Influencing the residual stresses in tubes drawn with a floating plug by changing tool parameters

Induced residual stresses (IRS) within tube wall produced by a floating plug drawing (FPD) is one of the vital material defects in tube drawing. Therefore, the measurements of these stresses and their correlation with manufacturing parameters are quite important in the design of the drawing tools. In the present work, DIN 17,100 St 37-2 steel tubes are pulled using the FPD process, then longitudinal and circumferential residual stresses are evaluated by the cutting method (CM). The finite element method (FEM) is also used to estimate the residual stresses in the FPD process. The influences of various tool parameters such as plug half angle, cone half angle of the die, fillet radius of the plug, and fillet radius of the die on the IRS are investigated using FEM. The results of IRS showed a good convergence between the CM and the FEM with slight differences in the values. On the other hand, the FEM results revealed that the plug half angle at 0 degrees and the cone half angle of the die at 9 degrees induce the minimum residual stresses compared to other angles. Further, the observation proposed that the fillet radius of the plug in the range of 0-10 mm with the fillet radius of the die in the range of 7.5-10 mm generates the compressive residual stresses which may prevent crack propagation in the tube wall.