Comparative Study on the Cleanliness of Ultra-Low Carbon Al-Killed Steel by Different Heating Processes

Cleanliness of aluminum-killed ultra-low carbon steel produced through BOF-RH-CC and BOF-LF-RH-CC was comparatively investigated by various test equipment. Three different heating processes were used when the converter tapping temperature was low: reheating by blowing oxygen and Al addition during RH early decarburization stage (Process-A); reheating by blowing oxygen and Al particles addition at the end of RH decarburization (Process-B); and no Al addition at RH decarburization stage but the process was BOF-LF-RH-CC (Process-C). The nonmetallic inclusions can be removed obviously in three refining processes. Statistical analysis of inclusion area fraction showed Process-A was substantially less than those in Process-B. Furthermore, the proportion of single inclusion area <8 mu m(2) increased from Process-A level 85% to Process-C level 95%. Moreover, this study proposed an XGBoost model based on big data mining methods to investigate the computational simulation and the introduction of the XGBoost model ensured 90% accuracy rate for seeking an optimum refining process.