1Department of Mechanical Engineering, Thiagarajar College of Engineering, Thiruparankundram, Madurai - 625 015, TamilNadu, India. Email: rajeshkannan_a@yahoo.com
2Maulana Azad National Institute of Technology, Bhopal - 462 007, Madhya Pradesh, India. Email: kspmet@yahoo.co.in
3Department of Mechanical Engineering, National Institute of Technology, Tiruchirappalli - 620 015, TamilNadu, India. Email: shunt@nitt.edu
4Department of Production Engineering, National Institute of Technology, Tiruchirappalli - 620 015, TamilNadu, India. Email address: narayan@nitt.edu
Cold upsetting experiments were carried out on sintered Fe-0.8%C steel preforms in order to evaluate the technical relationship that exist between the applied stresses against continuous deformation and densification. Powder preforms of 86% theoretical density and 0.40 of initial aspect ratio were subjected to incremental compressive loading of 0.04MN under two different lubricating constraints, such as nil and graphite lubricants until fracture appears at free surfaces. Experimental results revealed that the response of applied stresses with respect to induced strain and attained densification exhibits a continuous enhancement but with three different stages. Irrespective of friction conditions, the first and third stage shows steep rise, which offers high resistance to deformation, whereas the second stage shows virtually steady state; deformation needed gradual increase in applied stresses but with high rate of densification. Further, the work is extended to evaluate the strain hardening characteristics and it is found that the preform deformed under nil lubricant exhibited maximum strain hardening as well as an enhanced rate of strain hardening through out the deformation in comparison with graphite employed lubricant conditions.
Applied Stresses, Deformation and Densification, Friction Conditions, Strain Hardening
