Study On Thermal Spinning Theory Andtechnology Of Accumulator Shell

As an important auxiliary part of the hydraulic system,the accumulator is used to convert the energy in the system into compressed energy or potential energy at an appropriate time and to supplement the supply system when the system needs.When the system pressure increases instantaneously,the accumulator can absorb the energy of this part to ensure that the pressure of the whole hydraulic system is within the normal range.Under the action of non-equilibrium inertial loads such as pressure shock and pressure pulsation,the accumulator shell structure may be seriously damaged and the accumulator life may be shortened.Therefore,the processing quality of accumulator shell is the starting point and goal of accumulator product research and development.At present,the hot spinning processing technology is widely used in the accumulator shell manufacturing industry,but the problems of high energy consumption and low production efficiency of the hot spinning process seriously restrict the development of the hot spinning of the accumulator shell.The reason is the lack of effective thermal spinning theory and process optimization of accumulator shell.In order to meet the development demand of energy saving and high efficiency of the accumulator shell processing technology,and the challenge to the hot spinning processing technology,this paper studies the hot spinning theory and hot spinning processing technology of the accumulator shell.The main research contents and results are as follows:1.The hardening index,hardening parameters and initial yield strength of 34CrMo4 under quasi-static state were obtained by static compression test.The thermal softening parameters and strain rate strengthening parameters were obtained by Hopkinson compression bar test at different strain rates and temperatures.Finally,Johnson-Cook constitutive model of 34CrMo4 alloy steel was established.The theory of spinning forming is studied,the stress and strain distribution in different regions are analyzed,and the force of element is analyzed to obtain the formula of spinning pressure.By studying the friction mechanism of accumulator shell spinning forming,the friction model of accumulator shell during spinning forming was determined.2.According to the constitutive model of 34CrMo4 alloy steel and the thermal spinning process parameters provided by the factory,the simulation model of thermal spinning end of accumulator shell was established.Based on the simulation model,the influence of spinning temperature,spindle speed and friction coefficient on forming was studied.The optimum parameters of spinning temperature,spindle revolution and friction coefficient were obtained.3.On the basis of finite element simulation results,the appropriate thermal spinning process parameters interval was selected by the experimental method of central composite design,and a quadratic polynomial response surface model reflecting the relationship between the input of thermal spinning process parameters and the output of the maximum Mises stress and thickness increment was established according to the obtained maximum Mises stress and thickness increment.Based on the obtained response values,a quadratic polynomial response surface model reflecting the relationship between input and output of thermal spinning process parameters was established4.Set up a multi-objective optimization model of thermal spinning process of accumulator shell with the objective of small stress and low thickness increment;The multi-objective optimization model was solved and the Pareto optimization solution was obtained.Pareto optimization solution can provide a variety of feasible schemes.Under the condition that product quality is not affected,the scheme with low spinning temperature and low spindle speed can be selected to improve work efficiency and reduce energy loss.The thermal spinning theory and processing technology of accumulator shell studied in this paper are used to solve the accumulator shell with expected plastic processing performance through finite element method,experimental design and other methods,so as to realize the scientific and low energy consumption of thermal spinning processing technology of accumulator shell and provide predictive guidance for the actual production of accumulator shell.