How to check the Spring clip

In the selection and purchase of the Spring Clip,in addition to the price,specifications,but also pay attention to the quality of the Clip fastener.So how to test the quality of the clip?What kind of test should be used?

1.Residual deformation:After the static pressure of the spring bar for three times,the deformation value of the middle front end is less than 1mm.If you want to check whether the cartridge is residual deformation,you can put the cartridge on the platform,measure the relative height of the middle front end of the cartridge with a depth ruler,and then put the cartridge into a special tire shape,and put the tire shape on the bench of the experimental machine.Pad a 50mm flat washer between the test machine pressure head and the spring bar,so that the center line of the washer and the spring bar mark line overlap.Slowly load to 50kN and stabilize for 5 seconds,then unload back to zero.Repeat this three times,put the spring back on the platform,and measure the relative height of the front end.

2.Hardness:The hardness of the elastic bar is 41-46.The method of sampling is adopted to test the hardness of the elastic bar.