【作者】 李云峰；

【导师】 赵熹华；

【作者基本信息】 吉林大学 ， 材料加工工程， 2008， 博士

【摘要】 铜包铝线缆制造过程中,焊接质量是影响成材率的主要因素。由于线坯所用的铜带厚度很薄,焊接速度又很高,进行焊接质量的实时传感与控制十分困难,相关的研究也很少。本文在分析了铜包铝线坯高速TIG焊接生产工艺、钨极偏离焊缝和熔宽变化对焊接接头微观组织和力学性能影响的基础上,确定在该工艺条件下焊缝跟踪系统所应达到的焊缝实时传感及自动跟踪控制精度和熔宽实时传感及自动控制的精度。同时,对铜包铝线坯高速TIG焊接焊缝视觉传感及自动跟踪、熔宽视觉传感与自动控制方面进行了深入研究。研究结果表明:焊接电流在180A～200A范围内时熔宽变化范围为0.860 mm～1.217 mm,焊缝区组织致密、无明显的焊接缺陷。热影响区的厚度很薄,为等轴晶,与基体相比晶粒略有长大。随着焊接电流的提高焊缝区柱状晶的直径和热影响区的厚度、晶粒大小有增加的趋势;钨极偏离焊缝0.1mm、0.2mm与钨极未偏离焊缝时的焊缝组织、热影响区组织变化不大,焊缝均为较粗大单相α柱状晶,热影响区与基体比较长大不明显,仍保持等轴晶形态。钨极偏离焊缝中心距离小于0.2mm时,未发现各区组织存在明显变化,未发现焊缝区、热影响区有未熔合及未熔透等焊接缺陷。在铜包铝线坯高速TIG焊接生产中,采用视频摄像传感器超前于钨极20 mm检测铜带对口缝可以获得清晰的对口缝图像,采用专用的设计电路对视频信号进行处理,降低了图像信息处理时间,实现焊缝自动跟踪。实验测试结果为:在焊缝偏差为0.1 mm,采集两帧数据时系统响应周期为115 ms,采集六帧数据时系统响应周期为195 ms;系统焊缝跟踪误差为:±0.13 mm。以弧光为主动光源,经过对弧光的中性减光和采用中心波长为677 nm的窄带滤光处理,采用视频摄像传感器获得了清晰的熔池图像。为了实现快速响应,满足高速焊接生产的要求,采用特殊电路对视频信号进行处理。该处理过程耗时为纳秒级,并准确获得了熔池宽度方波信号,实现了对熔宽的实时检测及自动控制。实验测试证明:采集四帧数据时系统响应周期为80 ms,系统熔宽控制误差为:±0.14 mm。更多还原

【Abstract】 Copper-clad aluminum cable is bimetal compound cable that is produced on the method of copper level covering aluminum core. It is a good inner conductor to replace copper manufacturing RF coaxial cable. Using quality copper-clad aluminum cable instead of copper cable has a broad application prospects.Clad-process welding copper clad aluminum cable is the welding produces aluminum core covered by copper strip and TIG welding is commonly used welding method. But in the actual production, one hand, as the impact of the covering process, and often there is departure between electrode and Copper strip opposite seam; On the other hand, for the changes of copper the thickness, Using constant current welding often have some defects such as faulty fusion or melting loss. And the actual production welding speed is quickly. Rely on the operator to manually tracking seam welding current adjustment and it is very difficult to eliminate defects produced, and often produce a lot of waste, but also seriously affect the continuity of production, therefore, achieving Copper-clad aluminum wire welding seam automatic tracking and welding pool width control is very necessaryBecause copper cable used very thin, high welding speed, a constant current TIG welding, the welding process for welding quality of real-time sensing and control is very difficult, and very few relevant research. Based on careful analysis of the TIG welding production process of copper clad aluminum strip and the Tungsten deviating from welding seam and the influence of welding pool width change on the welded joint microstructure and mechanical properties .The process established under the conditions in the seam tracking system should meet the real-time sensing and automatic seam tracking control accuracy and welding pool width real-time sensing and automatic control accuracy, at the same time, carry out in-depth research on Copper-clad aluminum cable billet on the high-speed TIG welding seam visual sensing and automatic seam tracking and sensing welding pool width and control.The results showed that weld tungsten deviated from 0.1 mm, 0.2mm and tungsten did not deviate from the welding seam, the heat-affected zone microstructure changed little, the microstructure were large single-phaseαcoarse columnar crystals, and the heat-affected zone and the bases did not grow greatly, remained equiaxed grain. Weld tungsten from the centre was less than 0.2 mm, found no significant microstructure change in the different district and found no weld heat-affected zone of fusion and non-penetration welding defects, etc. automatically sensing and real-time seam tracking control detection and control accuracy, should not be less than 0.2 mm.Using constant current welding often has some defects such as faulty fusion, burning through or melting loss. With the increase of welding current, the width of the welding pool will increase. But welding current changes in excess of±10 A, will have a non-fusion welding wear or defects; thickness of 0.38 mm, welding speed of 10 m / min, welding current of 180 A-200 A change, welding pool width range of changes 0.860 mm to 1.219 mm, which have received the penetration. Thickness unchanged, in the welding current of 190 A±10 A of changes , the grain size of welded joints changed, the current larger the grain size larger. The thickness of the heat-affected zone is thin and the microstructure is equiaxed grain, and the grain is larger than the bases. With the improvement of welding current, the diameter of the weld district columnar crystal and the thickness of the heat-affected zone, grain size, with an increasing trend, melting wide detection accuracy of±0.15 mm, the availability of a suitable weld metal properties.Arc light as the active light source, during the production of Copper-clad aluminum strip in the high-speed TIG welding, video camera sensors used in tungsten-ahead 20 mm can detect Copper strip counterparts slit and can get clear image, circuit simulation using the video signal amplification, shaping, horizontal hold supply and moving average processing greatly reducing the image processing time, and get the accurate Copper strip counterparts slit pulse signal. Carrying out the judgement of the Copper strip counterparts slit deviation and the calculation of the size of deviation. Using the stepper motor and the delicate slipper driving the blowtorch for the rapid real-time tracking, automatic seam tracking system response speed and accuracy of the tests show that: in weld deviation of 0.1 mm, two frames data acquisition the system response cycle is 115 ms, the six frames data acquisition system response cycle is 195 ms; the error of the systems for seam tracking is±0.13 mm. During the production of Copper-clad aluminum cable billet in the high-speed TIG welding, the arc light as the active light source, after the arc light is neutral weakened and using the center wavelength of 677 nm of the narrow-band filter deal with, using the video camera sensors get a clear image of the welding pool. In order to achieve rapid response to meet the requirements of high-speed welding production, circuit simulation using the video signal amplification, shaping, horizontal hold supply and moving average processing, allowing the video signal processing for the nanosecond time-consuming, and get the accurate square wave signals of the pool width. And realize the real-time detection of the welding pool width. According to the trend of welding pool width changed and the size changed, using the fuzzy controller change the welding current rapidly to achieve the control of the welding pool width. The test of the control system response speed of the welding pool width and the accuracy of the control system showed that: the welding pool width deviation is±0.1 mm, four data acquisition system response time is 80 ms cycle and the welding pool width control system error is±0.14 mm.This paper test shows that using visual sensor for high-speed Copper-clad aluminum cable billet TIG welding seam tracking and automatic real-time sensor control, welding pool width automatic real-time sensing and control, in the high-speed Copper-clad aluminum strip TIG welding quality control has certain theoretical guidance and good prospects.更多还原