Extreme high-speed laser cladding (EHLA) is developed on the basis of Conventional laser cladding (CLA). EHLA technology uses high energy laser as heat source, adopts the way of coaxial powder feeding, which has excellent properties such as abrasion resistance and corrosion resistance, and melts the powder on the surface of parts at a very high scanning speed. Thus, the protective coating with a strong metallurgical bond, low dilute release rate and excellent abrasion resistance are prepared, thus extending the service life of parts.
Principle of ultra-high speed laser cladding technology
On the basis of conventional laser cladding technology, ultra-high speed laser cladding technology can control the rational distribution of laser energy in the cladding process by optimizing the interaction position between laser, powder and matrix, so as to realize the efficient deposition of coating powder. Compared with the traditional laser cladding technology, the focus of the laser and powder beam in the process of ultra-high speed laser cladding is located above the surface of the substrate, so that the coating raw material powder melts before being transported to the surface of the substrate, thus achieving a substantial increase in the cladding line speed. The cladding line speed of ultra-high speed laser cladding technology can reach 500m/min, and the cladding processing efficiency can reach 500cm2/min, which is more than 10 times higher than that of traditional laser cladding.
On the other hand, in the ultra-high speed laser cladding process, about 80% of the laser energy is used to melt the powder to be coated. Only 20% of the energy is used to heat the substrate, and the melted powder reaches the preheated substrate and quickly forms a dense coating with a metallurgical bond, so the coating has a low dilution rate, thus ensuring its excellent wear and corrosion resistance. In addition, the low energy input of the substrate surface can effectively reduce the heat deformation of the substrate during processing, so that it can be used for processing thin-wall and large sheet parts.
Xi'an Guosheng Laser Technology Co., Ltd. is a high-tech enterprise specializing in R&D, manufacturing and sales of automatic laser cladding machine, high-speed laser cladding machine, laser quenching machine, laser welding machine and laser 3D printing equipment. Our products are cost-effective and sold domestically and abroad. If you're interested in our products, please contact us at bob@gshenglaser.com.
Advantages of ultra-high speed laser cladding technology
Compared with traditional laser cladding technology, ultra-high speed laser cladding technology has many advantages in the preparation of surface protective coatings, which are mainly reflected in the coating macroscopic quality, internal microstructure of the coating, dilution rate and so on.
From the macroscopic quality of the coating, the surface roughness of the coating prepared by ultra-high speed laser cladding technology is lower, and the inside of the coating is dense and uniform. The surface of the coating prepared by ultra-high-speed laser cladding technology is smoother, and its Ra can be less than 10 μm, less than 10% of the conventional laser cladding, which can effectively reduce the cost of subsequent surface treatment. In addition, the ultra-high speed laser cladding coating presents a domino-like overlap form, which can reduce the mutual influence between the matrix and the coating and reduce the defects such as holes and cracks in the coating.
In terms of coating microstructure, the coating grains prepared by ultra-high speed laser cladding technology are small and evenly distributed. The microstructure of the ultrahigh-speed laser cladding coating is similar to that of the conventional laser cladding coating, which is mainly composed of dendrites. However, due to the extremely fast scanning speed of the ultrahigh-speed laser cladding technology, the coating has a very high cooling rate and supercooling degree during solidification, making the grain of EHLA much smaller than that of CLA.
In terms of service, the coating prepared by ultra-high speed laser cladding technology has better service performance and longer service life. A large number of studies have shown that the corrosion resistance and wear resistance of the coating prepared by ultra-high speed laser cladding technology are much higher than that of the substrate, and better than that of the conventional laser cladding coating. This is mainly due to the very small dilution rate of the EHLA coating (< 4%), which can maximize the excellent abrasion resistance of the cladding material.
Therefore, ultra-high speed laser cladding technology is considered to be the most effective surface coating technology to replace electroplating hard chromium, which is an efficient and green material surface processing technology and has broad application prospects.