Three factors affect spring fatigue strength

Three factors affect spring fatigue strength

1. The greater the size effect of material size, due to various defects caused by the cold and hot working technology, the higher the possibility to produce the greater the likelihood of surface defects, these reasons will lead to fatigue performance degradation.Therefore when calculating the fatigue strength of the spring to consider the influence of size effect.
2. The metallurgical defects of non-metallic inclusions in metallurgical defects refers to materials, bubble, element segregation, and so on.Exist on the surface of the inclusions is a source of stress concentration, can lead to inclusion and matrix interface between prematurely to produce fatigue crack.Adopt measures, such as vacuum smelting, vacuum casting can greatly improve the quality of steel.
3. The corrosive medium spring when you are working in a corrosive medium, because of the surface pitting or surface grain boundary corrosion and become a source of fatigue, under the effect of varying stress will gradually expand and cause fracture.Such as the spring steel work in fresh water, the fatigue limit is only 10% ~ 25% in the air.Corrosion influence on spring fatigue strength, not only related to the spring by the effect of variable load frequency, and associated with the working life.So design calculation affected by corrosion of the spring, it should be working life into consideration.