In order to increase the spring steel wire's yield strength to 90% of tensile strength, the temper is necessary; it can also improve the spring's resistance to creep. The drawing temper can also release the residual stress caused in the drawing and colling process and stabilize the spring's shape.
During the drawing temper of spring steel wire, we need to notice something:
1. Avoid the temper by measure of increase the temperature and shorten the time.
2.The residuum on the spring steel wire's surface and temperature are related to tempering color. If you want to keep the spring steel wire has an uniform color, you should manage the furnace and do not leave fingerprint on the surface.
3. Tempering temperature: generally the spring steel wire's tempering temperature is about 250-280 ℃. If we process spring steel wire under the temperature of 200-250 ℃, the strength will increase but the plastic toughness will loss. So you need to control the tempering temperature.
4. Hardness: With rise of the tempering temperature of spring steel wire, the hardness will be slightly increased then fell. The best temperature of fatigue properties is slightly lower than the maximum temperature of hardness.
During the drawing temper of spring steel wire, we need to notice something:
1. Avoid the temper by measure of increase the temperature and shorten the time.
2.The residuum on the spring steel wire's surface and temperature are related to tempering color. If you want to keep the spring steel wire has an uniform color, you should manage the furnace and do not leave fingerprint on the surface.
3. Tempering temperature: generally the spring steel wire's tempering temperature is about 250-280 ℃. If we process spring steel wire under the temperature of 200-250 ℃, the strength will increase but the plastic toughness will loss. So you need to control the tempering temperature.
4. Hardness: With rise of the tempering temperature of spring steel wire, the hardness will be slightly increased then fell. The best temperature of fatigue properties is slightly lower than the maximum temperature of hardness.
Apart from these notice during the spring steel wire's tempering, you also should pay attention during the process of extension spring, torsion spring, you should control the temperature, the variation and so on. So the spring will have a good performance.