Analysis of the problem of powder not hanging in laser cladding

Problem Overview
The inability of laser cladding powder to hang refers to the phenomenon where the powder cannot uniformly adhere to the substrate during the laser scanning process, resulting in phenomena such as powder falling off. This phenomenon not only affects the processing effect, but may also damage the equipment.

Root cause analysis of the problem
1. Surface oxidation
If the surface oxidation of the powder is severe, it will affect the bonding force between it and the substrate, leading to the phenomenon of inability to hang. Therefore, it is necessary to ensure that the storage, transportation, and processing environment of the powder is dry.
2. Poor liquidity
Poor fluidity may be caused by irregular shape, uneven size, and poor thermal stability of powder particles. If the powder cannot quickly melt and adhere to the substrate during the heating process, there may also be a problem of not being able to hang.
3. Uneven composition
If the powder composition is uneven, its hardness, melting point, thermal expansion coefficient, and other properties will also be different, which will lead to uneven distribution of physical parameters such as temperature, flow field, and stress during the laser cladding process, resulting in the phenomenon of inability to hang.

Solution
1. Surface treatment
By treating the surface of the powder with antioxidants such as alumina, the degree of oxidation can be reduced and the adhesion between the powder and the substrate can be improved.
2. Optimize alloy composition
Optimize the alloy composition, adjust the hardness, melting point, thermal expansion coefficient and other properties of the powder to make it more suitable for laser cladding process.
3. Improve the powder preparation process
Improve the powder preparation process, control the particle size, shape and other characteristics of the powder, enhance its flowability, and avoid the problem of hanging.
4. Strengthen storage and transportation management
Strengthening storage and transportation management to ensure that powders are stored in a dry and dust-free environment can effectively prevent powder oxidation.

Summary
Unable to hang is a common problem in laser cladding, which may be caused by powder surface oxidation, poor flowability, uneven composition, etc. Corresponding solutions should be adopted for different problems to achieve good processing results.