Introduction |
Grade 316 is the standard molybdenum-bearing grade, second in importance to 304 amongst the austenitic stainless steels. The molybdenum gives 316 better overall corrosion resistant properties than Grade 304, particularly higher resistance to pitting and crevice corrosion in chloride environments. Grade 316L, the low carbon version of 316 and is immune from sensitisation (grain boundary carbide precipitation). Thus it is extensively used in heavy gauge welded components (over about 6mm). There is commonly no appreciable price difference between 316 and 316L stainless steel. The austenitic structure also gives these grades excellent toughness, even down to cryogenic temperatures. Compared to chromium-nickel austenitic stainless steels, 316L stainless steel offers higher creep, stress to rupture and tensile strength at elevated temperatures. Key PropertiesThese properties are specified for flat rolled product (plate, sheet and coil) in ASTM A240/A240M. Similar but not necessarily identical properties are specified for other products such as pipe and bar in their respective specifications. CompositionTable 1. Composition ranges for 316L stainless steels. Grade CMnSiPSCrMoNiN316LMin-----16.02.0010.0-Max0.032.00.750.0450.0318.03.0014.00.10 Mechanical PropertiesTable 2. Mechanical properties of 316L stainless steels. GradeTensile Str(MPa) minYield Str0.2% Proof(MPa) minElong(% in 50mm) minHardnessRockwell B (HR B) maxBrinell (HB) max316L4851704095217 |