Nickel Insitute - Nickel Alloys in Organic Acids & Related Compounds

TABLE VI Effect of Thermal Treatments on Molybdenum-Containing Stainless Steels

Corrosive medium: Acetic acid 35%, formic acid 1.0%, water 64%. Conditions

: Process liquid at 131 ºC (268 ºF) (boiling) for 84 days, air free.

Corrosion Rate

Alloy

Condition of Specimen

mm/y

mpy

Annealed 1 hr 677 ºC (1250 ºF) AC 4 hr 871 ºC (1600 ºF) AC, 1 hr 677 ºC (1250 ºF) AC As-welded (316L rod) Welded, 1 hr 704 ºC (1300 ºF) AC Welded, 1 hr 871 ºC (1600 ºF) AC As-welded (310 Mo rod) Welded (310 rod) 1 hr 871 ºC (1600 ºF) AC Annealed

.06 .06 .04*

2.5 2.5 1.4*

Type 316L Stainless Steel

.08 .08 .07 .06 .06 .39 .39 .65 .40 .71 .05

3.2 3.0 2.6 2.3 2.4

15.5 15.3 25.5 15.9 27 . 7 2.0

Type 316 Stainless Steel

2 hr 621 ºC (1150 ºF) AC 1 hr 677 ºC (1250 ºF) AC As-welded (316 rod) Welded, 1 hr 871 ºC (1600 ºF) AC Annealed

Type 317 Stainless Steel

6.3* 26.9* 1.73 21.5* 2.6 2.6 25.1* 2.4 2.6 12.0

4 hr 593 ºC (1100 ºF) AC 1 hr 677 ºC (1250 ºF) AC As-welded (317 rod) Welded, 1 hr 704 ºC (1300 ºF) AC Annealed 1 hr 677 ºC (1250 ºF) AC 1 hr 1316 ºC (2400 ºF) AC + 1 hr 677 ºC (1250 ºF) AC As-welded (318 rod)

.16* .68* .04 .55* .07 .07 .64*

Type 318 Stainless Steel

.06 .07 .30

Welded + 1 hr 704 ºC (1300 ºF) AC Welded + 1 hr 871 ºC (1600 ºF) AC

Reference 11

* Intergranular attack noted

NOTE: AC = Air-Cooled

TABLE VII

Corrosion of Alloys in Acetic-Formic Acid Process Mixtures

Corrosion Rate

Type 316 Stainless Steel

Type 317 Stainless Steel

Stream

Test

CARPENTER alloy 20

INCOLOY alloy 825

HASTELLOY alloy C

HASTELLOY alloy B

INCONEL alloy 600

Nickel 200

MONEL alloy 400

Arsenical Admiralty

EVERDUR* 1010

Composition

Temperature Period

C

F

days mm/y mpy

mm/y mpy

mm/y mpy

mm/y mpy

mm/y mpy mm/y mpy

mm/y mpy

mm/y mpy

mm/y mpy

mm/y mpy

mm/y mpy

17% Acetic Acid 1 % Formic Acid 82% Water 18% Acetic Acid 40% Formic Acid 2% Water 40% Organics 6% Acetic Acid 10% Formic Acid

100 212 452

03

1

.03

1

–

–

–

–

–

–

05

2

.61

24

.25

10

–

–

08

3

.05

2

91 196

55

.08

3

.05

2

.05

2

.03

1

<.03 <1

–

–

–

–

–

–

–

–

.10

4

–

–

81 178

55

15

6

.13

5

.08

3

.08

3

<.03 <1

–

–

–

–

–

–

–

–

.10

4

–

–

3% Water 81% Organics

12% Acetic Acid 3% Formic Acid

121 250 355

05

2

–

–

–

–

–

–

–

–

<.03 <1

–

–

–

–

.05

2

.08

3

.03

1

85% Water

40% Acetic Acid 6% Formic Acid

106 223

99

.51

20

.28

11

38

15

–

–

.18

7

–

–

–

–

–

–

.51

20

.03

1

–

–

5% Water 49% Organics

*Trademark of Anaconda American Brass Co.

Page 9