PRODUCTION OF CR-NI STAINLESS STEEL SHEET HAVING EXCELLENT SURFACE QUALITY AND MATERIAL QUALITY

摘要

PURPOSE:To produce the stainless steel sheet having excellent surface quality and material quality by continuously casting a Cr-Ni stainless steel to a thin strip-like ingot under specific conditions and cooling the ingot to form the finer crystal grains and to prevent carbide precipitation, then working the ingot to a product. CONSTITUTION:The Cr-Ni stainless steel represented by 18% Cr-8% Ni steel is continu ously cast to the thin strip-like ingot having <=10mm thickness by a continuous casting machine in which the wall surfaces of the casting mold moves in synchronization with the ingot while the cooling rate at the time of solidifying is kept at >=100 deg.C/sec. The ingot is cooled down to 1200 deg.C at >=100 deg.C/sec cooling rate while the recuperation of the ingot is suppressed by starting the cooling from a high temp. region as far as possible to form the finer delta grains or gamma grains and thereafter, the ingot is cooled at >=50 deg.C/sec average cooling rate in a 900 to 550 deg.C temp. region to prevent the precipi tation of carbide. The ingot is thereafter subjected to one or >=2 kinds of hot working, warm working and cold working and is thereby made into the product. The Cr-Ni stainless steel sheet having no surface defects is obtd. by the simple production process in this way.