الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Distortion has significant effects on the assembly process of welded structures and remarkable influences on the strength of the welds especially when it comes to thick plates due to non uniform heat distribution during heating and cooling cycle. The purpose of this report is to investigate the angular distortion resulted during welding of different passes of butt welded joints of mild steel using shielded metal arc welding for every welding pass. A measurement of linear distortion was performed for root pass, hot pass, filling pass and cap pass using linear variable differential transformer LVDT. The study was performed on mild steel samples of thicknesses 6 mm, 10 mm and 12.7 mm with groove angel 450 and 600 . Welding fixture has been designed as a part of measuring setup to perform welding of steel plates under free conditions. from literature review, there are many methods used to measure distortion. In this research, LVDT is used due to its higher accuracy for measuring variations of angular distortion during for every welding pass with time. Drawing of linear distortion - time graph was presented to show the measured linear distortion every welding pass and also during cooling (time gap between successive passes). Finally, the total angular distortion was calculated. The results show that distortion occurs as intervals shows positive distortion, negative distortion or both for each welding pass. Reverse distortion (negative distortion) occurs when contraction in lower plan is greater than upper plan. The factors that affect the total angular distortion have also been reviewed.