DHA1 hot casting mold steel with excellent hardenability, high-temperature tempering strong, high-temperature impact resistance and good resistance to thermal fatigue damage of high temperature melting. 

 DHA1 features 
 1. Carbides evenly distributed small spherical 

 (2) good heat balance and hardenability of 

 3 high-temperature tempering strong 

 4 heat shock and thermal fatigue of the outstanding 

 5 high-temperature melt loss and strong 

 6. A good cut of 

 DHA1 use 
 : 

 1 aluminum die casting zinc 

 2 cast aluminum hot extrusion 

 3. Stamping Die 

 4 die casting parts 

 5 plastic mold 

 6. All mechanical components 

 Aluminum, zinc die casting mold: using the hardness HRC41 ~ 48; 

 Die Attachment (plunger sleeve, red top): Use hardness HRC45 ~ 50; 

 Hot extrusion die: Using the hardness HRC43 ~ 48; 

 Hot shear blades: Using hardness HRC35 ~ 45; 

 Hot stamping die: Using the hardness HRC42 ~ 50; 

 Chemical composition 
 : Datong steel DHA1 JIS corresponding steel SKD61 

 C 0.32 ~ 0.42 

 Si 0.80 ~ 0.10 

 Mn ≤ 0.5 

 Cr 4.50 ~ 5.50 

 Mo 1.00 ~ 1.50 

 V 0.80 ~ 1.20 

 Heat Treatment 
 The steel forging temperature of 1100 ~ 900 ℃, 

 Annealing temperature of 820 ~ 870 ℃, slow cooling, annealing hardness ≤ 229HB; 

 Quenching temperature of 1000 ~ 1050 ℃, air-cooled; 

 Tempering temperature of 550 ~ 650 ℃, air cooling. 

 After quenching and tempering hardness ≤ 53HRC. Corresponding phase transition point: Ac for the 847 ~ 918 ℃; Ar is 769 ~ 725 ℃; 1030 ℃ after austenitizing the Ms of 320 ℃. 

 1050 ℃ austenitizing the steel cold oil quenching hardness of up to 55HRC, at this time of the Charpy impact values ??remain at a high level (after 600 ℃ 1hr tempering); tempering after quenching at 560 ℃ 1hr peak hardness , close to 55HRC, tempering at 600 ℃ approximately 1hr hardness 50HRC. The steel can be implemented 570 ℃ × 3hr of salt bath nitriding process, can make the surface hardness of up to 1100HV (load 300g). 

 DH31-S steel hardenability, heat resistance and resistance to fatigue cracking of hot-melt mode is higher than the DHA-1. By introduce information to estimate, DHA-1 Steel 1030 ℃ austenitizing, φ150mm rod was cooled to quench martensite; for DJ31 ~ S φ200mm steel up about the same conditions. The hardness of steel after annealing ≤ 235HB, cutting relatively SKD61 slightly reduced. DAIDO Datong Steel DHA1 features: