Development of a novel multi-container technique for extruding wide-thin aluminium profiles with reduced force
File(s)
Author(s)
Lv, Jiaxin
Type
Thesis
Abstract
Large-scale wide and thin aluminium alloy components are essential in the transportation industry, with applications such as wing panels of aircraft, sidewalls and floor pans of trains and deck panels of vessels. Despite being one of the key manufacturing technologies, traditional extrusion technology has been limited to producing aluminium alloy products less than 800 mm wide due to the high extrusion force requirements. This results in the necessity for additional assembling operations and increased energy consumption for producing extra-wide components. Considering the demand for enhancement of energy saving and extruding ability for producing wide and thin profiles during extrusion process, innovations in extrusion technology become important and necessary.
The work in this thesis concentrates on the study of a novel extrusion technology from the proposal of concept to the industrial application. The aim of this research is to develop a new extrusion method, named multi-container extrusion to significantly reduce the extrusion force with respect to the conventional extrusion method. The specific objectives of this work include proposing the concept of multi-container extrusion, verifying its feasibility through experiments, analysing the manufacturing performance and potential extrusion issues using numerical modelling, and exploring possible industrial applications.
This research proposes, for the first time, multi-container extrusion technology, highlighting its key features of tooling design and the potential welding challenges between adjacent billets. To verify the feasibility of this technology, a three-container extrusion tooling set was designed and manufactured to extrude a 177 mm× 8 mm hollow profile. An extrusion system, comprising of a 300-tonne hydraulic press, tooling set and heating system, was established to conduct the three-container extrusion experiments under five different combinations of temperature and speed, namely 450 ℃/0.5 mm/s, 480 ℃/0.5 mm/s, 480 ℃/1 mm/s, 480 ℃/2 mm/s and 510 ℃/0.5 mm/s. The results indicated that the three-container extrusion method can greatly reduce the extrusion force up to only about 15% of that for the traditional porthole extrusion method. A set of microstructural observations and mechanical tests of the extruded profiles were then conducted which demonstrated that good weld quality was obtained during the three-container extrusion process.
To conduct a comprehensive analysis of the performance of the three-container extrusion process, finite element (FE) models were developed based on the extrusion tests and then validated by comparing with the experimental data. According to the simulated results, the metal flow behaviour during the three-container extrusion process was interpreted as five stages, namely separation stage and smooth flow stage where the material fills the upper die, welding chamber filling stage where the adjacent billets become bonded together and welding plane is formed, breakthrough stage and steady extrusion stage where the material flows through the die bearing and deformed into to the desired profile. The bonding quality on the welding plane was quantitively evaluated by combing the simulation and tensile testing results using Q and K criteria. The critical values of Q and K indices for achieving good weld quality were determined for different extrusion conditions. Furthermore, additional FE simulations were carried out by applying different tooling designs to investigate the effects of tooling on the performance of the multi-container extrusion process. By varying key design factors such as container diameter, upper die length and welding chamber length, the original extrusion tools were optimised to reduce the unevenness of the extrudate front shape by 75% and double the material yield.
Finally, two three-container extrusion cases were simulated and compared with an industrial practice where a 384 mm wide AA6N01 hollow structure was traditionally extruded by porthole extrusion with 7900 tonnes. The simulation results have shown that the three-container extrusion method only requires 15.8% of extrusion force (1521 tonnes) to produce the same 384 mm wide profile. On the other hand, about 3.5 times wide (1338 mm) profile can be produced using the three-container extrusion method with the same extrusion force of 7900 tonnes.
This study demonstrated that the proposed multi-container extrusion technology is feasible to produce well-welded profiles with significantly reduced extrusion force, and the multi-container extrusion performance can be easily controlled by optimising the tooling design. The proposed technology has the potential to improve the manufacturing capacity of extrusion press and offer a promising solution for fabricating wide, thin-walled aluminium alloy components with complex and hollow cross-sections required in the automobile, aerospace, marine, and architecture applications. Overall, this study provides valuable insights into the development and application of the multi-container extrusion technology, which can have a significant impact on the advancement of the extrusion manufacturing industry.
The work in this thesis concentrates on the study of a novel extrusion technology from the proposal of concept to the industrial application. The aim of this research is to develop a new extrusion method, named multi-container extrusion to significantly reduce the extrusion force with respect to the conventional extrusion method. The specific objectives of this work include proposing the concept of multi-container extrusion, verifying its feasibility through experiments, analysing the manufacturing performance and potential extrusion issues using numerical modelling, and exploring possible industrial applications.
This research proposes, for the first time, multi-container extrusion technology, highlighting its key features of tooling design and the potential welding challenges between adjacent billets. To verify the feasibility of this technology, a three-container extrusion tooling set was designed and manufactured to extrude a 177 mm× 8 mm hollow profile. An extrusion system, comprising of a 300-tonne hydraulic press, tooling set and heating system, was established to conduct the three-container extrusion experiments under five different combinations of temperature and speed, namely 450 ℃/0.5 mm/s, 480 ℃/0.5 mm/s, 480 ℃/1 mm/s, 480 ℃/2 mm/s and 510 ℃/0.5 mm/s. The results indicated that the three-container extrusion method can greatly reduce the extrusion force up to only about 15% of that for the traditional porthole extrusion method. A set of microstructural observations and mechanical tests of the extruded profiles were then conducted which demonstrated that good weld quality was obtained during the three-container extrusion process.
To conduct a comprehensive analysis of the performance of the three-container extrusion process, finite element (FE) models were developed based on the extrusion tests and then validated by comparing with the experimental data. According to the simulated results, the metal flow behaviour during the three-container extrusion process was interpreted as five stages, namely separation stage and smooth flow stage where the material fills the upper die, welding chamber filling stage where the adjacent billets become bonded together and welding plane is formed, breakthrough stage and steady extrusion stage where the material flows through the die bearing and deformed into to the desired profile. The bonding quality on the welding plane was quantitively evaluated by combing the simulation and tensile testing results using Q and K criteria. The critical values of Q and K indices for achieving good weld quality were determined for different extrusion conditions. Furthermore, additional FE simulations were carried out by applying different tooling designs to investigate the effects of tooling on the performance of the multi-container extrusion process. By varying key design factors such as container diameter, upper die length and welding chamber length, the original extrusion tools were optimised to reduce the unevenness of the extrudate front shape by 75% and double the material yield.
Finally, two three-container extrusion cases were simulated and compared with an industrial practice where a 384 mm wide AA6N01 hollow structure was traditionally extruded by porthole extrusion with 7900 tonnes. The simulation results have shown that the three-container extrusion method only requires 15.8% of extrusion force (1521 tonnes) to produce the same 384 mm wide profile. On the other hand, about 3.5 times wide (1338 mm) profile can be produced using the three-container extrusion method with the same extrusion force of 7900 tonnes.
This study demonstrated that the proposed multi-container extrusion technology is feasible to produce well-welded profiles with significantly reduced extrusion force, and the multi-container extrusion performance can be easily controlled by optimising the tooling design. The proposed technology has the potential to improve the manufacturing capacity of extrusion press and offer a promising solution for fabricating wide, thin-walled aluminium alloy components with complex and hollow cross-sections required in the automobile, aerospace, marine, and architecture applications. Overall, this study provides valuable insights into the development and application of the multi-container extrusion technology, which can have a significant impact on the advancement of the extrusion manufacturing industry.
Version
Open Access
Date Issued
2023-03-14
Date Awarded
01/06/2023
Advisor
Lin, jianguo
Shi, Zhusheng
Publisher Department
Mechanical Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)