公开(公告)号：US11767582B2

公开(公告)日：2023-09-26

申请号：US16760950

申请日：2018-11-08

Applicant: NATIONAL INSTITUTE FOR MATERIALS SCIENCE

Inventor： Tadanobu Inoue ,  Hai Qiu ,  Rintaro Ueji

IPC: C22C38/04 ,  C21D8/02 ,  C22C38/02 ,  C22C38/06 ,  C21D9/46

CPC classification number: C22C38/04 ,  C21D8/0205 ,  C21D8/0221 ,  C21D9/46 ,  C22C38/02 ,  C22C38/06 ,  C21D2201/00

Abstract: The present invention provides a steel material which has a plate shape and achieves both high strength and high rigidity by imparting large nonuniform deformation to the steel material utilizing rolling using a large-diameter work roll. The steel plate according to an embodiment of the present invention is produced by performing rolling using a rolling mill having a work roll diameter of 650 mm or more in a warm temperature region so that a nonuniform metallographic structure is formed in a plate thickness direction and thus the steel plate of the present invention is a high-strength and high-rigidity steel plate in which a yield strength is 580 MPa or more and a Young's modulus at a plate thickness center portion or a surface layer portion is 210 GPa or more and a difference in Young's moduli at the plate thickness center portion and the surface layer portion is 5 GPa or more in a case in which a tensile direction in a tensile test is at least any one of a rolling direction, a plate width direction, or a direction forming an angle difference of 45 degrees from the rolling direction and the plate width direction.