The following points should be noted when extending the service time of the leaf spring:

1. Selection of raw materials

Carbon spring steel is less used because of its low hardenability; manganese steel has good hardenability, but is prone to quenching cracks and temper brittleness. Therefore, silicon-manganese steel is widely used in my country.

2. Defects in raw materials

① Impurities greatly reduce the fatigue strength of electric vehicle leaf springs;

②The band structure seriously reduces the mechanical properties of the steel.

3. Heat treatment defects

Surface decarburization, quenched underheated structure, feather-like structure, etc. will reduce the fatigue strength of the leaf spring.

4. Quality of shot peening

Shot peening not only produces a strengthening layer on the surface of the spring, but also makes small defects and decarburization on the surface of the spring, reducing stress concentration and so on. The difference in shot peening quality is also one of the reasons for the difference in service life of the leaf spring.

5. Use Levels

The service life of the leaf spring of a vehicle that is operated safely is much higher than that of the leaf spring of a vehicle with bad road conditions, severe overloading, and rough driving.