Effect of Laser Polishing Post-Processing Technique on the Roughness and Wear Resistance of Inconel 625 Deposited by Laser Cladding on AISI 304L Stainless Steel

The use of laser cladding is a promising economic alternative for the production of coatings to with stand corrosion and wear, as well as for repairing aeronautical components after wearing out by using. Such technique allows the use of a wide variety of alloys for coating on flat and complex shapes, since it does not require strict controls compared to others powder-coating processes. The use of laser cladding is an ideal choice since it allows the deposition of superalloy on low-cost stainless steel substrate, for example. The resulting bimetalic material presents high performance at a much lower cost, hence making economically feasible a more intensive use of superalloys in many other circumstances. Inconel 625 alloy presents very high resistance to pitting in oxidizing chloride environments and good mechanical properties at elevated temperatures. Therefore, a hybrid metallic material made of AISI 304L stainless steel as substrate coated with Inconel 625 can be economically used in several situations with superior performance. However, surface finishing left by laser cladding is not always as smooth as required for most applications. In this work, coatings of Inconel 625 alloy were deposited by laser cladding on AISI 304L. The Inconel layer was post-processed by laser polishing (LP) for surface finishing improvements. The resulting coatings were evaluated for hardness, roughness and micro-abrasive wear tests. The LP post-processing significantly improved the roughness of Inconel 625 coating and did not significantly change its composition nor hardness. The coating layer also showed much better wear resistance, when compared to the AISI 304L substrate.