پديد آورنده :
هدايتي، هادي
عنوان :
بررسي تاثير ترتيب جوشكاري و فرآيند هيدروتست بر تنش هاي پسماند جوشي در لوله هاي فولادي زنگ نزن SUS304
مقطع تحصيلي :
كارشناسي ارشد
گرايش تحصيلي :
طراحي كاربردي
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك
صفحه شمار :
ده،121ص.: مصور،جدول،نمودار
يادداشت :
ص.ع.به فارسي و انگليسي
استاد راهنما :
محمد مشايخي
استاد مشاور :
محمدرضا فروزان
توصيفگر ها :
فرايند جوشكاري چند پاسه , تولد و مرگ المان
تاريخ نمايه سازي :
11/8/89
استاد داور :
محمود فرزين، احمد كرمانپور
چكيده فارسي :
به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي
چكيده انگليسي :
Effect of Welding Sequence and Hydrotest Process on Welding Residual Stresses in SUS304 Stainless Steel Pipes Hadi Hedayati h hedayati@me iut ac hdyt hd2007@yahoo com May 19 2010 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisors Mashayekhi M Assistant Professor Email mashayekhi@cc iut ac ir Abstract Weld joints often contain various types of flaws such as slag inclusions gas pores or stick spots From such flaws during the service cracks can initiate grow slowly and finally lead to failure Fatigue behavior of a welded structure is complicated by many factors intrinsic to the nature of welded joints Among these effects the residual stresses as consequence of thermal multi pass welding cycles can be a dominant effect on fatigue crack propagation Tensile residual stresses are generally detrimental increasing the susceptibility of a weld to fatigue damage stress corrosion cracking and fracture When assessing the risk for growth of defects such as surface flaws in piping systems the welding residual stress may give a large contribution to the total stress field than stress caused by design loads Moreover in order to prevent inter granular stress corrosion cracking in the root area of welds in stainless steel pipes it is necessary to satisfy certain requirements concerning process condition material properties and welding residual stress Therefore a good estimation of the welding residual stress fields is then needed In the present study temperature fields and residual stress states in the weld joints of SUS304 stainless steel pipes are computed numerically using a thermo elasto plastic analysis This weld joint is a circumferential butt weld joint and is done in two passes using gas tungsten arc welding Welding procedure is simulated in two and three dimensions using a subroutine developed in finite element ABAQUS software for applying heat flux The applied heat flux is represented by a double ellipsoid model Futhermore the element birth and death technique is used to simulate weld passes and filler metal deposition into the weld pool When the simulation is done the effect of welding sequence on welding residual stresses are considered using four different welding sequences proposed Finally the effect of hydrotese process in decreasing the residual stresses is evaluated To verify the validity of simulation results they are compared with the results of the experimental measurements of residual stresses attained by hole drilling method As the results of the simulation show selecting a suitable welding sequence can substantially decrease the amount of tensial residual stresses and can change them to compressive stresses in certain situations Also the results of this research show that applying a hydrotest pressure after welding process can reduce welding residual stresses up to 70 Key Words multi pass welding process welding residual stresses element birth and death welding sequence hydrotest process
استاد راهنما :
محمد مشايخي
استاد مشاور :
محمدرضا فروزان
استاد داور :
محمود فرزين، احمد كرمانپور
