Repair of Partially Penetrated Weld Joints in Copper-Nickel Seawater Piping on Naval Ships

摘要

The U.S. Navy has experienced several leaks in Cu-Ni seawater piping as a result of partially penetrated welds in the ships' original construction. If it were possible to repair the welds without cutting open the pipe, the Navy could realize significant cost savings on ship repair. This investigation evaluated whether it would be possible to achieve satisfactory weld repairs by remelting the weld zone, fusing the joint through its full thickness without cleaning the interior of the pipe. Elemental analysis of the internal deposits on pipes removed from service and manufacture of repair welds on these pipes show that it is possible to repair partially penetrated welded joints in Cu-Ni seawater pipe by remelting the weld zone. The repair weld is not likely to absorb contamination from the interior of the pipe, as shown by X-rays of the welds and elemental analysis of the weld bead, compared to the unwelded base metal.