The Exhaust Valve Application Of Laser Cladding Technology

The change of different scanning speeds has a significant impact on the quality of the cladding layer. The suitable scanning speed makes the cladding layer continuous, smooth, smooth and free of pores. Too fast scanning speed will cause the cladding layer to be discontinuous and appear intermittent beads. shape, with voids.Other factors affecting the quality of the exhaust valve laser cladding layer are the pressure of the protective gas. The test found that if the protective gas pressure is too large, the surface roughness will increase, the surface will be uneven and smooth, and wrinkles will occur. If the pressure of the protective gas is too small, first, the surface of the cladding layer cannot achieve the purpose of anti-oxidation, which will cause the oxygen in the air to participate in the action of the laser and the powder, resulting in defects in the cladding layer.

Lens contamination can also play a role. Because the beam and the shielding gas are coaxial, it not only protects the molten pool, but also protects the lens. In the process of laser processing, splash phenomenon is inevitable, and the protective gas can prevent the slag from flying to the focusing lens, so the pressure of the protective gas cannot be ignored.

Tooling fixtures are also an important factor affecting the quality of the cladding layer. During the laser cladding process, the tooling fixture must ensure that the exhaust valve can rotate at a constant speed, so that the scanning speed remains unchanged. The beam irradiation position coincides with the slotting position, otherwise, the cladding layer will deviate, causing 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 blending ratio of alloy powder and adhesive is 2%, an ideal the surface quality of the laser cladding layer.
2. The best process parameters for laser cladding of automobile exhaust valves are: laser power 1.8kW ~ 2.1kW, spot diameter 4.5mm ~ 5mm, scanning speed 5mm/s ~ 6mm/s. The cladding layer is continuous, flat and smooth , basically no pores, stable process, can be used for industrial production