The weld pool is the core of the welding process where complex welding phenomena originate. Skilled welders acquire their process feedback primarily from the weld pool. Observation and measurement of the three-dimensional weld pool surface thus play a fundamental role in understanding and future control of complex welding processes. To this end, a laser line is projected onto the weld pool surf...

In this paper, we propose a fuzzy-servoing controller method for automatic welding. The proposed method uses a vision based arc tracking to find the initial points of the weld seam and to track them without a prior knowledge. Due to a serious melt down in the weld pool during the welding process, the method requires to control the welding torch in two directions, up-down and left-right directio...

This paper deals with weld pool oscillation during pulsed gas tungsten arc (GTA) welding of unalloyed steel. Experiments were carried out in which the weld pool was triggered into oscillation during both the base time and the pulse time by short current peaks, superimposed on the pulsed welding current. The arc voltage was continuously measured during welding and the oscillation frequency spect...

Three-dimensional residual stress mapping of an aluminum 2024-T3 arcan specimen, butt-welded by the friction stir technique, was performed by neutron diffraction. Results indicate that the residual stress distribution profiles across the weld region are asymmetric with respect to the weld centerline, with the largest gradients in the measured residual stress components occurring on the advancin...

This report describes a study of the fatigue behavior of fillet welded joints stressed perpendicular to the weld line. The study included an experimental phase in which the stiess-life and cracking behavior of load and nonload carrying fillet weld joints was determined. This experimental study concentrated on the fatigue behavior in the transition region between high and low cycle fatigue 3 5 (...

Ill EXECUTIVE SUMMARY IV

The automatic weld seam tracking is an important challenge in None Destructive Testing (NDT) systems for welded pipe inspection. In this Study, a machine vision based seam tracker, is developed and implemented, instead of old electro-mechanical system. A novel algorithm based on the weld image centered is presented, to reduce Environment conditions and improve the seam tracking accuracy. The we...