Causes Of Fatigue Fracture Of Floor Springs

The surface state stress mainly occurs on the surface of the spring material

so the surface quality of the spring has a huge?influence on its fatigue strength.

Cracks, defects and scars produced during rolling, stretching and coiling of spring materials are often the cause of spring fatigue fractures. The smaller the surface roughness, the smaller the stress concentration and the higher the fatigue strength.

The effect of surface roughness on fatigue.

Fatigue strength decreases with increasing surface roughness. Under the same roughness, different steel grades and different rolling methods have different degrees of fatigue reduction. For example, the degree of deceleration of a cold coil spring is less than that of a hot coil spring.

Due to the steel heating coil spring and the heat treatment after heating, the surface of the spring material becomes rough, and decarburization occurs due to oxidation, so the fatigue strength of the spring decreases. Grinding, pressing, blasting and rolling of material surfaces. Can improve the fatigue strength of the spring.