ROLLED STEEL BAR OR ROLLED WIRE ROD FOR COLD-FORGED COMPONENT

摘要

In a rolled steel bar or rolled wire rod for a cold-forged component having a predetermined chemical composition, Y1 represented by Y1=[Mn]×[Cr] and Y2 represented by Y2=0.134×(D/25.4−(0.50×√[C])/(0.50×√[C]) satisfy Y1Y2, the tensile strength is 750 MPa or less, an internal structure is a ferrite-pearlite structure, and the ferrite fraction in the internal structure is 40% or greater.