| 摘要 |
PROBLEM TO BE SOLVED: To provide a die having excellent resistant force to a heat crack and a stress corrosive crack caused by repeated heat fatigue and excellent in a cooling passageway crack resistance. SOLUTION: After heat treatment of a quenching and a tempering to the die for working molten metal composed of an alloy steel material, a compressive stress is given with low concentrated nitriding of gas-nitriding or gas soft-nitriding or solid gas-nitriding, etc., on the surface of cooling passageway, and after applying non-electrolytic Ni-plating , a surface stabilizing-treatment (shot peening) for feeding steel balls, glass-beads, etc., with compressed air, is performed and a stress corrosive resistant function in the cooling passageway is intensified, and the crack of the die for working the molten metal is prevented and the service life is remarkably prolonged. COPYRIGHT: (C)2009,JPO&INPIT
|
