An assessment of residual stress mitigation strategies for laser clad deposits

Abstract

Laser cladding can be used for reclamation or for improving the corrosion resistance of engineering components. However, the process introduces substantial levels of residual stress, which can exacerbate corrosion. In this study, the effectiveness of different residual stress mitigation strategies was investigated. Laser clad overlays were produced by melting an austenitic stainless steel powder onto either an austenitic stainless steel or a mild steel substrate. Residual stresses were measured, using the hole-drilling technique, in the as-clad condition as well as after either laser shock peening (LSP) or post-weld heat treatment (PWHT). Samples were then subjected to corrosion testing. In all cases, LSP delayed the onset of corrosion cracks. However, PWHT was only effective when the substrate and overlay materials matched.

This paper is part of a Themed Issue on Measurement, modelling and mitigation of residual stress.

Keywords:

• Dilution
• Dissimilar materials
• Hardness
• Stress corrosion cracking
• Weld bead overlap
• Weld overlay

Acknowledgements

Alonso Martinez Hurtado gratefully acknowledges the full support of the Mexican National Council for Science and Technology (CONACYT). The authors would also like to thank Metal Improvement, part of Curtiss-Wright Surface Technologies, for carrying out the laser shock peening work in this study. In particular, we would like to thank Mr. Ben Hayes for coordinating and overseeing the laser shock peening operations.