A Rajeshkannan
,
K S Pandey
,
S Shanmugam
,
R Narayanasamy
钢铁研究学报(英文版)
Cold upsetting experiments were carried out on sintered Fe08%C10%Si04%Cu steel preforms in order to evaluate their deformation characteristics. Powder preforms of 86% of theoretical density, with two different ratios of height to diameter, were prepared using a suitable die set assembly on a 10 MN capacity hydraulic testing machine. Sintering was carried out in an electric muffle furnace for 15 h at 1 150 ℃. Each sintered compact was subjected to incremental loading of 004 MN under dry friction condition till a crack appeared at the free surfaces. The experimental results were critically analysed, the stress as a function of strain and densification was obtained, then the work hardening behaviour was analyzed. It has been found that in the process of enhancing densification, strength and strain hardening is also induced during upsetting, but the work hardening behaviour is not homogenously enhanced against strain and densification.
关键词:
cold upsetting;stress;height strain;densification;work hardening behaviour
S Narayan
,
A Rajeshkannan
钢铁研究学报(英文版)
An experimental investigation on the workability behaviour of sintered Fe-035C steel preforms under cold upsetting, have been studied in order to understand the influence of aspect ratio and lubrication condition on the workability process. The above mentioned powder metallurgy sintered preform with constant initial theoretical density of 84% of different aspect ratios, namely, 04 and 06 respectively were prepared using a suitable die-set assembly on a 1 MN capacity hydraulic press and sintered for 90 min at 1200 ℃. Each sintered preform was cold upset under nil/no and graphite frictional constraint, respectively. Under the condition of triaxial stress densification state, axial stress, hoop stress, hydrostatic stress, effective stress and formability stress index against axial strain relationship was established and presented in this work. Further more, attained density was considered to establish formability stress index and various stress ratio parameters behaviour.
关键词:
powder metallurgy
,
failure analysis
,
plastic behaviour
,
workability
S Narayan
,
A Rajeshkannan
钢铁研究学报(英文版)
Complete experimental investigation on the instantaneous strain hardening behaviour of powder metallurgy (P/M) preforms of pure iron, Fe-0.35%C, Fe-0.75%C and Fe-1.1%C was carried out. The strain hardening behaviour of the above-mentioned P/M sintered steel preforms with aspect ratio of 0.4 under triaxial stress state condition was determined by cold upsetting under nil/no and graphite lubricant conditions. The instantaneous strain hardening value (ni), strength coefficient (Ki), and the stress as a function of strain and densification were obtained and analyzed. Furthermore, a relation was obtained from a semi-log plot of stress against relative density and analyzed to study the hardening behaviour owing to densification as stress was a function of induced strain as well as densification in the P/M materials.
关键词:
strain hardening exponent
,
density hardening exponent
,
strength coefficient
,
densification
,
triaxial stress
