JIS SKT4 is a hot work tool steel grade with widely application. SKT4 is similar to L6 hot work tool steel, no matter in properties or in applications. the cost and price for both SKT4 and L6 steels only have a little different. Hot work JIS SKT4 tool steel grade in standard JIS G4404. In JIS G4404 include the SKT4 hot work tool steel, SKD6, SKD61 steel, It is standard specification of hot work tool steels for hot work 1.2714(L6, 55NiCrMoV7, SKT4,BH224-5) Hot-Work Mould Preheating:Heat 1.2714 (L6, 55NiCrMoV7, SKT4,BH224-5) Hot-Work Mould Steel at a rate not exceeding 204°C (400°F) per hour (222°C per hour) to 621-677°C (1150-1250°F) and equalize. Soak for 30 minutes for the first inch (25.4 mm) of thickness, plus 15 minutes for each additional inch (25.4 mm).