Original Date: 04/24/2007
Revision Date: / /

Research presently underway at the University of New Orleans, College of Engineering on improved welding methods for titanium pipes shows promise for improving quality and reducing welding costs for the shipbuilding and petrochemical industry.

In cooperation with the cole Centrale de Nantes, the University of New Orleans, College of Engineering (UNO COE) is investigating a new welding technique for welding the P-80 socket joint on titanium pipe. Fusion welding of titanium is particularly difficult due to its low thermal conductivity coupled with the intrinsic spreading nature of titanium melt. Atmospheric conditions surrounding the welded joint also contribute to the welding difficulty. The P- 80 Socket joint, which is very common in shipbuilding and petrochemical operations, typically takes two passes to meet specification. Reducing the number of passes while attaining proper joint geometry and strength reduces time spent achieving the welding and reduces opportunities for nonconformance. Parameters being investigated by the UNO COE and the cole Centrale de Nantes researchers are electrode shape, assist gas, electrode-to-work distance, weld current (steady and pulsating), travel speed, flux composition, and flux thickness. The first step of this research will be conducted on flat titanium plates. This will allow for the various parameters to be investigated while eliminating the orbital effects of pipe welding. Based on the results of this research, fabrication of socket joints on pipes will be accomplished.

To date, flat-plate welding research has resulted in significant findings. Weld depth has increased from approximately 3 mm to approximately 6 mm, while significantly reducing weld bead width. Because the shielding medium of chloride flux produces the desired results, it is more effective to use than chlorides.

For more information see the Point of Contact for this survey.