A new way to produce aluminised layer on austenitic refractory steel by electrolytic activated flux technique

An aluminum diffuse-alloyed layer on the austenitic refractory steel Cr30Ni20NRE designed for electric radiant tubes was investigated. A thin pre-coated layer was first formed on the steel's surface with the electrolytic activated flux technique. Thereafter, the austenitic steel was hot-dipped in the aluminum bath at 730?C for 5 min, and then diffuse treated at 960?C for 6 hours in an atmosphere containing NH4Cl plus CeO2. Finally, a dense diffused layer that had a good metallurgical combination with the steel substrate, accompanied by numbers of homogenously dispersed particle phase containing Cr and Si, was observed.