|
Vol.51, No.2, 113 ~ 119, 2013
|
| Title |
| Inclusion Modification by Al Deoxidation and Ca Treatment in Ti Containing 18%Cr Stainless Steel Melts |
| 김경호 Kyung Ho Kim , 도경효 Kyung Hyo Do , 최원진 Won Jin Choi , 이상범 Sang Beum Lee , 김동식 Dong Sic Kim , 박종진 Jong Jin Pak |
|
|
|
| Abstract |
| Titanium is added to ferritic stainless steels in the range of 0.2-0.3 wt% to improve corrosion resistance and mechanical properties. However, titanium is very reactive with oxygen in liquid steel, and it can cause an unstable Ti yield. Therefore, titanium is generally added after the aluminum deoxidation process in the ladle. However, the inclusions formed by Al-Ti deoxidation can cause nozzle clogging and various defects in final products. Calcium injection can be carried out to resolve these problems. In this study, two different deoxidation patterns of Al→Ti and Al→Ti→Ca additions were carried out in Fe-18%Cr ferritic stainless steel melt at 1873 K. The melt composition and the inclusion morphology changes during the deoxidation process were investigated. With Al→Ti addition, the Al2O3 inclusions changed to dual phase Al2O3-TiOX inclusions with time by the reaction with Ti in the melt. The morphology of the inclusions in the melt finally changed to a polygonal type indicating that the inclusions were sol d phase. The size and number of inclusions in the melt did not change with time after Ti addition. With of Al→Ti→Ca addition, Ca reacted with Al2O3-TiOX inclusions to form liquid CaO-Al2O3 inclusions embedded with solid CaTiO3 particles. The morphology of the inclusions in the melt were observed to be spherical and polygonal. The size of inclusions in the melt increased and the number of inclusions decreased by the coalescence of liquid inclusions. |
|
|
| Key Words |
| ferritic stainless steel, deoxidation, aluminum, titanium, calcium |
|
|
 |
|
