Influence of wire parameters on the formability of DP600 steel sheets during wire explosion impact forming

The acoustic pulses caused by the underwater wire explosion can be used to apply work on the surrounding medium. This work designed a set of adjustable wire explosion impact forming tooling to investigate the influence of wire parameters on the formability of DP600 steel sheets. The results obtained based on the current experimental conditions showed that a longer wire length mainly played a positive role in improving the energy utilization rate; a larger lifting height weakened the disadvantage of uneven distribution of pressure caused by the explosion of metal wire, and decreased the difference between the radial pressure and the circumferential pressure of the fractured elements, causing the limit strain pair to be closer to the equi-biaxial tensile strain path and increasing the limit dome heights of the tested specimens. Under the conditions of optimal wire length of 45 mm and lifting height of 37 mm, the limit dome heights and the major strains of the tested specimens were increased by 10% and 20%, respectively, as compared with quasi-static specimens; and the energy utilization rate was improved by 30–50% as compared with other combined wire parameters. The numerical simulation reproduced the dynamic deformation process of tested specimens and showed that the maximum effective strain rate was 1740/s, which was 106 times of that during the quasi-static hydraulic bulging process. The microstructural characteristics showed that under the action of high-speed impact load, the grain size of the tested specimen was reduced by 80%, as compared with that under quasi-static condition.