This simulation shows the formation multi diameter shaft using forging. The left hand side of the simulation shows the process of formation of multi diameter billet and the right hand side of the video shows the variation of temperature of the billet during the process. Initially the billet is heated at 1250o C and passed through the four piece die set. The upper and the lower die presses the billet in vertical direction whereas the left and right die presses the billet in horizontal direction and deform it laterally. After each blow the billet is moved in forward direction in steps. This ensures uniform deformation of billet. After one complete pass, the billet is passed through the dies in opposite direction. At the end of second pass, the round billet gets converted into a shaft of smaller dia. In the third pass billet is moved in forward direction in steps covering half of its length with the increased force of the dies. In further passes the force applied by dies on the billet is increased. Finally after six passes the billet is deformed into the multi diameter shaft. Initially the temperature of billet is 1250o C. But during the multi-pass forging process the billet temperature starts reducing and finally reaches up to 450o C after the sixth pass.