声波衍射时差法在非平面焊缝和小直径厚壁管中的运用和提升

Application and Improvement of Time of Flight Diffraction Ultrasonic Testing Method to Non-planar Welded Seams and Thick-wall Pipes with Small Diameters

在压力容器和压力管道等特种设备无损检测和定期检验过程中,要求必须系统停车,对检验的特种设备进行工艺处理后,再进行无损检测。为了提高检测效率,降低检测成本,提高缺陷检出率,特引用超声波衍射时差法(TOFD)对特种设备进行全面检验。该手段不仅比其他检测埋藏缺陷的方法可靠,而且,可以在设备运行过程中进行检测,大大降低了检验成本。但是,由于扫查架的结构问题,TOFD主要用于平焊和大直径压力设备环焊缝的检测,无法对非平面焊缝和小直径厚壁管进行检测。通过对对扫查架的结构改造,TOFD完全可以运用在非平面焊缝和小直径厚壁管的检测领域。

During the nondestructive testing and periodic inspection of special equipment like pressure vessels and pressure pipes, the plant must be first shut down to do process treatment for those special equipment and then nondestructive testing can be done. In order to increase detection efficiency and defect detection rate, and reduce inspection cost, time of flight diffraction（TOFD） ultrasonic testing was used to test overall for the special equipment. The method not only is more reliable than other methods for detecting buried defects, but also greatly reduces the cost of inspection because it can be carried out while equipment is running. Due to structure problem of scanning rack, TOFD is mainly applied to inspection of flat welding seams and circumferential weld seams of pressure equipment with large diameters, but it cannot be applied to inspection of plane welded seams and thick-wall pipes with small diameters.Through structure modification of the scanning rack, TOFD can be well applied to inspection of non-planar welded seams and thick-wall pipes with small diameters.