Page 18 - MetalForming September 2009

Robotic
Gas Tungsten Arc
Welding
...does it make sense for your metalforming company?
BY GEOFF LIPNEVICUOUS
As the allegory of the tortoise and the hare goes, the turtle wins the race by moving slowly and steadily, while the losing hare travels more quick- ly but stops frequently for breaks. Many people live by the saying, “slow and steady wins the race.”
The gas-tungsten-arc-welding (GTAW) process is similarly slow and steady, and precise. The quality of the weld— not how long it takes to complete the weld—often is the primary considera- tion when using this welding process. Skilled GTAW welders earn some of the industry’s highest wages, due to the precision and skill demanded by this manual technique.
However, as the metal-fabrication industry continues to deal with the
Geoff Lipnevicuous is manager, product development, automation division, The Lincoln Electric Co., Cleveland, OH: 216/481-8800; www.lincolnelectric.com.
Key benefits of robotic GTAW welding include repeatable, precise heat control and exact penetration to meet challenging quality standards, and on-the-fly pro- cedure adjustment, for automatic switching of procedures between thick and thin applications.
shortage of skilled welders, and at the same time manufacturers seek to increase productivity without compro- mising quality, they frequently turn to automating their welding operations. Becoming more common is the imple- mentation of robotic GTAW, bringing speed and productivity gains to users of this precise welding process.
Benefits of GTAW
The primary benefit of the GTAW process is the high-quality welds it deposits with nearly all types of metal alloys. While carbon steel, stainless steel and aluminum-alloy applications are commonplace, the process also works with more exotic materials such as alloys of titanium, zirconium, columbium, and tantalum, as well as austenitic nick-
el-chromium-based superalloys. These materials find use in the aerospace, mil- itary, motor sports, nuclear, pipe, power- generation industries, as well as for general maintenance and repair appli- cations. The common thread among these industries: Manufacturers typi- cally employ thin-gauge, high-per- formance materials that exhibit some combination of superior mechanical, electrical and thermal properties. They require consistent and precise weld pen- etration, and repeatable control of many factors, including weld travel speed, shielding-gas coverage, temperature control, and precise heat control to avoid shrinkage and distortion.
The GTAW process produces a narrow heat-affected zone (HAZ), which in turn reduces solidification stress cracking
16 METALFORMING / SEPTEMBER 2009
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