EFFECT OF HOT-WORKING VARIABLES ON MICROSTRUCTURE AND PROPERTIES OF FE-25AL

The evolution of microstructures of extruded ingot Fe-25Al material du ring multipass hot rolling at 800 degrees C (B2 ordered) and 1000 degr ees C (disordered) has been studied. GI ain refinement was found to be difficult at 1000 degrees C because, in the processing times, recryst allisation and grain growth were too rapid. At 800 degrees C, however, recrystallisation and grain growth were significantly slower; which m akes grain refinement and microstructural control feasible. Good agree ments were found between the loads measured in rolling and the flow st ress values obtained from plane strain compression testing. Roll chill ing was found to cause a significant increase inflow stress because th e surface of the Fe-25Al material is cooled below T-c in this case. Af ter a number of consecutive rolling passes, a dramatic increase in the pow str ess was observed, which cart be attributed to the additional effect of work hardening, combined with the effects of roll chilling a nd ordering. The properties of the material processed by different hot rolling schedules were examined by tensile testing and, by manipulati on of hot rolling and heat treatment parameters, it was possible to pr oduce higher proof stress and lower elongation, or vice versa. MST/387 0.