With the development of mechanized industry and compared with other cladding technologies (such as tungsten carbide spraying, tungsten carbide plasma spraying, or arc welding), laser cladding is a unique process with fundamental differences in its application. Using a highly concentrated heat source, laser cladding has a significant impact on the product. Due to its low heat input, high curing rate, and precise process control, laser cladding has many advantages.
1. Complete Metallurgical Bond
No peeling, cracking, or splitting: Laser cladding achieves a complete metallurgical bond with the substrate, meaning it will not peel or crack like plasma or thermal spray coatings.
Few or no voids or porosity: Unlike plasma or thermal spraying, laser cladding coating is suitable for completely dense coatings.
2. Low Heat Input Process
Significantly Reduced Thermal Deformation: Compared to arc welding of the same part, laser cladding inputs less than 20% of the heat. The reduction in thermal deformation of the part is significant. In many cases, fewer subsequent operations, such as machining and straightening, are required to address heat deformation issues. Due to the low heat and deformation, thin-walled parts that cannot be coated with an arc can be coated using a laser.
Small Heat-Affected Zone: The heat-affected zone is significantly reduced due to decreased heat input, increasing the strength of the part.
Very Low Dilution: Low heat input also reduces the dilution of the cladding. Reduced mixing of the base metal and the cladding results in a purer cladding with better metallurgical properties and higher corrosion and wear resistance.
Release Coating: Due to the lower dilution rate, thinner cladding layers (compared to arc welding) can exert the same wear or corrosion resistance. This can significantly reduce the cost of cladding materials.
High Solidification Rate: Because of the fast solidification rate and low heat input, materials such as carbides can be added, greatly improving the wear resistance of the coating. Traditional arc welding processes melt carbide particles.
Traditionally "unweldable" material coating capabilities: Low heat input and rapid curing enable the coating of materials such as carbon steel or nickel-based superalloys. These materials are difficult or even impossible to weld using traditional welding techniques.
3. Superior process control
Better layer thickness control and surface finish: Laser cladding allows for better control of layer thickness, enabling thinner coatings and better surface finishes. The ability to use near-net-shape coatings reduces the amount of finishing work required and reduces the amount of excess coating material applied.
Unlimited coating thickness: Any thickness can be achieved using multiple coatings.
High repeatability and process stability: Automated process control provides excellent parameter control, resulting in excellent process stability and reliable, repeatable results.
4. Overall performance
High deposition rate: High deposition rates can be achieved, especially with hot-wire technology, which can shorten uptime.
Significantly Extends Part Lifespan: Compared to plasma or thermal spraying and arc welding, laser cladding layers offer superior corrosion resistance and wear resistance, thus greatly extending the service life of parts.
5. Material Options
One of the many advantages of laser cladding is its compatibility with a wide range of materials, allowing the use of wire or powder forms; the options for material properties are virtually limitless.
Advantages of Powder
Material Selection: Powder provides virtually unlimited potential for changing alloy compositions, allowing the use of carbides and other wire forms that are unsuitable for other materials.
Advantages of Wire
Material Capture: Unlike powder, there is no material waste when using wire filler for cladding.
Lower Material Costs: The cost of wire filler material is far lower than that of the same material in powder form.
Unaffected by Gravity: Wire is unaffected by gravity and powder, thus enabling unsuitable cladding.
Using a hot wire with a deposition rate 2-5 times higher: Preheating the wire before it enters the molten pool reduces the laser energy required to melt the filler material, allowing for a higher deposition rate with the same laser power.