A Study on the Effect of Young’s Modulus on Springback for Carbon Steels during Cold Drawing of Seamless Tubes

Springback is inherent in sheet metal forming. It can be can be understood by looking at a material’s stress stain curve (discussed in the module on Tensile Testing) which characterizes the behavior of metal under applied force. During forming, the material is strained beyond the yield strength in order to induce permanent deformation. When the load is removed, the stress will return to zero along a path parallel to the slope of the elastic portion of the curve, which is the elastic modulus. A common deformation technique for producing seamless tubes is cold drawing. One of the main issues in tube drawing is springback. The elastic energy that was stored in the tubes during the forming process is what causes springback. It is discovered that the springback is dependent on the material's Young's modulus. In order to determine their Young's modulus and related springback, three kinds of steel—low carbon steel, medium carbon steel, and high carbon steel—were mechanically tested. The results shows that there is 10-20% variation in the Young’s modulus and inverse proportion between the springback and Young’s modulus. More the percentage of carbon, more the strength, less the value of Young’s modulus and more will springback. The study further leads to identify optimum die semi angle of 15 degree, land width of 10 mm and drawing speed of 8, 6 and 4 m/min for least springback in all the three grades respectively and die semi angle as a most dominant factor causing springback.