| 摘要 |
PURPOSE: A high hardness and toughness precipitation hardening type die steel and a manufacturing method thereof are provided to apply heat treatment after a welding repair to a flaw which is generated on the joint surface and to a crack in a corner area which is generated when a mold is treated, thereby significantly lengthening the service life of a mold. CONSTITUTION: A high hardness and toughness precipitation hardening type die steel is composed of, in wt%: C: 0.05-0.13; Si: 0.2-1.2; Mn: 1.3-1.7; Cr: 0.2-1.0; Mo: 0.2-1.0; Ni: 2.5-3.5; Cu: 0.7-1.5; Al: 0.7-1.5; Nb: 0.01-0.1; S: 0.006 or less; and the remainder Fe and other inevitable impurities. The die steel has more than HRC38 of high hardness and more than 20J of V notch Charpy impact value. A manufacturing method of the high hardness and toughness precipitation hardening type die steel is as follows. The die steel with constituents above is treated with solution heat after hot-processing. The dies steel which is treated with solution heat is treated with ageing. [Reference numerals] (AA) Indentation impression stain; (BB,DD) Base material unit; (CC) Welding unit; (EE,FF) Heat influence unit |
