窄间隙摇动电弧单面焊双面自由成形方法及熔透控制研究

To effectively solve the welding problem of thick plate structure which is difficult to be turned around or has narrow back space, this project proposes a novel process of narrow gap swing arc one-side welding with back free formation, and develops a free forming system of narrow gap swing arc backing weld based on the dual synergetic controls of arc swing with welding current. To control in real time arc swing angle and welding current, this system detects the gap width of groove root, area and gray of welding pool by infrared passive visual sensing, and extracts the penetration features of backing weld by fusing the features of welding current acquired synchronously, thus adapting the free forming process of narrow gap swing arc backing weld to a varying root groove automatically, and forming the backing weld with even and steady penetration. This research will be focused on the effects of swing arc welding process parameters on the free formation of backing weld, and the detection method and control strategy of backing weld penetration based on the synchronous sensing of welding pool figure and welding current. In addition, it will investigate the metal transfer phenomenon, metal flow behavior and weld penetration characteristics of swing arc backing welding, revel the free forming mechanism of swing arc backing weld, and analyze the effectiveness and real-time performance for the penetration control of swing arc backing welding process. The above work will help to establish the theoretical fundamentals of swing arc narrow gap GMA one-side welding with back free formation, and to promote the developments of high-efficiency and intelligent welding technology.

针对不易翻身和背面空间狭小的厚板结构件焊接问题，本项目提出一种窄间隙摇动电弧单面焊双面自由成形方法，构建电弧摇动与焊接电流双重协同控制的窄间隙摇动电弧打底焊缝自由成形系统。通过红外被动视觉传感方式检测坡口根部间隙宽度、熔池区域面积和灰度值，并与同步采集的焊接电流信号融合，提取打底焊缝熔透特征，实时控制电弧摇动角度和焊接电流，使窄间隙摇动电弧单面焊双面自由成形方法能自动适应坡口根部环境变化，以获得均匀稳定熔透的自由成形焊缝。重点研究摇动电弧焊接工艺参数对打底焊缝自由成形的影响规律、基于熔池图像和焊接电流信号同步传感的打底焊缝熔透检测方法及控制策略，研究摇动电弧打底焊接熔滴过渡现象、熔池流动行为及焊缝熔透特性，揭示摇动电弧打底焊缝自由成形机制，分析摇动电弧打底焊缝熔透控制的有效性和实时性，建立摇动电弧窄间隙GMA单面焊双面自由成形方法的理论基础，促进高效及智能化焊接技术的发展。

针对U形窄间隙坡口，本项目提出了一种窄间隙摇动电弧自由成形打底焊方法及系统，通过电弧摇动与焊接电流的协同配合，有效解决了窄间隙坡口两侧壁的熔透问题；通过红外被动视觉与摇动电弧复合传感，检测打底焊缝熔透状态和坡口根部间隙宽度，实现了对自由成形打底焊缝的熔透控制。项目研究了坡口侧壁熔透控制方法、打底焊缝熔透传感检测方法及控制算法、电弧摇动控制方法，揭示了电弧摇动参数和坡口根部间隙宽度对熔滴过渡行为、熔池搭接特性和焊缝自由成形的影响规律，阐明了摇动电弧力在坡口内的分布规律，分析了摇动电弧自由成形打底焊缝熔透控制的有效性，建立了摇动电弧自由成形打底焊接的理论基础，促进了高效焊接技术的发展。.研究结果表明，摇动电弧和坡口根部间隙宽度有效调节了电弧力在坡口内的作用范围，显著影响了坡口侧壁和根部的稳定熔透；增大电弧摇动参数，打底焊缝从焊穿状态逐步向自由成形熔透转变，但过大的电弧摇动参数易造成焊缝未焊透；增大坡口根部间隙可增强根部熔透，但过大的坡口根部间隙会产生未焊透缺陷；通过红外视觉传感和电弧传感，有效检测出摇动电弧自由成形打底焊缝的熔透状态，并在变坡口根部间隙条件下，通过调节电弧摇动参数和焊接电流，有效实现了打底焊缝的均匀稳定熔透。