Effect of Thickness of Packed Powder on Reduction Behavior in Vacuum Annealing of Cr-Alloyed Steel Powder

Abstract

Calculation results using a gas diffusion model suggested that a reduction time of Cr-alloyed steel powder in vacuum annealing was in proportion to the 2nd power of the thickness of the packed powder. However, the reduction time actually required in a vacuum furnace was in proportion to the 1/8 power of the thickness. It was therefore concluded that the reduction time was influenced as well by the heat transfer in the packed powder and the atmospheric pressure in the furnace.