Welding Suited to Shipbuilding

Current welding methods distort the structural steel plates used for shipbuilding, requiring manufacturers to invest time and money in postprocessing. The shipbuilding industry would like to take advantage of the speed and economy of laser welding, but lasers have insufficient power and produce welds of unacceptable hardness.

Researchers have suggested that a hybrid laser and gas-metal arc welding technique may solve these problems and enable manufacturers to weld thicker plates with less distortion. A team from VTT Manufacturing Technology of Lappeenranta, Finland, Kvaerner Masa-Yards Inc. of Turku, Finland, and the Lappeenranta University of Technology has confirmed the utility of the approach, which it reported in the October 2000 issue of Journal of Laser Applications.

The scientists combined the fiber-delivered output of a 3-kW Nd:YAG laser and a welding torch. They found that welding speeds of 0.7 m/min produced welds of acceptable hardness in 5- and 6-mm-thick plates of A36 steel. The results suggest that the process is suitable for welding V-groove joints in plates up to 11 mm thick.