SK5 
 SK85 (SK5) carbon tool steel Standard: JIS G4401 ● Features and Scope: after quenching and tempering the high hardness and wear resistance, but rigidly low thermal hardenability and easy to deformation, low ductility and strength. As a need to have high hardness and wear resistance of a variety of tools, such as simple shape of the mold and the punch, cutting metal cutting tools, drilling tools, woodworking cutter, cutters, axes, chisels, vertical hand saws , the fitter assembly tools, rivet die secondary tool. ● chemical composition: Carbon C: 0.80 to 0.90 Silicon Si :0.10-0 .35 Mn Mn :0.10-0 .50 sulfur S: ≤ 0.030 P: ≤ 0.030 Chromium Cr: Allow the residual content of ≤ 0.25, ≤ 0.10 (manufacturing lead bath quench wire ) Ni: to allow the residual content of ≤ 0.20, ≤ 0.12 (manufacturing lead bath quench wire) Copper Cu: allow the residual content of ≤ 0.30, ≤ 0.20 (manufacturing lead bath quench wire) Note: to allow the residual content of Cr + Ni + Cu ≤ 0.40 (manufacturing lead bath quench wire) ● Mechanical Properties: Hardness: Annealed ≤ 187HB, indentation diameter ≥ 4.40mm; quenching, ≥ 62HRC ● Heat treatment and microstructure specifications: Heat Treatment Specification: The specimen quenched 780 ~ 820 ℃ water-cooled. ● Delivery status: delivery of steel in annealed condition. By mutual agreement, delivery can also be annealed condition.