Pressure spring strengthening process technology treatment:
Round springs, due to their spiral geometry, are harder to strengthen than flat surface leaf springs. In addition, it is necessary to strictly evaluate the strengthening effect of the circular spring cross section, so as to fully understand the resistance of the circular spring to fatigue fracture.
The round springs are individually sent to the shot blasting chamber via a continuous conveyor chain system. A set of parallel roller tables are installed in the shot blasting chamber. While strengthening, the roller table keeps rolling, driving the circular spring to rotate while moving forward. This way of rotation allows the high-speed pill flow to pass between the rings of the circular spring and hit the metal surface of the inner ring, where the stress of the circular spring is most concentrated.
Shot/shot peening is the most effective strengthening method for suspension springs. After proper shot peening, the fatigue life of high-stress springs can be increased by more than 5 times. At present, most suspension springs are shot/shot blasted with steel wire cut blasting. Shot peening (different pellet diameters) is commonly used. The strength and depth of the spring surface compressive stress are important indicators to measure the effect of shot peening. The surface stress of good shot peening is at least above -600Mpa, and it can reach -800Mpa at a distance of 50um from the surface. The surface pressure stress of a stress shot peening spring can reach above -800Mpa, and it can reach -1200Mpa at a distance of 50um from the surface.
leaf spring reinforcement
A continuous pass-through shot blasting equipment can be used to strengthen the leaf springs one by one individually, exposing the geometric concave surface of the leaf spring to the high-speed shot flow. A typical model includes a throwing head for projecting the top of the leaf spring, and a throwing head is installed on the side to spray the left and right sides of the leaf spring at the same time.
The passing speed of this standard leaf spring strengthening equipment is 10 feet per minute. If a higher production speed is required, the number of polishing heads can be increased and the motor frequency can be adjusted. Under working conditions, leaf springs are repeatedly affected by unidirectional bending stress, so they are sometimes stressed by stress. In the strengthening process, it is simulated that the leaf spring will be subjected to “stress strengthening” in the future use process, so that it will be shot peened while applying a “static stress” in the direction of bearing the load. After strengthening, release the applied static stress. Experiments prove that stress strengthening can further extend the service life of leaf springs than conventional strengthening.