Development and process verification of a linear friction welding platform for small Ti6AI4V coupons
- Mohlala, Narishe Taetso Arnold
- Authors: Mohlala, Narishe Taetso Arnold
- Date: 2020
- Subjects: Friction welding , Pressure welding
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/46196 , vital:39513
- Description: This thesis reports on a study conducted to establish the feasibility of implementing linear friction welding as a joining technique for small Ti6AI4V coupons. The main of this project is to facilitate the manufacturing of high-integrity near-net-shape components for aerospace, automotive and medical appliances. LFW is a solid-state welding technique that uses frictional heat generated by the rubbing of surfaces under an axially applied load, thereby forming a weld at temperature below beta tranus. This technique is advantageous as it has the potential to reduce defeats normally associated with conventional welding of this material. The first part of the study will describe the development of an experimental platform to facilitate the evaluation of the influence of selected process parameters on joint integrity.
- Full Text:
- Date Issued: 2020
Development and process verification of a linear friction welding platform for small Ti6AI4V coupons
- Authors: Mohlala, Narishe Taetso Arnold
- Date: 2020
- Subjects: Friction welding , Pressure welding
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/46196 , vital:39513
- Description: This thesis reports on a study conducted to establish the feasibility of implementing linear friction welding as a joining technique for small Ti6AI4V coupons. The main of this project is to facilitate the manufacturing of high-integrity near-net-shape components for aerospace, automotive and medical appliances. LFW is a solid-state welding technique that uses frictional heat generated by the rubbing of surfaces under an axially applied load, thereby forming a weld at temperature below beta tranus. This technique is advantageous as it has the potential to reduce defeats normally associated with conventional welding of this material. The first part of the study will describe the development of an experimental platform to facilitate the evaluation of the influence of selected process parameters on joint integrity.
- Full Text:
- Date Issued: 2020
Friction stir welding of thin section aluminium extrusions for marine applications
- Authors: Chikamhi, Prince Philhelene
- Date: 2020
- Subjects: Friction welding , Welding
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/46030 , vital:39410
- Description: This dissertation focuses on the development of a welding extrusion feeder, tool and schedule for implementation of defect-free butt welds on long, thin and complex-shape aluminium extrusions, as used by the marine industry. Viability of employing Friction Stir Welding (FSW) as a welding technology for joining long extrusions with a short-bed and bolt-on feeder to facilitate onsite fabrication of flat structures in shipbuilding is evaluated. An FSW feeder, tool and process control unit were designed, developed and integrated with an existing FSW platform, to facilitate implementation of continuous welds. Weld data acquired from literature review, experimentation, mechanical testing and metallographic analysis was used in design considerations for the development of a feeder. Subsequently, butt welds were implemented successfully on long 3 mm AA6082-T6 extrusions, during continuous FSW on the feeder. A specially adapted tool, the Floating Bobbin Tool, used with the feeder to implement butt welds was designed and developed from literature tool heuristics and weld trials. The tool eliminated the need for a backing bar and enabled tool-workpiece auto-alignment, beneficial with thin-section extrusions. Effect of rotational and weld speed and tool geometry of two tools (Tool 1 and 2), on weld forces and quality was tested, to establish optimum parameters for attaining high quality welds. Tool geometry had a profound effect on weld forces and integrity; Tool 2 welds exhibited superior and consistent weld quality, meeting maritime rules and standards and proving the adequacy of using FSW for joining long thin extrusions. Feeder process control, automation and optimisation, was implemented by process control unit devices, in addition to force and position control provided by the existing FSW platform. Owing to process control, automation and optimisation during continuous FSW of thin long and complex-shape aluminium extrusions, welding setup times and process variations are minimised and chances for defect-free welds increased, boosting production and cost savings in large panel fabrication in shipbuilding.
- Full Text:
- Date Issued: 2020
- Authors: Chikamhi, Prince Philhelene
- Date: 2020
- Subjects: Friction welding , Welding
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/46030 , vital:39410
- Description: This dissertation focuses on the development of a welding extrusion feeder, tool and schedule for implementation of defect-free butt welds on long, thin and complex-shape aluminium extrusions, as used by the marine industry. Viability of employing Friction Stir Welding (FSW) as a welding technology for joining long extrusions with a short-bed and bolt-on feeder to facilitate onsite fabrication of flat structures in shipbuilding is evaluated. An FSW feeder, tool and process control unit were designed, developed and integrated with an existing FSW platform, to facilitate implementation of continuous welds. Weld data acquired from literature review, experimentation, mechanical testing and metallographic analysis was used in design considerations for the development of a feeder. Subsequently, butt welds were implemented successfully on long 3 mm AA6082-T6 extrusions, during continuous FSW on the feeder. A specially adapted tool, the Floating Bobbin Tool, used with the feeder to implement butt welds was designed and developed from literature tool heuristics and weld trials. The tool eliminated the need for a backing bar and enabled tool-workpiece auto-alignment, beneficial with thin-section extrusions. Effect of rotational and weld speed and tool geometry of two tools (Tool 1 and 2), on weld forces and quality was tested, to establish optimum parameters for attaining high quality welds. Tool geometry had a profound effect on weld forces and integrity; Tool 2 welds exhibited superior and consistent weld quality, meeting maritime rules and standards and proving the adequacy of using FSW for joining long thin extrusions. Feeder process control, automation and optimisation, was implemented by process control unit devices, in addition to force and position control provided by the existing FSW platform. Owing to process control, automation and optimisation during continuous FSW of thin long and complex-shape aluminium extrusions, welding setup times and process variations are minimised and chances for defect-free welds increased, boosting production and cost savings in large panel fabrication in shipbuilding.
- Full Text:
- Date Issued: 2020
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