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.

Sodium hydroxide, NaOH
Conc. %101010202025253030304040
Temp. °C2090103=BP209020112=BP20100116=BP8090
Grade or type of alloy:
Carbon steel0000
13 Cr001010201211
Alleima® 1802000000000100
Alleima® 3R120000000001s00
Alleima® 3R600000000000s00
18Cr13Ni3Mo 1)
17Cr14Ni4Mo 2)
Alleima® 2RK65 ('904L')0000000000s00
Sanicro® 28000000ND00
254 SMO00000ND
654 SMO000
SAF™ 230400000ND00
SAF™ 220500000ND
SAF™ 250700000ND
Titanium (CP Ti)

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

Sodium hydroxide, NaOH
Conc. %4040505050505060606070707090Molten
Temp. °C100128=BP6090100120140=BP90120160=BP90130180=BP300320
Grade or type of alloy:
Carbon steel222212222
13 Cr121122212212222
Alleima® 1802120111211211222
Alleima® 3R1211s01111s11211222
Alleima® 3R6011s01111s1121121s2
18Cr13Ni3Mo 1)
17Cr14Ni4Mo 2)
Alleima® 2RK65 ('904L')01s00001s0020021s2
Sanicro® 2800ND1ND0022
254 SMO1ND011ND22
654 SMO
SAF™ 230411ND00120201
SAF™ 22052122
SAF™ 25071ND2212
Titanium (CP Ti)110111101201222
SAF™ 29060010
SAF™ 2707 HD0121
SAF™ 3207 HD0010

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.