Sandvik 321 is an austenitic, titanium-stabilized stainless chromium-nickel steel. It is suitable for wet-corrosive service but also has good mechanical strength at high temperatures.

Applications
Good resistance to hydrogen sulphide gas and intergranular corrosion coupled with good high temperature strength make Grade 321 (Sandvik 6R35) a suitable material for applications as tubes in heating furnaces and heat exchangers in sulphurisation and hydro-treating plants. In the petrochemical industry the steel is used in cracking furnaces for the production of ethylene and vinyl chloride. It is also frequently used for heat exchangers and piping in the chemical and petrochemical industries.