spring steel wire will influence the fatigue strength of spring. The fatigue strength means the maximum stress of spring which will not be destroyed under the infinitely affects of cyclic loading. Here are the factors.
1.Yield strength. The yield strength of spring steel wire is related to the spring's fatigue limit. Generally speaking, the yield strength is higher, the fatigue strength is higher. So in order to improve the fatigue strength of spring, we should try to improve the yield strength of spring steel wire.
2.Surface status. The maximum stress usually happen on the surface of spring steel wire, so the surface quality play an important role to the fatigue strength of spring. During the drawing and rolling of spring steel wire, the cracks, scars or other defects is the reason of fatigue fracture of spring. The grinding and rolling of the surface of spring material can increase the spring's fatigue strength.
3.Dimensional effect. The dimension of spring steel wire is bigger, the defects appearing rate during the processing is higher, and the possibility of surface's defects is bigger. So we should consider the dimensional effect when calculating the spring’s fatigue strength.
4.Metallurgical imperfection. Metallurgical imperfection means that the spring steel wire has nonmetallic inclusion, bubble and so on. Applies the measures of vacuum melting and vacuum pouring can improve the spring steel’s quality.
5.Corrosion medium. We should choose some spring steel wire with high corrosion resistance if the spring needs to be used under the corrosion condition. In order to avoid the fracture of spring because of the corrosion medium.
6.Temperature. We should apply spring steel wire with high heat resistance, because the high temperature will influence the spring’s fatigue strength.