Hastelloy B-3 Nickel Based Superalloy
Hastelloy B-3 is a nickel-molybdenum alloy with excellent resistance to pitting, corrosion, and stress-corrosion cracking plus, thermal stability superior to that of alloy B-2. In addition, this nickel steel alloy has great resistance to knife-line and heat–affected zone attack. Alloy B-3 also withstands sulfuric, acetic, formic and phosphoric acids, and other non-oxidizing media. Furthermore, this nickel alloy has excellent resistance to hydrochloric acid at all concentrations and temperatures. Hastelloy B-3’s distinguishing feature is its ability to maintain excellent ductility during transient exposures to intermediate temperatures. Such exposures are routinely experienced during heat treatments associated with fabrication.
Limiting Factors of Hastelloy B-3
Alloy B-3 has poor corrosion resistance to oxidizing environments, 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 nickel steel 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.