Weld overlay cladding repair - An investigation of tensile strength variation in processed metallic substrate

Weld Overlay Cladding (WOC) is a surfacing technique commonly applied on subsea Oil and Gas components to provide additional properties such as wear and corrosion resistance at a more superior level. This process involves a clad metal with certain desirable characteristics – tends to be a superalloy – being fusion-welded onto a lower cost standard metallic substrate such as steel. In some cases, a repair is required to recondition damaged or corroded clad surfaces. This paper presents an investigation on tensile strength variation that occurs in the metallic substrate post-repair. Tensile tests were carried out on specimens extracted from a repaired substrate and a section of unclad substrate. Results were compared and have shown that variations occurred in both pieces – neither were close to the values stated on the material certificate or previous test certificate. Through literature review, suggestions were made for the reasons behind this phenomenon. Recommendations were proposed as to how such non-uniformity can be prevented or rectified through amending material procurement and cladding procedure.