扫描速度对激光选区熔融316L不锈钢表面粗糙度和力学性能的影响

Effect of Scanning Speed on Surface Roughness and Mechanical Properties of 316L Stainless Steel Prepared by Selective Laser Melting

摘要:

采用选区激光熔融法在不同扫描速度下制备了316L不锈钢成型件，通过物相分析、金相观察、拉伸试验、维氏硬度试验和表面粗糙度试验，研究了扫描速度对成型件相组成、熔池形态、表面粗糙度、密度和力学性能的影响。结果表明，在不同的扫描速度下（800~1200 mm/s）样品均能成功打印。此外，随着扫描速度的增加，未重熔的熔池深宽比降低，表面粗糙度从5.78 μm增加到22.79 μm。当扫描速度为800 mm/s时，裂痕出现；当扫描速度超过1100 mm/s时，出现收缩纹路。当扫描速度为800 mm/s时，由于激光输入能量过高，样品具有较高的孔隙率。当扫描速度为900 mm/s时，样品具有最佳的维氏硬度（2401 MPa）和最高的相对密度（99.2%）。

Abstract:

The 316L stainless steel part was prepared by the selective laser melting method at different scanning speeds. The effects of scanning speed on phase constitution, molten pool morphology, surface roughness, density, and mechanical properties of the part were investigated by phase analyses, metallographic microscopy, tensile test, Vickers hardness test, and surface roughness test. Results show that all specimens are successfully prepared at different scanning speeds (800–1200 mm/s). In addition, with increasing the scanning speed, the ratio of depth to width of molten pool without remelting is decreased, and the surface roughness is increased from 5.78 μm to 22.79 μm. The cracks appear at scanning speed of 800 mm/s, while the molten line shrinkage occurs when the scanning speed exceeds 1100 mm/s. When the scanning speed is 800 mm/s, specimens have relatively high porosity due to the overhigh laser input energy. When the scanning speed is 900 mm/s, the specimens have the optimal Vickers hardness (2401 MPa) and high relative density (99.2%).