Effect of rare earth elements on the structure and properties of super ferritic stainless steel

Taking super ferritic stainless steel as the research object,the microstructure and properties are improved by adding rare earth elements.The main study focused on the effects of rare earth on the inclusions,microstructure,mechanical properties,and corrosion resistance of experimental steel.The results indicate that when the amount of rare earth added is≤0.106％,rare earth can effectively purify molten steel,specifically by significantly reducing the content of T.O(Total oxygen,the total content of oxygen elements in steel)and S.At the same time,an appropriate amount of rare earth can significantly refine inclusions,transforming large-sized polygonal inclusions into nearly spherical small inclusions.And rare earth can modify inclusions in steel,transforming hard Al2O3 inclusions into Re-O,Re-S,and complex RE-P-S-O inclusions.On the other hand,when the amount of rare earth added is≤0.106％,rare earth can refine the grain size of the experimental steel.The influence of rare earth on the tensile properties of experimental steel is relatively small.Finally,rare earth elements can effectively improve the intergranular corrosion resistance of experimental steel.