24 July 2021 Spring Steel Wire
50CrVA Spring Steel Bar
50CrVA spring steel has good mechanical properties and process performance, high hardenability, adding vanadium to refine the grain of the steel, reduce overheating sensitivity, improve strength and toughness, have high fatigue strength, and have a relatively high yield ratio. high. However, 50CrVA spring steel has poor weldability and low plasticity due to cold deformation. It is a higher-grade spring, used as a high-load important spring with a larger section and a valve spring, piston spring, and safety valve spring with an operating temperature of <300 ℃.
Generally, the supply specification of the sheet material is between 1.5 and 10.0 mm, and it is often annealed, and more than 10 to 30 mm is mostly in the non-annealed state. There are few stocks on the market, so it is often necessary to order futures. The steel coil is in a hot-rolled state, and spheroidizing annealing is used to reduce the hardness in order to create conditions for further processing.
Chongqing Special Steel's 50CrVA is generally annealed sheet, eliminating the need for re-annealing. Medium-carbon alloy spring steel, the final heat treatment is quenching and tempering. After heat treatment, the steel has good toughness, high ratio limit and strength limit, and high fatigue strength, similar to the hardenability of 65Si2MnWA. Hardenability, low overheating sensitivity; when the parts are used at 300 ℃, their elasticity can still be maintained. The cutting performance of steel is still good, but the plasticity is low during cold deformation and the weldability is poor.
Chemical Composition:
| C(％) | Si(％) | Mn(％) | P(％) | S(％) | Cr(％) | Ni(％) | Cu(％) | V(％) |
|---|---|---|---|---|---|---|---|---|
| 0.46～0.54 | 0.17～0.37 | 0.50～0.80 | ≤0.030 | ≤0.030 | 0.80～1.10 | ≤0.35 | ≤0.25 | 0.10 ~ 0.20 |
Mechanical Propoerties:
| Yield Strength Rp0.2(MPa) | Tensile Strength Rm(MPa) | Impact Energy KV(J) | Elongation A(%) | Hardness |
|---|---|---|---|---|
| ≥ 1127(115) | ≥ 1274(130) | ≥ 98 | ≥ 10 | ≤ 321HB |
Heat treatment specification and metallographic structure:
Heat treatment specification:
hot-rolled steel is delivered in heat-treated or non-heat-treated state, and cold-drawn steel is delivered in annealed state.
Metallographic structure:
quenched at 850℃±20℃, oil-cooled; tempered at 500℃±50℃ (for special needs, ±30℃), the organization is tempered troostite or a mixed organization of troostite and sorbite.
Critical point temperature (approximate value) Ac1=752℃, Ac3=788℃, Ar3=746℃, Ar1=688℃.
Quenching and tempering treatment specification:
quenching temperature 860-880℃, oil cooling; tempering temperature 500±10℃, water and oil cooling.
Equivalent Grade:
American : G61500
Japanese : SUP10
German : 50CrV4
British : 735A51
French : 50CrV4