A Feasibility Study on Recycling of CM-247LC Ni-Base Superalloy for Production of Aeronautical-Grade Cast Parts of Gas Turbine Engines

In the present investigation, high temperature mechanical properties such as tensile, creep and low cycle fatigue of recycled directionally solidified CM-247LC Ni-base superalloy have been studied. CM-247LC superalloy is used for realizing aerofoil castings of modern gas turbine engines through vacuum investment casting route. High cost of few of the alloying elements, discard of runners, risers and pouring cups and inherently low yield of the vacuum investment casting process lead to a more than nearly 60-65% of loss in the superalloy used for making the castings. In order to make the casting process cost-effective, recycling (reusing) of the discarded parts for making the components is practiced in casting industry. Discarded CM-247LC parts such as sprue rods, gating, risers, etc., as mentioned above, have been re-melted and used for producing rods. Alloy chemistry, microstructure and advanced mechanical properties of the cast rods produced from recycled alloy have been compared with those produced using virgin alloy. The results of these scientific investigations indicate that there is strong possibility of using recycled CM-247LC superalloy for producing aerofoil castings of advanced gas turbine engines.