Variation of elastic modulus during cold drawing of seamless tubes and it's influence on springback

Inelastic recovery behavior of seamless tubes has been investigated by uniaxial tensile tests. Unloading stress-strain curves for different plastic strain reveals that the percentage of inelastic recovery to the total recovery increases with plastic deformation. The results of this study concludes that with increase in plastic strain, Young's modulus reduces drastically first then reduces somewhat slowly and finally stables to certain value. It is observed that this variation of Young's modulus is related to internal stresses, residual stresses, micro cracks, dislocations during plastic deformation. With increase in plastic deformation, residual stresses increases which lowers Young's modulus. This paper is an experimental study how Young's modulus decreases with plastic strain. The results of study concludes that 10-20% degradation occurs in Young's modulus for 5-7% plastic strain.