- Title
- Friction welding of thin walled zircaloy-4 tubes for the nuclear industry
- Creator
- Koloi, Nthatisi Dinah
- Subject
- Friction welding Zirconium alloys
- Date Issued
- 2017
- Date
- 2017
- Type
- Thesis
- Type
- Masters
- Type
- MEng
- Identifier
- http://hdl.handle.net/10948/18794
- Identifier
- vital:28724
- Description
- This work reports on the process development of solid state welding as an alternative joining process for assembling Zircaloy-4 fuel rod components for the nuclear industry. A typical fuel rod consists of a thin tube that is blocked at both ends by end-caps. The welding of the thin wall tubes onto the end-caps is currently accomplished by employing fusion techniques. Due to limited thin wall Zircaloy-4 tube supplied, preliminary welding was initially performed with thin wall 316L stainless steel tube for the development of a joint geometry and establishment of an experimental welding and testing setup. A suitable joint geometry that would achieve higher static strength equal or above that of the parent material, as well as complete circumferential bonding was investigated through welding a tube on different volume interface geometries of the end-caps. Higher joint efficiency was obtained from a tube-to-tube joint geometry that allowed sufficient frictional heat input at the interface. Consequently, the successful joint geometry was employed to develop a friction welding process for the joining of thin wall Zircaloy-4 tubes. The influential process parameters, axial force, rotational speed and upset distance were varied during the investigation. The completed weld joints were evaluated by visual, metallurgical and mechanical means. Successful welds showed complete circumferential bonding and high joint efficiency that was above the parent plate material as well as parent tube material. The evaluation of the microstructure showed transformation of grain structure on the heat affected zone (HAZ) and friction weld zone when compared to the parent materials. Even though, this work could not resolve inner flash formation, there is enough evidence that friction welding can be used for assembling fuel rod components in the nuclear industry.
- Format
- xii, 98 leaves
- Format
- Publisher
- Nelson Mandela Metropolitan University
- Publisher
- Faculty of Engineering, the Built Environment and Information Technology
- Language
- English
- Rights
- Nelson Mandela Metropolitan University
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