METHOD FOR MANUFACTURING MARTENSITE STAINLESS STEEL IN WHICH BATCH ANNEALING PROCESS IS SKIPPED

摘要

PURPOSE: A method for manufacturing a martensite stainless steel is provided to improve forming property due to soft-nitriding of a material by controlling cooling rate of the coil after coiling a hot rolled coil, thereby restraining high strength low temperature phase, martensitic phase badly affecting on coiling property due to the complete transformation of the structure of a coiled coil into a mixed phase of ferrite and carbide. CONSTITUTION: In a method for manufacturing a 420 series martensite stainless steel which is manufactured by annealing the hot rolled slab after reheating a slab and hot rolling the reheated slab, the method for manufacturing a martensite stainless steel in which the batch annealing process is skipped comprises the steps of hot rolling a 420 series martensite stainless hot rolled steel sheet comprising 0.16 to 0.40 wt.% of C, 12 to 14 wt.% of Cr and a balance of Fe and other inevitably contained alloy elements under the ordinary conditions; coiling the hot rolled steel sheet in the austenite state of 800 deg.C or more after hot rolling; and controlled cooling the coiled coil in a cooling rate of 25 deg.C/Hr or less.