50 巻 (2009) 585 号 p. 951-955
Friction for a large reduction in thickness in forging of plates was reduced by oscillating forging load. In this process, compressive load is partially released during the forming with a liquid lubricant to relubricate the outer portion of the plate. The gap between the die and the outer portion of the plate in each release is caused by the difference in elastic recovery between the die and the plate, and the liquid lubricant is automatically fed into the gap during the partial release of the load. In the compression of an aluminum alloy plate, the effects of the releasing ratio of the load and the number of releases on the reduction in compressive load were examined. Compressive load was reduced by load oscillation, and the thickness of the compressed plate was significantly decreased. The mechanism of automatic relubrication by the load oscillation was verified by inducing the corrosion of part of the gap in a forging experiment. It was found that load oscillation having an automatic relubrication function is effective in preventing the increase in the load in the forging of plates.