Avaliação do recobrimento de TiN aplicado em ferramenta de aço AISI 1045 para o processo de soldagem por atrito, FSW

Abstract

The Friction Stir Welding process, FSW, consists in the realization of the union of materials, dissimilar or not, with the use of a rotating tool, responsible for the heating and mixing of the parts to be welded. In this process the materials involved do not melt and many defects from the welding process are eliminated. Developed during the 1990s by the The Welding Institute, TWI, the FSW process has been increased in application due to the low cost of welding in alloys, that traditionally have difficulty to be joining by conventional welding processes. For example Al alloys of application in the aeronautical, aerospace and shipbuilding industries of the series 2XXX.X (Al-Cu), 5XXX.X (Al-Mg), 6XXX.X (Al-Mg-Si) and 7XXX.X (Al-Zn). Also, the FSW process has been applied not only to Al alloys, but also to alloys of higher hardness and strength such as steel and Ti alloys. A fundamental part in the FSW process, the tool is responsible for penetration, friction and formation of the weld joint and requires careful selection method, to obtain a viable cost-benefit ratio. The objective of this work is to evaluate the surface coating performed on AISI 1045 steel tools for the FSW process aiming at increasing the useful life and maintaining the low cost for its manufacture. The development of this work consisted in the coating samples of AISI 1045 with TiN by the Magnetron Sputtering method, characterization of the deposited film through X-ray diffraction (XRD), scanning electron microscopy (SEM), photoelectron spectroscopy by X-Ray (XPS) and Vickers microhardness tests (HV). The yield of the tools evaluated through the FSP process, comparing the resulting stresses and deformations between the tools, with and without recoating.