PRODUCTION OF COLD ROLLED STEEL SHEET FOR DEEP DRAWING BY CONTINUOUS ANNEALING METHOD

• Main Authors: NISHIMOTO YUZO, YAMADA TERUAKI, HAYASHIDA TERUKI, KOINO MICHIHIRO, FUJII KOJI, ODA MASAHIKO
• Format: Patent
• Language: English
• Published: 14.06.1991
• Subjects: ALLOYS; CHEMISTRY; FERROUS OR NON-FERROUS ALLOYS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; TREATMENT OF ALLOYS OR NON-FERROUS METALS

PURPOSE:To obtain the steel sheet free from material deterioration in the top part and the bottom part of a coil by the use of a low-cost stock by limiting C content in an Al-killed steel to a specific value or below, inhibiting the abnormal growth of crystalline grains in a hot rolled plate, and specifying manufacturing conditions. CONSTITUTION:A molten steel having a composition consisting of, by weight, 0.008-0.035% C, 0.003-0.10% Si, 0.05-0.35% Mn, 0.001-0.10% P, 0.001-0.030% S, 0.020-0.10% SOlAl, 0.0005-0.0060% N, and the balance iron is formed into a slab by means of continuous casting, etc. This slab is heated up to 1000-1170 deg.C, finish rolling is completed at 890-960 deg.C, and channel cooling is applied to the part between the position of 18m from the head end of a steel strip and the position of 15m from the tail end of the steel strip. The upper limit of coiling temp. is specified so that it is 850 deg.C in the part of <18m from the head end, 760 deg.C at the position of 18m from the head end, 740 deg.C at the position of 50m from the head end, a temp. obtained by connecting 760 deg.C and 740 deg.C with a straight line in the part between the position of 18m from the head end and the position of <50 from the head end, 740 deg.C in the part between the position of 50m from the head end and the position of 30m from the tail end, 740 deg.C at the point of 30m from the tail end, 760 deg.C at the position of 15m from the tail end, a temp. obtained by connecting 740 deg.C and 760 deg.C with a straight line in the part between the position of <30m from the tail end and the position of 15m from the tail end, and 820 deg.C in the part of <15m from the tail end. The lower limits of coiling temp. in respective parts are specified in a similar manner.