STEEL FOR RESOURCE SAVING COLD PRESS MOLD EXCELLENT IN SURFACE TREATMENT PROPERTY

摘要

PROBLEM TO BE SOLVED: To provide an inexpensive steel for cold press mold by securing hardness and toughness and reducing a used amount of expensive elements.;SOLUTION: There is provided a steel for cold press mold containing, by mass%, C:0.75-0.90%, Si:0.30-0.90%, Mn:0.35-1.00%, Cr:5.70-8.20%, Mo:0.20-0.50%, Al:0.01-0.15% and the balance Fe with inevitable impurities, and having R value of formula (1) of 1.50≤R value≤1.80, H value of formula (2) of H value≤10.0, the number of carbide having area of 900 μm² or more of 4.9 or less per 1 mm² and area percentage of the carbide having area of 900 μm² or more of 8% or less. [% element] represents an element amount by mass%, R value=0.983×[%C]/Ceq, where Ceq=0.063×[%Cr]+0.093×[%Mo] Formula (1), and H value=[%Cr]/(1.84×[%Mn]+3.44×[%Al] Formula (2).;SELECTED DRAWING: None;COPYRIGHT: (C)2018,JPO&INPIT