Test Equipment for Leaf Spring Chipping Test

Hello. Last time we talked about various corrosion problems and failure modes of coatings and materials. From today, we will learn about chipping, which has the greatest influence on leaf spring corrosion, and introduce test methods.

 

Chipping

 

chipping tests shall be performed on leaf springs for determination of test parameters on the test bench for comparison of impact patterns to the master sample. The parameters to be determined are gravel type and size. gravel amount, grit speed as well as shooting direction.

 

 

Test equipment

 

The grit impact simulation has been carried out on the large grit impact simulator. The peening material is filled in the storage filler. From there, the peening material is transported by an auger to a feeder which leads in between two touching tires. The tires are driven each by an electric motor, whose speed is infinitely variable. The peening material entering from the feeder is grasped by the rotating tires, accelerated to the speed of the tires and shot at the leaf springs. Thereby, defined and reproducible damage to the specimens is achieved. The storage filler can also be fed manually with an auxilary feeding tube to individualies the peening material.

 

For the speed adjustment, radial white lines are painted on the tires. The shooting speed corresponds to the tires' peripheral speed. Using the relation of the peripheral speed depending on the distance of the tires' centers and the tires' rotations per minute, the stoboscope's flashes per minute necessary for the adjustment of the speed desired can be determined. The tires' resulting speed is adjusted until the white lines on the tires "stand still" when using the stroboscope. For cross checking the speed, a display on the machine's control cabinet displays the rough magnitude of speed. 

 

Test procedure

 

A grit impact simulation has been performed for determining the test parameters on the test bench. The goal is to adjust the test parameter so that the impact pattern after the chipping test correlates to the impact pattern of the master sample Therefore, a variation of gravel type, size and its intensity of impact have been used.