There are #45, p20, 718, 2738, H13, S136  6 different steels for mould making, different price for different character and quality. And P20 is the cheapest steel for mould  making, Today, We discuss P20 at first. P-20 mold steel polishes out smother than tool steel which help with the release of molded plastic parts.   P-20 is mold quality alloy steel supplied in the prehardened condition. Special melting and refining practices are utilized to produce a uniform product with exceptional cleanliness.  These characteristics allow P-20 to be polished to an extremely high finish required for plastic molding. The material is tested to rigorous tool steel standards to ensure uniformity of structure and freedom from defects. P-20 is supplied prehardened to 262/321 BHN. The balanced alloy composition of P-20 ensures a uniform cross-sectional hardness. Injection mold factory