High-speed tool steel bars: T4
Standard: ASTM A600-1992a
● Features and Scope:
Department of General cobalt tungsten high-speed steels, compared W18Cr4V red hardness and high temperature hardness is slightly higher, but low toughness, after quenching, surface hardness up to 63 ~ 66HRC. Used for high-speed cutting tools, automated machine tools for cutting high strength materials.
● Chemical Composition:
Carbon C: 0.70 ~ 0.80 (tolerance: ± 0.01)
Si Si: 0.20 ~ 0.40 (tolerance: ± 0.05)
Mn Mn: 0.10 ~ 0.40 (tolerance: +0.04)
Sulfur S: ≤0.030
Phosphorus P: ≤0.030
Chromium Cr: 3.75 ~ 4.50 (tolerance: ± 0.05)
Ni: to allow the residual content ≤0.30
Cu: to allow the residual content ≤0.25
Vanadium V: 0.80 ~ 1.20 (tolerance: ± 0.05)
Mo Mo: 0.40 ~ 1.00 (tolerance: Size ≤6, ± 0.05; dimension> 6, ± 0.10)
Tungsten W: 17.50 ~ 19.00 (tolerance: Size ≤10, ± 0.10; sizes> 10, ± 0.20)
Cobalt Co: 4.25 ~ 5.75 (tolerance: ± 0.15)
● Mechanical Properties:
Hardness: Delivery hardness :( other processing methods) ≤285HB; (annealing) ≤269HB. Sample heat treatment and quenching hardness: ≥63HRC
● Heat treatment and microstructure specifications:
Heat treatment specifications: quenching, 820 ~ 870 ℃ preheating, 1270 ~ 1290 ℃ (salt bath) or 1280 ~ 1300 ℃ (box furnace) heating, oil cooler, 540 ~ 560 ℃ tempering two times, each time 2h.
● Delivery status: hot-rolled, forged, cold-drawn steel bars in the annealed condition delivery, hot-rolled, forged steel bars with after annealing + other processing methods (skinned, light pull, grinding or polishing, etc.) processing delivery .