Study on optimization of thermal spinning process of accumulator shell

In view of the shortcomings of the existing hot spinning process technology of the accumulator shell, a method for optimizing the multi-spinning process parameters is proposed. The Johnson-Cook constitutive model of the accumulator shell material – 34CrMo4 alloy steel − was established with its parameters obtained experimentally. The finite element simulation was carried out for the hot spinning and closing process. Based on which, three parameters with the greatest influence on the spinning formation were studied: spinning temperature, spindle speed and friction coefficient. Combined with the central composite test, the response surface model and the mapping relationship between the three parameters and the maximum mises stress as well as the maximum wall thickness increment of the shell were established. The Pareto optimized solution set was obtained through multi-objective optimization. Under the condition of not affecting product quality, the optimized solution with low spinning temperature and high spindle speed is selected to reduce energy loss and improve work efficiency. The results indicate that the optimized process is experimentally verified to reduce the process temperature by nearly 30 °C, and the efficiency is increased by 25%.

Research on Multipass Hot Spinning Process Technology of AZ80 Magnesium Alloy Shell

Combined with finite element numerical simulation analysis, the hot-spin forming technology of cylindrical AZ80 magnesium alloy parts was studied in the paper. The multipass hot-spin forming of magnesium alloy shell parts was simulated by the ABAQUS software to analyze the stress and strain distribution and change during spinning for the preliminary test process parameters in the magnesium alloy spinning test. Then, the process parameters were optimized during the hot spinning test, especially the matching relationship between temperature parameter and thinning rate parameter, and the hot spinning magnesium alloy shell parts with the expected technical specifications were finished.

Numerical and Experimental Analysis of Attaching-Mandrel Process Under Multi-Pass Cold Spinning Process on Superalloy GH3030

The superalloy products formed by multi-pass conventional spinning are widely used in rotary forming parts with complex shapes. As the connection of each forming pass, the attaching-mandrel process has an important influence on forming quality and production efficiency. The hot spinning process is usually adopted in superalloy forming because its poor plasticity in normal temperature, meanwhile, it brings the poor surface quality of the parts and huge energy consumption. For this reason, the cold spinning and the attaching-mandrel process of nickel-base superalloy GH3030 are studied. The combination method of experiment and simulation is used to study the attaching-mandrel process based on one-forward-pass spinning process. The effects of pass pitch and the attaching-mandrel velocity on the tool forces, parts stress field, strain field and wall thickness distribution are analyzed. The microstructure of the part is divided into three layers: outer, middle and inner layer. The grain size of each layer is compared. Then the effect of different pass pitch on the grain structure is clarified. The results show that the reasonable pass pitch and the attaching-mandrel velocity can improve the forming quality and production efficiency. The multi-pass cold spinning process on superalloy GH3030 is feasible. The excessive pass pitch can cause seriously grain elongation, the grain boundaries are blurred, and even cracking.