Research For The Parametric Feasible Region Of Mn18Cr18N Retaining Rings In The Process Of Hydraulic Expansion With Additional Liquid

Retaining ring is the important part of generator. It is subjected to complicated forces. Its integrality is the key that guarantee the movement of generator safe and dependable. As the material for retaining ring, Mn18Cr18N is a kind of austenitic steel. Its high strength can only be obtained by deformation-strengthening. Currently, the strengthening of retaining ring is mainly based on hydraulic bulging with additional liquid. During the hydraulic bulging process, the shape of retaining ring is influenced by a number of technological parameters. If these parameters can not be matched properly, physical imperfections could appear easily, such as convex drum, cave drum and so on. These imperfections will result in uneven distribution of mechanical properties in the retaining ring, and mechanical allowance will be enlarged. If the imperfections are serious, the retaining ring could even be scrapped. To guarantee the quality of retaining ring, it is very important to study and acquire the feasible zone of the technological parameters.In this paper, by using elastic-plastic mechanics theory, based on the retaining ring workpiece of given size, analytic solution of bulging press was calculated. It also derived the concerning computation formula of retaining ring workpiece. Hydraulic bulging device with additional liquid were analysed mechanically.Based on the finite element theory and the ANSYS software, a number of finite element models were established, according to the actual stress state of the retaining ring. The effect of different technological parameters on the hydraulic bulging of retaining ring was analysed. Pressure curve of deformation- strengthening, the best value of the die angle and the size of the resistance ring were found. The hydraulic bulging press and contact press control curve and its upper and lower limit were obtained, meet the requirements of seal up completely and hydraulic control accuracy.According to the aforementioned research, electro-hydraulic control system for hydraulic bulging device with additional liquid was designed. The main hydraulic components were determined. The parameters in the electro-hydraulic control system were given.