Method for smelting high-nitrogen steel

Abstract

The invention discloses a method for smelting high nitrogen steel, which comprises a smelting method of a high nitrogen steel which can effectively improve and guarantee the content of N in alloy, the technical proposal which is adopted comprises the following steps: firstly, smelting molten steel with an electric arc furnace or an induction furnace, secondly, simultaneously adopting another electric arc furnace or an induction furnace to smelt nitrogen containing alloy, adapting the sum of molten steel components in the step one and the step two with steel grade, thirdly, adding molten steel which is smelted in nitrogen containing alloy solution, and refining under the protection of nitrogen, and getting high nitrogen steel. The technical proposal of the invention which is adopted by the invention to smelt high nitrogen steel without needing complex pressurization and remelting equipment, the total smelting time is greatly shortened, which is only one half of the time for smelting high nitrogen steel in the prior art, the operation is simple, and chemical components in steel are stable, fluctuation of steel components among furnaces is small, which is beneficial for processing follow-up process. And meanwhile, the number of deoxidation reducing agent is greatly reduced, and smelting cost is lowered.

Description

technical field [0001] The invention relates to the technical field of iron and steel smelting, in particular to a method for smelting high-nitrogen steel. Background technique [0002] High nitrogen steel has attracted more and more attention due to its excellent mechanical properties and corrosion resistance. According to metallurgical regulations, steel whose matrix is ​​ferrite has a nitrogen content ≥ 0.08%, and steel whose matrix is ​​austenite has a nitrogen content ≥ 0.4% is high nitrogen steel. According to people's long-term research, it has been confirmed that the nitrogen content in steel depends on ① the content of alloying elements; ② smelting temperature; ③ the way of adding nitrogen-containing gas and nitrogen-containing alloy; ④ smelting method; Among these influencing factors, the content of alloying elements and smelting temperature are limited by the steel type and other conditions. What people can change is the way of adding nitrogen and nitrogen-contai...

AI Technical Summary

Problems solved by technology

However, low pressure conditions are not conducive to smelting high-nitrogen steel; the nitrogen added to the steel by the above-mentioned methods before or during vacuum treatment is very easy to remove, and the recovery rate is almost zero.

In addition, pressurized electroslag remelting (PESR) is used. Although the nitrogen content is higher than the above-mentioned processes, special equipment is needed, and the production cost is significantly increased.

[0004] Chinese Patent Application No. 200510030763.1 "Method for Smelting High Nitrogen Steel with Additional Cathode Glow Discharge" discloses a smelting method by setting an anode above the liquid surface of the molten pool in the vacuum melting furnace, and between the anode and the liquid surface of the molten pool An additional cathode with a hole is set, and the vacuum smelting method is used to heat, melt, refine and adjust the alloy element content of the furnace charge; the nitrogen content in the embodiment after pure iron smelting has reached more than 2%, and GCr15 nitrogen The nitrogen content of Cr-Mo structural steel reaches 0.5%, and the nitrogen content of Cr-Mo structural steel reaches 0.6%. This method is also smelted in a vacuum mode, and the nitrogen entering the molten steel is easy to remove, and it is difficult to implement in actual production.

Due to the smelting of low-carbon, low-phosphorus and high-manganese molten steel in an electric arc furnace, it takes a long time and complicated procedures to carry out three stages of steelmaking

After the molten steel is smelted and qualified, the temperature is raised, and nitrogen-containing materials are added for alloying and reduction refining. The furnace temperature is high, the time is long, and the operation is complicated.

High-temperature molten steel causes nitrogen to combine to form a large amount of nitrogen gas, and the nitrogen content in the steel must be very low, resulting in a low nitrogen recovery rate.

Images