Mechanical Properties of Sintered Iron Sheets Containing Reduced Iron Powder with Gangue

Abstract

In order to estimate the possibility of utilization of reduced iron powder produced by a fluidized bed, an examination was made on the effect of gangue minerals in iron are on the mechanical properties of sintered iron sheets which contained various oxides of the gangue. Reduced iron powder was carefully mixed with pure iron powder up to 50%. The mixed powder was sintered at 850°C or 900°C for 1 h in hydrogen after pressing, and then rolled and annealed.
The effect of gangue oxides dispersed in the sintered iron sheets on the mechanical properties was examined. As the content of oxides in the sheets increased, the yield stress and tensile strength increased, but the elongation decreased. After a high temperature annealing in hydrogen, its elongation was improved because of the decrease of oxygen content in iron sheets, while the strength decreased owing to the reduction of oxides during heat treatment in hydrogen.
These oxides of gangue minerals in iron are changed into glassy ones during reduction. The oxide layers were found to be parallel to the rolling face in iron sheet. These gangues contained in the sintered iron sheet are effective to increase the tensile strength of the sheets produced at lower temperatures. This is seemed to come from the reason that these oxides are crushed and become to be fine particles in the matrix during the rolling.