MA22
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.
Weldability/Workability
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.
Specifications
Information on specifications to which MA22 alloy can be ordered.
ASTM UNS N06022
| Plates | Bars, Forgings | Pipes and Tubes | Joints |
|---|---|---|---|
| B575 | B564 | B619 | B366 |
| B574 | B622 | ||
| B626 |
ASME UNS N06022
| Plates | Bars, Forgings | Pipes and Tubes | Joints |
|---|---|---|---|
| SB-575 | SB-564 | SB-619 | SB-366 |
| SB-574 | SB-622 | ||
| SB-626 |
JIS ALLOY NW6022
| 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 |