Stainless Steel, Application : Tunnel, Subway, Industry

Stainless steel is the generic name for a number of different steels used primarily for their resistance to corrosion. The one key element they all share is a minimum percentage of chromium: 10.5%. Although other elements are added to improve corrosion resistance, chromium is always present. The principal grades are austenitic (typically 16-26%Cr, 6-22Ni); ferritic (10.5-28%Cr with no/low Ni); martensitic (higher carbon content than ferritic and typically 12-19%Cr with low/no Ni); and duplex, a dual-phase austenitic/ferritic steel (Cr>21%, Ni