Study on the experiment of wall thickness deformation of coreless bended small-diameter tube

Through a great deal of small-diameter tube bending-deformation test, the strain distribution state of the tube in the direction of wall thickness is analyzed. It is pointed out that the deformation of wall thickness is affected mainly by mechanical property of material and geometry factors of deformation, and its distribution along bending line is uneven. Both maximum thinning and thicking occurred in the middle of bending inner corner. At last, the formulation of allowable minimum bending radius limiting the change of the tube-wall thickness is derived, and proved to be of practical value.