Research On High Efficiency Fabricated Of 316L By Selective Laser Melting

Selective Laser Melting?SLM?is a potential additive manufacturing?AM?technology,which fabricated samples possess high density,high precision,high properties,and complex metal structures can be formed.And 316L is a most common metal material,which is widely used in aerospace,shipbuilding,and automotive field.With the complexity of 316L structure parts increased,it is difficult to produce 316L structure parts by traditional manufacturing,using SLM technology to fabricate 316L complex structure parts will be a good choice.Hence the low layer thickness fabrication and high layer thickness fabrication have been comparative researched in this research.Single-track experiment and multi-layer fabrication were carried out respectively.The main contents are as follow:?1?Research on the characteristics of 316L low layer thickness fabrication by Selective Laser Melting.Orthogonal experiments of exposure time and point distance were carried out,and analyzing the surface quality of single track?stable track,instable track,spheroidization,and distortion?.The Response Surface Method?RSM?was used to analyze the geometric characteristics of single-track cross section.The hatch space was set at 0.5-0.8 times of molten width,Multi-layer fabrication can be fabricated the block sample with density of 99.99%.The microstructure is a mostly equiaxed crystal and a few columnar crystal,and the grain size increased from0.66?m to 1.31?m.As the exposure time increased,the elongation?EL?was also increased and the ultimate tensile strength?UTS?and yield strength?YS?were decreased slowly.?2?Research on the characteristics of 316L high layer thickness fabrication by Selective Laser Melting.The SLM fabrication with 150?m high layer thickness and D₅₀ of 18?m fine powder has been systematically researched.Based on single track experiment,the density of multi-layer fabrication block also can be obtained 99.99%.Meanwhile,the building rate can be up to 12mm³/s,which is about 3-10 times higher than previous studies.The grain size is from 0.98?m,the grain aspect ratio is close to1.And YS ranges are 450-600MPa,UTS ranges are550-700MPa,and EL ranges are39.7%-41.8%.?3?The optimal process parameter is exposure time-point distance-hatch space of120?s-40?m-240?m.The fabrication sample can be obtained approximation full density of 99.99%,which is possessed stable values of UTS,YS,and EL,with525±7MPa,625±3MPa,and 39.9±5%respectively.And the building rate can be reached at 12mm³/s.