A method for determining the quality of a screw joint tightening process performed by means of a torque impulse wrench, comprising clamp load determination via calculation of the time of flight for ultra sonic waves induced into the screw joint, and comparing of a total rotation movement of the screw joint with predetermined angle limit values as a target axial load level has been indicated by the time of flight of ultra sonic waves induced in the screw joint. Occurring discrepancies between the obtained total rotation movement of the screw joint and the angle limit values would indicate a faulty screw joint and/or a malfunctioning ultra sonic wave flight time measurement, which means an unacceptable tightening process quality.