In the previous paper, the yield stress in hot extrusion of pure aluminum was determined from the analysis of experimental results and an empirical formula was established to calculate the maximum extrusion pressure.
This paper describes that the yield stresses of various aluminum alloys were obtained by the analysis of experimental results in a way similar to that of pure aluminum.
In order to determine the yield stress in hot extrusion of pure aluminum, the factors to be taken into account were strain rate, work hardening, and temperature elevation; while, in case of aluminum alloys of especially hard ones, strain rate and work softening had to be considered.
An empirical formula for obtaining the maximum extrusion pressure from the chemical compositions was established for various aluminum alloys.
Although yield stresses were determined from the experiments by using a number of billets having various lengths, a new experimental method using a billet of only one definite length was proposed in order to minimize the number of tests.
