| 摘要 |
PURPOSE:To make production process simple and to improve working efficiency by warm forging a heated metallic blank material with a punch side master mold having a retractable mandrel in the axial center part thereby producing a hollow body in a breath with the same mold. CONSTITUTION:A heated steel material A is inserted between a die side metallic mold 1 and a punch side submold 2, and the mold 2 is pressed to the mold 1, whereby the material is preforged. At this time, the lower part of the material A is formed to a semispherical shape. The mold 2 is moved upward, the mold 8 is replaced with the mold 2, and with a part of a mandrel 9 held projected from the mold 8 to the die side, said die is pressed to the die 1, whereby the material A is formed to a spherical shape. The mandrel 9 is then advanced to blank part of the material A into the die side hole, thereby forming a hollow steel ball A'. The remaining blank material B is ejected upward by means of a knockout pin 6, and the ball A' is released from the mold 1. |
