Laser cladding technology is a new surface modification technology. By adding cladding material to the surface of the substrate and using a high-energy-density laser beam to melt it together with the thin layer on the surface of the substrate, a metallurgically bonded filler cladding layer is formed on the surface of the base. The following are some of the latest research progress in laser cladding technology:
Application of large-diameter gate sealing surface:
Huirui-Laser in China successfully used laser cladding technology on the sealing surface of large-diameter parallel single gate valves, achieving a breakthrough in high-hardness stl alloys, with the highest hardness reaching hrc58. This technology solves the problems of large deformation, uneven hardness, and cumbersome machining in traditional cladding technology, improves the performance of the gate sealing surface and realizes industrial application.
Application in aluminum alloy cylinder head valve seat ring:
Laser cladding valve seat ring technology was first used in racing cars and then developed in the field of passenger cars. This technology has the advantages of metallurgical bonding between the cladding layer and the aluminum alloy substrate, fast heat conduction, thinning the local wall thickness of the blank, facilitating heat dissipation, and being able to use larger valves to reduce throttling losses and improve wear resistance. For example, Toyota applies it to the TNGA series of models and promotes it as a global standard process; Nissan also applies it to the E-Power 1.5T engine. The use of this technology can achieve high tumble and large flow in the intake duct, and bring flexibility to the intake duct design. The simulation prediction of a domestic company in China shows that this technology can improve the performance of a certain range-extended self-priming engine in the high-speed section by about 10%. In addition, related processes are also constantly developing. For example, Toyota’s laser cladding valve seat ring process has been upgraded from a CO2 laser generator to a semiconductor laser, the laser beam form has been upgraded from an oscillating beam to a forming beam, the powder feeding form has been changed from side-axis powder feeding to coaxial powder feeding, and the processing form has been changed from workpiece rotation to lens rotation. These improvements have reduced energy consumption and reduced the space occupied by the equipment.
Application in the aviation field:
– Aircraft parts manufacturing: It can strengthen the surface of titanium alloys, reduce manufacturing time, reduce production costs and shorten production cycles. Several series of Ti-6Al-4V titanium alloy laser cladding parts produced by Aeromet in the United States have been approved for use in actual flights. Their performance exceeds that of parts manufactured by traditional processes, while production costs are reduced by 20%-40% and production cycles are shortened by about 80%.
– Repair of aviation parts: Advantages include automation of the repair process, low thermal stress and thermal deformation. For example, repairing cracks in aircraft parts, especially non-penetrating cracks; repairing damaged turbine blades, compared with manual tungsten inert gas arc welding, can save additional post-processing, reduce time and cost. The strength of aviation parts repaired by laser cladding technology can reach more than 90% of the original strength, shortening the repair time. The wear resistance of the laser cladding layer is proportional to the hardness. Through process improvement, the hardness of the cladding layer can be made higher than the surface hardness of the tungsten inert gas arc welding cladding.
– Surface modification of aviation materials: High-hardness, wear-resistant and high-temperature resistant coatings can be prepared to prevent rapid wear and corrosion failure of parts when working in high-speed, high-temperature, high-pressure and corrosive environments. Commonly used ceramic coating materials include aluminum oxide, titanium oxide, cobalt oxide, chromium oxide and their composite compounds, as well as metal ceramics prepared from tungsten carbide, titanium carbide, chromium carbide and cobalt- and nickel-based self-fluxing alloys. By adding transition layer materials and using pulsed laser cladding, the structure and performance of the coating can be improved.
In addition, the development of ultra-high-speed laser cladding technology has provided new impetus for China’s green manufacturing. Compared with traditional cladding laser technology, its working efficiency is 100 times faster, the cladding coating has high metallurgical quality, low dilution rate, small deformation, and high surface finish, which can greatly reduce the subsequent machining costs of enterprises, effectively extend the product life cycle, and save a lot of later maintenance costs. This technology was proposed by the Fraunhofer Institute for Laser Technology in Germany and improved and upgraded by its incubated enterprises. The China Academy of Mechanical Science and Technology conducted joint research with it, and through introduction, absorption and re-innovation, it conducted research and development based on the needs of the Chinese market and established a corresponding standard system. At present, this technology has achieved results in the preparation of corrosion-resistant coatings on the surface of coal machine hydraulic support columns, and has broad application prospects in additive manufacturing, parts remanufacturing, and composite performance material research and development in the future.
The research on laser cladding technology is still advancing, and new progress and applications are constantly emerging. At the same time, the development of this technology is also influenced and driven by many factors such as material science, laser technology and related process optimization.
