A spring factory in Beijing is one of the largest manufacturers of cold-coiled springs in China. Its main products are automobile engine valve springs and various clamp, tension, torsion and compression springs. In recent years, the manufacturer has carried out large-scale technological transformations and introduced spring shot peening equipment from Wellbrite Group to improve the fatigue life reliability of valve springs and plunger springs, making its products leading the industry. status.
Compression springs are subjected to high alternating loads and the maximum stress occurs mostly on the surface of the spring material, so shot blasting/shot peening strengthening is also an ideal process to improve the fatigue strength of compression springs. The spring material causes tensile stress during rolling, drawing, coiling and compression. In addition to the high alternating load conditions after service, the coiling process itself will cause destructive tensile stress on the inner ring of the spring.
Shot blasting/shot peening introduces a counteracting compressive stress, which transforms the surface into a residual pressure layer with a strength of about 150 ksi (1035 MPa). This is 60% of the ultimate tensile strength (UTS) of the spring. As a result, the fatigue life of the spring has been extended to 500,000 load cycles without failure.
In addition to compression springs, shot blasting/shot peening is also applicable to the strengthening of other springs such as tension springs, torsion springs, suspension springs, leaf springs, etc. The fatigue failure point usually occurs in the place where the residual tensile stress and the alternating load stress are concentrated, so the strengthening position of different springs is different.