PROCESS SEQUENCE DESIGN OF LARGE AXISYMMETRICAL FORGING PRODUCT OF AISI4130 IN NOZZLE TYPE

Abstract

Process sequence design of a large axi-symmetric hot forging product of AISI 4130 in nozzle type has been investigated by physical modeling using plasticine and lead and finite element modeling. In order to verify the validity of experimental data, a similarity study between plasticine and AISI 4130 has been made. The frictional conditions between dies and the workpiece were determined by ring tests using several lubricants such as vaseline, baby powder, facial tissue, plastic wrapping paper, and Teflon. Because of limit of the machine capacity, the maximum forging load during modeling was limited to 10,000 metric ton. Thus, the total required forging loads were larger than the limiting value and forming process should be divided into several stages. The intermediate stages were determined by estimating the required forging loads based on slab method for physical modeling experimentation. Finite element simulation was utilized to determine the intermediate stages of forming considering the pressure distribution along the radial direction. Both pancake forging and backward extrusion were investigated in making preform before the final forging. Based on these simulational results, the proper sequence design was obtained in forging nozzle type of a large axi-symmetric hot forging product of AISI 4130 using backward extrusion and finish forging process.