... 4)Surface Polishment and NDT Test 5)ISO9001:2 Gate Valve StemsStandard: ASTM, BF,BS, JIS, UNI, ANSI, ISO etc. ... include: Stainless Steel, Carbon Steel, Alloy Steel, Ductile Iron, Grey Iron, Copper, Aluminum Bronze, Malleable Iron etc.2) Process: Investment Casting, Sand Casting ( ... ) Standard: ASTM, BF,BS, JIS, UNI, ANSI, ISO etc.valve stem of 303 stainless steel4"API Gate ValveMaterial: Alloy Steel ...