In the past two years, high-speed laser cladding technology has received great attention from China's laser industry and metal surface processing industry. The main reason why high-speed laser cladding is widely appreciated is that, compared with conventional laser cladding, high-speed laser cladding has high processing efficiency, high processing accuracy, low subsequent processing cost, and small heat input to the workpiece Reduce the deformation of the workpiece and other advantages. A detailed comparison of the two is given below:
1. Compared with conventional laser cladding, the advantages of high-speed laser cladding are:
(1) The linear speed can reach 100m / min, which greatly improves the cladding efficiency. The diameter of 70 alloy steel substrate is clad with martensitic stainless steel. The thickness of the coating is 0.5mm. Under the condition of 70% overlap, the clad efficiency can reach 1.2㎡ / h. The overall processing efficiency is 3-4 times that of conventional clad.
(2) The cladding layer is flat and can be directly polished and polished without turning procedures, thereby greatly saving materials and processing costs.
(3) Thin layer cladding (0.2mm-0.3mm), medium and thick layer cladding (0.3-1.5), both thin and thick, and under special circumstances, multi-layer cladding .
(4) The heat input of the high-speed cladding to the workpiece is small, and the thermal deformation of the workpiece is small, which can be used to process thin-walled parts and small parts.
(5) The dilution rate can be controlled <3%.
(6) The laser power density is large, which can cladding high melting point powder materials.
(7) Non-ferrous metal materials such as copper, aluminum, and titanium can be surface strengthened (see detailed analysis below).
(8) High-speed cladding breaks many application restrictions of conventional cladding, has wide application fields, and is currently the only feasible method to replace electroplating.
2. The shortcomings of high-speed laser cladding intersecting with conventional laser cladding are:
(1) At present, the powder utilization rate of high-speed cladding is about 70%, which is slightly lower than that of conventional laser cladding, and it needs to be further improved by technical means.
(2) High-speed laser cladding In order to pursue higher surface quality to save materials and reduce processing costs, generally 20-53um fine spherical powder is used, and conventional laser cladding generally uses 50-150um coarse powder. The cost of fine powder is slightly higher than that of coarse powder.
(3) High-speed laser cladding is a new technology, and the process is slightly more complicated than conventional cladding.
3. The common points between high-speed laser cladding and conventional laser cladding are:
(1) Common cladding materials. Conventional laser cladding materials can be fused, high-speed laser cladding can be fused; some conventional laser cladding materials that cannot be cladding, such as high melting point materials, high-speed laser cladding can be fused.
(2) All are metallurgical combinations. However, the coating effect of high-speed cladding is similar to thermal spraying, and the surface is smooth. Conventional cladding has large fluctuations.
(3) The process routes are common. The key points of conventional laser cladding process adjustment are also the key points of high-speed laser cladding process adjustment.
(4) The application fields are consistent. That is, high-speed laser cladding can be applied in areas where conventional laser cladding can be applied, and high-speed laser cladding can also be applied in areas where conventional laser cladding cannot be applied. In layman's terms, live high-speed laser cladding that can be done by conventional laser cladding can be dried, and live high-speed laser cladding that can't be done by conventional laser cladding can also be dried.
4. Why high-speed laser cladding can be cladding on non-ferrous metals such as copper and aluminum:
Copper and aluminum surface strengthening has always been an urgent demand in the industry, but the process is difficult. At present, in the case of non-metallurgical combination, the spraying and electroplating process routes can be used; in the case of metallurgical combination, the current conventional laser cladding can use the YAG laser cladding route, but the YAG process route has low efficiency; other carbon dioxide, semiconductor, semiconductor fiber coupling and other conventional Some schools and enterprises have done a lot of research on the laser cladding route, but the final results are not satisfactory. The main reason is that copper and aluminum are difficult to cladding because the heat conduction is fast and the substrate is not easy to form a molten pool.
Zhongke Zhongmei applies high-speed laser cladding technology to the surface treatment of non-ferrous metals. From the preliminary test results, high-speed laser cladding can completely solve the difficulties in this industry. The power density of high-speed laser cladding is 5-10 times that of conventional laser cladding, and part of the light directly acts on the substrate, which can form a molten pool on the copper and aluminum substrate. This is high-speed laser cladding that can achieve copper and aluminum fusion The main reason for overwriting.