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

• Main Authors: TERAOKA SHINICHI, UEDA MASANORI
• Format: Patent
• Language: English
• Published: 22.02.1991
• Subjects: CASTING; CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES; CHEMISTRY; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVINGMATERIAL; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; PERFORMING OPERATIONS; POWDER METALLURGY; PUNCHING METAL; ROLLING OF METAL; TRANSPORTING

PURPOSE:To obtain the sheet having excellent surface quality b casting a molten Cr-Ni stainless steel having a specific compsn. to a thin strip-like ingot of a specific thickness at a specific solidifying and cooling rate, cooling the ingot at a specific cooling rate after the solidification, and then cooling the ingot at a specific cooling rate down to a specific temp. range. CONSTITUTION:The molten Cr-Ni stainless steel having the compsn. contg. <=0.090% C+N and having 30 to 60 deg.C Md30 is cast by a continuous casting machine in which the wall surfaces of a casting mold move in synchronization with the ingot. Namely, the molten steel is cast to the thin strip-like ingot of <=10mm thickness at >=100 deg.C/sec solidification cooling rate. The ingot is cooled from the highest possible temp. from below the solidification temp. at >=50 deg.C/sec cooling rate down to 1,200 deg.C and at >= 10 deg.C/sec down to 1,200 to 550 deg.C, following which the ingot is subjected to descaling, cold rolling and final annealing. The Cr-Ni stainless steel sheet having the excellent surface quality is obtd. in this way.