Study on the Law of Blank and Material Properties on the Free Bending of Pipes

To explore the impact of various material parameters on the three-dimensional free bending behavior of metal pipes and enhance the quality of such bending processes, this study focused on TP2 copper pipes with dimensions Φ12mm×1mm. Under uniform conditions of process parameters, free bending equipment, and key component characteristics, pipes with varying wall thicknesses and materials were investigated. The evaluation criteria were based on the maximum wall thickness thinning rate and maximum ellipticity of the pipes. The investigation aimed to understand how alterations in different material parameters affect bending radius, propulsive force, and wall thickness of the pipes. The results revealed that smaller bending radii correlate with more pronounced influences of wall thickness on pipe curvature. Additionally, an increase in wall thickness led to a decrease in pipe forming quality. The bending radius of the pipe was determined by multiple parameters, including the material's elastic modulus, yield strength, pipe hardening index, and strength coefficient. The maximum ellipticity of the pipe was found to be associated with material strength, while the alteration of pipe wall thickness was influenced by the hardening index, denoted as 'n'.