Design And Implementation Of Computer Testing And Evaluating System Of Welding Quality

In order to ensure continuous cold rolling in the plate production, prior to the formal entry of the pickling line tandem cold rolling mill, it is necessary to weld the advance band steel with the rear band steel, and then, the band steel’s welding seam features a smaller strength; therefore, during the actual rolling, this can easily result in an accident of band breakage, thus causing safety hazards and waste in human labor and finance. According to some surveys, there is a variety of causes that can lead to breakage at the weld seams, and among them, the flaws inside the weld seams are the main causes that can lead to the breakage of the band steel; based on this, it is only necessary to have rigid controls over the quality of the welding seams and such a measure will can significantly reduce the incidences of the breakages of the band steel, thus finally realizing the elevation of the production efficiency of the products. In addition, band steel edge cracks(shortened as edge cracks) are common problems encountered during the cold rolling process, and band steel edge cracks will directly lead to the reduction of the edge quality of the band steel, thus reducing the material yield of the steel and causing enormous resource wastes; Furthermore, in severe cases, these can result in the accident of breakage of band steel.Regarding flaws of the welding seams, this Paper proposes a detection system of welding seam quality which is based on the combination of the eddy current detection technique and laser contour detection. The system not only can detect the flaws inside the seams, but can also detect the contour flaws on the surfaces of the welding seams; as a matter of fact, the combination of these two techniques of eddy current detection and laser detection can ideally elevate the quality of the detections, and, by analyzing the corresponding relation of the impedance signals and the flaws through experiments, comparing the experiments of eddy current flaw detection, X-ray flaw detection and metallographs, it can also verify the reliability of the detection of the weld seams using the eddy current detection technique. This Paper simulated the eddy current probes through the numerical simulation technique so that the three dimensional electromagnetic response of the seam flaws were detected and finally the relationships between the eddy current signals and the seam flaws was obtained; it also summarized the numerical relationship between the eddy current signals and the flaws, for example, the relationships between the eddy current signals and the positions, types and sizes of the flaws; meanwhile, this Paper defined the relevant parameters of the eddy current detection based on the results obtained through detections. This Paper detected the contours of the welding seam surfaces mainly through the VB software, and through the designs of a series of programs for the monitoring of the system’s surfaces, it is possible to conduct real-time acquisition of the contour information of the welding seam surfaces; meanwhile, the acquired data were processed and analyzed through the principles of statistics, and finally the various kinds of threshold values for the welding seam flaws; finally, the accuracies of this method was derived through analysis through the observation of the actual on-site operational status of the eddy current detection method.