SK5 carbon tool steel 
 ● Features and Scope: quenching and tempering after high hardness and wear resistance, but the hot rigid low hardenability poor, deformation, plasticity and lower strength. As a need to have a high hardness and wear resistance of tools, such as the shape of a simple die and punch, metal cutting tools, drilling tools, woodworking cutters, hard drilling, axes, chisels, hand saws vertical , and the fitter assembly tools, dies and other secondary rivet tool. 

 ● Chemical Composition: C: 0.80 ~ 0.90 Si Si :0.10-0 .35 Mn Mn :0.10-0 .50 S S: ≤ 0.030 P P: ≤ 0.030 Chromium Cr: to allow the residual content of ≤ 0.25, ≤ 0.10 (when the manufacture of lead wire quenching bath ) Ni: to allow the residual content of ≤ 0.20, ≤ 0.12 (when the manufacture of lead-bath quenching wire) copper Cu: to allow the residual content of ≤ 0.30, ≤ 0.20 (when the manufacture of lead-bath hardening steel) Note: to allow the residual content of Cr + Ni + Cu ≤ 0.40 (manufacture of lead wire when the quenching bath) 
 ● Mechanical Properties: Hardness: Annealed, ≤ 187HB, indentation diameter ≥ 4.40mm; quenching, ≥ 62HRC 
 ● Heat treatment and microstructure specifications: heat treatment norms: specimen quenched 780 ~ 820 ℃, water-cooled. 
 ● Delivery status: Delivery of steel in the annealed condition. By mutual agreement, delivery can not annealed