COLD-ROLLED STEEL SHEET AND MANUFACTURING METHOD THEREFOR

• Main Authors: FUNAKAWA YOSHIMASA, YAMAGUCHI RYOSUKE, ONO YOSHIHIKO, NAKAMURA NOBUYUKI
• Format: Patent
• Language: Chinese; English
• Published: 01.12.2017
• 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

The invention relates to a cold-rolled steel and a manufacturing method thereofr. The cold-rolled steel sheet has a structure: which has a prescribed component composition; in which the total area ratio of tempered martensite and bainite with respect to the structure as a whole is 95% to 100%; in which there are not more than 0.8/mm2 of prescribed inclusion groups that extend and/or are distributed in a series of points in the rolling direction and are configured from at least one inclusion particle with a long axis of at least 0.3 [mu]m; in which there are not more than 3500/mm2 of carbides of a prescribed size that have Fe as the main component; in which there are at least 0.7 x 107/mm2 of carbides of 10-50 nm diameter that distribute in the interior of the tempered martensite and/or bainite; and in which the mean particle size of prior [gamma] grains is not more than 18 [mu]m. 本发明提供种冷轧钢板，其具有给定的成分组成和以下的组织：回火马氏体及贝氏体相对于组织总体的面积率总计为95％以上且100％以下，由沿轧制方向伸展和/或点列状分布的1个以上的长轴为0.3μm以上的夹杂物粒子构成的给定夹杂物群为0.8个/mm以下，以Fe作为主成分的