Improved GMAW/FCAW for Primed Steel and Aluminum (2013-453) (2015-443)
- Applied Thermal Sciences
- Robotic Technologies of Tennessee
July 2013 - July 2015
NSRP ASE Investment: $527K
Industry Investment: $168K
To take advantage of advances in welding power supplies by developing parameter sets for Gas Metal and Flux Core Arc Welding that will provide enhanced cathodic cleaning for primed steel and aluminum, resulting in higher speeds and higher quality welds.
This project addressed quality and productivity problems associated with welding through Pre-Construction Primers (PCPs) and in welding of aluminum. Most shipyards use PCPs to mitigate rusting during in-process operations. PCPs are inherently at odds with welding processes, and many yards spend extra time removing PCPs in way of welding, especially mechanized welding, to improve quality and productivity. Semi-automatic processes suffer from the same problems.
This project investigated and developed new parameter sets for advanced welding power supplies that enable “on-the-fly” breakdown of PCP’s during welding. Through the efforts of Team Partner RTT, these procedures were applied to crawler robots, expanding the opportunities for higher-productivity welding in unstructured (i.e., non-panel-line) areas, and allowing smaller yards to take advantage of robotic welding without the need to invest in high-capital cost gantries and panel lines.
Additionally, aluminum welding is often plagued with lack of fusion and porosity problems requiring frequent rework. These problems are caused most often by oxides and other contaminants of the base metal surfaces, and exacerbated by the low melting point and fast solidification of the aluminum alloys. A similar technical approach was used to provide “on-the-fly” removal of surface contaminants on aluminum butt and fillet welds.
The goal of this project was to improve the quality and speed of welding on PCP-coated steels and aluminum structure. The availability of these parameter sets in shipyards will provide improvements in throughput and reductions in total costs. Itemized benefits include:
- Higher levels of automation/mechanization will be enabled;
- Time spent removing primers will be reduced or eliminated;
- Workers will be more productive and gain greater satisfaction from achieving higher levels of “first-time quality”;
- Rework will be reduced;
- Since rework involves adding weld, net distortion will be reduced;
- Costs will be reduced; and
- Schedule performance will be improved.
Request Final Report from NSRP– Limited Distribution Authorized to U.S. Shipbuilding and Repair Industry and NSRP ASE Program Representatives
Point of Contact:
Gaylene McHale, Ingalls Shipbuilding