CO2 & Nd&COLCHEM;YAG laser orbital welding applied to offshore pipeline construction

The capabilities of CO2 and Nd:YAG laser beam welding (LBW) are established and recognised in applications where small thicknesses have to be high speed welded. The availability of compact CO2 laser with power up to 20 kW and the recent development on high power Nd:YAG laser permits nowadays to take advantage of LBW (high production rate, full automation) in other fields of application where higher wall thickness are required. The application developped by BOUYGUES OFFSHORE is related to offshore welding of pipeline where it is demonstrated that LBW is applicable in orbital welding and may be integrated in the difficult environment of a lay barge. This article describe the experimental program implemented by BOUYGUES OFFSHORE to develop the CO2 laser beam welding process and to dispose of an equipment applicable on barge for pipeline orbital welding and the main results obtained during the weldability tests with the Nd:YAG welding process carried out with the CLFA. The welding process development was conducted on plate and pipe diameter up to 24" and wall thickness 10 mm to 16 mm.