Creep aging heat treatment method for large cylindrical aluminum alloy casting

The invention relates to the technical field of heat treatment of large cylindrical aluminum alloy castings, and particularly discloses a creep aging heat treatment method for a large cylindrical aluminum alloy casting. The creep aging heat treatment method for the large cylindrical aluminum alloy casting comprises the steps that firstly, the aluminum alloy casting is machined into a semi-finished state; secondly, solution treatment is conducted on the aluminum alloy casting in the semi-finished state; thirdly, quenching treatment is conducted on the aluminum alloy casting subjected to solution treatment; fourthly, shape correction is conducted for the roundness of the end face of the aluminum alloy casting by means of a shape correcting tool; and fifthly, over-positioning restraint is conducted on the aluminum alloy casting by means of a creep aging tool, and the overall dimension of the aluminum alloy casting is corrected and approximates to the machining dimension precision by means of the tiny creep property of the aluminum alloy casting. According to the creep aging heat treatment method for the large cylindrical aluminum alloy casting, the creep aging heat treatment technique is adopted, the heat treatment dimension precision can be greatly improved on the premise that the high mechanical property of the large cylindrical aluminum alloy casting in the finished state is kept, the roundness of the end face of the large cylindrical aluminum alloy casting is smaller than or equal to 0.5 mm, and the heat treatment dimension precision approximates to the machining dimension level.