The Fundamental Investigation On Laser Cladding Process

The experimental study of laser cladding began ever since the 1970s. Through 30 years' development, the technology has made great progress and been more and more widely used in the industrial production. However, it still exists some problems to large-scale production applications.The most intractable problem of laser cladding is coating cracking. On the basis of selected substrate and coating material, generally we can minimize cracks by optimizing technological methods and parameters. The author proposed the process of unidirectional powder feeding and two-way scanning. By choosing appropriate laser technological parameters, the experimental study of single-pass cladding and multipass lap cladding was investigated, and the coating with no crackle was obtained, thus providing a simple and reliable solution to problems of cracking.As to the multipass lap cladding, the improvement of the smoothness of the coating surface is eager to solve. The choice of different overlapping coefficient has great impact on the smoothness of the coating surface, and directly determines the size of the late allowance. Through the introduction of theoretically deduce and tests on different overlapping coefficient, it is found that when overlapping coefficient is 0.4, the maximal thickness difference of the coating is smallest, the surface roughness of the overlap part is smallest, and the smoothness of the coating surface is the best, thus providing the basis for determining technological parameters in multipass lap cladding.Analyses on the metallograph of multipass coating show that it...