The spring is often subjected to variable load or impact load. In order to ensure that the spring can work permanently and reliably, the material must have high elastic limit and fatigue limit. At the same time, it should have enough toughness and plasticity and good heat treatment.

Spring materials and properties can be consulted in relevant manuals, specifications and standards (GB/T129.6-92, GB4357-89). The common spring steel is mainly:

1: carbon spring steel

This kind of spring (such as 65, 70 steel, etc.) has the advantages of cheap price, convenient source of raw materials, low elastic limit, easy to lose elasticity after repeated deformation, and can not work at 130 degrees.

2: low manganese spring steel

Compared with carbon spring steel, the spring steel, such as 65Mn, has the advantage of high hardenability and high strength. The disadvantage is that cracks and thermal embrittlement are easy to occur after quenching. However, because of the low price, the general machinery is often used to manufacture spring without size, such as clutch springs.

3: silicon manganese spring steel

Because of the addition of silicon in this steel (for example, 60Si2Mn), the elastic limit can be significantly increased and the tempering stability is improved so that the tempering can be tempered at a higher temperature so as to get good mechanical properties. Silicon manganese spring steel has been widely used in industry. It is commonly used to manufacture automobiles, tractors, helical springs, etc.

4: chromium vanadium steel

The purpose of adding vanadium in such steel (for example, 50CrVA) is to refine the structure and improve the strength and toughness of the steel. This material has good fatigue and impact resistance, and can work reliably at a temperature of -40 degrees - 210 degrees, but the price is more expensive. It is often used for higher requirements, such as spring used in manufacturing aeroengine governing system.

In addition, some materials, such as stainless steel and bronze, have the characteristics of corrosion resistance, and the bronze is also magnetic and conductive, so it is often used in the manufacture of chemical equipment or the spring in the corrosive medium. The disadvantage is that it is not easy to heat treatment and has poor mechanical properties, so it is seldom used in general machinery.

When selecting materials, the use of the spring, the importance, the use conditions (including the properties of the load, the size and circulation, the duration of the work, the working temperature and the surrounding medium), the processing, heat treatment and economic factors should be taken into account. At the same time, we should refer to the spring used in the existing equipment, and choose materials that are more suitable for use.