Laser cladding repair technology utilizes a high-power-density laser beam. Under CNC control, a laser processing system forms a very thin micro-molten layer on a designated area of the substrate surface. Simultaneously, self-fluxing alloy powders of specific compositions, such as nickel-based, cobalt-based, and iron-based alloys, are added in a pre-set or synchronous manner. These powders are uniformly spread on the part surface in a molten state to achieve a predetermined thickness, forming a strong metallurgical bond with the micro-molten substrate metal material with minimal dilution between them. During the subsequent rapid solidification process, a functional cladding material layer with predetermined special properties, completely different from the substrate, is formed on the part surface. This completely alters the surface properties of the material, enabling inexpensive materials to achieve extremely high wear resistance, corrosion resistance, and high-temperature resistance. This process can repair holes and cracks on the material surface and restore the geometry and performance of worn parts.
Features of Laser Cladding (Repair):
1. Rapid cooling rate (up to 106℃/s), a rapid solidification process, easily yielding fine-grained structures or generating new phases unattainable in equilibrium, such as unstable phases and amorphous states;
2. Coating dilution rate less than 5%, forming a strong metallurgical bond or interfacial diffusion bond with the substrate, resulting in a well-preserved cladding layer with controllable composition and dilution;
3. High power density and rapid cladding, resulting in minimal heat input, heat-affected zone, and distortion, which can be reduced to within the assembly tolerances of parts;
4. Virtually no restrictions on powder selection, allowing the deposition of high-melting-point alloys onto low-melting-point metal surfaces;
5. Wide range of cladding layer thickness and hardness, capable of cladding layers up to 20 mm thick with a hardness range of 18-60 HRC;
7. CNC-controlled process, beam aiming allows for cladding of hard-to-reach areas, automated operation, convenient, flexible, and highly controllable.
Laser Cladding
A process for repairing metals using lasers
1. High speed. Large depth and minimal deformation;
2. Laser welding can be performed at room temperature or under special conditions; the welding equipment is simple. For example, the laser beam will not deflect when passing through an electromagnetic field; the laser beam can perform welding in vacuum, air, and certain gas environments, and can weld through glass or materials transparent to the beam.
3. Can weld refractory materials such as titanium and quartz, and can weld irregularly shaped materials.
4. After the laser beam is focused, the power density is high. When welding high-power devices, the aspect ratio can reach 5:1, and the height can reach 10:1.
5. Enables micro-welding. The laser beam, after focusing, can obtain a very small spot and can be precisely positioned, which can be used for the assembly welding of micro and small workpieces in mass automated production.
6. Can weld hard-to-access areas, performing non-contact long-distance welding, providing great flexibility.
7. Laser beams can be easily split in time and space, enabling simultaneous multi-beam processing and multi-station processing, providing conditions for more precise welding.
However, laser welding also has certain limitations:
1. It requires high welding assembly precision and the beam position on the workpiece must not deviate significantly. This is because the laser spot size is small after focusing, resulting in a narrow weld seam. If the workpiece assembly precision or beam positioning precision does not meet the requirements, incomplete welds can easily occur.
2. The purchase cost of lasers and related systems is relatively high, requiring a large initial investment.