Press formed product, automobile structural member with the press formed product, and method for producing press formed product

A method for producing a hot stamp formed product from a single steel sheet,

• wherein the hot stamp formed product comprises:
• two vertical wall portions;
• a top plate portion which connects the two vertical wall portions with each other;
• at least one projecting portion which projects from at least one boundary portion of two boundary portions each of which connects the vertical wall portion and the top plate portion with each other, and
• a portion which is bent toward the projecting portion from an upper edge side of the vertical wall portion is a corner portion, wherein
• in the projecting portion, the steel sheet extending from the vertical wall portion and the steel sheet extending from the top plate portion project from the boundary portion so as to be bent and folded back to make an overlapping portion located at least at a distal end of the projecting portion, so that the steel sheet extending from the vertical wall portion and the steel sheet extending from the top plate portion have a part parallel with each other within a range from the corner portion to the projecting portion,
• the projecting portion is present at least at a portion of the hot stamp formed product in a longitudinal direction, and
• an angle formed between the top plate portion and the overlapping portion is larger than 180°,
• the method comprising:
• a first step of forming a preformed product including two first portions to be formed into the two vertical wall portions and a second portion to be formed into the top plate portion by deforming a blank steel sheet;
• and
• a second step of forming the hot stamp formed product by performing hot stamp forming on the preformed product after being heated to a quenching temperature, wherein
• the preformed product includes a surplus portion for forming the projecting portion,
• the preformed product has a substantially U shape in cross section, and
• in the second step, at least portions of the blank steel sheet constituting the surplus portion are made to overlap with each other, thus forming the overlapping portion.