7189

6695

كارشناسي ارشد

شناسايي و انتخاب مواد

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مواد

1391

ده، 86ص.: مصور، جدول، نمودار

ص.ع. به فارسي و انگليسي

مرتضي شمعانيان، احمد كرمانپور

توحيد سعيد

7/8/91

حسين ادريسي، مسعود عطاپور

1396/09/20

كتابنامه

مواد

مهندسي مواد

ID6695

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Friction Stir Welding of Gost 5632 Duplex Stainless Steel and Evaluation of the Joint Properties Mojtaba Esmailzadeh m esmailzadeh@ma iut ac ir Date of Submission 2012 09 18 Department of Material science and Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor M Shamanian shamanian@cc iut ac irSupervisor A Kermanpur Ahmad k@cc iut ac irAbstractIn this study microstructures and mechanical properties of friction stir welded Gost5632duplex stainless steels DSSs were investigated Friction stir welding FSW was appliedto a 1 5 mm thick Gost5632 DSSs plate Different speciments produced by employingrotation speeds of 400 600 and 800 rpm and welding speeds of 50 100 and 150 mm min The welding tool was made of a WC based material had a shoulder diameters and the pinlength of 16 and 1 25mm respectively The weld thermal cycles were determined throughthermocouples The measured temperature at maximum heat input 800 rpm and 50mm min showed that the peak temperature was about 1000 C Microstructures of the weldarea were examined by optical microscopy OM and scanning electron microscopy SEM equipped with an energy dispersive X ray spectroscopy EDS analysis system Identity ofphases was taken by X ray diffraction test vickers microhardness tests at a load of 300 gand mechanical properties by tensile tests were performed Fractugraphy of tensile sampleswere investigated finally Results of XRD showed any harmful phase for example sigma chi and etc The reason of this phenomene was high cooling rate of samples duringwelding The microstructure features can be separated into three broad regions includingthe stir zone SZ the thermo mechanically affected zone TMAZ and the base metal BM Because of severe deformation of material near rotation tool the grain size of theweld area was reduced It is generally known that reconstruction of fine and equiaxed grainin the SZ is a result of dynamic recrystallization Minimum grain size was determinedabout 1 m for 600 rpm rotation and 150 mm min welding speed Advancing side ofweldment was incurred maximum deformation according to flow materials during FSW Because of this reason grain size of this region was finer than the other regions Thehardness within the SZs in all conditions of present study was higher than the base metal The increase of hardness in the stir zone suggests that the hardness profile may be relatedto the small grain sizes of both phases in the weld zone The hardness of BM was 284 HVwhereas the mean hardness of SZ was about 423 HV The tensile strength of the weldment 774MPa was higher than those of BM 680 MPa The fracture region of all sampleswere in BM however fracture was occurred in interfaces of SZ BM for almost condition ofwelding The fracture surface of the weldment was indicated characteristics of ductiledimple fracture except the one with 400 rpm rotation and 50 mm min welding speed Theresults showed that microstructures and mechanical properties of the duplex stainless steeljoints were significantly affected by welding conditions The results of microstructure tempreture profile X ray diffraction and mechanical properties were defined 600 rpmrotation and 100 mm min welding speed as the optimum conditions for FSW of Gost 5632DSS Key word Friction stir welding Gost5632 lean duplex stainless steel Recrystallization dynamic

مرتضي شمعانيان، احمد كرمانپور

توحيد سعيد

حسين ادريسي، مسعود عطاپور