Abstract
As a working method of cold forging, the side extrusion working by a piercing punch was applied to a cylindrical specimen of 99.5% aluminum and cup-shaped products were tried to produce. In this study, effect of the pre-annealing and intermediate annealing on side extrusion working was studied.
The working methods are as follows. (1) One end of the cylindrical specimen is pressed by flat end punch. (2) Secondly it is piercied by a conical punch into the specimen. In this study, two processes were applied. In process A, the specimen was heat-treated before pressing by the flat end punch and in process B, it was heat-treated before piercing by the conical punch. In case of high pressed products being worked again, process B was studied to prevent the crack occurance and the skin roughing in the products. For different working process, the shape and the surface of the deformed head, and the results of hardness and plastic flow on the radial section of the deformed head were compared and studied. The results obtained are as follows. (1) As soon as the specimen contacts with the side of the circular die, it is excluded rearward. (2) Process A is superior to process B on the rate fulled materials in the circular die. (3) Process A is intence on the skin roughing phenomena of the surface of the deformed head.
