PRODUCT CATEGORIES

Vacuum Heat Treatment Furnace

Vacuum Sintering Furnace

Vacuum Brazing Furnace

Optimization of vacuum heat treatment of spring

The purpose of vacuum heat treatment is to give full play to the potential of the material, so that it can reach or approach the best mechanical properties, so as to ensure the long-term reliable operation of the spring in the service state.

Spring vacuum heat treatment

Springs must be subjected to vacuum heat treatment during processing. For various types, materials and springs processed by different methods, the purpose, method and requirements of vacuum heat treatment are different. In order to eliminate unfavorable residues, improve the stress distribution of the spring surface, and obtain higher effective stress, mechanical strengthening processes are often used in the manufacture of springs. Different vacuum heat treatment methods can be used to meet the requirements of spring design.

For most cold-worked austenitic stainless steels, after vacuum tempering at 320-440°C for 10-60 minutes, the mechanical properties, elasticity, fatigue strength and relaxation properties will be improved differently, and the tensile strength can be increased by about 10%. This is because a fine carbide M23C6 is precipitated in the atomic lattice structure during the vacuum tempering process, so that the material can increase the tensile strength; in addition, the vacuum tempering treatment after the spring is formed can reduce the damage caused by processing and forming. Internal stress increases the fatigue strength.

Effects of stress relief vacuum tempering temperature and holding time on the initial tension of the tension spring:

Stress-relief vacuum tempering has an influence on the initial tension of the tension spring. The vacuum tempering temperature is low, the holding time is short, and the retained initial tension is large, otherwise the initial tension is small.

The stress relief vacuum tempering temperature and holding time can be adjusted according to the initial tension required by the tension spring. For spring processing, stress-relieving vacuum tempering is sometimes carried out several times. In order to prevent the material strength from decreasing, it should be noted that the temperature of each subsequent vacuum tempering should be 20-50°C lower than the first vacuum tempering temperature.

Vacuum quenching and vacuum tempering

Vacuum quenching and vacuum tempering treatment specifications for commonly used spring materials:

In order to ensure the strength and performance of the spring, the spring formed by vacuum annealing material or hot roll forming (larger material diameter and thickness) and hot bending should be vacuum quenched and vacuum tempered.

Precautions for vacuum quenching and vacuum tempering:

The vacuum quenching of the spring should be carried out in a vacuum furnace. For materials with vacuum tempering brittleness, such as manganese steel, silicon-manganese steel, chromium-silicon steel, etc., they should be cooled in water or oil quickly after vacuum tempering, and immediately supplemented with low-temperature vacuum tempering below 200 ° C to eliminate cooling stress.

Due to the relatively high carbon content of alloy spring steel and certain alloy elements, the internal stress after vacuum quenching is relatively large, and it is easy to form vacuum quenching cracks, so it should be vacuum tempered as soon as possible after vacuum quenching. If the vacuum tempering cannot be done in time, it should be kept at a temperature lower than the vacuum tempering temperature for a period of time.