A method for smelting low-carbon, low-nitrogen, high-chromium steel

Abstract

The invention relates to a smelting method of low-carbon low-nitrogen high-chrome steel. The low-carbon low-nitrogen high-chrome steel comprises the following components in mass percent: less than 0.03% of C, equal to or less than 0.10% of Si, equal to or less than 0.20% of Mn, 3.0-3.55% of Cr, less than 0.05% of N, equal to or less than 0.020% of P, equal to or less than 0.020% of S, and the balance of Fe and unavoidable impurities. The smelting method of low-carbon low-nitrogen high-chrome steel comprises the following steps: molten iron is pretreated; the pretreated molten iron is boiled in a converter and steel tapping is carried out, during the steel tapping, C is controlled to be between 0.03-0.05%, the temperature is higher than 1710 DEG C, and the oxygen activity in steel in a tank is ensured to be between 500-700 ppm; if the oxygen activity in steel is greater than 700 ppm, the oxygen activity of molten steel in the tank is controlled to be between 500-700 ppm; steel ladles are carried back to the converter after being carried out of an RH furnace, after the large tank is moved to a steel tapping position, argon blowing is carried out, low-carbon chromium iron is fed in the tank through a stock bin at the same time, and argon blowing is carried out for 5 minutes and then stopped; temperature is measured after the steel ladles are fed in an LF furnace, if the temperature is higher than 1575 DEG C, the steel ladles are fed in a machine for pouring, and if the temperature is lower than 1575 DEG C, the steel ladles are moved out after the temperature is raised to 1575 DEG C. The smelting method of low-carbon low-nitrogen high-chrome steel has the advantages of realizing the purpose that low-carbon low-nitrogen high-chrome steel is produced in a plain carbon steel factory and ensuring the reliability of RH production.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, in particular to a method for smelting low-carbon, low-nitrogen, high-chromium steel. Background technique [0002] At present, the production of low-carbon, low-nitrogen and high-chromium steel is a difficult problem for the process of producing steel by converter. This is due to the high chromium content and the large amount of alloy, which makes it difficult to control the temperature throughout the process. The carbon content is low, which means that the molten steel must undergo RH deep decarburization. The characteristic of high-chromium steel is that molten steel and chromium-containing steel slag are relatively sticky, which will cause adhesion to the RH insertion tube, and in severe cases, production accidents will occur. And low nitrogen needs to ensure the nitrogen increase in the whole process of molten steel treatment, so in general, the control is more difficult. Low-carbon hi...

AI Technical Summary

Problems solved by technology

The characteristic of high chromium steel is that molten steel and chromium-containing steel slag are relatively sticky, which will cause adhesion to the insertion tube of RH, and in severe cases, production accidents will occur

And low nitrogen needs to ensure the nitrogen increase in the whole process of molten steel treatment, so in general, the control is more difficult