Basic Characteristics of Laser Cladding Technology
Laser cladding technology, a highly advanced surface modification technique, can be comprehensively categorized into two primary types according to the powder feeding process: the powder presetting method and the synchronous powder feeding method. Despite sharing similar end - results, the synchronous powder feeding method stands out with several significant advantages. It enables seamless automation control, which is crucial for large - scale industrial production. This method also boasts a high absorption rate of laser energy, optimizing the use of laser resources. Moreover, components fabricated through this approach are free from internal pores, ensuring their structural integrity. When dealing with metal ceramic cladding, the synchronous powder feeding method truly shines. It remarkably improves the crack resistance of the cladding layer and guarantees that the hard ceramic phases are evenly distributed throughout, enhancing the overall performance of the coated surface.
Laser cladding is defined by a set of distinctive characteristics. Firstly, it features an astonishingly fast cooling rate, reaching up to 10⁶ K/s. This rapid solidification process leads to the formation of a fine - grained microstructure. It also opens the door to creating new phases that are otherwise unattainable under normal equilibrium conditions, such as metastable phases and amorphous structures. These unique microstructural features endow the cladded materials with enhanced mechanical and physical properties.
Secondly, the coating dilution rate in laser cladding is typically less than 5%. This results in a strong metallurgical bond or interface diffusion bond with the substrate. By precisely tuning laser process parameters like power, scanning speed, and powder feeding rate, a high - quality coating with a low dilution rate can be achieved. This controllability over the coating composition and dilution degree allows for customization to meet specific application requirements.
Thirdly, laser cladding involves minimal heat input, which in turn causes very little distortion. When high - power - density rapid cladding is employed, the deformation can be reduced to an extent that it falls within the assembly tolerance of the part. This makes it suitable for processing precision components without sacrificing dimensional accuracy.
Fourthly, there are almost no restrictions on powder selection. This means that it is possible to deposit high - melting - point alloys on the surface of low - melting - point metals, expanding the material combinations and applications of laser cladding. The thickness range of the cladding layer is also quite extensive, with a single - pass powder - feeding coating thickness ranging from 0.2 to 2.0 mm.
Selective cladding is another notable advantage of laser cladding. It enables the targeted application of the coating, reducing material waste and providing an excellent performance - to - cost ratio. The ability to aim the laser beam allows for cladding in hard - to - reach areas, making it suitable for complex - shaped components. Finally, the process is highly compatible with automation, ensuring consistent quality and efficient production in industrial settings.
