Solidification Structure in La and Ti-containing FeCrAl Stainless Steel

Optical Microscope(OM) and Scanning Electronic Microscope(SEM) were used to analyze the solidified structure of La and Ti-containing FeCrAl stainless steel.The results show that the grain size in pure ferrite solidified structure without La and Ti treatment can be relatively big with the average values at 4.64 mm in longitudinal section and 4.71 mm in cross section.The grain size can be noticeably refined by addition of La as well as Ti to the steel.In addition,Ti can improve equiaxed grain ratio at the same time.The high-melting point second-phase particle formed after La and Ti addition is beneficial to refine grain and the large amount of TiN separated out in the steel contributes to improve equiaxed grain ratio.