The Research On Process And Microstructure Of Thin Parts In Laser Cladding Forming

The process and microstructure of Laser Cladding Forming (LCF) thin parts are experimentally and theoretically studied in this paper and main conclusions are as follows:l.A practical LCF equipment, including a 1KW continuous wave CO2 laser instrument, a three-axes CNC processing table and a powder feeding system, was established, by which thin metal components with better accuracy can be built.2. The process of LCF thin wall has been studied deeply, and a 0.55 mm width thin part with lower carbon steel has been successfully built for the first time; Next, It was investigated systematically that process parameters had an influence on the width of thin wall in deposition; Finally, it was found that the experimental results, in terms of the cross section of molten pool, are in good agreement with that of the theory, which plays an important role in lying out and determining process parameters.3. The thin wall's accuracy of LCF has also been investigated both experimentally and theoretically, it is presented that coaxial powder-feed nozzle, laser beam mode scanning path have great effects on the accuracy in LCF, for the changes of those factors have direct influences on the shape and stability of melt pool, As a result the accuracy is on the decline.4. The lower carbon steel thin wall's microstructure of LCF has been carefully analyzed experimentally, and it's microstructure was made up of tiny equiaxed grain, which is entirely different from that of current reports; By combining with theory of fast cooling, the main reason lies in the fact that the solidification microstructure would grow up towards equiaxed grain under lower laser power and smaller laser beam diameter; In addition, the middle carbon part's microstructure of LCF is mainly bainite, a little is wustite structure.5.Finally, the micro-hardness and density are also examined and experimental results are close to those of traditional processes, it shows that thin parts with near densities and better properties can be fabricated using LCF.