Production method of low-carbon high-chromium steel

Abstract

The invention provides a production method of low-carbon high-chromium steel. The method comprises the following steps: the converter tapping carbon content is controlled to 0.15-0.25wt% and the tapping temperature is controlled to 1660-1670 DEG C, and balanced steel is tapped; 1.2-3kg of small active lime particles are added in each ton of steel after tapping; the Ruhrstahl & Hereaeus (RH) furnace adopts high lance height hand pressure control, the lance height and the oxygen flow are adjusted dynamically at any time according to the carbon content of steel, the waste gas flow is controlled to no more than 3000Nm<3> / h, the stepped pressure-reducing way is adopted, and the molten steel liquid level of the vacuum chamber is always controlled to be below the boundary of the bottom groove and the middle groove; when the RH furnace performs light treatment to reduce the carbon content of steel to 0.10wt%, the pressure is adjusted, the oxygen lance adopts a low lance height and the lance height is lowered to the optimum decarburization location; and fluorite and aluminum powder are added in the low frequency (LF) furnace to reduce chromium in slag. By adopting the production method of low-carbon high-chromium steel, the carbon content can be reduced to below 0.01% and the chromium content is no less than 5%, thus the RH furnace can be used to produce pure and qualified low-carbon high-chromium steel.

Description

technical field [0001] The invention belongs to the technical field of steelmaking technology, and in particular relates to a method for producing low-carbon high-chromium steel by adopting a converter-vacuum circulation degassing furnace (RH furnace)-ladle refining furnace (LF furnace) process. Background technique [0002] The so-called low-carbon high-chromium steel refers to a class of steel containing C≤0.01% and Cr≥5% in steel. At present, ultra-low carbon steel with Cr content ≥ 5 wt% in converter smelted steel needs to add high-carbon ferrochrome in the converter. In order to ensure the yield of chromium, the carbon requirement of tapping is more than 0.2%. Due to the high carbon content in steel, most of them do not use RH furnace for processing, but use vacuum degassing furnace (VOD furnace) to produce ultra-low carbon high chromium steel, so domestic special steel factories use VOD furnace for production Low carbon high chromium steel. [0003] When domestic RH ...

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Problems solved by technology

[0003] When domestic RH furnaces produce low-carbon steel, in order to ensure the safety of production, it is required that the C in the furnace should be ≤0.10%. At present, there is no precedent for the production of high-carbon steel by RH furnaces.