100 percent x-ray weld inspection: A real-time imaging system for large diameter steel pipe manufacturing

The new, real-time microfocus X-ray system described here not only paid for itself and saved $1 million on the first job, it provided 100% inspection 12--14 times faster than the previously used conventional radiographic technique. Compared to conventional radiography, real-time X-ray inspection offers benefits that translate into significant cost and time savings. One primary advantage is the real time reporting capability to manufacturing for process control allowing the operator to receive instantaneous feedback during production and to make adjustments immediately. For example, with conventional film based radiographic systems, the operator would have to predetermine energy levels, exposure time, and orientation of the sample to be inspected before beginning the actual inspection run. Only after developing the film and analyzing the images was it possible to determine if the desired results were obtained. If not, the settings would have to be adjusted and the manufacturing process repeated. In contrast, with real-time X-ray, the operator has the ability to visually observe the inspection process on a video monitor while adjusting the energy level and/or orientation of the sample using a five-axis (x, y, z, tilt, and rotate) sample manipulator for optimum results. In addition, real-time monitoring allows visual observation of any mechanicalmore » movement which is internal to the sample. The application of this technique to still pipe welding at the Northwest Pipe Company is discussed.« less