Residual Elements in Stainless Steel—General Characteristics

Abstract

Residual elements in stainless steel are introduced during melting and originate from the scrap, the ferroalloys, the deoxidizers, and the furnace atmosphere. Several of the elements, in particular boron, can by themselves or in combination with other residual elements form low-melting eutectics which can affect hot workability and welding characteristics. If present in the steel, the elements vanadium, tantalum, columbium, titanium, and zirconium should be present as carbides or nitrides or both. Boron and cerium should be present as nitrides. Only a few of the elements, namely, cobalt, copper, manganese, nickel, carbon, and nitrogen are austenite formers at elevated temperature. All of the elements with the exception of cobalt (and possibly aluminum) increase austenite stability by lowering the Ms temperature. The formation of sigma and chi phase is enhanced by the presence of aluminum, columbium, molybdenum, silicon, tantalum, titanium, vanadium, and tungsten. The interstitial elements, hydrogen, carbon, nitrogen, and boron have the greatest effect on mechanical properties.