Shipyards typically use submerged arc welding (SAW), flux cored arc welding (FCAW) or gas metal arc welding (GMAW) to fabricate butt joints in thick steel plate. But there are drawbacks to these traditional welding methods, such as the necessity for weld joint preparation. In addition, multiple welds are often required to fill the joint. Now, there’s another option that can weld thicker plates in a single pass without any joint preparation – buried arc GMAW.
As the name suggests, buried arc GMAW is a variation on gas metal arc welding. The technique relies on a high-current, low-voltage electrical arc to penetrate deep beneath the surface of the base material.
Many heavy industrial applications are well-suited for buried arc GMAW, from construction equipment to offshore wind towers. EWI is participating in a two-part project funded by the National Shipbuilding Research Program – Advanced Shipbuilding Enterprise to demonstrate, implement, and validate the use of buried arc GMAW for shipboard production. The technology needs to be portable and to yield high-quality welds aboard a ship to supplant work usually done in a machine shop.
In the first project, the team used buried arc GMAW technology and equipment developed by OTC DAIHEN for two primary applications – butt joints in ½-inch thick DH36 steel plate and in 3/8-inch thick EH36 steel plate. Mechanical testing of two tensile specimens, two face bend specimens and two root bend specimens confirmed that buried arc GMAW met the U.S. Navy’s requirements.
During the second project, the buried arc GMAW system will undergo implementation trials in Seattle with a shipyard’s staff and weld tractor system. The goal is to demonstrate to a team of managers, foremen, and welders how the technology works and its usefulness to their operation.
The goal of these two projects is to demonstrate the benefits of buried arc GMAW compared to conventional multi-pass welding: The consistent ability to weld thick metal plate in one pass will lead to increased efficiency and reduced weld time and cost.
Questions about buried arc gas metal arc welding? Contact Jim Hansen, Project Engineer for arc welding and directed-energy deposition processes, at [email protected] or 614.688.5153.