Since weld distortion is a very costly problem for U.S. shipyards, the National Shipbuidling Research Program (NSRP) has embarked on a project to reduce weld distortion through innovative Induction Heat process. A new welding process -- HiDep Arc Welding -- has been invented, which uses induction heating to heat the weld joint ahead of the arc Welding torch.
By adjusting the induction heating it is possible to modify the thermal profile of the weld to prevent the asymmetrical cooling which causes most weld distortion. The process essentially substitutes induction heating instead of the arc plasma, to heat the metal being welded. The arc plasma, which occurs at the tip of the wire electrode, then is used primarily to melt the electrode. Two benefits emerge from this new process: significantly reduced distortion; and a substantial increase in welding speed and productivity. The project team is developing procedures and demonstrating the ability of this process to reduce distortion and increase productivity in steel plate butt welds and T-fillet welds for shipbuilding applications.