Effect of Si and Ce Contents on the Nozzle Clogging in a REM Alloyed Stainless Steel

• The influence of the cerium and silicon contents on the castability of a REM-alloyed stainless steel was investigated by using pilot scale experiments. The trials were carried out with three different silicon concentrations: i) low (LSi; Si < 0.5%); ii) middle (MSi; Si approximate to 0.8-1.4%); and iii) high (HSi; Si approximate to 1.5-1.9%). During the casting, the liquid steel was teemed out through a zirconia nozzle located at the bottom of the furnace. The results showed that the nozzle clogging did drastically increase with increasing concentrations of Si and Ce up to levels larger than the critical contents (>= 1.5% Si and >= 0.05% Ce) in the cast HSi steel. In addition, the Ce content in a cast steel was found to increase linearly with an increased concentration of Si, due to the determinant effect of the Si content on an initial content of O in the melt before an addition of mischmetal. Finally, it was found that the concentration of insoluble Ce (Ce-insol.) determines the amount of inclusions and clusters in steel samples. Overall, soluble Ce concentrations larger than 250 ppm were found to be an important reason for fast nozzle clogging during casting.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Metallurgi och metalliska material (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Metallurgy and Metallic Materials (hsv//eng)

Nyckelord

stainless steel

clogging

REM-treatment

clusters

soluble and insoluble Ce content

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