Overview of Joining and Repairing Techniques of Ni-Based Superalloy for Industrial Gas Turbine Applications

Abstract

In industrial gas turbine (IGT) engine manufacturing, nickel-based superalloys are used mainly to meet the needs of components of the hot gas pathway. Although these alloys have high-temperature capabilities, the parts are prone to damage during service. The high working temperatures of these engines lead to component degradation due to creep, fatigue, and oxidation reactions; therefore, due to the high cost of newly produced superalloy components, it is usually more cost-effective to repair the damaged parts rather than completely replacing them. Joining and repairing techniques are necessary when manufacturing and repairing these alloys. This article will present an overview of the Ni-based superalloy for industrial gas turbine application by studying the microstructure of Ni-based superalloy, weldability issues, and cracking phenomena. Joining/repairing techniques of Ni-base superalloy with advantages and limitations to each technique are discussed to know a suitable technique for use in the high-temperature application.