| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing an ultra-high strength member having tensile strength TS of ≥1,180 MPa, with which the ultra-high strength member excellent in a delayed fracture resistant characteristic can be produced with a hot-pressing process at a low cost, and a method for using the ultra-high strength member.SOLUTION: For producing the ultra-high strength member having the tensile strength of ≥1,180 MPa by heating a steel sheet to 700-1,000°C, forming into the member-shape at this heated temperature and at the same time, cooling in this forming die and applying a shear-punching work into the targeted shape, the heat treatment is applied in the temperature range of 100°C to <300°C for holding time of 1sec-60min, after the shear-punching work. |
