Round spring, due to the geometry of the spiral, the surface of the leaf spring due to its hardening operation than flat strengthening more difficult. In addition, there must be strict assessment of the cross-section of the strengthening effect round spring, in order to fully understand the size of the round spring fatigue fracture resistance.
Round spring is a separately fed by a continuous conveyor chain system blasting room, shot blasting room is equipped with a set of parallel rollers Road, strengthen, roller kept rolling, driven forward while rotating round spring. This rotation by way enables high-speed pills flow through the round spring between ring and hit the metal surface of the inside circle, where exactly is the most concentrated site of round spring stress.
For applications with high capacity requirements, you can choose one to simultaneously spray two round spring intensive equipment. The latest results of research and development, strengthen in the original shot blasting equipment on the basis of combining into a plurality of nozzles for round reed specific area (stress concentration to please) more targeted, concentrated firepower peening treatment. The leaf springs strengthening using a continuous-through shot blasting strengthen one by a single enhanced treatment device of the leaf spring, a leaf spring geometry concave exposure in high-speed pills shed. Typical models including a polishing head for the top of the projectile leaf spring, side mounted a throwing head while spraying the leaf spring to the left and right side.
The set of standard models leaf spring strengthening the passage speed of the device is 10 feet / minute, such as the need for higher production speed can be increased by the number of the polishing head, the adjustment motor frequency. Under the operating conditions, the leaf spring will be repeated by the unidirectional bending stress influence, it is sometimes enhanced by the stress. Strengthening process simulation leaf spring will be "stress hardening" process later use it in the direction of the load, giving a "static stress" while its shot peening. After strengthening the release of the external static stress. Experimental results show that stress hardening than conventional strengthening can further prolong the service life of the leaf spring.
The suspension spring reinforced lightweight design thanks to the high stress in recent years, the weight of the suspension spring greatly reduce the stress of the suspension spring of the new models> 1000Mpa common. Spring serving in such a high stress has exceeded the limits of the material can withstand, so must be supplemented by other means of strengthening (throw / shot peening).
Host manufacturers of automotive suspension springs with very stringent test standards, the longest one test cycle as long as 70 days (10 weeks), it should have is that the suspension springs work under high stress conditions, once the surface is subjected to stress corrosion that cause corrosion fatigue failure, broken springs port if the punctured tire may cause significant safety and personal accident.
Throw / shot peening is the most effective means of strengthening of the suspension spring, high stress spring after peening fatigue life can be increased by more than five times, throw / shot peening of the suspension spring is mostly used on several steel cut wire shot, process the peening (different pellets diameter) universal application. The strength and depth of the spring surface compressive stress is an important indicator for measuring peening effect. Good shot peening of the surface stress of at least the above-600Mpa, can reach-the distance from the surface of 50um at 800Mpa the stress peening spring surface compressive stress of up to more than-800Mpa, can reach-the distance from the surface of 50um at 1200Mpa.