Softening due to Annealing of Pure Al Extruded Rods (1). On Ununiform Softening and Effect of Extruding Temperature

Abstract

In this paper, it is described the effect of annealing on the softening of pure Al extruded rods. Generally, ununiform softening takes place in extruded rods by annealing at 300°, but long time heating (90 min) gives uniform softening to rods extruded at 325° and not to those extruded at 525°. It is thought that this ununiform softening is due to the different ability of recrystallization in extruded rods which are worked in different degree, by the facts that the softening curves in section of rods by annealing resembles that of cold worked metals. It was observed that the softening temperature is higher in rods extruded at higher temperature and that of surrounding or corner part in the section is lower than that inside the rods extruded at the same temperature.