PRODUCTION OF COMPOSITE PHASE STRUCTURE CHROMIUM STAINLESS STEEL SHEET OR STEEL STRIP HAVING SMALL INTRASURFACE ANISOTROPY AND HIGH DUCTILITY AND HIGH STRENGTH

摘要

PURPOSE:To produce a composite phase structure chromium stainless steel sheet or steel strip having small intrasurface anisotropy and high ductility and high strength by subjecting a cold rolled stainless steel or strip contg. C and Cr at specified ratios to an adequate finish heat treatment. CONSTITUTION:The chromium stainless steel sheet contg. =0.10wt% C and 10.0-18.0% Cr as essential components is subjected to ordinary hot rolling and cold rolling to form the cold rolled steel sheet or strip. The cold rolled steel sheet or strip obtd. in such a manner is subjected to the finish heat treatment to heat the same to the temp. to provide the two phase region of ferrite + austenite and to cool the same at 5-1,000 deg.C/sec cooling rate from said temp. The component adjustment of the above- mentioned steel is preferably so executed that the temp. in the above-mentioned treatment exceeds 800 deg.C. The heating in the above-mentioned finish heat treatment is preferably executed at =1,100 deg.C heating temp. and within 10min heating time and the cooling at the cooling rate and temp. enough for the austenite to make transformation to martensite. The steel sheet or strip which has the high strength and good ductility and workability, has low anisotropy and is free from ridging is thus obtd.