Six Major Inspection Parameters After High-Speed Laser Cladding

Detection parameters refer to the parameters that measure the quality of the cladding layer after high-speed cladding, mainly including porosity, hardness, bonding strength, dilution rate, thermal fatigue performance, surface roughness, etc.

(1) Porosity refers to the percentage of pores that appear in the cladding layer under certain conditions. Pores are inevitably present during the high-speed laser cladding process. The size of porosity is related to the temperature and speed of the metal powder, as well as the angle of powder movement. Generally, if the powder movement speed is slow during cladding, the porosity of the layer will be high.

(2) Hardness: Due to rapid cooling and high-speed impact during the formation of the high-speed laser cladding layer, grain refinement and lattice distortion in the cladding layer strengthen the coating. Therefore, the hardness of the laser cladding layer is higher than that of general materials. The surface hardness of the cladding layer produced by LT high-speed cladding laser equipment can reach up to 60 HRC.

(3) Bonding Strength: It is generally detected using a microhardness tester to determine the bonding strength of the cladding layer. It is calculated by subtracting the measured hardness value from the hardness value of a standard sample. The high-speed laser cladding layer forms a metallurgical bond with the substrate, meaning atomic diffusion occurs between the cladding layer and the substrate, creating a bond. This bond is formed under the high-speed motion of the powder. The bonding strength between the high-speed laser cladding layer and the substrate by Zhongwu Lituo can reach up to 360 MPa.

(4) Dilution Rate refers to the degree of dilution of the deposited metal, expressed as the percentage of the base material in the cladding layer. The dilution rate significantly affects the performance of the cladding layer. In the high-speed cladding process, the dilution rate can be controlled by adjusting the metal powder flow rate, laser power density, and cladding rate. The dilution rate of Zhongwu Lituo's high-speed laser cladding is extremely low, approximately 1%.

(5) Thermal Fatigue Performance refers to the resistance of the cladding layer to thermal fatigue or thermal shock. If the thermal shock resistance of the cladding layer is poor, it may crack during use. The thermal shock resistance of the cladding layer mainly depends on the difference in thermal expansion coefficients between the metal powder and the substrate, as well as the bonding strength between the cladding layer and the substrate.

(6) Surface Roughness refers to the undulations present on the surface during cladding. When there are significant undulations on the surface of the laser cladding layer, issues such as poor edge fusion and inadequate overlap may occur. Therefore, the degree of undulation should be controlled. Surface roughness, the flatness of the cladding layer surface, process testing, laser energy density, powder feed rate, and carrier gas pressure all affect surface roughness. There is an optimal value among these factors; if the value is set too high or too low, the surface smoothness will decrease. In the actual high-speed excitation of the substrate during optical cladding processing, appropriate processing parameters need to be set based on the characteristics of the powder substrate to ensure that all detection parameters meet standards and application requirements.

In actual high-speed laser cladding of the base material, appropriate processing parameters need to be set based on the characteristics of the powder base material to ensure that all detection parameters meet standards and application requirements.