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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.

Citric acid, C3H4(OH)(COOH)3
Conc. %11555101025252525255050505070
Temp. °C20BP20 -5085 -BP14020 -4085 -BP204085100BP2040100BPBP
Grade or type of alloy:
Carbon steel22222222222222222
13 Cr12222222222222222
Alleima® 180200000000000000001
Alleima® 3R1200001000012200222
Alleima® 3R6000000000000000001
18Cr13Ni3Mo 1)
00000000000000001
17Cr14Ni4Mo 2)
00000000000000001
Alleima® 2RK65 ('904L')00000000000000000
Sanicro® 280000000000000000
254 SMO0000000000000000
654 SMO0000000000000000
SAF™ 23040000000000000000
SAF™ 22050000000000000000
SAF™ 25070000000000000000
Titanium (CP Ti)00000000000100011

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.