Problems existing in laser cladding technology

       The quality of the laser cladding layer is evaluated from two aspects.

First, macroscopically, examine the shape of the cladding channel, surface unevenness, cracks, pores and dilution rate, etc.;

The second is microscopically, to examine whether a good organization is formed and whether it can provide the required performance. In addition, the types and distribution of chemical elements in the surface cladding layer should be determined, and attention should be paid to analyzing whether the transition layer is metallurgical bonding, and quality life testing should be carried out if necessary.

The research work focuses on the research and development of cladding equipment, the dynamics of the molten pool, the design of alloy composition, the formation, propagation and control methods of cracks, and the bonding force between the cladding layer and the substrate.

The main problems facing the further application of laser cladding technology are:

① The main reason why the laser cladding technology has not been fully industrialized in China is the instability of the quality of the cladding layer. During the laser cladding process, the heating and cooling speed is extremely fast, and the maximum speed can reach 1012℃/s. Due to the difference in temperature gradient and thermal expansion coefficient between the cladding layer and the base material, various defects may be generated in the cladding layer. It mainly includes pores, cracks, deformation and surface unevenness.

②The detection and implementation of automatic control of the optical cladding process.

③The cracking sensitivity of the laser cladding layer is still a difficult problem for researchers at home and abroad, and it is also an obstacle to engineering application and industrialization. Although the formation and propagation of cracks have been studied, the control method is still immature.