The Application Of Strategic Cooling Technique In Bobbin Friction Stir Welding To Improve Weld Strength
Bobbin Friction Stir Welding (BFSW) is a welding technique which utilizes welding (travel) and spindle speed of the tool by passing it through the welding plates to form a weld joint. The bobbin tool is a unique tool which has upper and lower shoulders, which results in a better weld joint as compar...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2021
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| Subjects: | |
| Online Access: | http://eprints.utem.edu.my/id/eprint/26841/1/The%20Application%20Of%20Strategic%20Cooling%20Technique%20In%20Bobbin%20Friction%20Stir%20Welding%20To%20Improve%20Weld%20Strength.pdf http://eprints.utem.edu.my/id/eprint/26841/2/The%20Application%20Of%20Strategic%20Cooling%20Technique%20In%20Bobbin%20Friction%20Stir%20Welding%20To%20Improve%20Weld%20Strength%2024%20pages.pdf |
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| Summary: | Bobbin Friction Stir Welding (BFSW) is a welding technique which utilizes welding (travel) and spindle speed of the tool by passing it through the welding plates to form a weld joint. The bobbin tool is a unique tool which has upper and lower shoulders, which results in a better weld joint as compared to Conventional Friction Stir Welding (CFSW). However, BFSW process still generates a lot of heat due to high frictional force from the spinning Bobbin tool. Such condition reduces the overall strength of the weld joint. In this research, an experiment will be conducted to study the effects of introduction of coolant during the welding process using Minimum Quantity Lubricant (MQL) concept. By introducing small amounts of liquid in the form of mist, it was expected to increase the strength of the weld joints. 2 constant parameters, which are spindle speed and welding (travel) speed were kept at 1250 rpm and 110 mm/min respectively. A varying parameter, liquid flow rate, have 3 different levels of 1, 3 and 7 mL/min. It was found that using a liquid flow rate of 7 mL/min gives the best result overall result. The temperature during the welding process dropped the most when compared to the other 2 sets. The ultimate tensile strength obtained was very high, which is 189.11 MPa. This means that crystallization in the stir zone is better when the weld joint was cooled, as heat was less likely to dissipate to other places. However, the average microhardness was 48.8 HV, which is the lowest among the 3 flow rates. On the other hand, using liquid flow rate of 1 mL/min produces the least ultimate tensile strength at 94.52 MPa. The average microhardness is the highest at 49.0 HV. It can be concluded that using higher amounts of liquid introduction during BFSW will help strengthen the weld joints. |
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