4. Experiments and applications
Ultrasonic LCR wave method has the characteristics of high resolution, high penetration, nondestructive and no
harm to the human body, and that it is the most promising technology in the development of residual stress testing.
Using the ultrasonic detector, we carried out experiment research on residual stress testing of oil pipeline weld joint.
The material of pipeline is X70 steel and welding procedure is manual arc welding. We tested residual stress
around straight weld joint in a section of pipeline. In order to verify the accuracy of the test results, a hydrostatic test
has been carried out. From the Fig. 2, it is observed that the blasting area is consistent with the dangerous area
evaluated by ultrasonic LCR wave method.