24 July 2021 Spring Steel Wire
SUP9 Sping Steel Wire
SUP9 is a grade of spring steel, which has higher strength, ductility and toughness, better hardenability, lower overheating sensitivity than manganese steel, decarburization tendency smaller than silicon manganese steel, large temper brittleness. For vehicles, tractors industrial heavy load, stress larger leaf springs and larger diameter coil springs.
Chemical Composition:
| C | Si | Mn | S | P | Cr | Ni | Cu | V |
|---|---|---|---|---|---|---|---|---|
| 0.52~0.60 | 0.65~0.95 | 0.17~0.37 | ≤0.030 | 0.030 | 0.65~0.95 | ≤0.35 | ≤0.25 | 0.10~0.20 |
Mechanical properties：
| Tensile Strength σb (MPa): | Yield Strength σ0.2 (MPa): | Elongation δ5 (%): | Section shrinkage ψ (%): | Hardness: |
|---|---|---|---|---|
| ≥ 1225 (125) | ≥1080 (110) | ≥ 9 | ≥20 | Hot rolled: ≤ 321HB; Cold pull + heat treatment: ≤ 321 HB |
Equivalent Grade:
| ASTM | GB | DIN | EN | Fr |
|---|---|---|---|---|
| G51550 | 55CrMnA | 55Cr3 | 525A58 | 55Cr3 |
Heat treatment Related
- Annealing of SUP9 Spring Steel
Slowly heated to 740-770 ℃ and allow enough times, let the steel to be thoroughly heated, Then cool slowly in the furnace. The SUP9 tool steel will get MAX 250 HB （Brinell hardness）.
- Hardening of SUP9 Spring Steel
SUP9 steels should be heated uniformly to 830-860°C (1526-1580°F) until completely heated through. About 30 min per 25 mm of ruling section is to be provided and then the steels should be immediately quenched in oil.
- Tempering of SUP9 Spring Steel
Tempering of SUP9 steels is performed at 460-510°C, Soak well at the selected temperature and soak for at least one hour per 25mm of total thickness.