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Hardness: Annealing ≤ 201HB; Quenching and tempering 50-55HRC.
Corrosion resistance: resistant to water vapor, weak acids, and dilute sulfates, suitable for corrosive conditions such as PVC, flame-retardant/chlorine containing plastics, etc.
Polishing performance: The mirror surface can reach Ra ≤ 0.05 μ m, suitable for transparent parts such as optical lenses and light guide plates.
Machinability: Easy to cut in annealed state, suitable for grinding/EDM after quenching, with minimal deformation during heat treatment.
GB | ISC | JIS | UNS | DIN | EN | W-Nr. | NF |
40Cr13 | S42040 | SUS420J2 | S42000 | X40Cr13 | X40Cr13 | 1.4031 | Z40C14 |
element | C | Si | Mn | Cr | Ni | S | P |
scope | 0.36-0.45 | 0.60 | 0.80 | 12.00-14.00 | 0.60 | ≤0.03 | ≤0.04 |
state | hardness | Tensile strength Rm (MPa) | Yield strength ReL (MPa) | Elongation A5 (%) | Reduction of area Z (%) | Impact energy AkV (J) |
Annealing (delivery) | ≤201 HB | 550–590 | 225–250 | 15–20 | 45–55 | ≥30 |
Quenching + Low-temperature tempering (oil quenching at 1050–1100℃, tempering at 200–300℃) | 50–55 HRC | 735–1140 | 540–910 | 12–15 | 32–40 | ≥24 |
Heating specifications (step heating, anti cracking)
Preheating: 650-750 ℃, hold for 1-2 hours, eliminate temperature gradient.
Initial forging temperature: 1130~1180 ℃ (the upper limit for steel ingots is 1180~1200 ℃, and the lower limit for billets is 1130~1150 ℃).
Insulation: According to a thickness of 1.5-2min/mm, ensure thorough burning and dissolution of carbides.
Forging process (two upsetting and two pulling, controlling forging ratio)
Forging ratio: The total forging ratio is ≥ 4, ensuring a dense structure and refined carbides.
Process: Steel ingot → upsetting (pressing amount 50-60%) → elongation (square → eight → flat) → secondary upsetting → finishing to size.
Final forging temperature: ≥ 800~850 ℃, to avoid precipitation of carbides at grain boundaries and cold cracking.
Deformation rate: medium low speed forging, large reduction (15-25% per pass), to prevent surface cracking.
Cooling and annealing after forging (crack prevention+improved cutting)
Cooling: Grey/sand cooling to below 500 ℃, then air cooling to avoid cracking due to rapid air cooling.
Annealing: Keep at 750~800 ℃ for 4~6h, cool in the furnace to 500 ℃ and air cool, hardness ≤ 217HB, eliminate internal stress and facilitate processing.
Thickness: 100-450mm
Width: 160-1300mm
Food grade: fresh-keeping boxes, water bottles, tableware, sealed containers.
Daily chemical/medical: cosmetic bottles and jars, syringe shells, disinfection boxes.
Optics/Electronics: lenses, prisms, phone frames, transparent buttons.
Automotive/home appliances: dashboard, lampshade, air conditioning panel, washing machine interior.
