Influence of process parameters on forming quality of largesize nickel-based alloy tubes

In order to improve the forming quality of largesize nickel-based alloy chemical tubes, the influence of different tube specifications and mandrel/tube clearances on the bending forming quality of largesize Hastelloy C-276 alloy tubes was studied. A finite element (FE) analysis model for NC rotary drawing bending (RDB) was established and verified. The results show that with the increasement of the clearance, the wall-thinning ratio ${\zeta }_1$ of different tube specifications gradually decreases, and the wall-thickening ratio ${\zeta }_2$ and ovality $\phi$ gradually increase. As the measuring angle increases, the ${\zeta }_1$ of different specifications initially increases and then decreases. The ${\zeta }_2$ exhibits a trend of initially increasing and then decreasing. It is reasonable to take about 1/8 of the wall thickness t for the mandrel/tube clearance. It is of great significance for guiding the bending forming of largesize nickel-based alloy chemical tubes and development of intelligent forming equipment.