I believe you all know that the spring needs to be electroplated, but you know, after making the spring need to temper (that is, heat treatment)? Let me tell you why the spring needs to be tempered, what do you need to pay attention to when you do the tempering?

Why should the spring be tempered?

1. Increase the yield strength of the material to about 90% of the tensile strength to improve the creep resistance of the spring.

2. Release the residual stress caused by wire drawing and spring winding process, and improve the fatigue performance and creep performance.

3. Stable spring shape: after tempering for 15-30 minutes, the outer ring of the spring will shrink to a stable level.

What are the matters needing attention in the treatment of spring tempering?

1. Avoid spring tempering by increasing the temperature and shortening the time.

2. Hardness: with the increase of tempering temperature, the hardness will decrease after a slight increase. The temperature of better fatigue performance is slightly lower than that of higher hardness.

3, reducing diameter: carbon steel spring tempering outside diameter will be reduced, so when the spring should be reserved some size.

4, spring return color: return color is related to temperature and the residue on the surface of the wire, the color is not uniform and the temperature distribution or the gas flow in the furnace.

5. If the color is expected to be uniform, the furnace and charging method should be well managed; If there is localized oil or fingerprints, the color will change after tempering.

6, tempering temperature: generally used tempering temperature in 250-280℃, such as 200-250℃ steel wire treatment, although can improve the strength, but plastic toughness will also lose, can lead to tension spring bending hook or torsion spring bending leg fracture.

7. Compression spring: mild low temperature tempering can reduce deformation after hammering.

8. Tension spring: there will be loss of initial stress after tempering treatment. The allowable loss should be considered when setting the deviation.

9, torsion spring: coil spring after 280℃ tempering treatment, such as coil spring after processing, low temperature tempering temperature of 250℃.

10, the hook of the tension spring and the arm of the torsion spring: the position will change after tempering, if there is an accurate position requirement, should master the change.