Patent ID: 7494618
Filing Date: 2009-02-24
Classification: C21D,C22C,Y02P

Abstract:
1. An alloy tool steel comprising: from 0.50 wt % to 0.60 wt % C; from 0.10 wt % to 1.00 wt % Si; from 0.20 wt % to 2.00 wt % Mn; not more than 0.020 wt % P; not more than 0.015 wt % S; not more than 1.00 wt % Cu; not more than 1.00 wt % Ni; from 3.50 wt % to 5.00 wt % Cr; from 0.00 wt % to 3.00 wt % Mo; from 0.00 wt % to 10.00 wt % W; from 1.00 wt % to 2.00 wt % V; from 0.00 wt % to 8.00 wt % Co; not more than 0.10 wt % Al; not more than 0.01 wt % O; not more than 0.02 wt % N; and the balance substantially consisting of Fe and unavoidable impurities, wherein Weq is from 2.0 to 10.0, 2Mo/Weq is not more than 0.50, and ΔC is from −0.3 to 0.0, where wherein room-temperature hardness is not less than 55 HRC, room-temperature strength is not less than 1900 MPa, and a ratio of high-temperature strength at 700° C. to room-temperature strength is not less than 0.30.