Hot forming method and a hot formed member

摘要

A hot press-formed member having stable strength and toughness is manufactured from a high strength steel sheet by hot press forming. In the cooling stage during hot press forming, the cooling rate is at least the critical cooling rate until the Ms point is reached and it is then in the range of 25-150° C./s in the temperature range from the Ms point to 200° C. The Vickers hardness of the hot pressed member is less than the value of (maximum quenching hardness -10) and at east the value of (maximum quenching hardness -100).