Equipment Furthers Welding Research Discoveries Adding to the body of knowledge about welding requires a variety of specialized equipment The work welding researchers do requires the use of a variety of specialized equipment in addition to power sources, wire feeders, filler metals, shielding gases, lasers, robots, computer numerical controls, and other more or less commonplace types of welding equipment and consumables. Depending on their areas of interest, researchers need equipment that can, among other things, simulate the conditions that occur during welding, see into the welds and base metals, monitor the welding process, and test the welds for a variety of conditions. The goal of these researchers’ work is to not only add to the body of knowledge about welding in general, but also discover solutions to problems and develop methodologies that will eventually find their way out of academia or government laboratories and into the private sector. The Welding Journal asked some prominent researchers to detail some of the special equipment they use and why they are useful, outline breakthroughs accomplished, and for their equipment “wish list.” Lehigh University The research at Lehigh University, Lehigh, Pa., “addresses fundamental issues of weldability and properties — mechanical properties and corrosion resistance — of fusion welds in advanced engineering alloys,” explained John N. DuPont, the R. D. Stout Distinguished Professor of Materials Science & Engineering and Associate Director of Lehigh’s Energy Research Center. “Our group also conducts research in additive manufacturing. Much of our research is conducted through the National Science Foundation Manufacturing and Materials Joining Innovation Center (M2aJIC),” for which DuPont is the Lehigh site Director. The university’s welding-related facilities and infrastructure are concentrated in six areas: microstructural characterization; thermal analysis, heat treating, high-temperature corrosion; mechanical testing; additive manufacturing; and microstructural modeling. “The Electron Microscopy Laboratory at Lehigh University houses one of the most advanced suites of electron microscopes in the world and includes four scanning electron microscopes (see boxed item, page 52), two transmission electron microscopes, two scanning transmission electron microscopes (STEMs), one focused ion beam instrument, and an electron microprobe,” DuPont said. The pride of the facility is a JEOL JEM-ARM200CF aberration-corrected STEM, a state-ofthe art instrument purchased through a National Science Foundation MRI grant — Fig. 1. This atomic resolution electron microscope has among the best resolution in the world. The university also houses a modern light optical microscopy lab with a full range of reflection, transmission, polarized light, dark field, bright field, and Nomarski optical microscopes, as well as a Leco 2001 quantitative image analyzer. DuPont manages a complete welding laboratory with equipment for arc and laser welding, preparation of experimental alloys, weldability testing, and welding simulation. The lab also houses a Gleeble 3500 high-temperature thermo-mechanical simulator for a wide range of welding simulation and phasetransformation studies (see boxed item). In addition, DuPont said, “The Gleeble system has a high-speed dilatometer that is ideally suited to detect and measure phase transformation temperatures under the high heating and cooling rates associated with welding.” Also available is a varestraint tester for solidification cracking studies and a Thermonetics welding calorimeter for conducting transfer efficiency measurements. According to DuPont, the university has made a significant investment in developing a state-of-the-art Additive Manufacturing (AM) laboratory. Students, faculty researchers, and staff have access to this centralized facility. “The facility has capabilities for all major forms of additive processes,” DuPont explained. “As a central campus facility for AM, the laboratory also serves as a site for industry partners 50 WELDING JOURNAL / JULY 2016 BY MARY RUTH JOHNSEN Fig. 1 — This atomic resolution electron microscope offers some of the highest resolutions in the world.
Welding Journal | July 2016
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