利用选区激光熔化(SLM)技术对S136模具钢粉末进行较优成形工艺参数下的块体成形试验, 试验测定了成形件相对致密度, 分析激光能量密度和熔道搭接率对成型致密度的影响规律。实验结果表明, 在激光功率140 W, 扫描速度550 mm/s, 扫描间距0.08 mm时, 相对致密度超过99%; 在最优相对致密度条件下, S136钢SLM成形线能量密度范围为0.255～0.26 J/mm, 熔道搭接率范围为25.77%～27.93%, 相对致密度与体能量密度之间满足关系式d＝-0.001 76×ψ2＋0.559 87ψ＋53.421 92, 并且体能量密度为159.05 J/mm3, 试件相对致密度到达最大值。

Bulk forming test of S136 die steel powder with selective laser melting(SLM)under optimized process parameters is done. The relative density of formed parts is measured. The influence law of laser energy density and overlap ratio of weld seam on forming density is analyzed. The results show that the relative density is up to 99% when the laser power is 140 W, scanning speed is 550 mm/s and scanning space is 0.08 mm. Under the condition of optimized relative density, the linear energy density of SLM forming S136 is in the range of 0.255～0.26 J/mm, overlap ratio of weld seam is 25.77%～27.93%. And the relation formula of relative density and bulk energy density satisfies d＝ -0.001 76×ψ2＋0.559 87ψ＋53.421 92. While the bulk energy density is 159.05 J/mm3, the relative density of forming parts is up to the maximum.