HOT FORGING DIE AND HOT FORGING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a hot forging die that is also applicable to a hot forging die for rough forging and that can reduce a local tensile stress.SOLUTION: Provided is a hot forging die including an upper die and a lower die. The upper die is constituted by divided dies formed by combining a plurality of die pieces, a circular recess or through-hole is provided in a central portion of a circular press surface of the upper die for forming a pad of a forging target material, and the hot forging die is divided into the upper and lower dies at a tensile stress concentration portion during hot forging. It is preferable that a diameter of the recess or through-hole is 3 to 30% of a diameter of the circular press surface. It is more preferable that the lower die is an assembly member of a plurality of die pieces.