These corrosion data are mainly based on results of general corrosion laboratory tests, carried out with pure chemicals and water solutions nearly saturated with air (the corrosion rate can be quite different if the solution is free from oxygen).

All concentrations are given in weight-% and the solvent is water if nothing else is shown. The corrosion data apply to annealed materials with normal microstructure and clean surfaces, throughout.

Acetic acid, CH3COOH + formic acid, HCOOH
Conc .CH3COOH,%55782020253040405050505050
Conc. HCOOH,%5953280 80 5 660 60 10 15 20 25 
Temp. °CBP102BPBP95 103BP 20090 105 BPBPBPBPBP
Grade or type of alloy
Carbon Steel2
13% Cr-Steel2
Alleima® 18022
Alleima® 3R121122
Alleima® 3R601001211111
18Cr13Ni3Mo 1)
17Cr14Ni4Mo 2)
Alleima® 2RK65 ('904L')100000020011
Sanicro® 2800000000111
254 SMO00000000000000
654 SMO00000000
SAF™ 230400000001111
SAF™ 220500000000001
SAF™ 250700000000000
Titanium (CP Ti)0
SAF™ 29060000
SAF™ 2707 HD0001
SAF™ 3207 HD000

1) ASTM 317L, e.g. Alleima® 3R64
2) EN 1.4439, e.g. Alleima® 3R68

Conc. CH3COOH,%506060808090959899
Conc.HCOOH, %504040202010521
Temp. °CBp90109 =BP95113 =BpBP117 =BPBPBP
Grade or type of alloy:
Carbon steel
13 Cr
Alleima® 1802
Alleima® 3R120
Alleima® 3R6000000
18Cr13Ni3Mo 1)
17Cr14Ni4Mo 2)
Alleima® 2RK65100000000
Sanicro® 2800000
254 SMO000000000
654 SMO00000
SAF™ 230410100
SAF™ 220510000
SAF™ 250700000
Titanium (CP Ti)
SAF™ 29060
SAF™ 2707 HD0
SAF™ 3207 HD0

1) ASTM 317L, e.g. Alleima® 3R64
2) EN 1.4439, e.g. Alleima® 3R68

Symbol clarification

These corrosion tables use a number of symbols, having the following meanings:

Symbol Description
0 Corrosion rate less than 0.1 mm/year. The material is corrosion proof.
1 Corrosion rate 0.1—1.0 mm/year. The material is not corrosion proof, but useful in certain cases.
2 Corrosion rate over 1.0 mm/year. Serious corrosion. The material is not usable.
p, P Risk (severe risk) of pitting and crevice corrosion.
c, C Risk (Severe risk) of crevice corrosion. Used when there is a risk of localised corrosion only if crevices are present. Under more severe conditions, when there is also a risk of pitting corrosion, the symbols p or P are used instead.
s, S Risk (Severe risk) of stress corrosion cracking.
ig Risk of intergranular corrosion.
BP Boiling solution.
ND No data. (Used only where there are no actual data to estimate the risk of localised corrosion instead of p or s).

Disclaimer: Laboratory tests are not strictly comparable with actual service conditions. Accordingly, Alleima makes no warranties, express or implied, and accept no liability, compensatory or consequential, for the performance of different materials in individual applications that may be based on the information provided in this publication.