C Carbon Cr Chromium W Tungsten Mn Manganese Si Silicon V Vanadium
0.95 0.5 0.5 1.1 0.3 0.1 M238 factory specifications: hardened and tempered to 980-1080N/mm² (30-34HRC).
M238 steel characteristics: This steel is P20 plus 1.1% nickel, so it has excellent hardenability, uniform hardness from the surface to the center of the steel, excellent electrical corrosion and polishing performance, suitable for nitriding, hard chromium plating and titanium plating.
M238 Purpose: Suitable for all plastic molds, especially molds over 400 thick.
M238 forging: Start at 1050°C to 850°C, then return to the furnace to cool down slowly.
M238 annealing: 720-740℃, heat through and keep for enough time, then cool down to 600℃ with the furnace, then cool in the air, the resulting hardness is about 240HB (the highest)
Stress elimination: Heat to 600°C in a protective gas furnace for about 2 hours, and then slowly cool down with the furnace.
M238 quenching: 840-860℃ heat preservation and then oil quenching, or 860-880℃ heat preservation and air cooling at slightly higher temperature and immediate tempering, so the hardness is about 54HRC
M238 tempering: immediate tempering after quenching, time not less than 2-2.5 hours, and then out of the furnace air cooling round (MM)
25.8 30.8 32.8 40.8 45.8 50.8 55.8 60.8 66.0 71.0 76.0 81.0 86.0 91.0 101.5
106.5 116.5 126.5 141.5 151.5 182.0 202.0 232.0 262.5 282.5 302.5 363.0 403.0
square (MM) 25323540455060708090105
700X20-25-32-35-40-45-50-60-65-70-80-260-310-360 Forging: Cool in a furnace at 1050-850℃. Regenerate: Cool in a furnace at 850-900℃.
Stress elimination: After the heat is uniform, stay for 1-2 hours to cool in the furnace.
Quenching: oil 840-860℃ or air: 860-880℃. Stay for at least 10 minutes. If the thickness is more than 20mm, it will be more than 1/2 minute per 1mm, so the hardness is about 54HRC.
Tempering: Stay for at least 1 hour during tempering, and 1 hour for every 20mm thicker than 20mm.
Annealing: Heat through 720-740℃ for sufficient time, then cool to 600℃ with the furnace, and then cool in the air, the resulting hardness is about 240HB (the highest).
Link to this article：What is M238 steel? What are the applications of M238 steel?
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