SBIR-STTR Award

Double-sided arc welding is a novel process recently developed at the University of Kentucky. The current procedure for ship hull joining involves bevel preparation, root pass welding, second side joint preparation, multiple fill passes, associated equipment set-up for each pass, cleaning following each pass,and costly/time-consuming correction of workpiece distortion.The double-sided arc welding process has the potential to reduce the current procedure to a single pass for typical 1/2" ship hulls while eliminating bevel preparation (both sides).Hull plate distortion is minimized by eliminating multiple passes and the deep narrow penetration typical of the double-sided process, with its symmetrical heating mechanism and resultant narrow symmetrical weld bead. However,to allow use in a shipyard environment,the current laboratory version requires further development and several innovations. This SBIR Phase 1 project focuses on proving the feasibility of several proposed innovations which are critical to improving the suitability of DSAW for a shipyard environment.These include the concept of using a single power supply; using feedback control to improve the process's robustness with respect to variations in manufacturing conditions such as fit-up gap;using back-side modules to simplify system setup; and on finding more economic filler metals.

Keywords:
Welding,Plasma,Double-Sided Arc Welding,Hull Joining,

The current procedure for ship hull joining requires joint preparation and multiple weld passes on both sides of the hull joint. Associated with this welding is significant distortion resulting from non-uniform weld shrinkage.Weld distortion becomes increasingly significant with thinner hull dimensions and becomes a major cost driver.Double-sided Arc Welding (DSAW), a new process, minimizes plate distortion, as welds are made in a single pass for plate material up to 1/2".The objectives of this Phase II proposal are to develop a commercialized DSAW system which is ready to be deployed in shipyards;to further improve control algorithms, travel speed, and back-side shielding;create a demonstration center to handle large plates for parameter development; develop and test procedures for two standard hull materials DH-36 and HSLA-80/100; Demonstrate and train Bath Iron Works personnel, and have them repeat these welding procedures; subcontract BIW to perform welds for submission and approval of the DSAW process by NAVSEAS; seek approval of the DSAW process for use in the DD(X) program.

Keywords:
Welding, Plasma, Double-sided Arc Welding, Hull Joining