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Abstract: A
two-dimensional model of friction stir welding is established to study
the distributions of the longitudinal residual stress and the material
flow under different process parameters. In the friction stir welding
process, the tangent flow constitutes the major part in material flow.
The faster material flow occurs on the retreating side. In the tangent
flow, the flow direction is not simple and there may exist a swirl in
the material flow on the advancing side. With the increase of the
translational velocity and the angular velocity of the pin, the flow
becomes faster on the retreating side. But in the region where the
material velocity is smaller, the effect of the variation of the process
parameters is not clear. The maximum longitudinal residual stress occurs
on the boundary of the heat affected zone and the longitudinal residual
stress is positive near the welding line but negative near the
boundaries of the welded plate. The maximum longitudinal residual stress
can be increased with the argument of the translational velocity of the
pin. But the change of the angular velocity of the pin does not affect
the longitudinal residual stress significantly.
Key words:Friction
stir welding Residual stress Material flow Finite element simulation
CLC No: TG404
国家自然科学基金(10302007，10225212，10421002)、国家重点基础研究发展计划(2005CB321704)及长江学者和创新团队发展计划资助项目.
Received 20050618, received in revised form 20060110
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