Upset forging tests on iron preforms of cylindrical shape with different in
itial aspect ratios, forged at the temperature of 1150 degrees C suggest th
at the experimentally determined theoretical density ratio has a straight-l
ine relationship with the new strain parameter (e(epsilon z-epsilon 0)) and
the geometrical parameter ratio [(h(0)/h(f))(3D(0)(2)/(2D(b)(2) + D-c(2)))
]. The barrel-radius curvature fits a circular are. This shows that the bul
ged and contact diameters and height can be related to the theoretical dens
ity ratio. Also, an attempt has been made to establish the relationship bet
ween the measured barrel radius and the stress ratio parameters namely sigm
a(theta)/sigma(z), sigma(z)/sigma(m), and sigma(theta)/<(sigma)over bar>, a
nd Poisson's ratio. (C) 2000 Elsevier Science S.A. All rights reserved.