Low-carbon Automotive Steel Cleanliness Analysis And Process Optimization

In order to improve the quality of tanggang TC510L beam steel and optimize theproduction process, each process is sampled systematically. Through metallurgicalmicroscope, oxygen and nitrogen Analyzer, detail analysis of electrolytic method andscanning electron microscopy method and other methods to analyze their cleanliness.And the subject researches its technology optimization and ultimately improves thequality of TC510L beam steel.The study shows that: the number of microscopic inclusions of every process ismostly about0-5m and size larger means less quantity. The average content of T[O] is23.7x10^-6,T[N] is21.8x10^-6, micro-inclusions of volume rate is0.01054675%. Themicroscopic inclusions is predominantly A1₂O3to form various compound inclusions,There are also MnS inclusion and CaS inclusion throughout the process, accompanyingwith Zr early in the casting and inclusions. There are five main classes micro inclusionsin slab: Al₂O₃-CaS-MnO composite inclusions, Al₂O₃-CaS composite inclusions, MnSinclusion, Al₂O₃inclusion and CaS inclusions. The compound Al₂O₃-CaS-MnO inclusionaccount for the most part. The size of large inclusions in tanggang TC510L steel ismainly more than300μm, accounting for64.82%of the total number; The inclusioninclusions whose size is between140μm and300mm μm exist as a percentage of25.81%;The inclusions between80μm and140μm diameter is the least part accounting for9.47%of the total number. From electrolysis results, it reflects that the most inclusions in slabare silicate, aluminum silicate salt whose average level is65.4mg/10kg. And the processalso produces Na₂O and K₂O inclusions. It means that the crystal device protection slaginvolves into the molten steel because of liquid surface fluctuations when changingpackage and starting casting. Comparative analysis of oxide variability index found thatwhen the added amount of Ca190m line when the effect of inclusion variability is notideal, should be appropriate to increase the amount of added calcium lines; automaticallyadjust the level with the middle package, target weight and measured weight of the errorsignal with ladle slide gate control switch control to maintain the stability of the tundishlevel; steel replacement package, artificial added to the flux in the mold, the mold powderinvolved with liquid steel, which requires optimization.