Method for controlling non-metallic slag inclusion in medium and heavy plate of hydrogen-induced cracking resistance pipe line steel

The invention provides a method for controlling non-metallic slag inclusion in a medium and heavy plate of a hydrogen-induced cracking resistance pipe line steel, belonging to a technical field of steel-making. Process route of the method is: converter steelmaking, ladle furnace refining RH vacuum refining, Ca processing, soft blow and killing, and continuous casting. Characteristics of the technology are: controlling contents of carbon and oxygen at a smelting end-point of the converter, adding a strong aluminum deoxidizer in a tapping process; adding high alkalinity refining slag in the ladle furnace refining process, and controlling flow and time of bottom-blowing argon and components of the refining slag; controlling increase of the argon flow and vacuum treatment time in the RH vacuum refining process; controlling [Ca] content in steel in the Ca processing process; controlling the flow and time of the soft blow liquid steel and the killing time; and adopting full protection casting in the continuous casting process. The method provided in the invention has the advantages that: by adopting the technology, requirement of the non-metallic slag inclusion in the hydrogen-induced cracking resistance pipe line steel is satisfied; according to GB/T10561-2005 criterion for the non-metallic slag inclusion in the steel, various non-metallic slag inclusions in the steel are controlled within 0.5 grade; adopting a NACE standard A solution to carry out a detection of anti-HIC performance to the medium and heavy plate rolled by the casting blank, and the detection result of anti-HIC performance is qualified; and realizing batch and stable production of the medium and heavy plate in the hydrogen-induced cracking resistance pipe line steel.