汽车发动机连杆激光3-D打印工艺研究

摘要

为了研究汽车发动机连杆激光3-D打印制造工艺,采用理论分析和实验验证的方法,建立了连杆3-D数据模型,进行了分层切片处理,通过S型扫描和轮廓偏移扫描,规划两种连杆加工路径.选用铁基合金粉末以及相应的工艺参量,在激光3-D打印系统中进行连杆打印试验.扫描单层轨迹用时4min30s～4min56s,总用时4h20min.结果表明,连杆成形区底部的金相组织主要是柱状晶和树枝晶,中上部是细小的等轴晶,层间致密搭接,形成良好的冶金结合;成形连杆显微硬度为450HV～ 490HV,屈服强度为754MPa,抗拉强度为1189MPa,延伸率为9％.连杆激光3-D打印成形制坯性能相比于锻造、粉锻制造工艺,减少了工装成本支出并缩短了生产准备工时,其屈服强度、抗拉强度等力学性能超过钢锻连杆,与国外粉锻连杆相比,差别不大,能满足连杆制坯要求.%In order to study the manufacturing process of laser 3-D printing for automobile engine connecting rods,by means of theoretical analysis and experimental verification,3-D model of a connecting rod was established and slicing was done.By S-type scanning and contour offset scanning,two machining paths of connecting rods were planned.Alloy powders based on iron and the corresponding technological parameters were selected to carry out the rod print test in a laser 3-D printing system.It took 4min30s ～4min56s to scanning a single layer and it took 4h20min totally.The results show that the metallographic structure at the bottom of the forming zone of the connecting rod is mainly columnar crystal and dendritic crystal.The middle and upper part are small equiaxed crystal.Interlayer is dense and good metallurgical bonding had been formed.The microhardness of the formed connecting rod is 450HV ～ 490HV,yield strength is 754MPa,tensile strength is 1189MPa,and elongation rate was 9％.Compared to forging,powder forging manufacturing processes,laser 3-D printing forming reduces tooling costs and shortens the production preparation time.Its mechanical properties,such as yield strength and tensile strength,exceed those of steel forging links.Compared with foreign powder forged connecting rod,the difference is not very big.The process can meet the requirements of connecting rod blank making.