شبيه سازي تاثير پارامترهاي مختلف بر اعوجاج حاصل از جوشكاري با روش GMAW

چكيده انگليسي :

Simulating the Effect of Different Parameters on Distortion Induced from GMAW Welding Meysam koohi Fayegh Dehkordi m koohi@ma iut ac ir March 17 2012 Department of Materials Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiDr Hamid Reza Salimi Jazi Assis Prof Supervisor E mail hrjazi@cc iut ac irDr Mohammad Reza Toroghinejad Assoc Prof Supervisor E mail toroghi@cc iut ac irAbstractWelding is a reliable and effective metal fabrication process which is widely used in industries Localized heating during welding followed by rapid cooling generates residual stress and distortion inthe weld and base metal In the last few decades various research efforts have been directed towards thecontrol of welding process parameters aiming at reducing the residual stress and distortion Distortion atthe structures due to the welding process limits their applications especially complex shape structures Accurate prediction and reduction of welding residual stress and deformation are critical in improvingthe quality of welded structures Stainless steels 316 sheets are widely used in industries due to theirsuperior ant oxidation and corrosion properties that are widely used in applications requiring corrosionresistance superior to Type 304 or good elevated temperature strength Type 316 is used extensively forweldments where its immunity to carbide precipitation due to welding assures optimum corrosionresistance In the current study the main aim of the work was to investigate a simplified finite elementsimulation of the out of plane distortion caused by fusion butt welding Distortion of the stainless steel316 during welding at different process parameters was experimentally investigated Stainless steelswere welded by GMAW with butt joint in two passes at different conditions such as heat input andpresetting parts The process under the same welding conditions was simulated by numerical finiteelement with using Ansys software A hybrid model of thermal mechanical on a scale of three dimensional elastoplastic by programming was employed At the first the thermal analysis wasperformed A macro code based on Goldak heat source model programmed in the software Then results of this section as load was applied the default for subsequent mechanical analysis In order tovalidate the hybrid model used in this study the temperature measured by thermocouple that fixed atsome point on the piece during the welding And thermal analysis was compared with the experimentalresults At the end of Welding the amount of angular distortion was measured Experimental test resultsshowed that using the minimum heat input to reduce distortion is suitable Also to avoid distortion presetting parts is suitable way Comparison of simulation and experimental results showed that theproposed model to simulate the heat source is consistent Goldak model therefore accuracy of programhas been confirmed Simulation results of thermal analysis is matches on experimental results Regardto the sources of error in the experimental tests mechanical analysis of simulation results are also fitwith experimental results satisfactory In the most case fifty eight hundredths degree of angulardistortion in the simulation and experimental results is different That is related to the welding heatinput of 1 097 kJ mm in the first pass and 1 31 kJ mm in the second pass In terms of distortionmeasured value the simulation results in the first second and third case have differences about fiftypercent forty eight percent and Forty percent respectively with the experimental results Keywords Welding Stainless steel 316 GMAW Distortion Simulation

كوهي فايق دهكردي، ميثم

شبيه سازي تاثير پارامترهاي مختلف بر اعوجاج حاصل از جوشكاري با روش GMAW

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