Rear casing assembly manufacturing method capable of solving problems of deformation and cracking

The invention provides a rear casing assembly manufacturing method capable of solving the problems of deformation and cracking and belongs to the technical field of aero-engine part manufacture. When webs and supporting board heads are preassembled, welding joint shrinkage deformation is considered in the preassembly size aspect, it is guaranteed that the size generated after welding operation is identical to the design size of an outer casing, shrinkage stress can not be generated on welding joints, stress concentration is avoided, and cracks are prevented from being generated. Due to the fact that shrinkage stress can not be generated on the welding joints, the situation that a front installation edge and a rear installation edge are deformed due to the shrinkage stress effect is avoided; an inner ring and a flat supporting board pipe are preassembled and welded, the flat supporting board pipe with the inner ring and the supporting board heads of the outer casing are assembled and welded in a butt joint mode, the welded flat supporting board pipe bears tensile stress, the tensile stress exactly counteracts pressure stress borne by the flat supporting board pipe in the operation process of an engine, the stress concentration force receiving state is reduced, and cracks and deformation are avoided. In the thermal treatment process, structural stress is distributed in a balanced mode through a thermal treatment clamp and the situation that a rear casing assembly is deformed due to stress release is avoided.