Study On Ni-based Alloy Powders For The Laser Cladding And The Rapid Forming

Laser cladding is used to form a kind of surface coating, which has a good metallurgical bonding with the substrate, without gas holes and crack, by using a high energy laser beam to melt coating material and a thin layer base metal. It has been becoming one of new techniques that have infinite development future and characteristic very much in the modern surface technique system, and bigger application foreground in "remanufacturing engineering in the 21th century". Laser rapid forming(LRF)is a new and advanced manufacturing technology that has been developed on the basis of high power laser cladding technology and rapid prototyping. Cracks are easy to generate in laser-clad layers for laser cladding is a process of sharply heating and solidifying, which is one of the main problems hindering the industrial application of laser cladding and the rapid forming.In this article, we have carried out laser cladding experiments of NiCrBSi powders and composite powders on the surface of 45steel substrate by a GLS-6 cross current type of CO₂ laser apparatus. A proper Ni-based powders alloy for the laser cladding and the rapid forming was ascertained by the comparison of analyses basing on the microscopic and macroscopic qualities of different cladding layers. Here is the technic guideline of Ni-based powders alloy for the laser cladding and the rapid forming:First, the microhardness of the cladding layers could surpass 540.Secondly, using tribological wear experiment machine, it has been found that the cladding layers of the frictional coefficient is 0.5,and the substrate of the frictional coefficient is 0.8.The wear-resistance of the cladding is 3 times higher than that of the substrate.The third, without any preheating and slow cooling, over 10mm thick layer of laser cladding can be made with a smooth surface and without gas holes and crack.The influence of CaF₂, MgO, Y₂O₃, Mo, Fe and Co on the macroscopic features,...