In order to improve the precision of rotary-draw bending of copper-titanium composite tube

the effects of rigid mandrel parameters on section distortion and wall thickness thinning of the composite tube were studied

based on the established finite element model. The effects of rigid mandrel were compared with that of elastic mandrel. Research results show that: (1) with the increase of the extension amount of the rigid mandrel

the section distortion rate of the base\ covered tube of the bimetallic composite tube decreases gradually

and the wall thickness reduction rate increases gradually. The optimal extension amount of the mandrel is 7mm. (2) Compared with the coreless filling

the section distortion significantly reduces with the rigid mandrel filling

but the wall thickness thinning rate increases. When controlling the section distortion

the influence of the mandrel on the thinning rate of the composite tube should be considered

and the filling condition should be selected flexibly according to the actual production requirements and the tube size and structure. (3) When the elastic mandrel is filled

the section distortion rate along the bending direction is more uniform than that of the rigid mandrel. Compared with the elastic mandrel

the rigid mandrel can control the section distortion of the composite tube better

but the maximum difference is only 1.13%. The controlling effect of wall thickness reduction rate of elastic mandrel is better than that of rigid mandrel

and the maximum difference is 3.27%. Considering the cross section distortion and the wall thickness reduction

the filling effect of the elastic mandrel on the bimetallic composite tube is better.