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Forming and Fabricating Research Roundup

 Ellen Kehoe

 

 

 

 

 

 

 

By Ellen Kehoe
Senior Editor

As one of the three original topic areas (with material removal and manufacturing systems) for the North American Metalworking (later Manufacturing) Research Conference (NAMRC), and as a perennial focus that continues to evolve, material forming has a solid foundation at SME. Forming and fabricating as a segment of the SME Technical Paper library is nearly 800 papers from 1951 to present. Educational sessions at FABTECH add to the resources with industry user best practices.

The June 2014 International Manufacturing Research Conference, which co-located NAMRC, ASME’s Manufacturing Science and Engineering Conference (MSEC) and JSME’s International Conference on Materials and Processing (ICMP), featured several tracks on forming and fabrication aspects. Here are some of the 2014 highlights in anticipation of the upcoming June 2015 NAMRC-MSEC event hosted by the University of North Carolina at Charlotte.


Keynotes

Two MSEC keynote presentations on forming and joining were given by Prof. Dr.-Ing. Dr.-Ing. E.h. A. Erman Tekkaya of the Institute of Forming Technology and Lightweight Construction at the Technical University of Dortmund (Germany), discussing extrusion of multimaterial components, and Professor Toshihiko Kuwabara, Division of Advanced Mechanical Systems Engineering, Institute of Engineering, Tokyo University of Agriculture & Technology (Japan), on multiaxis stress tests on lightweight materials in support of material modeling and accurate sheet forming simulations.

The paper presented by Professor Tekkaya described three innovative extrusion processes for the manufacture of multimaterial parts: coextrusion of discontinuously steel reinforced aluminum profiles, composite extrusion of continuously steel wire reinforced profiles and composite rod extrusion. The embedded steel elements were not deformable for the first two processes but were both deformable in composite rod extrusion. In composite rod extrusion, the billet design also was evaluated to decrease scrap in the cross sections. Further experimental and numerical analysis will increase the flexibility of the processes for such applications as bumpers or stringers or locally reinforced forged parts as connecting rods (MSEC 2014 paper #4197).

A typical workpiece after hydroforming in 11 mm diameter die (W. Emblom et al., NAMRC 2014 paper #4497)

Professor Kuwabara presented mechanical tests to accurately measure the anisotropic plastic deformation behavior of metal sheets and tubes under multiaxis stresses. Measurement and modeling of lightweight metals commonly used in industry was particularly focused on, as well as validating the material models based on anisotropic yield functions for large plastic strain ranges. How material models used in metal forming simulations improve the predictive accuracy of forming defects was also discussed (MSEC 2014-#4002).

 

Modeling Forming Processes

Several NAMRC papers focused on modeling of forming processes, innovative forming methods and novel forming materials. University of Louisiana-Lafayette’s William Emblom and coauthors evaluated texture and surface roughness in multiscale open-die hydroforming, with the results useful for designing microscale hydroformed parts such as fuel cell bipolar plates, where roughness is a critical manufacturing issue (NAMRC 2014-#4497). 

Ghassan Kridli of the University of Michigan-Dearborn and coauthors from Ford Motor Company addressed formability prediction of aluminum sheet alloys under isothermal forming conditions. Determining the forming limit diagram (FLD), a tool used by automotive engineers to assess and compare the formabilities of sheet metals, becomes more time consuming in warm forming of aluminum sheets. A finite element based criterion is presented for predicting the FLD under isothermal conditions. The paper provides experimental validation for the predicted results using select automotive 5xxx series aluminum alloys. The findings indicate that the developed criterion can adequately predict the forming limit for each strain path (in press, Journal of Manufacturing Processes).

New Processes and Materials

Researchers from the Technical University of Darmstadt (Germany) presented a study on the performance of environmentally benign lubricants at elevated temperatures in bulk metal forming (cold forging). The authors concluded that previous investigations regarding the influence of the relative velocity on the tribological system could not only be verified for environmentally benign lubricants; however, the assumption was confirmed that temperature has a primary effect on reduction of the friction coefficient, making it possible to determine an ideal temperature for cold forging operations to improve the process (in press, Journal of Manufacturing Processes).
Phase distributions at the end of the forging process (S. Bruschi et al., NAMRC 2014 paper #4490)
Surface damage of polymer-coated sheet metal during forming was studied by Zalak Purohit, Ying Zhang and Jyhwen Wang from Texas A&M University (College Station). Prepainted sheet metals in building construction, packaging, appliance, transportation and automotive industries can sustain damage from tooling contact during forming. Various polymer coatings were subjected to bending under tension with sliding contact. It was found that coating damage was commonly caused by low coating strength, high contact pressure and poor lubrication. The experimental approach can be used to facilitate better tooling design and lubricant selection (in press, Journal of Manufacturing Processes).

Experiments and analysis of phase evolution in hot forging of dual-phase titanium alloys were discussed by Italian colleagues Stefania Bruschi, Gianluca Buffa, Antonino Ducato, Livan Fratini and Andrea Ghiotti. To reduce operational consumption and production costs in aerospace engineering, there is an increasing use of materials characterized by high specific resistance, such as titanium alloys. Hot forging allows the production of complex shapes with limited edge trim removal and machining rework needed afterward, taking into account the material characteristics of Ti-6Al-4V titanium alloy for adequate plasticity. The model presented in the paper was in good agreement with experimental findings, providing a viable design tool in complex hot forging processes of titanium alloys (in press, Journal of Manufacturing Processes). 

 

Twin-Roll Casting

Advanced casting and semisolid forming techniques were covered in two ICMP tracks. Toshio Haga and Hiroshi Fuse of the Osaka Institute of Technology added iron (Fe) or copper (Cu) to typical casting aluminum alloy (Al-11%Si) to model recycled Al-11%Si. Iron and copper impurities in recycled Al-11%Si come from recycling aluminum alloy automobile parts, which may contain unremoved iron bolts or copper from electrical parts, for example. The modified alloys were cast into strip on a twin-roll caster, then homogenized, cold rolled down to 1 mm and annealed before tension and cup testing of several mechanical properties (ICMP 2014-#4906).

In other papers, Haga, Watari Hisaki and other authors also investigated using a vertical-type tandem twin-roll caster with and without a scraper to cast aluminum alloy clad strip to save process time and energy consumption (ICMP 2014-#5003); cladding aluminum and magnesium alloys by using horizontal twin-roll casting (ICMP 2014-#4974); and sheet metal fabrication of magnesium alloy with high aluminum by twin-roll casting (ICMP 2014-#4992).

SME Journals and Technical Papers

Peer-reviewed research articles touching on forming and fabricating areas are regularly found in SME’s Journal of Manufacturing Processes (now SCI indexed!), Journal of Manufacturing Systems and Manufacturing Letters. JMP published a special issue on advances in material forming in 2013.

With more than 16,000 papers and presentations online, SME’s Technical Paper collection of manufacturing knowledge is the largest of its kind. Find papers on best practices, advancements and industry trends. Add your insights to help others Learn More & Do More.

For more information on NAMRC, MSEC or ICMP papers, contact ekehoe@sme.org.  


Published Date : 3/18/2015

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