1. High strength
In order to improve the fatigue failure and relaxation resistance of inclined coil spring, the material of inclined coil spring should have high yield strength and elastic limit, especially high yield strength ratio. Generally speaking, the elastic limit of the material is directly proportional to the yield strength. Therefore, the design and manufacturer of inclined coil spring always hope that the material has high yield strength.
2. Good plasticity and toughness
In the manufacturing process of inclined coil spring, the material needs to be processed and deformed to varying degrees, so the material needs to have a certain degree of plasticity. For example, when the bending radius is very small, when the bending radius is very small, the inclined coil spring material shall not have defects such as crack and folding during processing, winding or stamping bending. At the same time, when the inclined coil spring is subjected to impact load or variable load, the material should have good toughness, which is of great benefit to improve the service life of the inclined coil spring.
3. Excellent surface condition and fatigue performance
When the inclined coil spring works, the surface stress is large, and the fatigue failure often starts from the surface of the steel wire. The oblique ring springs used in important occasions, such as oblique ring spring, valve oblique ring spring and suspension oblique ring spring, have hundreds of thousands, thousands or more cycle life, which puts forward high requirements for the fatigue performance of materials. There are many factors affecting the fatigue properties of materials, such as chemical composition, hardness, steel purity, surface quality and metallographic structure, especially the surface quality of materials.
4. Strict dimensions
Many inclined coil springs have high requirements for load accuracy. For example, the load deviation of valve inclined coil spring shall not be greater than 5% ≤ 6% of the specified load. Taking wire rope tension and compression ring spring as an example, when the wire diameter deviation is 1%, the load deviation is about 4%. Therefore, strict size accuracy is also very important to ensure the quality of inclined coil spring.
5. Good consistency
The requirement for material uniformity refers to the uniformity and stability of the chemical composition, mechanical properties, dimensional deviation and other indicators of the material. If the properties of the material are inconsistent, it will bring great difficulties to the production of inclined coil spring, resulting in the dispersion of product geometric size, hardness, load and other parameters, and serious heterogeneity will even cause waste of products.
