Manufacturing method of Ti-containing ultra-low carbon steel

摘要

In the method of refining molten steel using an RH vacuum degassing apparatus, after vacuum decarburization treatment and followed by deoxidation treatment of molten steel with Al, a flux having a higher melting point than the molten steel temperature is added into the vacuum chamber of the RH vacuum degassing apparatus. A method for producing a Ti-containing ultra-low carbon steel comprising adding a Ti source and then adding a Ti source. In addition, the molten steel reflux time t 1 after adding a predetermined amount of flux and adding the Ti source in the RH vacuum degassing device, and the transport time t 2 from the end of the RH treatment to the start of the molten steel pouring into the tundish for continuous casting are , is adjusted so as to satisfy the following formula (wherein, G: reflux gas flow rate, P: vacuum degree, P 0 : atmospheric pressure, W M : molten steel weight, and D: molten steel surface part diameter within the flow). 190(G ln(P 0 /P)/W M ) 1/3 t 1 + 11.8(D 2 /W f ) t 2 ≤ 1800