The effect of laser shock peening on the life and failure mode of a cold pilger die

The laser shock peening (LSP) process was used to increase life of pilger dies made of A2 tool steel by imparting compressive residual stresses to failure prone areas of the dies. The result of X-ray diffraction analysis indicated that deep, high-magnitude compressive residual stresses were generated by the laser shock peening process, and the peened dies exhibited a significant increase of in-service life. Fractography of the failed dies indicates that the failure mechanism was altered by the peening process.