Detachable assembly type variable cross-section fixing bolt

The utility model discloses a detachable assembly type variable-cross-section fixing bolt which is composed of a uniform-cross-section stud and a variable-cross-section stud base. The uniform-section stud comprises a torsion upper mounting table; the variable cross-section stud base comprises a torsion lower mounting table, a bottom anti-torsion reinforcing ring, an external fixed thread table and a self-connecting internal thread; the uniform-section stud and the variable-section stud base form a fixed bolt through the self-connecting internal thread; and the external fixed threaded table is fixed on the external connecting plate. According to the detachable assembly type variable cross-section fixing bolt, on one hand, two-section assembly type connection of the bolt is achieved in an isolation space; on the other hand, the variable-section stud design saves the material cost and meets the strength requirements of different sections of the bolt. Particularly in a low-temperature thin film enclosure system,