With the development of mechanized industry, and compared with other cladding technologies (such as tungsten carbide spraying, tungsten carbide spraying plasma spraying, or arc welding), laser cladding is a unique process and its application is fundamentally different. The use of laser cladding, a highly concentrated heat source, has a great impact on the product. Laser cladding offers many benefits due to its low heat input, high solidification rate, and precise process control.
1. Full metallurgical combination
No peeling, chipping, or cracking: Laser cladding has a thorough metallurgical bond with the substrate, which means it won’t peel or crack like plasma or thermal spray coatings. Little or no voids or porosity: Unlike plasma or thermal spraying, laser cladding allows for a thoroughly dense coating.
2. Low heat input process
Significantly reduced thermal distortion: Laser cladding uses less than 20% of the heat input compared to arc cladding of the same parts. The reduction in thermal deformation of the component is evident. In many cases, less follow-up operations such as machining and straightening are required to resolve thermal deformation issues. Because of the low heat and deformation, thin-walled parts that cannot be clad with arc can be clad with laser.
Small heat-affected zone: Due to the reduced heat input, the heat-affected zone is greatly reduced, increasing the strength of the component.
Very low dilution: Low heat input also reduces the dilution of the cladding. Cutting back on the mix of base metal and cladding means a purer cladding with better metallurgical properties and greater resistance to corrosion and wear.
Release coating: Because of the lower dilution rate, a thinner coating (compared to arc welding) is able to exert the same wear or corrosion function. This can significantly reduce cladding material costs.
High condensation speed: Due to the fast condensation speed and low heat input, carbides and other materials can be added to greatly improve the wear resistance of the coating. The traditional arc welding process melts carbide particles.
Cladding capabilities of traditionally “non-weldable” materials: Low heat input and rapid solidification enable cladding of materials such as carbon steel or nickel-based superalloys. These materials are difficult or even impossible to weld using traditional welding techniques.
3. Excellent process control
Better layer thickness control and surface treatment: Laser cladding enables better control of layer thickness, application of thinner coatings and better surface finish. The ability to apply coatings closer to net shape reduces the amount of finishing required and reduces the amount of remaining cladding material applied.
Unlimited cladding thickness: Ability to apply multiple cladding layers to achieve any thickness.
High repeatability and process stability: Automated control of the process provides excellent parameter control, resulting in outstanding process stability and reliable, repeatable results.
4. Summarize
High accumulation speed: high accumulation speed can be achieved, especially using hot-line technology, which can shorten the use time.
Greatly extends the service life of parts: Compared with plasma or thermal spraying and arc welding, laser cladding has excellent corrosion resistance and wear resistance, thus greatly extending the service life of parts.
5. Data options
One of the many advantages of the laser cladding process is that it is compatible with a variety of material options, either in wire or powder form; the options for material properties are virtually endless.
Advantages of powder
Material Selection: Powders offer virtually unlimited potential for varying alloy compositions, allowing the use of wire patterns not possible with carbides and other materials.
Advantages of wire
Material Capture: Unlike powders, there is no wasted material when coated with wire filler materials.
Lower material cost: The cost of wire-filled materials is much lower than the same material in powder form.
Unaffected by gravity: The wire is not affected by gravity and is not affected by powder, so it can complete unsuitable coatings.
2-5 times higher deposition rate using hot wire: Preheating the wire before entering the molten pool can reduce the laser energy required to melt the filling material, thereby achieving higher deposition rates using the same laser power rate.
