| 摘要 |
PROBLEM TO BE SOLVED: To improve durability of a ram 10 (a metal mold installing member).SOLUTION: A strengthening method executes a preparation step of preparing a tempered alloy tool steel ram body 11 (a body member) having a recess-projection structure 11A and a low carbon alloy steel reinforcement plate 12 hardly causing martensitic transformation, a preheating step of setting the ram body 11 and the reinforcement plate 12 to the temperature higher than the martensitic transformation starting temperature of alloy tool steel and equal to or lower than the tempering temperature, a welding step of forming the reinforcement plate 12 as the ram 10 in response to the recess-projection structure 11A of the ram body 11 and a stress removable step of reducing residual stress of the ram 10. The welding step sets the ram body 11 and the reinforcement plate 12 to the temperature higher than the martensitic transformation starting temperature of the alloy tool steel and to the temperature equal to or lower than the temperature for tempering the ram body 11 except for a thermal influence part. In the stress removal step, the ram 10 is set to the temperature for tempering the thermal influence part 11C of the ram body 11 at the temperature higher than the martensitic transformation starting temperature of the alloy tool steel and equal to or lower than the tempering temperature. |
