Patent ID: 9061340
Filing Date: 2015-06-23
Classification: B21D

Abstract:
1. A mold for hot stamping that stamps a heated blank having a welding portion, comprising: a lower mold having a lower forming surface formed at an upper surface thereof; an upper mold having an upper forming surface formed at a lower surface thereof and a supply line and an exhaust line formed therein, wherein a recess is formed at the upper forming surface corresponding to the welding portion of the blank and that defines a cooling space between the recess and the blank; a supply control valve mounted at a side surface of the upper mold and adapted to supply a cooling fluid to the cooling space through the supply line; an exhausting device mounted at the other side surface of the upper mold and adapted to exhaust the cooling fluid from the cooling space through the exhaust line; a temperature detecting device mounted in the upper mold, detecting a temperature of the upper mold near the cooling space, and outputting a temperature signal; and a controller controlling the supply control valve and the exhausting device depending on the temperature signal output from the temperature detecting device, wherein: the blank having the welding portion is a tailor welded blank manufactured by welding boron steel plates having different thicknesses together; the tailor welded blank is hot stamped such that the welding portion is formed at a boundary region of the boron steel plates; the upper mold has an upper die and a lower die assembled with each other, laying recesses are respectively formed at confronting surfaces of the upper die and the lower die, and a coolant pipe for indirectly cooling the tailor welded blank is laid in the laying recesses; the cooling space is the recess having a predetermined width formed at the upper forming surface of the lower die of the upper mold along the welding portion of the tailor welded blank; and the cooling fluid is supplied to the cooling space corresponding to the welding portion such that the cooling fluid directly contacts and cools the welding portion of the tailor welded blank in the cooling space after the tailor welded blank is stamped.