Stainless steel pipe is a pipe made of stainless steel as raw material through multiple processes.
Stainless steel is divided into five categories according to the crystal structure: austenitic stainless steel (A1, A2, A3, A4, A5), ferritic stainless steel (F1), martensitic stainless steel (C1, C4, C3), duplex stainless steel and precipitation hardening stainless steel.
Austenitic stainless steel contains 16%-26% chromium and less than 35% nickel. It usually has the highest corrosion resistance, cannot be strengthened by heat treatment, and is non-magnetic; the most common type is 18/8, or 304 grade, which contains 18% chromium and 8% nickel; typical uses include aircraft industry, dairy products and food processing industry.
Ferritic stainless steel contains 10.5%-27% chromium and no nickel. Due to its low carbon content (less than 0.2%), it cannot be strengthened by heat treatment and is only used in occasions where corrosion protection is not required, such as construction and automotive decoration.