الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
During operation in aluminum extraction cells, the anodic yoke is exposed to high temperatures and harsh operating conditions that effect on it and cause many distortions, whether a decrease in the diameter of the Pins, a decrease in the length of the pins, or a fracture of the pins, making it not conform to international standards and a maintenance process must be carried out to rehabilitate it and use it again in the production process of anodic conductors. There are two aspects to the problem, which are that during the passage of the electric current in the welding area, it is exposed to a loss in voltage, and this raises the economic cost of extracting aluminum metal, as well as the welding process itself and the attendant damages and risks. Hence the need for this project arose, which is the application of a new welding technology with its advantages of saving voltage losses and eliminating or reducing the risks that arise from traditional welding methods at aluminum. There are two purposes to this thesis, the first purpose was to deals with the challenging interdisciplinary task of combining the design and assembly of a rotary friction welding (RFW) machine to be used for welding a complex geometrical part of the anodic yoke in the aluminum industry, and the second was to perform pins welding and to determine the variables and gaine the best understaning to their potentially reverse effects on welding quality. An inclusive experiential testing program was undertaken to identify and optimize the variables and their effects. This thesis comprises of two main branches. The first branch in which a semi-industrial model of a machine with a small capacity was designed and manufactured to perform welding on 40 mm diameter wires to investigate the possibility of welding low-carbon steel by friction and conducting tests to see the feasibility of the project. The results showed that the electrical resistance of friction welded joints is equal to the original unwelded samples and much less than that of the fusion welded joints. In the second section of the work, a force platform with a rigid system for a consistent welding result was designed and built, and the effect of welding variables, rotation speed, the forging pressure, and forging time was studied. Regarding the welded stubs beside Virtual examination of the joints, electric resistance, and mechanical properties have been measured. The experiment results confirmed that the friction welded yoke pins (joints) have a mechanical properties better than those of fusion welded samples. It was cleared that the tensile strength of the joints welded by friction welding increased with the increasing of rotational speed, with the pressure increase, and with the compression time increase. For example at a pressure of 45 MPa, rotatione speed of 500 rpm and a compression time of 15 seconds the tensile strength was equal to 410 Mpa, while the tensile strength increased to reach to reach 635 MPa when the pressure was increased to 75 MPa, with a rotatione speed equall to 1800 rpm, and the compression time was 50 seconds. The microscopic examination of the samples and corelating them to the results of the mechanical properties measurements showed that the mechanical features increase with increasing the amount of perlite and the fineness of the grains, as the greater the amount of pearlite and the finer the grains that constitute the microstructure, the greater the tensile strength of the weld joint increases.
Regarding the electrical properties of the welded part, which is the most important issue is, as the voltage DROP through the welded part affects the total voltage through the anode and thus the amount of electricity consumed, Friction welding has been determined to not cause an additional voltage DROP than the original alloy because of complete diffusion between welded parts, no filling material or voids or impurities in the welding area and no presence of a micro space between the welded parts as in case of conventional welding. This economic beneficial will return to the company, as more defective yokes will be welded and will not be executed, and several yokes that were previously executed will be reused. In addition, the number of new forks that are purchased annually, estimated at about 2000 yoke, will be reduced. The total saving is about 24000000 Egyptian pounds per year.