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.

Phosphoric acid, H3OP4
Conc. %1113555101010102020203030
Temp. °C20100
=BP
140100
=BP
20-6085100
=BP
406080101
=BP
3560102
=BP
20-3560
Grade or type of alloy:
Carbon steel2222222222222222
13 Cr0212002222222222
Alleima® 18020000000000000000
Alleima® 3R120000000000000000
Alleima® 3R600000000000000000
18Cr13Ni3Mo 1)
0000000000000000
17Cr14Ni4Mo 2)
0000000000000000
Alleima® 2RK65 ('904L')0000000000000000
Sanicro® 280000
254 SMO0000
654 SMO0000
SAF™ 2304000000
SAF™ 22050000
SAF™ 250700000000000
Titanium (CP Ti)0001012012201201

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

Phosphoric acid, H3OP4
Conc. %30404040405050505050506060606070
Temp. °C1003550100

106
=BP

20355085100110
=BP
2035100116
=BP
35
Grade or type of alloy:
Carbon steel2222222222222222
13 Cr2222222222222222
Alleima® 18021001200012200220
Alleima® 3R121001200001200220
Alleima® 3R600000100001200120
18Cr13Ni3Mo 1)
0000100001100120
17Cr14Ni4Mo 2)
0000000000100120
Alleima® 2RK65 ('904L')0000100000100010
Sanicro® 2800000000011
254 SMO10000001
654 SMO000010000
SAF™ 23040100000100020
SAF™ 220500000000001
SAF™ 250700000000001
SAF™ 2707 HD0
SAF™ 29060
SAF™ 3207 HD0
Titanium (CP Ti)2122201222211222

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

Phosphoric acid, H3OP4
Conc. %707080808080808586868686868686
Temp. °C90126
=BP
203580100146
=BP
10520508595105115156
=BP
Carbon steel22222222222
13 Cr22222222222
Alleima® 180222002220122
Alleima® 3R12220012200122
Alleima® 3R6012000120012
18Cr13Ni3Mo 1)
02000120012
17Cr14Ni4Mo 2)
02000120012
Alleima® 2RK65 ('904L')0100012000012
Sanicro® 2801112
254 SMO01000010000112
654 SMO010000100012
SAF™ 23040200002112
SAF™ 2205011200012
SAF™ 25070202000112
SAF™ 2707 HD121
SAF™ 29060111
SAF™ 3207 HD220
Titanium (CP Ti)22222222222

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.