Control method of interference amount of threads of buttress special threaded oil casing

The invention discloses a control method of the interference amount of threads of a buttress special threaded oil casing and accordingly the test times can be reduced and the test cost can be reduced. The control method comprises determining the interference amount and the machining tolerance of the threads of the buttress special threaded oil casing according to the conventional experience; determining the maximum thread tightening torque acting on the oil casing threads, wherein the formula as follows, T1 is the thread torque, T2 is the sealing surface torque, T3 is the cone torque, and T4 is the shoulder torque; calculating the maximum contact stress of the threads by a finite element method according to Ts; utilizing the determined interference amount and machining tolerance to perform machining if the maximum contact stress does not exceed 80% of the thread material yield strength; performing redesign if the maximum contact stress exceeds 80% of the thread material yield strength.