High speed hydroforming and direct quenching: An alternative method for production of hot stamped parts with high productivity

摘要

An innovative method for high speed hydroforming and direct quenching is presented. In the presented method, the forming is done hy the electrohydraulic forming (EHF) process where the electrical energy stored in a bank of capacitors, discharges between a pair of electrodes submerged in a fluid and initiate a shock wave in the fluid. The shock wave propagated through the fluid and forms the sheet metal. Before performing EHF, steel sheets are heated to form austenite. The forming process will be done within few milliseconds without any phase transformation in the formed sheet during forming. Immediately after forming, a compressed air is entered into the fluid chamber which moves the water and pressurized air toward the metal sheet and directly quenches it in few seconds which results in the martensitic microstructure. The new method is used for high speed hydroforming and direct quenching of 1.1231 carbon steel sheet. The metallography and hardness test are performed to investigate the condition of the deformed sheet after proposed process. The achieved hardness of the specimen was uniformly above 63 HRC. The hardness test and the optical micrographs show the martensitic microstructure of the deformed part.