Ternary phase diagram isothermal section, containing 0.4% C steel, there will be increased with the Cr (FeCr) 3C (M3C) and (CrFe) 7C3 (M7C3) alloy carbides. Note that the 870 ℃ chart, only containing greater than 11% Cr appears M23C6). Also, according to a vertical section of Fe-Cr-C ternary system at 5% Cr and containing 0.40% C steel in the annealed condition of α-phase (about solution 1% Cr) and (CrFe) 7C3 alloy C thereof. When heated to above 791 ℃ austenite A and enter the (α + A + M7C3) phase regions, at about 795 ℃ into the (A + M7C3) two-phase region, about 970 ℃ when, (CrFe) 7C3 disappear, A region into single phase. When the matrix C content <0.33% is only present at about 793 ℃ (M7C3 + M23C6 and A) of the three-phase region, at 796 ℃ into the (A + M7C3) region (0.30% C), the future remains to liquid phase. Steel remaining M7C3 have prevented A grain growth role. Nilson suggested to 1.5% C-13% Cr alloy components, less stable (CrFe) 23C6 does not form [20]. Of course, alone Fe-Cr-C ternary system analysis will be some deviation, to consider the effect of alloying elements. H13 Heat Treatment 1. pre-heat treatment on the market supply of H13 steel and die steel billet, steel mills are ready annealing, to ensure a good microstructure, proper hardness, good workability, no further annealing . But after forging factory renovation and destroyed the original organization and performance, increase the forging stress, must be re-annealing. Isothermal spheroidizing is: 860 ~ 890 ℃ heat insulation 2h, cooled to 740 ~ 760 ℃ isothermal 4h, furnace cooled to about 500 ℃ baked. 2. quenching and tempering requires good toughness die quenching process specification: heating temperature 1020 ~ 1050 ℃, oil-cooling or air cooling, hardness 54 ~ 58HRC; requirements based thermosetting die quenching process specifications, the heating temperature 1050 ~ 1080 ℃, oil cooling, hardness 56 ~ 58HRC. Recommended tempering temperature: 530 ~ 560 ℃, hardness 48 ~ 52HRC; tempering temperature of 560 ~ 580 ℃; hardness 47 ~ 49HRC. Tempering should be carried out twice. In tempering at 500 ℃, tempering secondary hardening peak occurs, tempering maximum hardness peak at about 55HRC, but the toughness worst. Therefore, tempering process should avoid about 500 ℃ appropriate. The mold of the need to use, in the range of preferably 540 ~ 620 ℃ tempering. Quenching should be twice preheated (600 ~ 650 ℃, 800 ~ 850 ℃), to reduce the heating process generates heat stress. 3. Chemical treatment H13 steel if the gas nitriding or nitrocarburizing mold can be further strengthened, but it should not be higher than the nitriding temperature tempering temperature to ensure that the core hardness is not reduced, thereby enhancing the life of the mold. Features: High toughness hot mold steel, wear heat resistance particularly good, can withstand drastic changes in dissolved aluminum, magnesium, zinc, and the corrosive effects of heat, the high temperature strength and toughness balance, easy processing, it can make extend tool life and better performance. . Uses: suitable for the manufacture of aluminum, magnesium, zinc alloy die casting mold Hot punch work, and hot Reamer, rolling cutter, grooving knives, scissors and forging red top, PA, POM, PS, PE, EP plastic.