Hybrid laser arc welding process and apparatus

An apparatus for welding at least two workpieces together by metallurgically joining faying surfaces thereof that face each other to define a joint region comprising an intersurface portion defined by and between the faying surfaces and immediately adjacent surfaces of the workpieces that remain exposed, the apparatus comprising:

• means for welding the workpieces together by performing forward and aft hybrid welding processes in sequence along the joint region, the welding means comprising means for conducting the forward hybrid welding process on the joint region and means for conducting the aft hybrid welding process on a weldment formed by the forward hybrid welding process;
• the forward hybrid welding process means being adapted to project a forward laser beam onto the joint region and cause a projection of the forward laser beam to travel along the joint region and penetrate the intersurface portion of the joint region, the forward hybrid welding process means being further adapted to direct a forward electric arc onto the projection of the forward laser beam while feeding a first weld filler material into the forward electric arc to form the weldment in the joint region;
• the aft hybrid welding process means being adapted to project an aft laser beam onto the weldment and cause a projection of the aft laser beam to travel along and penetrate the weldment, the aft hybrid welding process means being further adapted to direct an aft electric arc onto the projection of the aft laser beam while feeding a second weld filler material into the aft electric arc to form an aft weld pool;
• the welding means spacing the forward and aft laser beam projections apart along the joint region and spacing the forward and aft electric arcs apart along the joint region so as to cause the aft weld pool formed by the aft hybrid welding process means to cascade onto, remelt and intermix with the weldment to form a combined weld pool.