Closed Die Forging of Superplastic Zn-22Al Alloy

Abstract

Closed die forging of the water quenched superplastic and the furnace cooled non-superplastic Zn-22Al alloys was made in the axi-symmetric conditions to investigate the effects of superplasticity on the working force and material flow behaviours. The results are as follows.(1) Working force of the quenched material was 1/3-1/5 of that of the furnace cooled materials, but there was no remarkable difference in the material flow behaviours between both the materials. Surfaces of worked pieces were smoother in the quenched materials than in the furnace cooled materials.(2) In the axial flow type forging, working force for the movable container type die was 1/3 of that for the fixed type die in both the materials.(3) Working force in the centrifugal flow type forging was the lowest in both the materials, when a forging type was adopted by which nearly perfect centrifugal flows of materials were produced.