马氏体时效钢激光增材制造工艺及组织研究

发布时间：2019-05-05 21:10

【摘要】：探究了使用同轴送粉激光直接沉积增材制造方法制造18Ni(300)马氏体时效钢零件的可行性。采用正交实验设计,分析了不同工艺参数对单道成形的影响,发现扫描速度、送粉速率、激光功率对稀释率的影响较大。在单道多层试验中发现在合适的参数下18Ni(300)能获得良好的外观成形,但内部仍然容易出现非致密性缺陷。激光直接沉积制造过程的高冷却速率使得晶粒最小可以达到8μm,晶粒生长方向大致与散热方向相同,但在层间位置存在晶粒转向区,而在顶部存在柱状晶/等轴晶转变区。在扫描电镜下发现由于加工过程中热循环的特点,先沉积层出现了析出相造成了硬度值的变化。硬度试验发现,越靠近基材的硬度值越高,最高可达358HV。
[Abstract]:The feasibility of manufacturing 18Ni (300) maraging steel parts by coaxial powder feeding laser direct deposition was investigated. The influence of different process parameters on single pass forming was analyzed by orthogonal experiment design. It was found that scanning speed, powder feeding rate and laser power had great influence on dilution rate. It is found that 18Ni (300) can obtain good appearance under suitable parameters in single-channel multi-layer test, but it is still easy to appear non-compactness defect in the interior. The high cooling rate of laser direct deposition process makes the minimum grain size of 8 渭 m, and the direction of grain growth is approximately the same as the direction of heat dissipation. However, there is a grain turning region in the interlaminar position and a columnar / equiaxed transition region at the top of the laser deposition process. It was found under SEM that due to the characteristics of thermal cycle in the process of processing, the precipitated phase appeared in the deposition layer, which resulted in the change of hardness value. The hardness test shows that the higher the hardness value is, and the highest value can reach 358HV.
【作者单位】：哈尔滨工业大学(威海)山东省特种焊接技术重点实验室;哈尔滨工业大学先进焊接与连接国家重点实验室;工业和信息化部电子第五研究所;
【分类号】：TG142.11;TG665

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