HANS GS found that the different scanning speed had a significant effect on the quality of the cladding layer. The suitable scanning speed made the cladding layer continuous, smooth, smooth and without pores. The faster scanning speed led to the discontinuity of the cladding layer, and the intermittent bead and void.

Other factors that affect the quality of the laser cladding layer of exhaust valve include the pressure of the protective gas. The experiment found that the excessive pressure of the protective gas will make the surface roughness increase, and the surface is uneven and smooth, resulting in wrinkle. The pressure of protective gas is too small. First, the surface of cladding layer can not reach the purpose of preventing oxidation. It will make the oxygen in air participate in the action of laser and powder and cause the defect of cladding layer.
The pollution of the lens will also have an impact. Because the beam and the protective gas coaxial, not only to protect the role of the molten pool, but also to protect the role of the lens. In the process of laser treatment, splashing is unavoidable. Shielding gas can prevent slag from flying to the focus lens. Therefore, the pressure of protective gas can not be ignored.
The pollution of the lens will also have an impact. Because the beam and the protective gas coaxial, not only to protect the role of the molten pool, but also to protect the role of the lens. In the process of laser treatment, splashing is unavoidable. Shielding gas can prevent slag from flying to the focus lens. Therefore, the pressure of protective gas can not be ignored.
Fixture is an important factor affecting the quality of cladding layer. In the laser cladding process, fixture must ensure that the exhaust valve can rotate at a uniform speed, so that the scanning speed is constant. The position of beam irradiation coincides with the position of the slotting, otherwise the cladding layer will deviate and cause the workpiece to be scrapped.
(1) In the exhaust valve pre coating process, when the laser power, spot diameter and scanning speed are constant, the coating thickness is 1mm to 2mm, and the alloying ratio of the alloy powder to the adhesive is 2%. The ideal surface quality of laser cladding can be obtained.
(2) The best process parameters of laser cladding of automobile exhaust valve are: laser power 1.8kW to 2.1kW, spot diameter 4.5mm to 5mm, scanning speed 5mm/s to 6mm/s., cladding layer continuous, smooth and smooth, basically no pores, stable process, and can be used for industrial production.