دانلود مقاله on the formation of onion ring structure in friction stir butt welds of copper plates produced by non -threaded tool pin
سال انتشار: ۱۳۸۸
محل انتشار: کنگره بین المللی جوش و روشهای اتصال
تعداد صفحات: ۵
j teimournezhad – university of tehran
a masoumi –
onion -ring structure is a probinent feature of the many friction stir welds the aim of this investigation is to understand the formation of onion -ring structure in the welded joint produced by a non-threaded tool pin in copper plates. It is shown that the phenomenonof onion – ring structure formation is the consequence of dimple in middle area o feach layer of material which deposited to back of the tool in one rotation and cutting through the section of the material moreover onion-ring structure can be created by non-threaded tool pin in transverse cross -section and the space and depth of semi-circular surface features are equal to welding pitch displacemnet /revolution and plunge depth respectively. a micrl -structural study shows that the weld has lamellar structure and the bonding force in friction stir welds is caused by the mixing of materials from the sides of layer interfaces.