Research On Ball Spinning Process Of304Stainless Steel Tube

Ball spinning is a branch of power spinning processes, which has thecharacteristics of a wide of products, low surface roughness, high dimensional accuracy,etc. In recent decades, this process approach has been widely used in the field ofnational defense industry and civilian industry producing and processing thin-walledtube with high precision and strength.The three dimensional elastic-plastic finite element model of backward ballspinning process for304stainless steel tube was built by using the simulation softwareDEFORM-3D. It revealed the stress and strain state of the tube in ball spinning process,The influences of the variation of technical parameters such as ball diameter, axial feedratio, reducing ratio, spindle speed on the tube spinning process have been analyzed inthe paper. The qualified spinning tube was obtained though the analysis of theequivalent stress, equivalent strain, deformation uniformity coefficient, spinning forces.The emergence of some common quality defects such as bulge, ripple and diameterexpansion was explained. At last, the obtained reasonable process parameters arereducing ratio of15%, ball diameter of6mm, axial feed ratio of0.5mm/r and spindlespeed of300r/min.The modified Cockroft-Latham and Oyane ductile fracture criterion werecombined with finite element simulation to predict the distribution of damage valueduring the tube ball spinning. The results showed that the Oyane ductile fracturecriterion can predict the position where damage occurs during ball spinning process,which was consistent with the experimental results. While the modifiedCockroft-Latham ductile fracture criterion is not suitable for predicting the transversecracking defects during the tube ball spinning. The influences of the variation oftechnical parameters on the damage value were obtained by using the Oyane ductilefracture criterion.According to the finite element simulation results, the simulation results are verified through experiments. It indicates the unreasonable matching relationships oftechnical parameters will result in the defects.The tube product with good quality canbe obtained in the experiment by using the optimized process parameters in thesimulation results. The research results can guide the mass manufacturing of smalldiameter stainless steel tube.The large diameter tube ball spinning process has been analyzed by using thesoftware of DEFORM. The influences of the variation of technical parameters such asreducing ratio, ball diameter, axial feed ratio on the equivalent strain and surface qualityhave been analyzed. The obtained reasonable process parameters are ball diameter of20mm, reducing ratio of20%, axial feed ratio of1.9mm/r and spindle speed of300r/min.