Classification : Hastelloy Alloy Hastelloy Alloy Sheet is a versatile austenitic nickel-chromium-molybdenum-tungsten alloy with enhanced resistance to pitting, crevice corrosion and stress corrosion cracking. The high chromium content provides good resistance to oxidizing media while the molybdenum and tungst en content give good resistance to reducing media.Hastelloy Alloy Sheet is particularly useful for resistance to pitting and crevice corrosion in acid-halide environments.