بررسي اثر شانه ابزار بر نفوذ و شروع فرآيند جوش اصطكاكي اغتشاشي به روش اجزاء محدود

چكيده انگليسي :

An Investigation of the Influence of Tool Shoulder on Plunging and Initiatnig of Friction Stir Welding Process Using FEM Method Mojtaba Allahkarampour m allahkarampour@me iut ac ir Date of Submission 2011 7 25 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Mehran Moradi moradi@cc iut ac irAbstractFriction stir welding FSW is a solid state joining process utilizing a rotating tool which consistsof a pin and tool shoulder that apply severe plastic deformation and frictional heating into the basematerial The softened material is extruded underneath and around the tool as the tool travelsalong the welding line and subsequently meets to form a strong metallurgical joint First FSWapplied to weld some low melting tempratue materials such as aluminium later developingtechnology realized to weld steel rustproof steel and titanium Quality and welding rate is highlydependent on tool geometry It s done many researchs in order to improve FSW and optimizedtools But for any design and optimization it must be enough and reasonable understanding ofthe type of process effective parameter and relationship It s effort to clear one of these and try toimprove this process that is used more and more everyday In friction stir welding FSW thewelding tool geometry plays a fundamental role in obtaining desirable microstructures in the weldand the heat affected zones and consequently improving strength resistance of the joint Thegeometric parameters of the tool such as the height and the shape of the pin and the shoulder have a great influence on both the metal flow and the heat generation due to process In classifyweldable plate by this process less than 6mm is thin 6 12mm middle and more than 12mmsituated in thick set Many researchs has done on thin plate and very little effort has been made tostudy the thick plate Among the key components of the FSW tool geometry is the tool shoulderand the pin In the welding of thin plate the shoulder is the main source of heat generated duringthe process the primary constraint to material expulsion and the primary driver for material flowaround the tool the pin is the primary source for material deformation and the secondary sourcefor heat generation in the nugget Consequently the geometry of both the shoulder and pin areimportant to the FSW process While in the welding of thick plate addition to cited roles for thinplate shoulder volume has essential effect on mixing and keeping softened material as a result offurther plasticized material Hence both pin and shoulder are sources for material deformationand heat generation during the process Even pin is dominant in the welding of thicker plate Inthis reasearch a process with varying shoulder and pin geometries is numerically modeled Theobtained results allow finding optimal tool geometry Because of cost and take a more time forexprimental process it s modelled by different pakhages Some of these modelling of flowpattern and heat flow Since we use ABAQUS Explicit package to analysis objective process Forthe cited reason modelling divided in three stages At the first angle of shoulder is changed byfix pin and fix shoulder diameter about horizon Second pin geometry is converting to taper bychange shoulder angle instantaneously and simulations is continued Last in third stage it willmodel by loss of shoulder volume and falatten effect by flat the outer shoulder and increase theflat effect through pin Keywords 1 Fiction stir welding FSW 2 Modeling 3 Thick plate 4 Shoulder

اله كرمپور، مجتبي

بررسي اثر شانه ابزار بر نفوذ و شروع فرآيند جوش اصطكاكي اغتشاشي به روش اجزاء محدود

مدلسازي , ورق ضخيم