Plastic deformation produced during indentation phase of rotary forging

Abstract

The concept of rotary forging in its two basic forms is described and a technique is presented for simulating the indentation phase of the process. Annealed aluminium alloy work pieces of differing height/diameter ratios were indented and examined internally. The approximate shapes of the deformation zones were established by hardness measurements on sections from as-worked samples and by metallographic observations of sections from work pieces which were recrystallized after indenting. Large recrystallized grains define regions which were cold worked by critical amounts during indentation. The three-dimensional shapes of the plastically deformed zones are discussed and the implications are considered in relation to the rotary phase of forging. Mechanisms are suggested for forging faults such as mushrooming of the surface worked by the indenting tool.