摘要 |
The newly proposed austenitic stainless steel has composition consisting of (C+1/2N) up to 0.060 mass %, Si up to 1.0 mass %, Mn up to 5 mass %, S up to 0.006 mass %, 15-20 mass % Cr, 5-12 mass % Ni, Cu up to 5 mass %, 0-3.0 mass % Mo and the balance being Fe except inevitable impurities under the condition that a value Md30 (representing a ratio of a strain-induced martensite) defined by the under-mentioned formula is controlled within a range of -60 to -10. Hardness increase of the steel sheet after being cold-rolled is preferably 20% or more as Vickers hardness. A metallurgical structure of the steel sheet is preferably adjusted to grain size number of #8 to #11 in a finish annealed state. The steel sheet is blanked with high dimensional accuracy, and a die life is also prolonged. <DF>Md30=551-462(C+N)-9.2Si-29(Ni+Cu)-8.1Mn-13.7Cr-18.5Mo </DF> |