M238 ASSAB high-quality Pre-hardened plastic mold steel, this steel is P20 plus 1.1% nickel, steel surface to the center of uniform hardness, good cutting, EDM and polishing excellent performance, suitable for gasification, hard chrome plating and coating titanium. Uniform hardness and metallurgical structure, has a special heat treatment and hard to 30-34HRC, good polishing performance, easy to reach a mirror-polished, low deformation after use, and the materials available rate, reduce costs, the size requirements for high plastic mold, especially for electrical erosion operation.
Factory state: pre-and hard to 980-1080N/mm2 (30-34HRC)
This has been heat-treated steel, even hardness, up to 278-311HB ,29-33HRC, never made mold variant, cutting and polishing performance for electrical erosion operation can be used as flame hardened, chrome plated and nitrided.
M238 chemical composition:
Carbon C: 0.95
Chromium Cr; 0.5
Tungsten w: 0.5
Manganese Mn: 1.1
Si Si: 0.3
Vanadium V: 0.1
M238 heat treatment process:
Forging :1050-850 ℃ furnace cooling.
Mass recovery :850-900 ℃ furnace cooling.
Stress Relief: Redu even after 1-2 hours in the furnace to stay cool.
Quenching: Oil 840-860 ℃ or air :860-880 ℃. Stay at least 10 minutes, more than 20mm in thickness more than 1mm see every 1 / 2 minutes, so the hardness of approximately 54HRC.
Tempering: tempering time to stay at least one hour, 20mm more than 20mm thick will have more and more every hour.
:720-740 ℃ annealing and heat through insulation sufficient time, then cooling with the furnace to 600 ℃, then cooling in air, from hardness of approximately 240HB (highest).
Factory state: pre-and hard to 980-1080N/mm2 (30-34HRC)
This has been heat-treated steel, even hardness, up to 278-311HB ,29-33HRC, never made mold variant, cutting and polishing performance for electrical erosion operation can be used as flame hardened, chrome plated and nitrided.
M238 chemical composition:
Carbon C: 0.95
Chromium Cr; 0.5
Tungsten w: 0.5
Manganese Mn: 1.1
Si Si: 0.3
Vanadium V: 0.1
M238 heat treatment process:
Forging :1050-850 ℃ furnace cooling.
Mass recovery :850-900 ℃ furnace cooling.
Stress Relief: Redu even after 1-2 hours in the furnace to stay cool.
Quenching: Oil 840-860 ℃ or air :860-880 ℃. Stay at least 10 minutes, more than 20mm in thickness more than 1mm see every 1 / 2 minutes, so the hardness of approximately 54HRC.
Tempering: tempering time to stay at least one hour, 20mm more than 20mm thick will have more and more every hour.
:720-740 ℃ annealing and heat through insulation sufficient time, then cooling with the furnace to 600 ℃, then cooling in air, from hardness of approximately 240HB (highest).
