Mechanical Testing of Laser Clads

摘要

The diversity of requirements for materials and the economic impact of material loss due to surface degradation, have led to the development of variety of efficient and cost effective surface modification processes. Well established surface treatment techniques include painting, electroplating, anodizing, nitriding, carburizing, thermal spraying, chemical vapor deposition (CVD) and physical vapor deposition (PVD). Each of these techniques has found applications depending on service requirements. Research in surface engineering has shown that Laser Cladding is effective in extending life of costly equipment in service environments where dimensional tolerance is critical. Laser cladding is a process of coating service dictated material on substrate using heat of laser. In critical applications laser clads improve wear and corrosion resistance in specific locations on surface and are especially useful for locally worn and corroded machinery. Testing, inspection and failure analysis are important for quality control of the laser clads. Producing defect free clads is equally important as selecting proper parameters for laser cladding process. This project was conducted to develop standard tests, instrumentation and practices for characterization of laser clads produced. Laser clads produced with variable heat input were tested. Side bend test was carried out to characterize the laser clads for ductility, while hardness tests to study the hardness profile of the clad, fusion zone and the substrate. Electron Dispersive Spectroscopy (EDS) analysis was carried out to obtain the metallurgical composition of clad and substrate to characterize clads for corrosion resistance.