Investigation of the effect on mechanical properties of spray forming by using close coupled laval nozzle

In this study, a Laval type closed coupled nozzle and 4, 6 and 8 mm length protrusion apparatuses were designed and manufactured. By operating this nozzle, with the help of gas atomisation method, tin powder was produced using 4 mm, 6 mm and an 8 mm protrusion apparatuses; then the protrusion apparatus which produces the smallest powder particle was determined and tin powder was produced under 10 bar and 30 bar pressure using this protrusion apparatus. Considering the parameters on which the smallest powder particle was produced some various pieces in length were formed by Spray Forming (SF) method. Extrusion process was then applied on these pieces. The processes of SF were held with the spray distance of 80-120 mm and under a gas pressure of 30 bar. Those samples were extruded and 6 mm in diameter rods were obtained. Then the tensile tests were examined on the extruded rods. It was observed from the tensile tests that the extruded SF pieces have higher tensile strength values between %16 to %36.8 than the extruded cast pieces. Atomized powder were analyzed by the SEM, and the effect of SF variables the extrusion processes were analyzed using an optical microscope.