Abstract :   The isothermal oxidation behaviour of  austenitic heat resistant steel  ( 28%Ni, 12%Cr, 8%Al and balance Fe ) has been evaluated in the temperature range of ( 1000-1300 ºC ) .   The effect of different amount of aluminum on the oxidation of the heat  resistant  steel  have also been evaluated. the results indicate that addition of  ( % 8 ) Al  to the mentiond steel  exhibit  superior oxidation  resistance up to 1300 ºC due to formation of a very adherent , continous  and  thin  film  of  α- Al₂O₃  ,  But the existance of Al below ( % 8 ) in this alloy causes low oxidation  resistance even  in  1000 ºC , because the continous , adherent layer of  α- Al₂O₃   doesn't form on the surface of  the alloy.

 

 

Key Words : Heat resistant steel , Oxidation resistance , Protective α - Al₂O₃ film , Oxide Kinetic , High Aluminum  steels .