Cold-work die steel and dies for cold pressing

Abstract

The present invention provides a cold-work die steel useful as a material of dies for cold pressing, which has basic properties such as hardness, toughness and dimensional change by heat treatment, and besides, which causes no problem in terms of machined surface roughness and cutting tool life, and also its dies for cold pressing. The invention relates to a cold-work die steel comprising: 0.5 to 0.7 mass % of C; 5.0 to 7.0 mass % of Cr; 0.5 to 2.0 mass % of Si; 0.1 to 2.0 mass % of Mn; 0.001 to 0.010 mass % of Al; 0.25 to 1.00 mass % of Cu; 0.25 to 1.00 mass % of Ni; 0.5 to 3.0 mass % of Mo+0.5×W; 0.5 mass % or less of V; 0.05 mass % or less of P; 0.1 mass % or less of S; 0.005 mass % or less of O, wherein the following requirements are satisfied: [C]×[Cr]≦4; FP=[Si]/5+[Cr]/5+2×[Mo]+[W]+2×[V]+10×[Al]≦5.0; and AP=[Mn]+3×([Cu]+[Ni])≦2.5, and also relates to a die for cold pressing which is manufactured by using the cold-work die steel.

Dependencies are inferred from the claim text.