Shape Changes in the Upsetting of Slender Cylinders

Abstract

Mild steel and aluminum alloy cylinders were incrementally upset with good lubrication and with sticking friction, and the development of shape was followed by measuring the diameters of the barrel and the contact face. These dimensions changed according to a power law as a function of reduction and initial diameter-to-height ratio of the specimen. Formulas are given for predictive calculations of barrelled dimensions, and these were found to be reasonably applicable also to hot forging. The expansion of the original end face was highly sensitive to friction and the material’s strain hardening characteristics, and could not be generalized.