Abstract
The present study discusses the effects of an applied magnetic field on the tensile characteristics and formability behavior of a dual-phase steel sheet. The work also reports the novel design of electromagnetic tool for uniaxial tensile test and Erichsen cupping experiments with their performance analysis. The electromagnetic tool is developed as an external attachment to a conventional uniaxial tensile test specimen while testing in a universal testing machine. For the simulations, the electromagnetic tool is modelled with different magnetic flux density values. The electromagnetic tool is designed and fabricated based on the predicted results of magnetic flux density distribution in the specimen obtained from simulations. Furthermore, the experimental results obtained from tensile tests show a significant improvement in the tensile strength and normal anisotropy due to the magnetic field. The microstructural investigations are carried out on samples taken from the specimens tested to 20% of plastic strain with and without the magnetic field by electron backscattered diffraction and correlated with the changes in the tensile properties. The effect of magnetic field shows that the material's texture becomes stronger, the grain dislocation density decreases, and the material's twin boundary increases. The magnetic force microscopy frequency analysis is also performed to evaluate the evidences of magnetic field on the tensile tested specimens. A significant increase in the values of strengths and anisotropy but a slight decrease in ductility and strain hardening exponent are observed in the specimens tested with the magnetic field. A modified electromagnetic tool is designed as an attachment to the sheet samples to be tested in the Erichsen cupping machine to study the influence of a magnetic field on the forming behavior. The results of Erichsen cupping experiments are obtained with and without a magnetic field. It is observed that the magnetic field increases the values of the Erichsen Index, suggesting an enhanced formability, which may be attributed to the increase in normal anisotropy of the sheet.