Springs are often subjected to variable loads or impact loads during operation. In order to ensure that the springs can work reliably for a long time, the material must have high elastic limit and fatigue limit, and at the same time, it should have sufficient toughness and plasticity, as well as good heat treatment. For spring materials and properties, please refer to relevant manuals, specifications and standards (GB/T129.6-92, GB4357-89). Commonly used spring steel mainly includes:

1: Carbon spring steel
The advantage of this kind of spring (such as 65 and 70 steel, etc.) is that it is cheap and the source of raw materials is convenient. The disadvantage is that the elastic limit is low. It is easy to lose elasticity after repeated deformation and cannot work normally at a temperature of 130 degrees.

2: Low manganese spring steel
Compared with carbon spring steel, this kind of spring steel (such as 65Mn) has the advantages of better hardenability and higher strength; the disadvantage is that it is prone to cracks and hot brittleness after quenching. However, due to the low price, it is often used to manufacture springs of small size, such as clutch springs, in general machinery.

3: Silicon-manganese spring steel
This kind of steel (such as 60Si2Mn) is added with silicon, so it can significantly increase the elastic limit and improve the tempering stability, so it can be tempered at a higher temperature to obtain good mechanical properties. Silicon-manganese spring steel has been widely used in industry, and is generally used in the manufacture of coil springs for automobiles and tractors.

4: Chrome vanadium steel
The purpose of adding vanadium to this kind of steel (such as 50CrVA) is to refine the structure and improve the strength and toughness of the steel. This material has good milk fatigue and impact resistance, and can work reliably at temperatures from -40°C to 210°C, but the price is more expensive. It is mostly used in high-demand occasions, such as the spring used in the manufacture of aero engine adjustment systems.

In addition, some materials such as stainless steel and bronze have the characteristics of corrosion resistance. Bronze is also magnetic and conductive, so it is often used in the manufacture of springs in chemical equipment or working in corrosive media. Its disadvantage is that it is not easy to heat treatment and its mechanical properties are poor, so it is rarely used in general machinery. When selecting materials, consideration should be given to the spring's purpose, importance, use conditions (including load properties, size and cycle characteristics, working duration, working temperature and surrounding medium conditions, etc.), processing, heat treatment and economic factors. At the same time, refer to the springs used in the existing equipment and choose a more suitable material.