Influence of carbon content on densification behaviour in forming of sintered plain carbon steel preforms

Abstract

Complete experimental investigation on the deformation and densification behaviour of sintered plain carbon steel cylindrical preforms with carbon contents of 0, 0.35, 0.75 and 1.1 per cent, under cold upsetting, have been studied in order to understand the influence of various forming parameters such as true axial strain, flow stress, Poisson's ratio, forming limits and formability stress index on the densification process. The above-mentioned powder metallurgy sintered preforms with constant initial theoretical density of 84 per cent and aspect ratio of 0.4 were prepared using a suitable die-set assembly on a 1 MN capacity hydraulic press and sintered for 90 min at 1200 °C. Each sintered preform was cold upset under two different frictional constraints, namely, nil/no and graphite lubricant conditions. Densification–true strain and fracture strain–carbon content relationship was established and presented in this work. Further, attained density is considered to establish flow stress and formability stress index behaviour. The present work provides a guideline for producing P/M components free from open surface pore.