公开(公告)号：US20190055621A1

公开(公告)日：2019-02-21

申请号：US16084313

申请日：2017-03-21

Applicant: JFE Steel Corporation

Inventor： Taro Kizu ,  Imanuel Tarigan ,  Minoru Utake ,  Yuichi Ozawa

IPC: C21D9/46 ,  C21D8/02 ,  C21D6/00 ,  C23C2/06 ,  C23C2/02 ,  C23C2/40 ,  C22C38/60 ,  C22C38/58 ,  C22C38/54 ,  C22C38/50 ,  C22C38/48 ,  C22C38/46 ,  C22C38/44 ,  C22C38/42 ,  C22C38/06 ,  C22C38/02 ,  C22C38/00 ,  B32B15/01

Abstract: A steel sheet and a method for producing the steel sheet are provided. The steel sheet is provided having a composition including C: 0.05% to 0.15%, Si: 0.1% or less, Mn: 1.0% to 2.0%, P: 0.10% or less, S: 0.030% or less, Al: 0.10% or less, and N: 0.010% or less, and including one or two or more of Ti, Nb, and V, the remainder being iron and incidental impurities. The steel sheet has a microstructure containing, on an area percent basis, ferrite: 80% or more, and bainite and martensite: 1% to 20% in total. The ferrite has an average grain size of 10.0 μm or less, and a phase containing bainite and martensite has an average grain size of 3.0 μm or less. The ratio of the average grain size of the phase containing bainite and martensite to the average grain size of the ferrite is 0.3 or less.