STEEL FOR HOT STAMP DIE, HOT STAMP DIE AND MANUFACTURING METHOD THEREOF
A die steel which enables manufacturing a hot stamp die that has both high hardness and high thermal conductivity, a hot stamp die, and a manufacturing method thereof are provided. This steel for a hot stamp die has a component composition, in mass% of 0.45-0.65% C, 0.1-0.6% Si, 0.1-0.3% Mn, 2.5-6.0% Cr, 1.2-2.6% Mo, and 0.4-0.8% V, the remainder being Fe and unavoidable impurities. Further, this hot stamp die has the aforementioned component composition, and the manufacturing method is for manufacturing said hot stamp die.
1 . A steel for a hot stamp die having a component composition including, in mass %, C: 0.45 to 0.65%, Si: 0.1 to 0.6%, Mn: 0.1 to 0.3%, Cr: 2.5 to 6.0%, Mo: 1.2 to 2.6%, V: 0.4 to 0.8%, the remainder being Fe and unavoidable impurities.
2 . A hot stamp die having a component composition including, in mass%, C: 0.45 to 0.65%, Si: 0.1 to 0.6%, Mn: 0.1 to 0.3%, Cr: 2.5 to 6.0%, Mo: 1.2 to 2.6%, V: 0.4 to 0.8%, the remainder being Fe and unavoidable impurities.
3 . The hot stamp die according to claim 2 ,
wherein the hardness is 45 HRC or more, and the thermal conductivity λ(W/(m·K)) satisfies the following Formula (1):
λ≥−0.5 H+ 53 Formula (1)
H: Rockwell hardness (HRC) of die
4 . The hot stamp die according to claim 3 ,
wherein the hardness is 52 HRC or more.
5 . The hot stamp die according to claim 4 ,
wherein the thermal conductivity λ is 25 W/(m·K) or more.
6 . The hot stamp die according to claim 2 ,
wherein a working surface has a nitrided layer.
7 . A method of manufacturing a hot stamp die, comprising
quenching and tempering the steel for a hot stamp die according to claim 1 at a quenching temperature of 1,020 to 1,080° C. and a tempering temperature of 500 to 625° C.
8 . The method of manufacturing a hot stamp die according to claim 7 ,
wherein the tempering temperature is 540 to 600° C.
9 . The method of manufacturing a hot stamp die according to claim 7 ,
wherein, after the quenching and tempering are performed, a working surface is additionally subjected to a nitriding treatment.