Application of shot peening in springsApplication of shot peening in springs

1、Why springs require shot peenning?

Due to the influence of external random load or cyclic load, the service life of suspension coil spring greatly reduces due to the crack, scratch, flash, hemp edge, surface roughness, etc., on the surface of the spring, which is very prone to fracture failure. The main reason of fracture failure is fatigue fracture.

Shot peening can produce a hardening layer on the surface of springs, and then reduce or eliminate the small cracks, concave convex defects and the harmful effect of decarburization layer on the surface of springs, so as to effectively improve the fatigue life of springs.

2、Shot peening process commonly used in springs

2.1 Spring shot blasting - one shot blasting (free shot blasting)

a) Shot blasting intensity: 0.4-0.45mmA

b) Coverage (30 times magnifier method): 98%

c) Recommended shot: CW32 (0.8mm) / HV640 / G3

d) Shot blasting position: whole spring

2.2 Spring shot blasting - composite shot blasting (free shot blasting)

a) First shot blasting intensity: 0.4-0.45mmA

Second shot blasting intensity: 0.2-0.25mmA

b) Coverage (30 times magnifier method): 98%

c) Recommended shot: first shot blasting - CW32 (0.8mm) / HV640 / G3

Second shot blasting - CW17 (0.4mm) / HV640 / G3

d) Shot blasting position: whole spring 

2.3Spring shot blasting -- prestressed shot blasting

a) Shot blasting intensity: 0.4-0.6mmA

b) Coverage (30 times magnifier method): 98%

c) Recommended shot: CW32 (0.8mm) / HV640 / G3

d) Compression load of single workpiece: max20KN

e) Shot peening position: whole spring

f) Residual stress: 50% higher than that of one shot blasting

2.4Spring shot blasting -- hot shot blasting

a) Shot blasting intensity: 0.4-0.45mmA

b) Coverage (30 times magnifier method): 98%

c) Recommended shot: CW32 (0.8mm) / HV640 / G3

d) Temperature of shot blasting area: 200 ~ 240℃

e) Applicable type: cold coil spring

f) Shot peening position: whole spring 

g) Loading and unloading with robot

3、Shot blasting machines for springs

3.1 Spring shot blasting -- one shot blasting / composite shot blasting

Recommended equipment: WB750-P380/4/15 Through type shot blasting machine