Chemical composition of SK4
Carbon C:0.95 ~ 1.04
Silicon Si: less than or equal to 0.35
Manganese: less than 0.40 Mn
Sulfur: less than 0.030 S
P: less than 0.035 P
Cr Cr: allows residual content less than 0.25, less than 0.10 (manufacturing lead bath quenching steel wire)
Nickel: allows the residual Ni content less than 0.20, less than 0.12 (manufacturinglead bath quenching steel wire)
Cu: allows the residual copper content less than 0.30, less than 0.20 (manufacturinglead bath quenching steel wire)
Note: the allowable residual content of Cr+Ni+Cu is less than or equal to 0.40(manufacturing lead bath quenching steel wire)
Hardness: annealing, is less than or equal to 197HB, the indentation diameter greater than or equal to 4.30mm = 50HRC; quenching, heat treatment and microstructure of SK4 specification
Heat treatment quenching specimen specification: 760 to 780 DEG C, cooling.
Supply hardness:
Soft, semi hard, hard (hard material heat treatment)
The color of the surface:
White, blue, golden color, heat treatment
Delivery state: Steel in annealing state of delivery. By mutual agreement, may also notannealed state of delivery.
