SLM成形316L工艺对滑动磨损特性及硬度的影响

Effect of 316L SLM Forming Process on Sliding Wear Characteristics and Hardness

目的提高选区激光熔化(SLM)成形316L不锈钢的耐磨性和硬度。方法在能量密度为50~110 J/mm3、扫描间距为0.04~0.12 mm范围内,改变能量密度和扫描间距两种工艺参数,采用选择性激光熔化技术(SLM)制备了12种316L不锈钢试样。通过表面粗糙度测量、孔隙率测量、销盘摩擦试验和布氏硬度试验,研究了工艺参数对SLM成形316L不锈钢试样的摩擦磨损特性和硬度的影响。结果能量密度为90 J/mm^3且扫描间距为0.12 mm时,表面粗糙度Ra最小,为5700 nm。孔隙率范围为12.35%~0.94%,扫描间距为0.12 mm的试样的孔隙率比扫描间距为0.04 mm和0.08 mm的孔隙率小。扫描间距不变时,孔隙率随能量密度增大而减小。能量密度为50 J/mm3时,扫描间距为0.12 mm的试样的摩擦系数和磨损率比扫描间距为0.04 mm和0.08 mm的要小;能量密度不变时,扫描间距为0.12 mm的试样硬度比扫描间距为0.04 mm和0.08 mm的试样高。结论改变扫描间距和能量密度会直接影响成形试样的表面粗糙度、孔隙率。研究范围内,表面粗糙度和孔隙率随扫描间距增大而减小。孔隙率与磨损量及硬度存在相关性:孔隙率越小,硬度越大,磨损率越小。因此,合理选择工艺参数可以降低孔隙率,进而提高表面质量,降低磨损率,增大硬度。

The work aims to improve the wear resistance and hardness of 316L stainless steel formed by selective laser melting(SLM).In the range of energy density 50 to 110 J/mm3 and hatch space 0.04 to 0.12 mm,12 kinds of 316L stainless steel samples were prepared through SLM by changing the energy density and hatch space.The effects of process parameters on the wear characteristics and hardness of SLM-formed 316L stainless steel samples were investigated by surface roughness masurement,porosity measurement,pin-on-disk friction test and Brinell hardness test.When the energy density was 90 J/mm3 and the hatch space was 0.12 mm,the surface roughness was the smallest,reaching 5700 nm.When the porosity ranged from 12.35%to 0.94%,and the porosity of the sample with hatch space of 0.12 mm was smaller than that of sample with the hatch space of 0.04 mm and 0.08 mm.When hatch space remained unchanged,the porosity decreased as the energy density increased.When the energy density was 50 J/mm3,the friction coefficient and wear rate of samples with hatch space of 0.12 mm were smaller than those with s hatch space of 0.04 mm and 0.08 mm.When the energy density remained unchanged,the hardness of the sample with hatch space of 0.12 mm was higher than that with hatch space of 0.04 mm and 0.08 mm.The surface roughness and porosity of the molded samples are affected directly by the change of hatch space and energy density.The surface roughness and porosity decrease with the increase of hatch space.Wear and hardness have correlation with porosity:the smaller the porosity,the greater the hardness and the smaller the wear rate.Therefore,the reasonable selection of process parameters can reduce porosity,thereby improving surface quality,reducing wear rate and increasing hardness.