Measuring welding internal stresses by ε-field analysis and ultrasonic method

Although the different parameters of the origin of welding internal stresses are intensively examinated, the nondestructive or pseudodestructive methods are necessary to determine the real internal stresses. These are measured here in a multiple submerged layer welding with an ultrasonic method and a new developed 'ε-field analysis' (abbreviated: EFA), which gives the internal stress and its distribution until a depth of nearly 10 mm. The ultrasonic method for measuring superficial internal stresses is based on their influence on the velocity of an ultrasonic longitudinal wave, passing in the upper surface. The good accordance of both stress measurements confirms the principles and indicates new possibilities for internal stress measurements in situ. (orig.)