اثر سرعت جوشکاری اصطکاکی اغتشاشی در زیر آب روی آلیاژ آلومینیوم

Effect of welding speed on microstructures and mechanical properties

of underwater friction stir welded 2219 aluminum alloy

اثر سرعت جوشکاری بر ریز ساختارها و خواص مکانیکی آلیاژ آلومینیوم 2219

جوشکاری اصطکاکی اغتشاشی شده در زیر آب 

ABSTRACT

Underwater friction stir welding (underwater FSW) has been demonstrated to be available for the strength improvement of normal FSW joints. In the present study, a 2219 aluminum alloy was underwater friction stir welded at a fixed rotation speed of 800 rpm and various welding speeds ranging from 50 to 200 mm/min in order to clarify the effect of welding speed on the performance of underwater friction stir welded joint. The results revealed that the precipitate deterioration in the thermal mechanically affected zone and the heat affected zone is weakened with the increase of welding speed, leading to a narrowing of softening region and an increase in lowest hardness value. Tensile strength firstly increases with the welding speed but dramatically decreases at the welding speed of 200 mm/min owing to the occurrence of groove defect. During tensile test, the joint welded at a lower welding speed is fractured in the heat affected zone on the retreating side. While at higher welding speed, the defect-free joint is fractured in the thermal mechanically affected zone on the advancing side.

  

جوشکاری اصطکاکی اغتشاشی صفحات AA 2219 نورد شده

Interface behaviours and mechanical properties of filling friction stir weld joining AA 2219 

رفتارهای فصل مشترک وخواص مکانیکی جوشکاری اصطکاکی اغتشاشی

پرکردن اتصال AA2219

ABSTRACT

Being brittle and having low thermal conductivity, refractories suffer damage and sometimes fail in service as a result of thermal shock. While the approach of those making fine-grained technical ceramics is to make their products sufficiently strong to withstand thermal stresses the refractory technologist is more cunning. He uses, often little known, devices to provide resistance to thermal shock that minimise but do not eliminate damage to the component. In this paper the basic equations of thermal conduction and elasticity are presented and followed by some immediate results that should guide the designer of components subject to severe thermal environments. The influence of size and shape of the refractory components is then discussed along with ways in which refractory producers can engineer the thermal and mechanical properties. In particular, the methods used to tailor fracture behavior to optimize the thermal shock resistance are treated in some detail.

  

سیلان مواد در طول جوشکاری اصطکاکی اغتشاشی Ti-6Al-V

Material Flow During Friction Stir Welding of Ti-6Al-4V

سیلان مواد در طول جوشکاری اصطکاکی اغتشاشی Ti-6Al-V

ABSTRACT

6 mm thick Ti-6Al-4V butt joints were produced with a tracer material embedded in the joint under a variety of process conditions, namely rotational speed and traversing speed, in an attempt to relate the welding process parameters to the material flow behavior via post weld radiographic and metallographic evaluations. It was found that by embedding refractory alloy powder into the joint line, welding through it, and subsequently x-raying the joint, the material flow patterns could be examined. The tracer material was distributed over a wider area in the weld zone relative to its starting position, implying a fair amount of mixing occurred even though little vertical movement of the tracer material was observed. There was minimal effect of material flow patterns as a function of welding parameters observed using the tracer material and radiographic examination, but defect formation in the root, where there was no tracer material, examined by cross sectional metallographic evaluations were found to be dependent on the rotational speed and traversing speed conditions. Lack of penetration defects were generally associated with relatively “cold” welding conditions (low rotational speed/high traversing speeds) and voids with “hot” conditions (high rotational speed/low traversing speeds).