A Comparison Between Single Sided and Double Sided Friction Stir Welded 8mm Thick DH36 Steel Plate

As part of an ongoing process to fully evaluate the potential for friction stir welding to be used in the shipbuilding process, a comparison has been made between two variants of the process.

8mm thick DH36 steel plate was friction stir welded using a single sided process and the relevant data was compared against a double sided process friction stir welded process. An assessment of the processes was made using distortion susceptibility, hardness, yield strength, toughness, microstructure and fatigue performance. Of particular interest is the overlap area between the two wedls where the effect of the second pass on the first pass will be evaluated. As background some work on 8mm thick submerged arc welded has been included as the current shipbuilding benchmark.

The overall process feasibility will be assessed including the issue of the requirement to turn the workpiece over to carry out the double sided process.