Research On Mechanical Properties Of 304 Stainless Steel By Selective Laser Melting

Selective Laser Melting (SLM) is a kind of manufacturing method that builds whole metal parts layer by layer, which can fabricate the terminal metal productions directly and easily. It has great practical value and potential applications in the areas of biomedical and aerospace. Because the research term of SLM technology is short and the report on mechanical performance is rarely, which retards the engineering applications.In this thesis, the effects of the main parameters, such as layer thickness, overlapping rate, phase position angle, tilt angle, laser power and scanning speed, on the mechanical properties of parts by SLM has been studied. The results show that layer thickness and overlapping ratio have almost no influence on mechanical properties of parts when the laser energy density is high enough. When other parameters are fixed, the mechanical property of parts at the phase position angle of 105°is the best. Especially, the tensile strength of the built parts increases with laser power and laser scanning speeds before stabilization when other parameters are fixed. The mechanical property of parts has high tensile strength and low Elongation in vertical direction. Overall, the mechanical property of parts by SLM is equivalent or higher than that of forging.The microstructure of parts formed by SLM show that parts is homogeneous with good lap between the scan lines and cladding layers. The microhardness of the parts by SLM is uniform in the XOZ and the XOY planes ranging from HV 240 to 270. Finally, the fracture of the parts presents a typical ductile fracture with uniform and small-size circular dimples.