METHOD FOR MANUFACTURING HOT PRESS FORMING PART AND HOT PRESS FORMING PART

摘要

In manufacturing a hot press forming part by hot pressing, using a tool of press forming, a coated steel sheet, the tool of press forming having a die, a blank holder, and a punch, edges of the coated steel sheet heated to a temperature range of Ac3 transformation temperature to 1000° C. are cooled with the edges squeezed between the die and the blank holder to a temperature of 550° C. or lower and 400° C. or higher at a cooling rate of 100° C./s or higher, press forming is performed so that the press forming is started when the edges reach a temperature of 550° C. or lower and 400° C. or higher, and after the press forming, a formed body is quenched with the formed body held at the press bottom dead center while being squeezed by the tool of press forming.

主权项

1. A method for manufacturing a hot press forming part by hot pressing, using a tool of press forming, a coated steel sheet that is obtained by forming a Zn—Ni coating layer on a surface of a steel sheet, the tool of press forming having a die, a blank holder, and a punch, the method comprising:
cooling edges of the coated steel sheet heated to a temperature range of Ac3 transformation temperature to 1000° C., with the edges squeezed between the die and the blank holder, to a temperature of 550° C. or lower and 400° C. or higher at a cooling rate of 100° C./s or higher; performing press forming so that the press forming is started when the edges reach a temperature of 550° C. or lower and 400° C. or higher; andafter the press forming, quenching a formed body with the formed body held at the press bottom dead center while being squeezed by the tool of press forming.