电弧增材高频微锤击系统及工艺特性的初步物理模拟

High frequency micro-hammer system and preliminary physical simulation in arc additive manufacturing process

内部缺陷、晶粒粗大等因素引起的力学性能降低是电弧焊接和增材制造面临的主要挑战之一。电弧增材过程辅以同步的微区锤锻、冲击是改善、解决此问题的可行思路。为此,文中提出了一种基于紧凑小型直线促动器的随焊微锤锻技术,具有体积小、位移分辨率高、响应速度快、输出力大且频率高等优点。通过定点焊配合延时锤击模拟验证了同步锤击对高温凝固区域的作用效果,通过定点焊配合同时在焊点附近锤击模拟验证了锤击振荡熔池的作用效果。研究表明,加入锤击作用后晶粒均得到了一定程度细化,可观察到粗大的柱状晶转变为细小的等轴晶。锤击频率和锤击力大小均对锤击效果有较大影响。

The reduction of mechanical properties caused by internal defects,coarse grains and other factors was one of the main challenges in arc welding and additive manufacturing.Making the WAAM process supplemented by synchronized micro-area hammering and impacting would be a feasible way to solve the problem.Therefore,a micro-hammering technology based on compact and small linear actuators was proposed in the paper,which had advantages of small size,high displacement resolution,fast response speed,large output force and high frequency.The effect of synchronous hammering on the high-temperature solidification area was verified by the fixed-point welding and delayed hammering simulation,and the effect of the hammering oscillating molten pool was verified by the fixed-point welding and the hammering simulation nearby the welding point.The research result showed that after the hammering was added,grains were all refined to a certain extent,and it could be observed that coarse columnar crystals were transformed into fine equiaxed crystals.Both the hammering frequency and the hammering force had a great influence on the hammering effect.