Some aspects of workability studies on sintered high strength P/M steel composite preforms of varying TiC contents during hot forging

Abstract

Workability is a measure of the extent of deformation that powder metallurgy materials can withstand prior to fracture occurred in the forming or upsetting processes. Workability of a material is obtained from several parameters namely strain, strain rate and temperature. Hot upsetting of the composite steel preforms with varying TiC contents, namely, 3% and 4%, and aspect ratios, namely, 0.45, 0.71 and 1.25, was carried out at a temperature of 1120 °C and the formability behaviour of the same under triaxial stress state condition was determined. The curves plotted for different preforms were analysed and a relationship was established between the axial strain and the formability stress index (β). The influence of TiC addition, in the steel composite, on the formability stress index, the relative density (R) and various stress ratio parameters, namely, (σθ/σeff), (σm/σeff) and (σz/σeff) were studied. An attempt is also made to relate the fracture strain of the preforms with the formability stress index (β) under triaxial stress state condition.