Pre-Pressure Jig Welding of a Large Stainless Steel Aircraft Fuel Tank

摘要

The report describes the pre-pressure resistance spotwelding technique which was developed to spotweld internal former to the skin of a saddle shaped fuel tank. The component parts to be welded are clamped together over the entire joint area in a welding fixture to ensure an intimate fit at the interface joint. The clamping bars holding the joint have a dual purpose in that the bar on one side has location holes to position the welding electrode (held in the portable gun) while the other bar which is made of copper provides the (electrode) backing bar that the spotweld is made upon. The portable resistance welding gun is of the expander type and the electrode force is developed by the action of the gun against a reaction member attached to the electrode location clamping bar. The contact face of the reaction member is made of copper from which the welding current is picked up by the gun and transferred to the component joint, location holes are also provided to ensure the alignment of the gun normal to the surface of the component. A detailed description of the design of the welding fixture incorporating the secondary resistance welding circuit is given in the report with the results of welding tests carried out. (Author)