Dimensional Accuracy Enhancement in Hydroforming of Tubular Components with Rectangular Cross-Sections

This article proposes a method for regulating elastic deformation of die and dimensional accuracy of tubular components with rectangular cross-sections by controlling the forming pressure during hydroforming process. SAPH440 low-carbon steel tube and 6063 aluminum alloy tube were employed to examine the effect of forming pressure and clamping force. This indicated that the die cavity is flattened by clamping force and expands because of the rise in internal pressure, which leads to an increase in the cross-sectional width of the rectangular tubular component. The section width dimension accuracy of SAPH440 and 6063 tubes obtained under the forming pressure of 150 MPa and 60 MPa, respectively, is the highest, suggesting that expansion deformation of the die cavity can just compensate for springback in the width direction of the cross-section. At this point, the cross-sectional heights show positive deviation + 0.26 mm and + 0.17 mm, respectively. In addition, when the clamping force is > 3200 kN and 1400 kN, respectively, the cross-sectional size of the two tubular components becomes significantly affected by the clamping force. Finally, seven repeated experiments were conducted on two tubes, and the results showed that the cross-sectional width was very stable, with a deviation of +/- 0.02 mm.

Automated summary

This article proposes a method to regulate the deformation and dimensional accuracy of tubular components by controlling the forming pressure during hydroforming process. The study found that the clamping force and internal pressure can cause expansion and flattening of the die cavity, thus affecting the cross-sectional dimensions of the rectangular tubes. Further experiments showed that under appropriate forming pressure, the expansion deformation of the die cavity can compensate for springback, resulting in more accurate dimensions of the tubular components.