• CN:11-2187/TH
  • ISSN:0577-6686

›› 2013, Vol. 49 ›› Issue (18): 114-118.

• 论文 • 上一篇    下一篇



  1. 山东大学材料液固结构演变与加工教育部重点实验室
  • 发布日期:2013-09-20

Measurement of Dynamic Keyhole Behaviors in Controlled-pulse Plasma Arc Welding

WU Chuansong;LIU Zuming;CHEN Ji   

  1. Key Lab for Solid-Liquid Structure Evolution and Materials Processing of Ministry of Education, Shandong University
  • Published:2013-09-20

摘要: 受控脉冲穿孔等离子弧焊接新工艺能有效扩展适用的焊接工艺参数区间,在中厚度高性能金属结构成形制造领域有广阔应用前景。为掌握这一新工艺涉及的热物理机制,检测其熔池小孔随脉冲电流的动态变化过程有重要意义。介绍受控脉冲穿孔等离子弧焊接小孔动态行为的试验检测系统和方法。在受控脉冲电流波形作用下,通过调控电流脉冲后沿的两个下降斜率,主动地控制热输入和小孔的形成与闭合,保证熔池穿孔、工件熔透。采用视觉传感技术实时拍摄受控脉冲穿孔等离子弧焊接过程中小孔的序列图像,提取不同时刻小孔形状、尺寸和位置的数据。展示一个受控脉冲周期内在“小孔形成-长大-缩小-闭合”周期性过程中小孔尺寸和位置偏移量随焊接电流的瞬态变化规律。研究结果为受控脉冲穿孔等离子弧焊接工艺优化和过程控制奠定基础。

关键词: 等离子弧焊接, 视觉检测, 受控脉冲穿孔, 小孔行为

Abstract: The developed novel variant process of controlled-pulse keyholing plasma arc welding is able to effectively extend the suitable process parameters window, and is of great application potential in joining high-performance metals with medium thickness. To fully understand the underlying thermo-physical mechanisms of this welding process, it is critical to measure and monitor the dynamic variation of the keyhole status in each pulse cycle of the welding current. The experimental sensing system and technique of the dynamic keyhole behavior in controlled-pulse keyholing plasma arc welding are introduced. Under the action of controlled-pulse current waveform, both heat input and keyhole’s establishment and closure are actively controlled through adjusting the dropping slopes at the trailing edges of the pulse current, so that complete keyhole formation and full penetration are ensured. The sequential images of the keyhole exit are captured by the vision sensor during the controlled-pulse keyholing plasma arc welding. The information on the shape, size and deviation distance of the keyhole exit is extracted based on the image processing and calibration. It presents the transient variation of the keyhole dimension and location relative to the torch axis during the cyclic process of keyhole establishing-expanding-contracting-closing in each pulse. The research results lay solid foundation for the process optimization of the controlled-pulse keyholing plasma arc welding.

Key words: Controlled-pulse keyholing, Keyhole behavior, Plasma arc welding, Vision-based sensing