Conventional Non Destructive Testing (NDT) techniques for assessing the weld quality are applied after welding is completed. It results in wastage of time, material and manpower. These inherent limitations of the conventional welding processes can be overcome with an automated adaptive welding system to correct the deviation in the welding current and torch speed to provide defect free welds. T...

In this research longitudinal shrinkage of two steel plates with identical thickness that are joint together through butt welding and another steel plate with bead welding. This study begins withthe introduction of a model, in which the thermoelastoplastic zones near the weld line is simulated with a thermoelastoplastic flat bar, and full-elastic areas beyond the weld line is simulated with a f...

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...

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...

The determination of quality parameters of resistance spot weld in real time is of great importance in today’s industry. Acoustic waves can solve this problem in the sense of measuring certain features directly related to the weld quality – degree of heating of the weld zone, moment of beginning of melting and some others. The ultrasonic transducer incorporated into an electrode sends short aco...