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T、K、Y管节点焊缝的超声波探伤存在诸多技术困难,定位技术是最困难的环节之一。随着焊缝位置参数(钟点数)的变化,管节点焊缝的截面形状不断地发生变化,半跨距声程表现出较大的差异。因此,无法运用一般平板对接、角接焊缝常用的定位方法,也不能直接套用厚壁焊接管纵缝的定位方法。作图解析法是工程上较早应用的定位技术手段,也是缺陷判定的基本手段,受到人们的广泛关注。 作图解析法的最大优点是方法简单、结果直观,其缺点是步骤繁杂、难于掌握,且结果的准确性很大程度上取决于操作人员的熟练程度及技术水平,操作程序的合理与否也有甚大影响。因此,有必要对这种基本定位方法进行深入的研究。 1 缺陷定位技术要求与作图解析法原理 1.1 缺陷定位技术要求 在T、K、Y管节点焊缝的超声波探伤中,首先是对反射信号的位置测定,只有确认反射波并非“伪缺陷信号”之后,所进行的定位工作才是真正意义上的“缺陷定位”。
T, K, Y pipe joints ultrasonic flaw detection there are many technical difficulties, positioning technology is one of the most difficult part. With the variation of weld position parameters (number of clocks), the cross-sectional shape of the weld at the joint of the pipe joints constantly changes, and the semi-span acoustic path shows a big difference. Therefore, it is impossible to apply the common positioning method of flat plate butt joint and corner joint weld, and also can not directly apply the method of positioning longitudinal seam of thick-walled welded pipe. Mapping analysis method is the earlier application of positioning technology means, but also the basic means of determining defects by people’s attention. The biggest advantage of the mapping analysis method is the method is simple, the result is intuitive, the disadvantage is that the steps are complicated, difficult to grasp, and the accuracy of the results depends largely on the operator’s proficiency and technical level, the operation process is reasonable or not Very big impact. Therefore, it is necessary to conduct an in-depth study of this basic positioning method. 1 defect positioning technical requirements and the principle of mapping analysis method 1.1 defect positioning technology requirements T, K, Y pipe joints ultrasonic flaw detection, the first is the location of the reflected signal, only to confirm the reflected wave is not “false signal” After the positioning of the work carried out is the true sense of the “defect position.”