Research on the grain refinement method of cylindrical parts by power spinning

The influence of spinning methods and the distributions of equivalent strains on grain refinement were studied to realize the overall grain refinement along the thickness direction of the cylindrical parts manufactured by spin-forming. The metal flow model of counter-roller spinning was established based on upper bound method and compared with that of the stagger spinning; the processes of the stagger and the counter-roller spinning were simulated based on the commercial FEA software, MSC.Marc. The results show that the distribution of equivalent strains of spun part obtained by counter-roller spinning is more homogeneous than that of stagger spinning; the simulation results of the equivalent strains of the counter-roller spinning conform well to the theoretical calculation results, and the relative deviations between the calculation and simulation results are less than 10 %. The corresponding metallographic analysis was further carried out to verify the theoretical analysis. The results indicate that the percentage of grain refinement on inner layer is far less than that of the outer layer during stagger spinning, whereas the percentage of grain refinement on the inner and outer layers of the spun parts are nearly the same during counter-roller spinning.