English 
| Quantity: | |
|---|---|
Dense organization and uniform carbides: Forging shatters the cast network carbides, eliminates looseness/holes, disperses the carbides, avoids band segregation, and significantly improves strength and toughness.
High hardness, wear resistance, and long service life: With a quenching hardness of 58-65HRC, it has excellent wear resistance and is suitable for high load stamping/cold heading conditions. Its service life is increased by more than 30% compared to ordinary processes.
High hardenability and uniform performance: Large cross-section (≤ 300mm) can be uniformly hardened, with stable core hardness, suitable for large/deep cavity sleeves.
Good toughness and resistance to cracking: Molybdenum vanadium refines grain size, improves toughness, and has strong bending/impact resistance, making it less prone to corner cracking.
Stable size and high precision: heat treatment deformation rate ≤ 0.05%, easy control of inner hole/outer diameter accuracy, suitable for precision mold requirements.
High material utilization rate and excellent cost: forging near net shape, reducing cutting allowance, saving material and machining costs.
GB | JIS | ASTM | UNS | DIN | W-Nr. | ГOCT | SS |
Cr12Mo1V1 | 一 | D2 | T30402 | X155CrVMo12-1 | 1.2379 | 一 | 一 |
element | C | Si | Mn | Cr | V | Mo | S,P |
scope | 1.40~1.60 | ≤0.60 | ≤0.60 | 11.0~13.0 | 0.50~1.10 | 0.70~1.20 | ≤0.03 |
Hardness (HRC) | Tensile strength (MPa) | Yield strength (MPa) | Elongation ( δ₅ ) | Reduction of area (ψ) | Impact AKV (J) |
60～64 | ≥1470 | ≥1080 | ≥12% | ≥40% | 30-50 |
Preheating: 500-600 ℃ for 1-2 hours to eliminate thermal stress and prevent cracking caused by poor thermal conductivity.
Heating: 1080-1120 ℃, through burning insulation (insulation for 1 hour per 100mm diameter), to avoid overheating/overburning.
Tool preheating: Preheat the forging hammer, core rod, and anvil to 200-250 ℃ to prevent cracking due to contact quenching.
Adopting "two light and one heavy"+six sided forging, crushing mesh/strip carbides to improve lateral toughness.
Forging (2-3 times):
Initial forging: Lightly strike at 1050-1100 ℃, with a pressing amount of ≤ 15%/time, to prevent end face cracking.
Heavy impact: 980-1020 ℃, total upsetting ratio ≥ 2.5, crushing eutectic carbides.
Pull out (2-3 times):
Pull in multiple directions, rotate 90 ° each time, forging ratio ≥ 2, eliminate anisotropy.
Final forging: Lightly strike at ≥ 850 ℃ to avoid low-temperature cracking, and prevent grain coarsening when the final forging temperature is ≤ 900 ℃.
Punching (inner hole of sleeve):
Temperature: 900-950 ℃, preheat the punch to 250 ℃, clean the burrs promptly after punching to prevent crack propagation.
Hole enlargement (core rod):
Expand the hole 2-3 times, lightly strike with a small hammer at high frequency, and finally forge at ≥ 850 ℃ to ensure the roundness and uniform wall thickness of the inner hole.
Cooling after forging: furnace cooling/sand cooling to below 500 ℃ and air cooling, rapid cooling is strictly prohibited to prevent cracking.
Process: Insulation at 850-870 ℃ for 3-4 hours → Furnace cooling to 740-760 ℃ and isothermal for 4-5 hours → Air cooling.
Goal: Hardness ≤ 255HB, uniform carbide spheroidization (≤ level 3), easy to machine.
Coarse car: Leave a grinding allowance of 0.3-0.5mm per surface to avoid cutting overheating.
Stress relief: 600-650 ℃ x 2h furnace cooling to eliminate processing stress and prevent heat treatment deformation.
Precision machining/drilling: Ensure size and coaxiality, leaving a grinding allowance of 0.1-0.2mm.
Quenching (one-time hardening method)
Secondary preheating: 600 ℃× 20min → 850 ℃× 30min, anti cracking.
Austenitization: 1020-1040 ℃ × 25-40 minutes (based on effective thickness), oil/air cooling, hardness 60-65HRC.
Tempering (must be done at least twice)
High wear resistance: 180-230 ℃ × 2-3 times/2h, hardness 60-64HRC.
High toughness/stable size: 500-540 ℃ x 2 times/2h, hardness 58-62HRC (secondary hardening).
Cryogenic treatment (optional, high precision): After quenching at -70~-80 ℃ for 3-4 hours, residual austenite is transformed, hardness is increased by 1-3 HRC, and the size is more stable.
Grinding: Grind the inner/outer circle to the drawing accuracy, with a surface roughness Ra ≤ 0.4 μ m.
Inspection: Hardness (HRC), metallography (carbide ≤ 3 level), dimensional accuracy, non-destructive testing (MT/UT).
Automobile: stamping/extrusion molds, transmission parts, bearing components
Electronics: silicon steel sheet punching, precision terminals, injection mold inserts
Hardware: wire drawing die, thread rolling die, cold heading die sleeve
Plastic: Fiberglass reinforced plastic molding, extrusion die sleeve
