Experimental and numerical investigation of a new constrained ironing process with capability of extra high thickness reduction

Ironing is a conventional metal forming process for producing thin walled cans with uniform thickness components manufactured from deep drawn cups. The most important drawback of the conventional ironing is the lower thickness reduction ratio (TRR) causes needing annealing process and multi stage ironing. Recently, a new ironing process named constrained ironing was presented by the current authors to achieve an extra TRR to solve the conventional ironing problems. This process that is based on the compressive stresses makes it possible achieving high TRR without interruption for additional processing such as multi-stage ironing and annealing. In this paper, FEM simulation was performed to investigate the effective parameters. The simulation results showed that process the process load increases with increasing the friction coefficient. Also, the state of the stresses is fully compressive in constrained ironing process while it is tensile in the conventional ironing method. Thus, compressive stress components minimize formability problems, and higher thickness reduction ratio is achievable in the new ironing method. Also, experimental results showed that the tensile strength and hardness increased after constrained ironed of the deep drawn cup.