Evaluation of welding characteristics for manual overlay and laser cladding materials in gas turbine blades

A Ni-based super-alloy is widely used in manufacturing the first stage blade of high power land-based gas turbines as these first stage blades operate under high temperature and high pressure. The blade of a gas turbine must withstand the most severe combination of temperature, stress, and. environment. After continued operation, the blade may be damaged by the turbine operation mode. To recover its initial mechanical properties, the blade of the Ni-based super-alloy undergoes a replacement repair process. Typical repair processes include blending, welding, re-machining and precision grinding. In this paper, the effects of manual overlay and laser cladding were investigated as part of the welding characteristic evaluation. Results are compared with those for post-heat treatment known as hot isostatic processing (HIP).