Hardfacing Alloy Powders

Hardfacing alloying is one of the inevitable methods to protect the components which are used in heavy-duty machinery. Specifically, this process is performed to improve the tribological properties of industrially important materials, such as AISI 304 stainless steel (SS) bushes in nuclear power plants, SS 316 control valves in coal power plants, polycrystalline martensitic steel valve seats in steam turbines, aluminum-based body sheet materials in the automobile, Co-based, Fe-based and Ni-based alloys. These materials have unique advantages to use for their specific application. However, these materials are preferred to use for hard-facing as those alloys have poor tribological properties at the different working conditions as they are prone to abrasive, adhesive wear and corrosion. Tribological properties, such as hardness and wear resistance of the alloyed material, mainly depend on the proper selection of hardfacing alloy powders, which have equal importance in the selection of process. Colmonoy-5, Colmonoy-6, Stellite-6, Inconel-625, H13 Steel, stainless steel 420, stainless steel 304, Ti-64, IN-718, AlSiMg, Scalmalloy, SS316L and CuCrZr are some of the important hardfacing alloy powders to enhance the tribological properties. Laser surface treatments, Gas Tungsten Arc-based alloying and Plasma Transferred Arc are the major hardfacing processes. Laser surface treatments are one of the most effective surface alloying processes for enhancing materials properties due to their unique advantages over other processes, such as flexible operation, high energy density and chemically clean operation. Moreover, it produces good metallurgical bonding of the alloyed region with the substrate material, minimizes the heat-affected zone (HAZ) and forms finer microstructure. This chapter provides a detailed understanding of various research works carried out on hardfacing alloying by laser-treated processes on different substrates. The outcome of this chapter would be beneficial for the present and future research based on laser-based hardfacing and also for many hardfacing industries.

Keywords: AlSiMg, Coefficient of friction, Colmonoy powder, CuCrZr, Inconel powder, Stellite powder, Scalmalloy, Tribological property, Wear resistance.