08 0.14 0.18 0.32 0.46 0.412 0.32 0.2
' 387 . . Annealed : 14,0295 0.04 0.04 0.07 0.11 0.16 0.21 0.32 0.49 0.44c 0.38 0.3
413 Cold Wbrked 50% 13.7684 0.23 0.27 0.30 0.33 0.36 0.75 0.71 0.92 0.87° - 0.60 0.5
Rene 62 392 Annealed 13.6678 0.18 0.16 0.19  0.22 0.25 0.33 0.55 0.55 0.51¢ 0.40 0.3
393 Annealed 13.8791 0.15 0.14 0.17 0.18 0.23 0.30 0.46 0.54 0.48°¢ 0.29 0.3
411 Cold Worked 13.7580 0.15 0.16 0.20 0.24 0.29 0.56 0.62 0.61 0.57° 0.45 0.5

OO~ OHEH® NG NON 0w

 

2 pnneals ‘dre for 1 hr in argon at 1176°C.

b7,700 hr.
8,700 nr.

6¢

 

 
Table A8. Weight Change Data for Specimens of Modified Hastelloy N Laboratory Heats®

 

Weight Gain, mg/cmz, at Various Times in hr

 

 

Heat Specimen (Ac l:z‘)

1,000 2,000 4,482 6,000 7,000 8,000 10,000 15,000 16,100 17,000 18,000 19,000 19,700 21,000 22,000
185 . 87 13.6149 0.14
185 88 13.6431 0.21  0.29 0.49  0.54 0.59 0.65 0.74  0.81 0.98 1.01 1.11 1.00 0.99 1.02
185 89 13.6603 0.20 0.32
185 90 13.6048 0.12  0.24 0.41  0.55 0.53 0.58
186 91 13,5903 0.21  0.24
186 92 13.6285 0.12 0,21  0.36  0.49 0.48 0.59
186 521 13.6410 0.05 0.14 0.36° 0.28 0.27 _
188 37 13.6213 0.29 0.40 0.62  0.57 0.68 0.71 0.78  0.84 0.99 1.05 1.15 0.99 0.95 1.00
188 38 13,5819 0.09 0.19 0.32 0.32 0.40  0.46 ' ‘
231 35 13.6267 0.12  0.21 0.28 0.29
231 36 13.6386 0.26  0.43 '
231 105 12.5198  0.27 0,38  0.58 0,62 0.65 0.69 0.72 0.79 0.93 1.06 1.09 0.94 0.89 0.89
232 103 13,5416 0.18  0.22 0.39  0.43 0.44 0.47 0.55 0.59 0.78 0.80 0.84 0.72 0.71 0.72
232 104 13.5230 0.21  0.24  0.39  0.46 0.47 0.50 :
236 101 13.6424 0.11  0.17 0.35 0.41 0.45 0.52 0.60  0.66 0.88 0.89 0.93 0.84 0.84 0.85
236 102 13.6070 0.18  0.26  0.43 ~ 0.46 0.49 0.54
237 99 13.6422 0.10 0.15 0.26 0.28 0.29 0.33 0.38 0.43 0.65 0.65 0.73 0.58 0.59 0.60
237 100 13.6359 0.0 0.4 0.23 0,32 0.26 0.32

 

8Annealed 1 hr in argon at 1176°C.
b4,700 hr.

0%

 
Table A9.

 

 

Weight Change Data for Specimens of Standard

Hastelloy N Large Commercial Heats

 

 

Weight Gain, mg/cm®, at Various Times in hr

 

 

Heat Specimen Condition® “‘::‘;‘"‘ (“"‘,‘) :
om 1,000 2,000 4,882 6,000 8,000 10,000 15,000 16,100 17,000 18,000 19,000 19,700 21,000 22,000

U1 0 0.77 136662  0.15 0.2F 0.3 0.33 0.38 0.41 0.48 0.5 0.69 0.75 0.86 0.68 0.68 0.70

2477 24 0.77 13.5224  0.13  0.25

2817 55 0.2% 12,8177 0.07 0.12 0.22 0.26 0.23 0.27 0.29 0.34 0.51 0.54 0.59 0.47 0.45 0.53

277 56 0.2 12,7622 0.09 0.1 ©0.24 0.29

2417 %7 0.25 12.6151  0.10 0.17

2477 58 0.25 12,4513 0,07 0.13 0.18 0.26 0.22  0.26

417 59 0.25 12.7940  0.07 0.09 0.25 0.26

477 60 0.25 12.6220  0.11 0.13 . ‘

2477 € Cold Worked 50% 2.25 126409  0.13 0.15 0.27 0.31 0.3 0.42 0.5 0.55 0.720 ©0.73 0.81 0.73 0.72  0.75

2477 62 Cold Worked 50% 0.25 12,9948  0.15 0.18

2477 63 Cold Worked 50X 0.25 12,9303 0.13 0.20 0.33 0.2

2477 64 . Cold Worked 50% 0.25 12,5853 0.10 0.17 0.28 0.36 0.36 0.45 0.52 0.58 0.76 0.77 0.90 0.76 0.76 0.79

5065 1 - 0.2 12,5543  0.14 0.20 0.29 0.32 0.29 0.33

5065 2 0.25 12,5932 0.10 014 0.33 0.28 0.30 0.33 0.36 0.41 0.57 0.64 0.68 0.66 0.5 0,5

5065 3 0.51 12,9448  0.15 0.20 0.30 0.32 0.35 '0.37 0.4l 0.45 0.5 0.63 0.72 0.70 0.5  0.57

5065 : 0.51 12,9558  0.16 0.22 0.3 0.35 0,33 036 041 0.47 0.5 0.67 0.73 0.73 0.66  0.61

5065 5 0.77 13.4914  0.16 0.22 0.3 0.33 0.33 0.36 0.3 0.45 0.58 0.63 0.70 0.67 0.5  0.56

5063 6 0.77  13.%92  0.15 0.22 0.3% 0.35 037 0.4l 0.45 0.51 0.65 0.69 0.80 0.73 0.63 0.61

065 7 1.52 16.5614  0.14 0.2¢ 0.3 0,40 0.41 0.45 0.55 0.62 0.78 0.82 0.90 0.8 0.77 0.7

5065 8 1.52 14.5693  0.14 0,21 0.33 0.3 0.38 0.2 0.47 0.5 0.66 0.71 0.76 0.71 0.67  0.66

5065 9 0.77 13.5302 0.18 0.22 0.3 0.33 0.33 0.34 0.38 0.43 0.55 0.58 0.64 0.63 0.55 0.53
" 5065 10 ) . 0.77 13.6351 0.15% 0.22 0.31 0.32 0.37 Q.40 0.43 0.48 0.64 0.64 0.70 0.6% 0.62 0.60

5065 11 Abraded 0.77 13.5%60 0.29 0.40 0_.55 0.60 0.63 0.70 0.81 0.87 1.0 1.04 1.08 1.08 1.04 1.03

5065 12 Abraded 0.77 13.5079  0.25 0.39 0.55 0.60 0.6 0.69 0.78 0.85 1.04 1.07 1.08 1.07 1.01 1,01

5065 . 13 Electropolished 0.77 11.3979  0.04 0.08 0.13 0,16 0.16 0.18 0.22 0.27 0.42 0.52 0.52 0.49 0.42 0,42

5065 14 Flectropolished 0.77 13,2262  0.03 0.09 0.15 0.15 0.18 0.22 0.29 0.33 0.45 0.50 0.5 0.43 0.45 0.6

s065 15 0.25 12.5496  0.08 0.37 0.25 0.29

5065 16 0.25 12.5359  0.07 0.18

5065 17 0.25 12.5742 0.14 0.22 0.3 0.32

5067. 18 0.77 13,3301 0.14 0.22 0.30 0.31

5065 19 0.25 12.4907  0.10 0.22 0.26 0.3

5067 - 20 0.77 13319  0.12 0.21 0.30 0.30 0.3 0.35 0.40 0.47 0.5 0.5 0.66 0.56  0.56  0.56

5067 67 0.77 13.2601  0.12 0.20

5067 . 68 077 13.197%  ©0.06 0.11 0.23 0.28 0.26  0.32

s085 21 0.77 13.6078  0.12 0.23 0.32 0.32 0.32 0.37 0.44 0.49 0.65 0.66 0.79 0.60 0.57  0.59

5085 22 0.77 13.5278 0.13 0.18 0.3 0.3

5085 [} 0.77 13.7014 0.11 0.17 0.34 0.36 0.37 0.43

5085 66 0.77 13.5821 0.13 0.18

M566 3% 0.77 13.6297  0.09 0.09 0.8 0.29 0.5 038  0.39°

MI566 395 0.77 13.6678  0.11 0.12 0.22° 0.32 0.62 0.37  0.40°

M1566 406 Cold Worked 50X 0.77 13.8262 0.12 0.15 0.33° 0.64 0.92 0.85 0.91°

 

*Unless otherwise specified, annealed 1 hr at 1176°C in argon, tested with

b4,000 hr.
11,000 he.

the surface in the as-rolled condition.

 

o
=

 
Table Al10, Weight Change Data for Specimens of
Modified Hastelloy N Commercial Heats?

 

Weight Gain, mg/cmz‘, at Various Times in hr

 

 

Y

 

Heat Specimen (‘t 1;:23)
1,000 2,000 4,482 5,000 6,000 8,000 10,000 13,000 14,000 15,100 16,000 17,000 18,000 18,700 20,000 21,000
21545 27 13.4661  0.19
21545 28 13.4492  0.25 0.34 0.42 0.43 0.43 0.48
21545 97 13.3940  0.13 0.22
21545 98 13.4485  0.15 0.19 0.34 0.42
21546 25 13.5637  0.23 0.31 0.40 0.37 0.41 0.44
21546 26 13.5364  0.18
21546 95 13.6380  0.23 0.29 0.40 0.45
21546 96 13.5981  0.25 0.31
21554 83 13.5252  0.21 0.31 0.49 0.59
21554 84 13.5208 0.22 0.33
21554 85 13.5629  0.19 0.28 0.43 0.56 0.52 0.60
21554 86 13.5674  0.27 '
21555 79 13.4514  0.25
21555 80 13.5829  0.13  ©0.22 0.35 0.46
21555 81 13.5219  0.11 0.18 0.29 0.35 0.36 0.41
21555 82 13.4692  0.29 0.39
68688 75 13.6022  0.12 0.18
68688 76 13.5285 0.10 0.14 0.24 0.33
68688 77 13.5245  0.04 0.13 0.24 0.30 0.27 0.33
68688 78 13.5056  0.10 b c s .
68688 194 - 13.1127 —0.01 0.13° 0.25° 0.19 0.19 0.24 0.26 0.31 0.39  0.49 0.63  0.44° 0.40
68689 71 13.2735  0.12 0.18 0.31 0.41
68689 72 13.5373  0.10 0.18 0.30 0.41 0.40 0.44
68689 73 . 13.4412  0.13 0.19
68689 74 13.4479  0.14 b - d e
68689 195 12,9800 0.03 0.13° 0.25° 0.17 0.18 0.26 0.29 0.34 0.44 0.5 0.61  0.55% 0.49
69641 160 13.4860  0.10 |
69641 161 13.5752  0.09  0.12, 0.24 0.22 0.25 0.39 0.40  0.44 0.60 0.69  0.65, 0.55  0.52  0.55
69641 196 13.5937  0.04 0.17° 0.18° 0.21 0.27 0.32 0.38 0.43 0.53 0.60 0.60 0.52° 0.51
69648 157 13.5881  0.12 0.14 0.26 0.3% 0.32 0.36 0.52 0.57  0.69 0.78 0.80 0.70 0.71 - 0.73
69648 158 13.5307  0.10 b d
69648 197 13.6013  0.03 0.18° 0.26° 0.24 0.29 0.36 0.45 0.51 0.57 0,70 0.84 0.76° o0.67%
%Annealed 1 hr in argon at 1176°C.-
b),482 hr.
€4,000 nr.
917,700 hr.

€19,000 hr.

 
 

43

L Table All, Weight Change Data'for Specimens of
Modified Hastelloy N Commercial Heats?

 

Ares Weight Gain, mg/cm®, at Various Times in hr
Heat Specimen

 

2
(ca®) 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,100 11,000 12,000 13,000 13,700 15,000 16,000

 

 

: 21541 314 13.6926 0.12 0.14 0.19 0.22 0.18 0.20 0.26 0.28 0.34 0.41 0.59 0.26 0.20 0.22
j 21541 315 13.7063 6.11 0.18 0.20 0.23 0.20 0.20 0.30 0.32 0.38 0.45 0.60 0.33 0.26 0.26
21542 312 ' 13.6926 0.02 0.06 0.09 0.13 0.12 0.12 0.18 0.23 0.29 0.37 0.53 0.25 0.19 0.19
21542 313 13.8022 0.10 ©.12 0.16 0.17 0.16 0.19 0.21 0.25 0.33 0.40 0.57 0.28 0.21 0.23
21543 310 13.7611 0.09 0.12 0.13 0.15 0.14 0.15 0.22 0.27 0.33 0.35 0.40 0.17 0.06 0.06
21543 311 13.7748 0.12 0.1 0.17 0.19 0.16 0,17 0.24 0.28 0.33 0.42 0.51 0.19 0.08 0.09
i 21544 308 13.7200 0.26 0.35 0,36 0.31 0,19 .0.23 0.36 0.43 0.51 0.60 0.79 0.78 0.60 0.63
21544 309 13.7959 0.17 0.26 0.31 0.36 0.28 0,27 0.41 0.48 0.57 0.62 0.91 0.83 0.62 0.63

 

21545 343 13.4363 0.19 0.25 0.27 0.31 0.31 0.3% 046 048 0,60 0.58b

0.41 0.36
21546 344 13.6956 0.27 0.3 0.3 0.39 0.41 0.45 0.5 0,58 0.71 0.61b 0.533 0.51
21554 345 13.6301 0.13 ©0.17 0.20 ©0.27 0.31 .0.38 0.47 0.54 0.9 0.78b 0.55 0.54

21355 346 13,3827 0.07 ©.12 0.13 0.19 0.25 0.28 0.38 0.40 0.56 0.52° 0.40 0.27
b

 

 

70727 342 14.1173 —0.05 ~0.04 —0.05 —0.03 —0.03 0.01 0.08 0.18 0.38 0.11 0.09 0.11
70785 306 13.7337 0.05 0.1r 0.17 0.23 0.18 0.19 0.30 0.37 0.45 0.55 0.79 0.63 0.53 0.52
70785 0 13.7063 0.12 0.12 0.18 ©0.20 0.21 0.23 0.26 0.34 0.40 0.47 0.74 0.67 0.51 0.55
70786 304 13,7063 0.07 0,11 0.16 0.20 0.20 0.20 0.33 0.39 0.47 0.58 0.80 0.59 0.55 0.61
70786 305 - 13.7474 0.09 0.09 0.14 0.15 0.17 0.21 0.33 0.39 0.48 0.57 0.90 0.66 0.58 0.63
70787 302 13,7337 0.10 0.15 0.24 0.25 0.27 0.28 0.44 0.50 0.60 0.71 0.96 0.71 0.64 0.69
70787 303 13.6926 0.07 0.15 0.23 0.26 0.23 0.25 0.38 0.45 0.55 0.64 0.98 0.69 0.60 0.64
70788 300 13.7337 0.09 0,16 0,15 0.15 0.17 0.18 0.30 0,37 0.45 0.66 0.77 0.66 0.60 0.66
70788 301 13,7885 0.01 0.01 0.06 0.05 0.07 0.08 0.18 0.25 0.36 0.49 0.62 0.46 0.43 0.49
70795 298 13.6515 0.03 0.08 0.14 0.20 0.18 0.18 ©0.27  0.36 0.45 - 0.56 0.80 0.64 0.50 0.55
70795 299 13.6789 0.01 0.06 0.08 0.16 0.16 0.16 0,28 0.3 0,42 - 0.54 0.68 0.59 0.47 0.49
: 70796 296 13,8323 0.06 0.10 0.17 0.20 0.15 (.13 0.25 0.34 0.42 0.51 0.93 0.74 0.46 0.50
- 70796 297 13.8296 .09 0.12 0.17 0.23 - 0.13 0.12 0.28 0.38 0.46 0.55 0.75  0.68 0.54 0.57
10797 294 13.7666 0.03 0.4 0.09 0.14 0,12 0.12 0.19 0.25 0.32 0,41 0.60 0.52 0.33 0.33
70797 295 13.7611 0.04 0.07 0.10 0.13 0.13 0.12 0.20 0.26 0.32 0.41 0.63 0.51 0.37 0,319
y 70798 292 13.7081 0.03 0.03 0.09 0.12 0.09 0.09 0.16 0.21 0.24 0.36 .51 0.39 0.30 0.28
70798 293 13.6877 0.04 0.08 0.12 0.1¢6 0.15 0.15 0.25 0.31 0.35 0.44 0.61 0.52 0.40 0.41
70835 290 13.9187 0.05 0.02. 0.06 0.08 0.07 0.07 0.09
70835 291 13.7819 0.04 0,04 0.09 0.09 0.09 0.08 0.14 0.17 0.22 .31 0.54 0.35 0.27 0.28
70835 529 13,8030 0.11 0.31 0.41 0.46 0.41 0.35 0.35 )
71114 338 13.7502 0.10 ©0.17 0©0.17 0.23 0.28 0.33 0.42 0.56 0.76 0.&1: 0,43 0.45
i 71114 339 13.4699 0.10- 0.15 0.15 o0.20 0.23 0.33 0.39 0.51 0.69 0,37 0.41 0.45
: 71583 340 13.6410 0.08 0.11 0.13 0.20 0.25 0.32 0.42 0.53 0.73 0.&3: 0.46 0.54
71583 341 13.5512 0.08 0.13 0.15 0.21 0.26 0.33 0.4 0.55 0.72 0.47 0.50 0.58
72115 396 13.7987 0.18 0.23 0.3 0.4 0.52 0.65 0.88 0,96 0.92° 0.82 0.86
72115 397d 13.7606 0.17. 0.20 0.31 0.41 0.48 0.78 0,89 1.00 0.94° 0.73 0.75
72115 414 13.7200 0.18 0.29 0,42 0.51 0,59 0.76 0.82 0,94 0.93° 0.84 . 0.83
72503 398 13.8469 ©0.12. 0.1&4 0.22 0.27 0.36° 0.50 0.66 0.71 0.72: 0.65 0.70
72503 399d 13.8060  0.11 0.12 0.20 90.27 0.35 0.44 0.59 0.64 0.64c 0.60 0.83
72503 415 13.7870 0.04 0,02  0.02 0,04 0.06 0.12 0,24 0.32 033 0.27 . 0.25
: 72604 400 14.0059 0.39 0.40 0.47 0,54 0.61 0.72 0.85 0,91  0.855 0.75 0.72
! . 72604 401 13.9300 0.34 0.3 0.39 0.46 O0.55 0.69 0.83 0.87 - 0.8° 0.70 0.71
i 72604 416 12.4655 0.15 0.23 0.36 O0.44 0.57 0,71 0.84 0.96 0.99° o0.97 0.99
i . 73008 530: 13,1383 0.00 0.05 0.12 0.15 0.17 0.18 0.19
! 73008 531 13,3845 0.08 0.25 0.25 0.34 0.32 0.31 0.32
I : : 73008 532 13.5265 0.10 0.14 0.21 0.26 0.24 0.23  0.22
73008 533 13.5265 0.23  0.44 - 0.47  0.62 0.62 0.58 0.57

 

 

%ynless otherwise specified, annealed 1 hr at 1176°C in argon.
b9,700 . c o :
€8,700 hr.

80014 worked 50%.

 

i
i
i
|
i
 

Table Al2. Weight Change Data for Specimens of Modified Hastelloy N Commercial Heats®

 

Weight Gain, mg/cm®, at Various Times in hr

 

 

 

Area
Heat Specimen (cmz)
' 1,812 3,330 4,330 5,330 6,330 8,330 12,330

69344 258 13.6713 0.21 0.17 0.19 0.21 0.23 0.22 0.26
69344 259 13.6708 0.12,  0.20,  0.24,  0.21 0.25.  0.25 0.28
69344 522 14.0641 0.14)  0.237  0.24; 0.21° 0.23 0.25%
69344 523 14.3600 0.18 0.29 0.33 0.23°  0.25 0.278 |
69345 260 13.6722 0.18 0.13 0.16 0.20 0.26 0.21 0.26
69345 261 13.6106 0.15,  0.20  0.19, 0.19,  0.23.  0.2L 0.26
69345 524 14.0517 0.29)  0.26C  0.387  0.37_  0.32 0.308
69345 525 13.9051 0.32 0.32 0.40 0.40 0.32 0.298
69714 262 13.6283 0.16 0.22 0.20 0.21 0.23 0.24 0.31
69714 263 13.6248 0.16,  0.20 0.18,  0.21 0.30,  0.28 0.34
69714 526 13.6273 0.42 0.43° 0.54% 0.572 0.45 0.438
69714 527 13.6956 0.34 0.37  0.46 0.48 0.39 0.388
70727 264 13.6558 0.19 0.24 0.27 0.29 0.39 0.37
70727 265 13.6675 0.19,  0.20 0.18,  0.20  0.27,  0.26 0.33
70727 528 14.2668 0.25 0.29%  0.41 0.33 0.23’ 0.198

8Annealed 1 hr at 1176°C in argon.

b5,000 hr.

€3,000 hr.

44,000 hr.

€5,000 hr.

£¢,000 hr.

87,000 hr.

™3

Y

 
 

 

"

1-2.
3.
4—18.
19.
20.
21.
22.

23,

24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
4042,

88—89.

90-91.

45

ORNL/TM-5781
Distribution
Category UC-76

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