Ni-28Mo (mass%)

Highly effective in hydrochloric acid and sulfuric acid environments.

Aerospace & Energy Materials Dept.

Main Features

Superior resistance to hydrochloric acid and sulfuric acid MA-B2 is especially suited for equipment that handles hydrochloric acids of all concentrations and at any temperature up to the boiling point. Also it is corrosion-resistant to hydrogen chloride gases, sulfuric acids, acetic acids, and phosphoric acids. However, it is not recommended to be used in environments which contain a certain amount of ferric salt or cupric salt, since corrosion may occur in somecases. For example, if hydrochloric acid comes into contact with iron or copper, ferric salt or cupric salt may be formed. In processes containing hydrochloric acids, if the alloy is used to connect steel (iron) pipes or copper pipes, MA-B2 might be damaged by corrosion at an early stage.
MA-B2 is the improved version of the alloy, MA-B. It has the same superior corrosion resistance as MA-B, while having an improved corrosion resistance against the knife-line-attack and in the heat-affected zone. Since MA-B2 has little carbide precipitation along the crystal grain boundaries of the welded heat-affected zone, this alloy can be used in the as-welded state for almost any chemical processes.

High temperature resistance atmosphere

Since MA-B2 loses its ductility when it is exposed to temperatures between 538∼870°C, processing and use in this temperature range must be avoided. When using MA-B2 within oxidizing gases such as air, the temperature should be 538°C or lower. For use in reducing gases or vacuity, the alloy can be used at high temperatures, such as 870°C or higher.


MA-B2 is an original alloy provided only by Proterial, Ltd. Okegawa Works, has drastically improved the decreasing tendency of mechanical elasticity at medium temperatures, which used to be an initial problem.

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 MA-B2 alloy can be ordered.


Plates Bars, Forgings Pipes and Tubes Joints
B333 B335 B619 B366
  B564 B622  

ASME UNS N010665

Plates Bars, Forgings Pipes and Tubes Joints
SB-333 SB-335 SB-619 SB-366
  SB-564 SB-622  


Plates Bars Pipes and Tubes Wires
H4551 H4553 H4552 H4554

Corrosion Resistance

Corrosion data

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

Solution Concentration(wt%) Temperature(°C) Corrosion Rate(mm/Year)
Hydrochloric acid 1 boiling <0.03
3 50 0.19
5 room temperature 0.07
36 boiling 0.03
Sulfuric acid 1 boiling 0.025
40 100 0.04
40 80 0.06
40 60 0.01
40 40 0.01
80 120 0.01
80 100 0.01
80 80 0.00
80 60 0.00
80 40 0.00
98.5 150 0.70
98.5 130 0.14
98.5 110 0.04
98.5 90 0.02
Phosphoric acid 5 boiling 0.205
50 50 0.016
Formic acid 88 boiling 0.02
Acetic acid 99 boiling 0.03