dc.contributor.author |
Pistorius, CP
|
|
dc.contributor.author |
Presoly, P
|
|
dc.contributor.author |
Tshilombo, KG
|
|
dc.date.accessioned |
2010-02-18T14:35:32Z |
|
dc.date.available |
2010-02-18T14:35:32Z |
|
dc.date.issued |
2006-08 |
|
dc.identifier.citation |
Pistorius, CP, Presoly, P and Tshilombo, KG. 2006. Magnesium: Origin and role in calcium-treated inclusions. SOHN International Symposium on Advanced Processing of Metals and Materials: Principles, Technologies and Industrial Practice, San Diego, California, 27-31 August 2006, pp 373-378 |
en |
dc.identifier.uri |
http://hdl.handle.net/10204/3954
|
|
dc.description |
2006 TMS Fall Extraction & Processing Meeting. Sohn International Symposium on Advanced Processing of Metals and Materials: Principles, Technologies and Industrial Practice, San Diego, California, 27-31 August 2006 |
en |
dc.description.abstract |
Calcium treatment of alumina inclusions, to convert the alumina to molten or partially molten calcium aluminates, is a well-established treatment for steel, to improve the castability of aluminium-killed steel. However, the role of magnesium in calcium-treated steel is not fully clear, nor is the origin of the several percent of magnesium oxide that is often present in calcium-treated inclusions. To study this, steel was sampled after calcium treatment at an industrial steel plant, and the inclusions identified by energy-dispersive X-ray microanalysis (EDX) on polished sections of the samples (analysing the samples in a scanning electron microscope). The predicted fraction liquid in the inclusion was estimated from the ternary alumina-magnesia-lime phase diagram. Inclusions with higher CaO contents generally had lower MgO contents, indicating that the calcium wire is not the origin of the magnesium in the inclusions; this was also confirmed by wet chemical analysis of the calcium wire. Instead, it appears that magnesium-alumina spinel inclusions form during extended ladle contact after aluminium killing and before calcium treatment. While such spinels have been stated to cause poor castability (clogging the submerged-entry nozzle), it is clear that calcium treatment successfully modifies the spinel inclusions to mixed alumina-lime-magnesia inclusions, where the magnesia content contributes substantially to liquefaction of the inclusions: for typical MgO contents of around 10%, the range of Ca:O ratios which yield liquid (or partially liquid) inclusions is extended substantially to lower Ca:O ratios. |
en |
dc.language.iso |
en |
en |
dc.subject |
Aluminium killed steel |
en |
dc.subject |
Metallurgy |
en |
dc.subject |
Calcium treatment |
en |
dc.subject |
Magnesium |
en |
dc.subject |
Spinel |
en |
dc.title |
Magnesium: Origin and role in calcium-treated inclusions |
en |
dc.type |
Conference Presentation |
en |
dc.identifier.apacitation |
Pistorius, C., Presoly, P., & Tshilombo, K. (2006). Magnesium: Origin and role in calcium-treated inclusions. http://hdl.handle.net/10204/3954 |
en_ZA |
dc.identifier.chicagocitation |
Pistorius, CP, P Presoly, and KG Tshilombo. "Magnesium: Origin and role in calcium-treated inclusions." (2006): http://hdl.handle.net/10204/3954 |
en_ZA |
dc.identifier.vancouvercitation |
Pistorius C, Presoly P, Tshilombo K, Magnesium: Origin and role in calcium-treated inclusions; 2006. http://hdl.handle.net/10204/3954 . |
en_ZA |
dc.identifier.ris |
TY - Conference Presentation
AU - Pistorius, CP
AU - Presoly, P
AU - Tshilombo, KG
AB - Calcium treatment of alumina inclusions, to convert the alumina to molten or partially molten calcium aluminates, is a well-established treatment for steel, to improve the castability of aluminium-killed steel. However, the role of magnesium in calcium-treated steel is not fully clear, nor is the origin of the several percent of magnesium oxide that is often present in calcium-treated inclusions. To study this, steel was sampled after calcium treatment at an industrial steel plant, and the inclusions identified by energy-dispersive X-ray microanalysis (EDX) on polished sections of the samples (analysing the samples in a scanning electron microscope). The predicted fraction liquid in the inclusion was estimated from the ternary alumina-magnesia-lime phase diagram. Inclusions with higher CaO contents generally had lower MgO contents, indicating that the calcium wire is not the origin of the magnesium in the inclusions; this was also confirmed by wet chemical analysis of the calcium wire. Instead, it appears that magnesium-alumina spinel inclusions form during extended ladle contact after aluminium killing and before calcium treatment. While such spinels have been stated to cause poor castability (clogging the submerged-entry nozzle), it is clear that calcium treatment successfully modifies the spinel inclusions to mixed alumina-lime-magnesia inclusions, where the magnesia content contributes substantially to liquefaction of the inclusions: for typical MgO contents of around 10%, the range of Ca:O ratios which yield liquid (or partially liquid) inclusions is extended substantially to lower Ca:O ratios.
DA - 2006-08
DB - ResearchSpace
DP - CSIR
KW - Aluminium killed steel
KW - Metallurgy
KW - Calcium treatment
KW - Magnesium
KW - Spinel
LK - https://researchspace.csir.co.za
PY - 2006
T1 - Magnesium: Origin and role in calcium-treated inclusions
TI - Magnesium: Origin and role in calcium-treated inclusions
UR - http://hdl.handle.net/10204/3954
ER -
|
en_ZA |