SKH9 SKH9 
 Tool steel is also known as YXM1 cold model amounted to 5.5% tungsten over Japan's Hitachi SKH9 more special high-quality high-speed tool steel standards and features: M2 chemical analysis results (%): [1] 0.8-0.9 Carbon Silicon: 0.45 The following chromium :3.8-4 .5 Mn: 0.45 The following Molybdenum 4.5-5.5 Tungsten Vanadium :1.6-2.2 :5.5-6.7 P: 0.03 S: 0.01 Steel properties: high-speed steel steel general purpose: cutting wear appropriate to create powerful, high-heng die, screw die, the more complicated to be resilient and shape tools, milling cutters, drills and other factory condition and hardness (surface): HB900-1100/HRC63 SKH9 theoretical calculation test name (units) Example calculation formula symbolic significance 
 Round steel wire rod 
 (Kg / m) W = 0.006165 × d × dd = mm diameter of 100 mm diameter round bar, find the weight per m. Weight per m = 0.006165 × 1002 = 61.65kg 
 [2] SKH9 forging technology and features: Forged: 1.100 ~ 900 ℃ annealing: heating to 800-850 ℃, stay at this temperature in two to four hours in the furnace is allowed to gradually cool. Quenching: the first pre-heated to 550-600 ℃, time heated to 950 ℃, and then heated to a: 1,220 ~ 1250 ℃; b: 1,200 ℃ ~ 1230 ℃. Hardened in oil, but oil must be moisture 40-60 ℃ (a. general tools; b. form a complex type of tools needed toughness) Tempering: heating to 550-570 ℃, to stay at this temperature, then still air cooling, tempering must repeat the second hardness: HRC63 ℃ above. Uses: This high-speed steel tungsten steel, appropriate for manufacturing powerful cutting wear and impact resistance tools, advanced die, screw die, the more complicated to be resilient and shape of the tool, cutter, drill, etc.