Friction Stir Welding and Processing IX: Industrial Applications
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Shaping and Forming Committee
Program Organizers: Yuri Hovanski, Brigham Young University; Rajiv Mishra, University of North Texas; Yutaka Sato, Tohoku University; Piyush Upadhyay, Pacific Northwest National Laboratory; David Yan, San José State University
Thursday 8:30 AM
March 2, 2017
Location: San Diego Convention Ctr
Session Chair: Anthony Reynolds, University of South Carolina; Lars Cederqvist, SKB
8:30 AM Keynote
Growth of Friction Stir Welding and Processing: Contributions of Murray W. Mahoney: Rajiv Mishra1; 1University of North Texas
Friction stir welding and processing has grown tremendously in just over two decades after invention. The publications have grown from a handful in 1998 to approaching 1000/year in the period of 2014-2016. In this period, very few researchers had impact on both technological and scientific aspects; and Murray Mahoney contributions stand out. In this overview presentation, an effort has been made to link key scientific developments in the field of friction stir welding and processing with publications of Murray Mahoney. From the very first paper publishing detailed measurements of temperatures during friction stir welding to a paper documenting the effect of very long term (~53000 hours) natural aging, it has been a remarking set of contributions. In recent years, he continues to lead efforts on developing friction stir welding of high temperature materials with very systematic tool studies; a hallmark of his entire involvement in this field.
9:10 AM Invited
Industrial Application of FSW at HFW: Bryan Tweedy1; 1HFW
Friction stir welding use is growing rapidly among industrial users especially recently with the expiration of the TWI patent. HFW Solutions has been using FSW in a production setting for 9 years across 4 machine platforms, large and small and in many different alloys and metal combinations. Production applications at HFW range from small size relatively high volume (80k parts/year) to large size at 50+ feet and lower volume (300 parts/year). Engineers have used FSW to design products with tailored properties using alloys where high strength may be required in one area and high corrosion resistance is required in another. Many programs focus on pin tool design and process parameters where machine interaction, fixture interaction and prototyping are not addressed. These three factors prove to be equally important and the implementation of one application is presented. A review of the diverse applications and the implementation into production is provided.
9:30 AM Invited
Friction Stir Welding Parameter Development of AA7075 for Hot Stamping Applications: Francois Nadeau1; Nia Harrison2; 1National Research Council of Canada (NRC); 2Ford Motor Company
In order to compete with advanced high strength steels in structural parts, automotive manufacturers are looking to introduce high strength aluminum alloys like AA7075 which have high peak-aged mechanical properties. Formability of these high strength aluminum alloys is possible through hot stamping. A further weight reduction of an aluminum blank is possible using tailor welded blank (TWB) sections throughout the B-pillar which can lead to weight reductions between 10-12%. Friction stir welding, as a solid-state welding process, has already been proven suitable without hot cracking issues for welding AA7075 aluminum alloy. However, abnormal grain growth (AGG) issues arise when post-weld operations at high temperature are required such as solution heat treatment or hot stamping operations. This paper relates the development of friction stir welding procedures and process parameters which will be adapted to hot stamping to join effectively AA7075-T6 tailor welded blanks.
9:50 AM Cancelled
Friction Stir Welding, Development Approach and Feedback for Aerospace Applications: Amarilys Ben Attar1; Jean-Pierre Bonnafé2; 1Institut de Soudure; 2Airbus Safran Launchers
In the scope of Airbus Safran Launchers R&T program, friction stir welding has been evaluated for the assembly of large cylindrical structures (tank, inter-tank and inter-stage structure) in replacement of TIG welding. Indeed, friction stir welding enables to overcome many problems associated with conventional welding processes for the joining of aluminium alloys. The development of process parameters has been performed and representative propellant tank demonstrators have been successfully manufactured for further testing. This study demonstrated the relevance of friction stir welding for this assembly and the TRL-5 has been achieved. FSW is now a major joining technology for the assembly of many parts in the next European Launcher Ariane 6 programme. Laboratory qualification and industrial test bench definition are now in progress.
10:10 AM Break
A Novel Approach for Joining EN AW 1070 Stranded Wire and EN CW 004A Contact Elements by Friction Stir Spot Bonding: Anna Regensburg1; René Schürer1; Jean Pierre Bergmann1; Helmut Steinberg2; Jan Ansgar Gerken1; 1Technische Universität Ilmenau; 2Nexans Autoelectric GmbH
The increasing demand for comfort and safety features leads to a rising amount of electronic components in modern vehicles. As a consequence, copper is increasingly substituted by aluminum, which raises the challenges for conventional joining technologies especially for stranded wire connections. In this case, the use of aluminium leads to larger cable cross sections in order to obtain constant electrical properties, which limits the applicability of technologies like crimping and ultrasonic welding. Therefore, a new friction based process was developed, which enables the joining of EN AW 1050 59mm² stranded wire to EN CW 004A contact elements by friction stir spot welding. By positioning the strand in line to the tool axis and into a cap-like contact element, this process enables joining the end face of the strand to the contact element without excessive cable deformation, so that the energy transport can take place throughout the whole cable cross section.
Joining Al 6061 to ZE41A Mg Alloy by Friction Stir Welding Using a Cold Spray Transition Joint: Todd Curtis1; Victor Kenneth Champagne, III2; Michael West1; Christian Widener1; 1South Dakota School of Mines and Technology; 2University of Massachusetts
The joining of highly dissimilar metals such as aluminum and magnesium has proven to be a difficult challenge using most of the technologies available today. This paper presents a novel method to join dissimilar materials using a combination of two advanced metals processing technologies, friction stir welding (FSW) and cold spray. By utilizing both technologies the strengths of each can be employed, while at the same time mitigating otherwise disqualifying aspects if used alone. In this study, cast ZE41A-T5 magnesium was joined to wrought 6061 aluminum. The joint was accomplished by first cold spraying a 6061 transition zone onto the magnesium alloy, followed by FSW of a 6061 plate to the cold sprayed 6061 zone. Utilizing this method, the formation of detrimentally thick intermetallic layer between the aluminum and magnesium was avoided, providing a resultant joint which matched the strength of the magnesium cast alloy. Detailed materials characterization by electron and optical microscopy, along with mechanical test results is presented. Comparisons to conventional joining techniques and potential applications of this technique is discussed.
11:10 AM Invited
Refill Friction Stir Spot Welding Aerospace Aluminum Alloys: Enkhsaikhan Boldsaikhan1; Shintaro Fukada2; Mitsuo Fujimoto2; Kenichi Kamimuki2; Hideki Okada2; Brent Duncan1; Brian Brown1; 1Wichita State University; 2Kawasaki Heavy Industries
Refill Friction Stir Spot Joining (RFSJ) developed by Kawasaki Heavy Industries (KHI) is a derivative technology of friction stir spot welding for joining aerospace aluminum alloys. The aerospace aluminum alloys were previously considered not weldable using conventional fusion welding methods. RFSJ does not consume any filler materials so that no additional weight is introduced to the assembly. As the solid-to-liquid phase transition is not involved in RFSJ in general, there is no lack of fusion or material deterioration caused by liquefaction and solidification. Unlike the conventional friction stir spot welding, RFSJ produces a spot joint with a perfectly flush surface finish without a key/exit hole. KHI has advanced the original friction stir spot welding concept and developed a robotic system that is capable of producing refill friction stir spot joints. The goal of this study is to demonstrate process parameter optimization of RFSJ for baseline aerospace aluminum alloys.
Effect of Tool Runout in Friction Stir Welding of Aluminum Alloy for Structural Applications: Luqman Hakim Ahmad Shah1; Shi Hui Guo1; Scott Walbridge1; Adrian Gerlich1; 1University of Waterloo
This paper investigates the effect of tool runout in mitigating root defects in friction stir welding (FSW) of aluminum alloy. Samples were butt joined parallel to rolling direction, using a threaded, tapered, 3 flats tool pin with various runout parameters. The weld speed and tool rotation was optimized to eliminate visible defects. A high speed camera was employed to capture the tool runout motion during the FSW process. The samples microstructure was characterized using optical microscopy and scanning electron microscopy. The results of tool runout effect on the weld quality and its mechanism were discussed accordingly. It can be concluded that the tool runout technique is an effective method to mitigate root defects.