Laser cladding, also known as laser metal deposition, is a technology to add one material to the surface of another material so that the material can be deposited accurately and selectively with minimal heat input to the underlying substrate. It is one of the most accurate welding processes to establish this mechanical bonding between the substrate and the coating.
What is laser cladding?
Laser cladding uses high-energy laser beam irradiation to clad a layer of special material on the surface of the workpiece through rapid melting, expansion, and solidification, thereby manufacturing a new material. It can add a lot of properties to the workpiece and can integrate many materials according to the performance requirements, such as alloys of various components, metal composite materials, etc., so that the workpiece material has the structure and properties that are not provided by conventional treatment, such as heat resistance, corrosion resistance, wear resistance, friction reduction, oxidation resistance, and non-magnetism.
Laser cladding technology can integrate precise forming and high-performance additive manufacturing technology. At the same time, it uses many modern advanced technologies such as laser technology, computer technology, numerical control technology, and material technology. It belongs to the future intelligent manufacturing technology.
How does laser cladding work?
In laser metal cladding, the laser beam first locally heats the workpiece and then forms a molten pool. Fine metal powder is then sprayed directly into the molten pool from the nozzle of the laser processing head. These materials are melted here and bonded to the base material. A coating approximately 0.2 to 1 mm thick is left behind. In this way, weld beads are formed, and multiple layers can be stacked up and down as needed. With laser metal deposition, very high build-up or volume rates, i.e. up to several cm³/min units, and feed rates from 500 mm/min to several meters per minute can be produced on 3D surfaces. The automatically controlled laser processing head moves over the workpiece to coat lines, flat surfaces, and contour shapes. The intelligent sensing system ensures that the layer thickness is always uniform everywhere.
How is laser cladding different from other laser processing?
Compared with traditional cladding and welding methods, laser cladding is unique in some respects. Laser cladding has high-speed thermal cycling, which can achieve higher strength and finer microstructure, all of which contribute to improved corrosion resistance.
What are the advantages of laser cladding machine?
1) High metallurgical bonding strength. Laser cladding utilizes the characteristics of high-energy laser beams to make the workpiece surface micro-melt instantaneously and completely melt the alloy powder preset on the workpiece surface or automatically sent it with the laser beam synchronously. After laser beam scanning, the substrate is self-cooled and rapidly solidified to obtain a dense coating alloy layer metallurgically combined with the substrate.
2) Optional hardness and thickness. The hardness of the cladding layer after laser cladding can be selected, and the cladding thickness can be adjusted according to needs.
3) Wear-resistant and corrosion-resistant. Laser cladding can process a corrosion-resistant, wear-resistant, and high-performance alloy layer on the surface of ordinary carbon steel workpiece to improve the service life.
4) Reduce cost and energy consumption. Laser cladding can form alloy coatings with metallurgical bonding, alloy composition, and properties on the surface of the substrate, so that a high-performance alloy functional layer can be made on a low-cost substrate, saving material costs.
5) High cladding quality. The cladding layer has fine grains and a compact structure, which can obtain high hardness, wear resistance, and corrosion resistance.
What are the disadvantages of laser cladding?
Everything has advantages and disadvantages, and laser cladding is no exception. The disadvantages of laser cladding can be divided into 3 different categories such as:
1)Process limitations: The method of laser cladding is largely automated. While this improves accuracy, it also reduces flexibility. Not only is the machine inconvenient to transport, but it can also complicate the handling of larger parts.
2)Material limitations: Laser cladding is usually applied with only a few materials. Inconel, Hastelloy, and Stellite are nickel and cobalt-based alloys. Stainless steels in the 300 and 400 range, and carbides such as tungsten carbide. They’re great for abrasion and corrosion resistance, but if you need other coating properties you’ll have to look elsewhere.
3)Coating thickness issues: Laser cladding is difficult when thin coatings are required because it deposits too much at once.
What is laser cladding suitable for?
Coating
The coating of strengthened parts is formed by laser cladding with laser powder to make it resistant to salt water, chemical substances, or weather. Unlike conventional processes such as thermal spraying, the workpiece is only subjected to a low thermal load here, so there is very little, if any, deflection. With the help of LMD, a wide variety of material mixtures and layer structures can be realized. Production costs can be saved by producing parts from ultra-affordable materials and then coating them with high-quality coatings.
Additive manufacturing
Laser cladding enables greater freedom of design when manufacturing individual components, especially compared to conventional stamping. It can form new structures or modify the shape and surface structure of existing components with auxiliary materials. Even large-format parts that do not fit within the build area of the 3D printer can be completely produced in this way.
Repair
Do you want to achieve more added value? Laser metal deposition can quickly and easily repair expensive parts or molds. Damage, large and small, can be repaired quickly and virtually seamlessly. It is also possible to change the design. This saves time, energy, and material. Quite worth it, especially against expensive metals like nickel or titanium. Typical application examples are turbine blades, various pistons, valves, shafts, or dies.
Senfeng has rich experience in laser cladding technology and has done numerous repairing and enhancing jobs for different workpieces in different industries. If you have any questions about the parts to be processed, please feel free to contact senfeng.
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