Effect of Rare Earth Ce on Modifying Inclusions in Al-killed X80 Pipeline Steel

Mechanism of cerium-based inclusion formation and influence on impact toughness in industrial Al-killed steel

“…In the lab, the evolution was simple, such as following Al 2 O 3 →CeAl 11 O 18 →CeAlO 3 →Ce 2 O 3 in labs. [11][12][13] And in industry, the evolution was complex, such as following CaO-Al 2 O 3 → (Ca-Ce-S-O) + (Al-Ca-O-Ce) and following MnS + Al 2 O 3 -MnS → MnS + Ce-Al-O-MnS + Ce-O-MnS → MnS + Ce-S-MnS + Ce-S + Ce-O-S-MnS + Ce-O-S → Ce-S + Ce-O-S. [14][15] As known, a key of research value was industrial application. Considering complexity of actual inclusions in steelmaking process, it was meaningful to research the formation of Ce-based complex inclusions.…”

“…21 And Ce 2 O 2 S was often observed in steel and the Ce 2 O 2 S was responsible for the grain refinement of δ-Ferrite. 14,15,22 Generally, most studies of steel bearing RE were from labs, with high content of RE. However, the content of RE in industrial products was very low, because of nozzle clogging problem and economic problem.…”

“…21 And Ce 2 O 2 S was often observed in steel and the Ce 2 O 2 S was responsible for the grain refinement of δ-Ferrite. 14,15,22…”

Evaluation and Analysis of the Influence of Rare-Earth Ce on Inclusions in Heavy Rail Steel

“…Meanwhile, the number density of Al 2 O 3 inclusions increased, but the area density decreased during the continuous casting and rolling process. Cheng et al [9] studied the effect of rare earths on modifying inclusions in Al-killed X80 pipeline steel subjected to Ce treatment and found that Ce treatment modified and refined the inclusions. With the increase in Ce content from 0 wt.% to 0.025 wt.%, the mean size of inclusions first decreased from 2.41 am to 1.80 µm and then increased to 1.87 µm; moreover, the proportion of inclusions smaller than 2 µm gradually increased, while that of inclusions larger than 3 µm initially decreased and then increased owing to the aggregation of Ce-O-S inclusions.…”