Calculation of stresses in the wall-ironing of cups

Abstract

The experimentally determined effects of die angle, friction and reduction on the ironing process are briefly described and the limitations of the slab method for the calculation of the ironing load are outlined.Hill's two-centred fan slip-line field for ironing is discussed and the static inadmissibility of some of the solutions is described. A further limitation on these fields is shown to occur when the hydrostatic pressure at the slip-line cusp at the punch surface is less than or equal to − k. Under these circumstances, it is predicted that thinning of the material at the punch will occur, which in practice would give a product with a reduced wall thickness and an increased internal diameter.