Development of the laser-foundry process for manufacture of bimetals
The new highly effective method for the production of bimetal sheets was proposed. According to a thin surface layer of the functional component of the bimetal moving at a certain speed on a certain area is melted by the concentrated laser radiation. Simultaneously, the pre-prepared solutions of the bimetal base are fed to the zone of its action from a special dispensing device with a specified flow rate, resulting in a reliable connection between them when cooling. The method is characterized by high productivity and universality of the process of manufacturing a wide range of bimetals of various purposes, the great strength of the grip of their components, the possibility of complete automation. The thermal processes occurring in the surface layer of the functional composition of bimetal from 40H13 stainless steel (AISI 420) under different laser radiation conditions are analyzed. The parameters of laser irradiation, which provide submelting of the 50 mm wide surface layer to a depth of 50-100 microns (the radiation power is 8.5 kW, the speed of the movement is 1 m/min) are determined. The conditions of feeding of the molten metal of the base of St.3 structural carbon steel (AISI A284Gr.D) (the height of the melt column 7.6 mm, the size of the outlet 50×3 mm) on the fused functional layer, which provide the formation of the bimetal with the specified dimensional characteristics, are substantiated. The productivity of the considered laser-foundry process is determined by the parameters of scanning and power of the laser beam, the cost characteristics of the melt of one of the components, the speed of relative displacement. The fusion zone formed during cooling and relative displacement of the components of the bimetal causes the metallurgical bond between them. This allows producing bimetallic products of the required quality.