الفهرس 
chapter 1Only 14 pages are availabe for public view
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Abstract
The friction welding of similar and dissimilar aluminum and
copper pipes joints are very important. As some of these
welded joints are used in very critical applications such as
aerospace, nuclear power plants, cryogenics, rocket fuel
systems, petroleum, ship-building and automotive industries.
Therefore the weld strength and joint interface properties are
extremely important because failure of these parts during
service can lead to huge losses. Friction welding of the
dissimilar materials is more complicated compared to similar
materials due to differences in physical, mechanical, chemical
and thermal properties. The fusion welding processes are
undesirable in welding these material combinations. The
friction welding, the low welding temperatures, short welding
times and energy saving involved in this method allow a much
higher quality to be achieved in those pipes welded joints.
In the present investigation, attempts have been made to
explore the quality of similar aluminum pipes welded joints
using the friction welding technique. In this direction the
process parameters including; rotational speed, welding time,
and friction force were investigated for two types of similar
aluminum joints and also dissimilar aluminum/copper joints.
Also attempts have been made to eliminate formation of inner
and outer flashes during friction welding process of dissimilar
aluminum/copper pipes joints. Present work succeeded in
introducing a simple and smart technique named (Die
Modification Technique) to eliminate inner and outer flashes
of dissimilar aluminum/copper pipes joints. Evaluation of the
pipes welded joints was performed using tensile strength and
axial shortening (burn-off) measurements.
The results demonstrated the importance of managing the
process parameters during friction welding of similar
aluminum pipes joints to produce joint with enhanced
properties. Moreover, the Die Modification Technique shows
an effective tool for flashes elimination especially in small
diameter pipes joints and opens a new field for welding
dissimilar pipes with limited axial shortening and with
remarkable strength.