A method of reducing submerged nozzle clogging by calcium aluminum iron alloy treatment

Abstract

The invention discloses a method for reducing blockage of a submersed nozzle through ferroaluminum treatment, and belongs to the technical field of steelmaking refining. In the RH refining process, forced decarbonization or natural decarbonization is adopted according to the pull-in condition, an aluminum block is used for complete deoxygenation after decarbonization is completed, 3 min after thealuminum block is added, the Alt content in steel is adjusted according to the objective through calcium-aluminum-iron, other alloys and calcium-aluminum-iron are simultaneously added through a vacuumhopper, molten steel vacuum circulating treatment continues to be carried out under vacuum, and uniform distribution of calcium in molten steel is guaranteed. Calcium in the alloys and aluminum oxideinclusions in the molten steel react to form low-melting-point inclusions, thus, accumulation of the aluminum oxide inclusions on a water gap is reduced, blockage of the water gap in the casting process is reduced, and the quality of casting blanks is improved. The method has high process application value, spot operation is easy and convenient, and blockage of the water gap can be obviously reduced.

Description

technical field [0001] The invention relates to a method for reducing clogging of a submerged nozzle through calcium-aluminum-iron alloy treatment, and belongs to the technical field of steelmaking and refining. Background technique [0002] When casting ultra-low carbon steel (C<0.0030%), the RH refining process mostly uses aluminum particles to deoxidize the steel, and the aluminum particles and the oxygen in the molten steel form Al 2 o 3 In the later stage of sedation and casting process, although the small particle inclusions are easy to collide and aggregate to grow up and be removed by floating, some of them still exist in the molten steel, and they are easy to gather at the outlet of the submerged nozzle of the crystallizer to cause nozzle blockage. The blockage of the nozzle can lead to the asymmetric flow of molten steel in the flow field in the mold, which will affect the fluctuation of the liquid level, cause the occurrence of slag entrainment defects, and th...

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Problems solved by technology

[0003] For the above-mentioned RH refining process, aluminum particles and oxygen in molten steel generate Al 2 o 3 The problems caused by inclusions, the present invention provides a method to reduce the clogging of submerged nozzles through calcium-aluminum-iron alloy treatment, aiming at making Al 2 o 3 The inclusions are denatured to form calcium aluminate, which makes it difficult to aggregate and at the same time ensures the uniform distribution of calcium in the molten steel, thereby reducing the blockage of the submerged nozzle of the crystallizer and improving the quality of the cast slab

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