# Study of Copper/Aluminum Bimetallic Tube Rotary Ring Spinning Composite Forming Characteristics
###### Abstract  
As a plastic forming process developed based on rotary wheel spinning technology, the rotary ring spinning process has the excellent characteristics of high forming accuracy and high material utilization rate, and has been gradually applied to the manufacture of bimetallic composite pipes. In this paper, the forming law of a bimetallic tube in the process of rotary ring spinning was analyzed by numerical simulation and experimentation. The results show that the deformation coordination of the basic and cover tubes increased with the increasing press amount, and the feed ratio had less of an effect on the thickness variation. In addition, the three-way strain of the basic and cover tubes and the degree of influence of the process parameters on the equivalent strain of the tubes were also studied. The results show that the radial strain on both tubes was the largest, followed by the axial strain, and the tangential strain was the smallest; the press amount had the largest effect on the equivalent strain of the tubes, followed by the angle of attack and the feed ratio. These results provide some guidance for the manufacture of high-performance bimetallic composite tubes by rotary ring spinning.  
bimetallic composite tube; rotary ring spinning; three-way strain; deformation characteristic +
Footnote †: journal: Applied  
boundary position, which was finally verified by simulation and testing. [PERSON] et al. [11] used finite element simulation and experiments to investigate the stresses and thickness variations of bimetallic composite tubes of two materials, copper and aluminum, during the rotary wheel spinning composite process. [PERSON] et al. [12] investigated the influence of technological parameters such as thickness thinning, process temperature, feed rate, and post-annealing temperature on the combined strength of steel/aluminum bimetallic tubes in the rotary wheel spinning composite forming process. [PERSON] et al. [13] used numerical simulations, an orthogonal experimental design, and polar differences to obtain significant process parameters for the rotary wheel spinning of bimetallic composite tubes, and verified the accuracy of the process parameters by experimentation. [PERSON] et al. [1] carried out research on the stress, strain, and shear bond strength of copper/aluminum bimetallic composite tubes during rotary wheel spinning and forming through simulation, and investigated the impact law of the main technological parameters on the shear bond strength of bimetallic tubes through experiments and simulations. [PERSON] et al. [14] investigated the effects of the original thickness ratio, heat treatment temperature, and thinning amount on the spinning bond strength and deformation synchronization of aluminum/aluminum composite tubes by process tests and finite element simulations.  
While many scholars have carried out enriching studies on rotary wheel spinning, little research has been reported on the forming process of rotary ring spinning. Rotary ring spinning technology inherited the advantages of a simple process, low cost, and high forming efficiency. However, the relationship between the basic tube and the cover tube in the forming process of rotary ring rolling directly affects the molding quality and wall thickness distribution of bimetallic composite tubes, and plays a determinative role in the adjustment of the process parameters. In this study we used a method that integrates numerical simulation and experimentation to investigate the stresses during the rotary ring spinning forming process and the effects of different technological parameters on the thickness and three-way strain of bimetallic tubes. We also investigated the extent of the impact of the main technological parameters on the equivalent strain of the basic tube and the cover tube. The precision of the simulation model was validated by comparing the experimental and simulation results.