Abstract: Based on the summarization of the die-sets for flashless-die-forging at home and abroad, double-action hydraulic die-sets for the flashless-die-forging were developed.The opening and closing of the mould is performed by an upper and a lower hydraulic cylinders.The movement of the upper and lower punches are controlled by a four-barlinkage.The developed die-sets were tested in an 8000 kN frame type hydraulic press for the cold forging of Jetta car differential half-axle gears. The results show that the design of the die sets is reasonable, its function can be realized safely,and the performance parameters meet the design specifications.

Key words: plastic forming processing and equipment, flashless-die-forging, double-action hydraulic die-sets, half axle gear