Laser clading belongs to welding overlay technology, the heat source is high energy laser beam, melt the substrate and coating material by laser radiation, form melting pool. The melting pool consist of material from base material and powder, the liquid metal temperature is determined by composition of melting pool. As the coeffect of laser impulse, gravity, beyoncy, powder impaction, gas stream, the melting pool is violet turbulenced, and could unify within very short time.
As the laser beam move away from melting pool, the absence of heat input lead to fast cooling, fast solidify and generate a welding bead. The temperature increase and drop speed is as fast as 105~7K/s. The extreamly high cooling speed enforce the solidify and form very special microstructure compare to casting, forging or ordinary welding. The special feature of laser cladding coating: corrosion resistance, wear resistance, heat resistance, oxidation resistance are obtained. The coating is metallurgical bonded to the substrate, furthermore, some material could be cladded multiple layer, so could be used as refurbishing, even 3D printing.
