Ni-22Cr-13Mo-4Fe-3W (mass%)

Most versatile nickel-chromium-molybdenum-tungsten alloy

Aerospace & Energy Materials Dept.

Main Features

MA22 is a multi-faceted Ni-Cr-Mo alloy with better overall corrosion resistance than other Ni-Cr-Mo alloys. MA22 has excellent corrosion resistance to both reducing and oxidizing mediums. Also, its versatility enables it to be used for processes that repeats both reducing and oxidizing conditions as well as for multipurpose equipments. In particular, MA22 shows outstanding corrosion resistance to oxidizing water solutions (acids which contain oxidizing substances, wet chlorine gas, nitric acid mixed mediums, oxidizing acids which contain chlorine ion, etc).

Corrosion Resistance Data

MA22 is highly resistant to pitting corrosion, crevice corrosion and stress corrosion cracking. MA22 shows superior corrosion resistance against a wide range of environments in chemical industrial processes. Some examples are: strong oxidizing agents such as ferric chloride and cupric chloride; high temperature mediums which contain organic or inorganic material; chlorine; formic acid; acetic acid; acetic anhydride; sea water and salt water.


MA22 is readily welded by gas tungsten arc, gas metal arc, and shielded metal arc welding techniques. Submerged arc welding is not recommended as this process is characterized by high heat input to the base metal and slow cooling of the weld.
MA22 can be formed or molded just like stainless steel. Every normal welding method is applicable to MA22, but when using it for parts where corrosion should be prevented, oxy-acetylene method and submerged arc welding are not recommended. Also, excessive heat must be avoided.

Heat Treatment

Except when noted otherwise, solution treatment is normally performed beforehand to MA22 material. By cooling it rapidly after solution treatment, best ductility, corrosion resistance, and workability of the material is achieved. Parts produced by warm processing require solution treatment before the final assembling process or use.

Available Product Forms

Various shapes, such as flat-rolled plates, forgings, welding wires, wires, welded pipes and tubes, seamless pipes and tubes can be manufactured.


Information on specifications to which MA22 alloy can be ordered.


Plates Bars, Forgings Pipes and Tubes Joints
B575 B564 B619 B366
  B574 B622  


Plates Bars, Forgings Pipes and Tubes Joints
SB-575 SB-564 SB-619 SB-366
  SB-574 SB-622  


Plates Bars Pipes and Tubes Wires
H4551 H4553 H4552 H4554

Corrosion Resistance

Corrosion dat

The data below illustrates beaker tests, and does not guarantee maximum or minimum values. Selection of materials for individual usage requires tests on actual equipment.

Solution Concentration(wt%) Temperature(°C) Corrosion Rate(mm/Year)
Hydrochloric acid 1 50 0.009
1 boiling 0.13
2 boiling 1.72
3 50 0.003
5 room temperature 0.008
5 boiling 7.95
36 boiling 0.16
Hydrofluoric acid 2 50 0.08
Sulfuric acid 1 boiling 0.060
10 boiling 0.23
40 boiling 1.89
40 100 1.11
40 80 0.02
40 60 0.00
40 40 0.00
80 120 10.3
80 100 1.36
80 80 0.53
80 60 0.07
80 40 0.02
98.5 130 4.51
98.5 110 5.65
98.5 90 1.66
Phosphoric acid 5 boiling 0.005
85 boiling 3.38
50 50 0.001
Formic acid 88 boiling <0.03
Acetic acid 99 boiling 0.001
Nitric acid 10 boiling 0.03
60 boiling 0.63
60 60 0.02
65 boiling 1.3