In most cases, fittings can be used in a “welded” condition, where preheating is not required. UNS S30400 grade fittings have excellent resistance to pitting, crevice and general corrosion in compounds containing sulfuric, phosphoric and nitric acids. Although generally regarded as a traditional metal, it is labeled as nickel-based. It is known for making explosives, compounds, gasoline, solvents, and more.