Patent ID: 7373822

Claim:
A method for evaluating, during a welding process, a welded joint as the welded joint is forming between at least two parts of a joint using at least one ultrasonic transmitter penetrating a region of the forming welded joint with ultrasonic waves and at least one ultrasonic receiver, which registers the changes in sound transmittance of the ultrasonic waves penetrating the region of the forming welded joint in order to evaluate the welded joint, wherein sound is transmitted with longitudinal (l) and transverse (t) ultrasonic waves into the region of the welded joint, the time-dependent changes in sound transmittance D l (t), D t (t) of the longitudinal ultrasonic waves (l) and the transverse ultrasonic waves (t) are registered separately, and using a ratio of D l (t) to D t (t), the time point t s at which a molten mass forms in the region of the welded joint is determined and which serves as a basis for evaluating the welded joint.