Failure Analysis of a Spring

Summary A company experienced two failures of their spring during testing and requested that a failure analysis be performed. Two springs were supplied (see Figure 1 in PDF), one failed prematurely and the other successfully completed 2 million cycles. The failed spring possessed circumferential notches beneath the coating. Both springs are approximately 10% below the strength requirement of ASTM A228.

Analysis Testing included dimensional inspection, visual examination, metallography, microhardness testing, chemical analysis, Scanning Electron Microscopy (SEM), and computer modeling.

Results A simple stress analysis shows that the highest levels of stress are in the location where failure did occur. This demonstrates that there were no unknown forces acting on the spring that might have contributed to failure.

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