Characterization of surface modification by laser cladding using low melting point metal

A bearing is an essential mechanical element that is used to fix the axis of a rotating machine and helps rotate the shaft while supporting its weight and load. Numerous types of bearings have been developed depending on the functions and sizes of the machines in which they are utilized. In particular, power generating units such as gas turbines use medium or large hydraulic bearings for smooth operation. White metal is a tin alloy and a soft material that is often bonded to the inner surfaces of medium and large bearings to lubricate and protect the bearing shafts. Currently, gravity or centrifugal casting is used to bond the white metal to the surface of the bearing material. The casting process requires pretreatments such as chemical treatment and preheating and has many disadvantages with respect to the work environment, worker safety, productivity, and potential for automation. In this study, the process of binding white metal to bearings is simplified and improved by applying a laser cladding using powdered white metal. Depositing a metal that has a very low melting point compared to the base metal is different from the conventional cladding process; therefore, the focus of this work is to analyze the new cladding procedure for various process conditions. White metal specimens fabricated with this laser cladding were evaluated using cross-section images, hardness tests, and energy-dispersive X-ray spectroscopy analysis.