Nickel Base Alloy Heat Exchanger Tube , ASTM B622 Alloy C22, Hastelloy Seamless Tube Nickel-base Alloy (UNS N06022) is a Ni-Cr-Mo alloy that provides outstanding resistance to pitting, crevice corrosion, intergranular attack, and stress corrosion cracking. The combination of Cr, Ni, Mo, and W provides excellent resistance to a broad range of both oxidizing and reducing environments. This grade also has high strength, good ductility, excellent welding and forming characteristi