Press-formed product, hot press-forming method and hot press-forming apparatus

A hot press-forming method to obtain a press-formed product, comprising:

• a heating step that heats a steel sheet to an initial temperature not less than an austenite transformation temperature (Ac3 point);
• a positioning step that positions the steel sheet between a die having a forming concave and a punch having a forming convex corresponding to the forming concave;
• a forming step that press-forms the steel sheet into a desired shape by causing the forming concave of the die and the forming convex of the punch to be close to each other, the steel sheet being held by a blank holder and the die, the punch being inserted in the blank holder, wherein the forming step is a forming-with-gap step that performs the press-forming by setting a gap between the die and the blank holder for the flange region of the steel sheet, the gap being larger than a sheet thickness of the steel sheet by placing a distance block between the die and the blank holder, such that the press-forming is performed without clamping/pressing the flange region of the steel sheet by the die and the blank holder;
• and
• after the forming step, returning the die to a predetermined position and then removing the distance block from between the die and the blank holder,
• the press-formed product comprising a formed portion, the formed portion having a side portion and a top portion, the side portion rising up from an inner circumferential edge area of a flange portion having been held by the die and the blank holder, the top portion stretching from the side portion,
• the hot press-forming method further comprising a cooling step that cools only a particular region of the steel sheet to a temperature lower than that of regions peripheral to the particular region during a particular time period, the particular region being a region that is to be at least a part of the side portion and is along an inter-edge area formed between an opening circumferential edge area of the forming concave and a top circumferential edge area of the forming convex before the forming step is completed, the particular time period being a time period at least after the heating step has been completed and before the forming step is completed.