| 摘要 |
PURPOSE:To prevent the thermal deformation of the angular part of a metal member and to satisfactorily harden the member with laser by allowing the peripheral part around the angular part to absorb a larger quantity of heat due to laser beams. CONSTITUTION:When a metal member having an angular part 2 such as the cutting edge of a press is hardened with laser, the peripheral part 4 around the angular part 2 is coated with a heat absorbent 5 such as zinc phosphate or graphite and laser beams 3 are projected. At this time, the range of the coated part and the angle of projection of the beams 3 are regulated in accordance with the shape of the angular part 2 so that the coated part absorbs energy at a higher absorption factor than the uncoated angular part 2. The absorption of heat in the angular part 2 is controlled, the thermal deformation of the part 2 is prevented and satisfactory hardening is carried out. |
