Effect of feeding stroke on shape accuracy of tube shear hydro-bending

The effects of feeding stroke on cross section distortion, corner radius dimension and thickness distribution of 5A02 shear hydro-bent tube are studied by experiment under the condition of constant internal pressure. Nnumerical simulation further conducted to analyze the effect of feeding on thickness strain. The results show that when the feeding ratio(axial feeding stroke over transversal stroke)is smaller than 1.2, the ultra-small bending tube can be successfully manufactured. While it is up to 1.3, the cross section distortion reaches 2.2% at the first corner. When the feeding ratio rises from 1 to 1.2, the extrados corner radius is varied from 4.5mm to 2.25mm and decreased by 50%. The thickness is increased with the increasing of the feeding ratio. The maximum thickening is increased from 27.47% at intrados and 26.67% at extrados to 38% and 34.67%, and the maximum thinning is decreased from 14.53% and 6.64% to 8.73% and 5.8%, respectively. It can be concluded that the corner radius dimension and thickness distribution are improved with the increase of feeding ratio, but the cross section distortion is easily generated if the feeding ratio is too large.