The factory winding method of spring is divided into cold coil method and hot coil method.
(1) Cold winding method: the spring wire diameter D ≤ 8mm shall be wound by cold winding method. The high-quality carbon spring steel wire which is cold drawn and pre heat treated is usually used for the spring wound in cold state. Generally, quenching treatment is not required after winding, and only low-temperature tempering is required to eliminate the internal stress during winding.
(2) Hot coiling method: the spring with larger wire diameter (d > 8mm) is wound by hot coiling method. The spring rolled in hot state must be quenched and tempered at medium temperature.
The manufacturing process of different types of spring is different, and the basic operation is machine winding. After forming most elastic parts, heat treatment is required to form elasticity and keep it. Therefore, heat treatment is required in the production process of spring
It is difficult to “rework” a spring, whether it is a coil tension spring or a coil compression spring
Stress relief after quenching
1、 Operation: the workpiece is slowly heated to 500-600 ℃ and slowly cooled to below 300-200 ℃ with proper heat preservation (also known as softening annealing)
2、 Features: due to annealing temperature