Hydrochloric Acid Resistant ASTM Ss Nickel Molybdenum Alloy

Hastelloy B2 is a solid solution strengthened, nickel-molybdenum alloy, with significant resistance to reducing environments like hydrogen chloride gas, and sulfuric, acetic and phosphoric acids. Molybdenum is the primary alloying element which provides significant corrosion resistance to reducing environments. This nickel steel alloy can be used in the as-welded condition because it resists the formation of grain-boundary carbide precipitates in the weld heat-affected zone.

This nickel alloy provides excellent resistance to hydrochloric acid at all concentrations and temperatures. In additions, Hastelloy B2 has excellent resistance to pitting, stress corrosion cracking and to knife-line and heat-affected zone attack. Alloy B2 provides resistance to pure sulfuric acid and a number of non-oxidizing acids.

Limiting Factors of Hastelloy B2

Alloy B-2 has poor corrosion resistance to oxidizingenvironments, therefore, it is not recommended for use in oxidizing media or in the presence of ferric or cupric salts because they may cause rapid premature corrosion failure. These salts may develop when hydrochloric acid comes in contact with iron and copper. Therefore, if this alloy is used in conjunction with iron or copper piping in a system containing hydrochloric acid, the presence of these salts could cause the alloy to fail prematurely. In addition, this nickel steel alloy should not be used at temperatures between 1000° F and 1600° F because of a reduction in the ductility in the alloy.

Characteristics

Great resistance to stress corrosion cracking and pitting

• Significant resistance to reducing conditions like hydrogen chloride, sulfuric, acetic and phosphoric acids
• Resistance to hydrochloric acid at all concentrations and temperatures

Chemical Composition

Application

Chemical processes

• Vacuum furnaces
• Mechanical components in reducing environments

ASTM Specifications

Mechanical Properties

Annealed Material

This is a nickel-molybdenum alloy that is particularly suited to handling reducing acids at high concentrations and temperatures. It may be used in the as-welded condition since it is not susceptible to grain-boundary carbide precipitation following welding. The alloy should not be used in the presence of oxidizing media.

This alloy finds its main uses in the chemical manufacturing industries, particularly in the production of acetic acid, herbicides, insecticides, ethylene glycol and ethyl benzene. It is also used in the production of high-octane gasoline.