Steel plate and its manufacturing method

专利名称：Steel plate and its manufacturing method发明人：小野 義彦,戸畑 潤也,秋元 浩幸,松井 洋一郎,金子

真次郎

申请号：JP2020505520申请日：20191016公开号：JP6787526B2公开日：20201118

摘要：Provided are a steel sheet and a manufacturing method therefor. The presentinvention provides a steel sheet having a specific component composition and a steelstructure wherein: in terms of area ratio, at most 5% of ferrite and 95-100% of astructure comprising one or two or more of upper bainite, fresh martensite, temperedmartensite, lower bainite, and residual γ are contained; in terms of volume ratio, 5-20% ofresidual γ is contained; the area ratio S of residual γ having a particle width of 0.25-0.60µm, a particle length of 1.0-15 µm, and an aspect ratio of 3.1-25 is 0.2-7.0%; the number ofdistributed particles N of residual γ having a particle width of 0.08-0.24 µm, a particlelength of 0.6-15 µm, and an aspect ratio of 4-40 is 10-120 particles per 100 µm; the totalarea ratio S of fresh martensite having a circle-equivalent particle diameter of 0.5 µm ormore and less than 1.3 µm and an aspect ratio of 3 or less and/or residual γ particleshaving a circle-equivalent particle diameter of 0.5 µm or more and less than 1.3 µm andan aspect ratio of 3 or less is 1-10%; and the total area ratio S of fresh martensite havinga circle-equivalent particle diameter of 1.5–20 µm and an aspect ratio of 3 or less and/orresidual γ particles having a circle-equivalent particle diameter of 1.5–20 µm and anaspect ratio of 3 or less is 5% or less (including 0%).

申请人：ＪＦＥスチール株式会社

地址：東京都千代田区内幸町二丁目２番３号

国籍：JP

代理人：磯村 哲朗,熊坂 晃,坂井 哲也,森 和弘

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