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.

Sulphuric acid, H2SO4 + ammonium sulphate, (NH4)2SO4
Conc. H2SO4%0.211122555555
Temp. °C100BP80BP80BP40406080BP60
Grade or type of alloy:
Carbon steel222222222222
13 Cr222222222222
Alleima® 1802111212001221
Alleima® 3R12111212001221
Alleima® 3R60011212000220
18Cr13Ni3Mo 1)
17Cr14Ni4Mo 2)
Alleima® 2RK65 ('904L')000000000010
Sanicro® 28001
254 SMO11
654 SMO0000000
SAF™ 2304001
SAF™ 2205001
SAF™ 25070000000
Titanium (CP Ti)121212111221

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

Sulphuric acid, H2SO4 + ammonium sulphate, (NH4)2SO4
Conc. H2SO4 %5101010101010
Conc. (NH4)2SO4 %40202020404051
Temp. °CBP4080BP4080100
Grade or type of alloy:
Carbon steel2222222
13 Cr2222222
Alleima® 18022122122
Alleima® 3R122122122
Alleima® 3R602012012
18Cr13Ni3Mo 1)
17Cr14Ni4Mo 2)
Alleima® 2RK65 ('904L')1001011
Sanicro® 280
254 SMO20
654 SMO0
SAF™ 23040
SAF™ 22050
SAF™ 25070
Titanium (CP Ti)2222222

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.