METHOD FOR DETERMINATION OF TEMPORALLY VARIABLE THERMOMECHANICAL STRESSES AND/OR STRESS GRADIENTS ALONG THE WALL THICKNESS OF METALLIC PIECES

摘要

The present invention relates to a method for detecting temporally varying thermomechanical stresses and/or stress gradients over the wall thickness of metal bodies, in particular pipelines. In the method, the temperature on the outer surface of the body is measured in order to determine a temperature progression and stress progression therefrom. In addition, electromagnetic ultrasonic transducers are used at at least one measuring point on the outer surface in order to determine the progression of the stresses and/or stress gradients over time over the wall thickness of the body in conjunction with the result of the temperature measurement. The method allows the fatigue monitoring of pipelines even in the event of rapid stress changes.