基于三维焊接的金属零件直接快速制造研究

对用于直接快速制造金属零件的基于机器人CO2气体保护焊的新型快速成形技术进行了初步研究。通过分析堆焊层的几何形状、微观组织和性能，获得了较佳的成形工艺参数。研究结果表明，焊接工艺参数对堆焊层的几何形状、显微组织、表面粗糙度和硬度有很大影响，其中焊接电流和焊接速度是主要的影响因素。由于后续焊道再热循环的作用，堆焊层焊缝的上部为细小的等轴晶，中下部为粗大的柱状晶，堆焊层与基体材料相比硬度略有增大。制造了一个由30层焊道堆积而成的简单空心筒状零件，其直径和高度误差小于1％，垂直度误差小于2％，表面粗糙度Rα约为50～200μm。

Direct Rapid Manufacturing of Metal Parts Based on 3D Welding

This paper present an preliminary investigation on a novel rapid prototypmg technique based on robotic CO2 gas arc welding that is utilized to direct rapid fabricate metal parts. The optimized processing parameters were acquired through analyzing the geometry, microstructures and properties of deposited layers. Welding parameters, especially the welding current and welding velocity strongly affect the geometry, microstructures, roughness, and hardness of deposited layers. Due to the reheating of the next bead, the deposited layers have a fine dendrite structures at the top, and coarse columnar grain structures in the middle and at the bottom. The deposited layers exhibits slight increasing trend in hardness from substrate. A hollow cylindrical part with 30 layers was built up,the roughness Ra of which is about 50 to 200/am. Its deviation of verticality is less than 2%, while the de viation of diameter and height is less than 1 %.