Near-Net Forging of Titanium and Titanium Alloys by the Plasma Carburized SKD11 Dies

The carbon supersaturated SKD11 punch and core-die were prepared by the plasma carburizing at 673 K for 14.4 ks. The upsetting experiment was performed by using this punch to describe the plastic flow of pure titanium and β-titanium works in higher reduction of thickness than 50%. The measured load – stroke relationship was utilized to describe the frictional behavior on the contact interface of punch to work materials and their work hardening process. The contact interface of carbon supersaturated punch to work was analyzed to investigate the formation of isolated carbon tribofilms from punch material and to describe the in situ solid lubrication on the contact interface. The micro-hardness mapping technique was also utilized to investigate how to suppress the workhardening behavior by this in-situ solid lubrication. Free near-net forging experiments were performed to shape the circular β-titanium alloy wires to triangular bars.