The welding group of the Casting Processing Department of Factory 239, under the Third Academy of China Aerospace Science and Industry Corporation, currently has four members. Though small in number, they shoulder the repair welding work for all casting products of the entire factory. With their excellent professional skills and rich operational experience, they perform repair welding on various complex castings, just like experienced “surgeons” who eliminate various “difficult and complicated diseases” of “patients” one by one, giving castings a new lease on life.

The welding group are the executors of “minimally invasive” surgery. A certain product’s oil tank is a key production task, and the repair welding requirements for the castings are very strict, especially regarding the number of repair welds and the repair welding area. After precision machining, the single repair welding area must not exceed 2 square centimeters, posing high demands on the welders’ operations. At the same time, the wall thickness of the oil tank is only 2-3mm, and the slightest carelessness can result in excessive repair welding area or part deformation. Therefore, during the repair welding process, from defect removal, groove preparation to final repair welding, meticulous care is required, using appropriate tools to perform “minimally invasive” surgery on defects as small as possible, ensuring that the product meets technical requirements and becomes a qualified product. The welding group are the eliminators of “difficult and complicated diseases.” During the production of a certain oil tank product, an intractable situation arose where the internal cavity chill was bonded to the body and could not be removed with any cleaning tools. The traditional method would be destructive: opening a hole from the outer wall of the casting, pushing out the chill, and then repair-welding the hole, which is time-consuming and labor-intensive. Was there a method that wouldn’t damage the product? After discussion with technical personnel, the welding group determined that argon arc welding could be used to directly melt the chill, allowing it to drop off automatically. After designing and fabricating an extended welding torch, the welding group successfully removed the chill bonded to the body deep inside the casting cavity, with the casting completely unharmed. Product quality comes from the control of every process, and repair welding is one of the key links. Whether in the as-cast or precision-machined state, whether it is a part or a complete oil tank, before the welder, it is like a surgeon facing different patients — the goal is to cure the disease with skill, achieving first-time qualification.