Unified numbering T20502; grades 4Cr5MoSiV1. Good overall performance in the medium temperature (~ 600 °) under high hardenability (ie can hardened in air), low heat deformation rate, the performance and life than 3Cr2W8V. Can be used for forging hammer forging die, aluminum die casting, hot extrusion mold, high-speed precision forging die and forging presses mold. Mechanical properties of hardness: annealing, 245 ~ 205HB, quenching, ≥50HRC delivery status Brinell hardness HBW10 / 3000 (≤235)) the main characteristics H13 steel is the most extensive and most representative of the hot work die steel, its The main features are: [1] (1) has a high hardenability and high toughness; (2) the ability to excellent resistance to thermal cracking, in the workplace can be cooled; (3) with moderate abrasion resistance, also can carburizing or nitriding process to increase the surface hardness, but slightly lower thermal cracking capacity; (4) because of its low carbon content, tempering secondary hardening ability is poor; (5) at higher temperatures By having a softening resistance, but the use of a temperature higher than 540 ℃ (1000 ℉) the hardness of a rapid decline (ie, the ability of the operating temperature of 540 ℃); small deformation (6) heat treatment; (7) medium and high machinability ; (8) the ability to moderate the anti decarbonization. Even more serious note, it can also be used to make important member on the aviation industry. Life Purpose and 9CRWMN tool steel is basically the same, but because of its higher vanadium content, so the temperature (600 degrees) performance than 4Cr5MoSiV steel, hot work die steel is so widely used as a representative steel. H13 tool steel for the manufacture of large impact load forging dies, hot extrusion die, forging die; aluminum, copper and alloy die-casting mold. Chemical composition c Si Mn Cr Mo VPS 0.32 ~ 0.45 0.80 ~ 1.20 0.20 ~ 0.50 4.75 ~ 5.50 1.10 ~ 1.75 0.80 ~ 1.20 ≤0.030 ≤0.03 hardening: 790 ° + -15 degrees preheat 1,000 degrees (salt bath) or 1010 degrees (oven controlled atmosphere) + - 6 degrees heating, air-cooled heat 5 ~ 15min, 550 degrees + -6 degrees tempering; annealing, thermal processing;