The Fabricator: Could GTAW hot-wire go mainstream?
Consider an automated pipe welding application. Most likely you’d use a wire-fed gas tungsten arc welding (GTAW) process for the root pass, then stop and switch to a flux-cored arc welding (FCAW) or submerged arc welding (SAW) process for the fill and cap passes. You’d do this by either moving the pipe to a separate weld station or by swapping out the power sources and torch setup
It’s a common procedure, to be sure, but it does take time. Thing is, why not just keep the automated GTAW power source, wire feed, and torch—and heat the wire instead of using separate processes for the root and fill passes? Why not just use the GTAW hot-wire (GTAW-HW) process? It’s not a far-out notion considering the historical success of GTAW-HW in the oil and gas industry, particularly with cladding.
Sure, this doesn’t apply to certain pipe welding applications, and GTAW-HW can’t outpace the deposition rates of, say, twin or tandem SAW. But it’s really not a simple matter of one welding process outpacing another. Keeping the same equipment for all weld passes in a pipe weld eliminates changeover, simplifies operator training, and takes up less floor space.
Low deposition rates and slow travel speeds have been GTAW’s Achilles’ heel. Across manufacturing, if a plant has automated its GTAW, via robotics or otherwise, it’s likely because stringent weld quality requirements demand it and throughput requirements are too great for manual processes. But GTAW need not be slow, and therein lies GTAW-HW’s true potential.
Read more at The Fabricator: https://www.thefabricator.com/article/arcwelding/could-gtaw-hot-wire-go-mainstream