Variable Balance Submerged Arc Welding (2005-386)
- BMT Fleet Technology, Ltd.
- Ingalls Shipbuilding
- Naval Surface Warfare Center - Carderock (NSWCC)
- Miller Electric
- Hobart Brothers
March 2006 - February 2007
NSRP ASE Investment: $116K
Industry Investment: $116K
Utilize recent technological advancements in submerged arc welding power source and consumable design to improve productivity rates and reduce the construction costs of both commercial and Naval vessels in U.S. shipyards.
This project has demonstrated improved productivity rates which can reduce the construction costs of both commercial and naval vessels in U.S. shipyards by exploiting recent technological advancements in submerged arc welding power source and consumable design. Northrop Grumman Ship Systems and BMT Fleet Technology Limited developed an optimal cored wire/flux combination, along with single sided submerged arc welding procedures for 0.5 and 1.0 inch thick high-strength steels using a new generation of digital square wave alternating current variable balance power source. This equipment has the capability to reduce heat input and increase weld metal deposition rates to improve productivity. The benefit of this new generation welding system is that it can be easily implemented in most existing panel lines that use the submerged arc welding process with minimal modifications. Deposition rates have increased significantly over conventional direct current electrode positive power sources using the same welding parameters and wire types/sizes. The return on the investment for most large operations resulting from higher productivity rates and lower consumption costs is realizable in as little as a few months. The project team has completed development of procedures for high speed multi-pass welding of DH36, HSLA-65 and HSLA-100 steels. Productivity improved from 10% – 1200% and costs were reduced from 11% – 64% depending on steel type and thickness. Procedures developed in this investigation met the applicable requirements and the welds contained zero defects or flaws. An NSRP panel project was awarded in November 2006 to secure ABS and NAVSEA qualification of these weld procedures. Northrop Grumman Ship Systems and Northrop Grumman Shipbuilding – Gulf Coast and Newport News are planning to implement this technology.
In 2006, a follow-on project applied the same technological advancements to longitudinal fillet welding. The main goal of this project was to increase the productivity rate of longitudinal fillet welding operations by 300%, compared to current shipyard practice, while controlling distortion and maintaining weld quality and mechanical properties. The actual productivity enhancements approached 300% for 3/16” and ¼” fillet sizes, and 500% for 5/16” and 3/8” fillet weld sizes. The measured distortion was similar or in some cases better, but at much higher travel speeds. The twin-wire “tandem” technique used in this project involves two twin-wire torches used in tandem (a leading and trailing torch), with four electrodes being fed into the joint all at the same time, (as shown in the above left picture.)
Final Report – Approved for public release; distribution is unlimited
Point of Contact:
Darren Begg, BMT Fleet Technology, Ltd.