A method for smelting low-nitrogen boron-containing steel to increase the yield of boron element

A smelting method and a yield technology, applied in the field of low nitrogen boron-containing steel smelting, can solve the problems of increased production cost, complicated process route, etc., and achieve the effects of reducing oxidation, improving yield and reducing oxidizability

Active Publication Date: 2020-05-26
INST OF RES OF IRON & STEEL JIANGSU PROVINCE +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The above-mentioned different boron-added steel smelting process routes can increase the yield of boron and control the N content of molten steel by selecting the timing and treatment method of ferro-boron addition, but all require additional production costs or complex process routes

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] (1) Boiling tapping at the end of the converter, the slag is controlled during the tapping process, 1.2kg / t of slag adjusting agent and 2.3kg / t of lime are added to the slag surface after tapping, argon is blown at the bottom of the ladle during the tapping process, and the bottom of the ladle is blown The flow rate is 80NL / min, keeping the molten steel agitated, but not splashing.

[0025] (2) The ladle is hoisted to the RH station. The oxygen content of the RH station is 0.0435%, and the T.Fe+MnO is 9.65%. After the ladle is lifted in place, it is vacuumed and decarburized. The vacuum degree is controlled below 2mbar, and the decarburization takes 12.5min After decarburization, the oxygen content of the molten steel is 0.0185%, and then add metal aluminum, ferrosilicon, low-carbon ferromanganese, carbon powder, etc. The particle size is 30-60mm, and the composition of the slagging agent is: 20%≤Al≤45%, 5%≤Ca≤15%, 20%≤CaO≤30%, 10%≤Al 2 o 3 ≤15%, 5%≤CaF 2 ≤10%, and o...

Embodiment 2

[0028] (1) Converter tapping is boiling tapping, and the slag is controlled during the tapping process. After tapping, 2.9kg / t of slag adjusting agent and 3.3kg / t of lime are added to the slag surface. The blowing flow rate is 180NL / min to keep the molten steel agitated, but not toss and splash.

[0029] (2) The ladle is hoisted to the RH station. The oxygen content of the RH station is 0.035%, and the T.Fe+MnO is 7.58%. After the ladle is lifted in place, it is vacuumed and decarburized. The vacuum degree is controlled below 2mbar, and the decarburization takes 11.8min After decarburization, the oxygen content of the molten steel is 0.0083%, and then add metal aluminum, ferrosilicon, low-carbon ferromanganese, carbon powder, etc. The particle size is 30-60mm, and the composition of the slagging agent is: 20%≤Al≤45%, 5%≤Ca≤15%, 20%≤CaO≤30%, 10%≤Al 2 o 3 ≤15%, 5%≤CaF 2 ≤10%, and other unavoidable impurities, circulate for 6.5min, molten steel T.O is 0.0014%, slag T.Fe+MnO is...

Embodiment 3

[0032] (1) Converter tapping is boiling tapping, and the slag is controlled during the tapping process. After tapping, 2.3kg / t of slagging agent and 2.5kg / t of lime are added to the slag surface. Argon is blown at the bottom of the ladle during the tapping process. The blowing flow rate is 120NL / min to keep the molten steel agitated, but not toss and splash.

[0033](2) The ladle is hoisted to the RH station. The oxygen content of the RH station is 0.0380%, and the T.Fe+MnO is 8.62%. After the ladle is lifted in place, it is vacuumed and decarburized. The vacuum degree is controlled below 2mbar, and the decarburization takes 12.3min After decarburization, the oxygen content of the molten steel is 0.0124%, and then add metal aluminum, ferrosilicon, low-carbon ferromanganese, carbon powder, etc. The particle size is 30-60mm, and the composition of the slagging agent is: 20%≤Al≤45%, 5%≤Ca≤15%, 20%≤CaO≤30%, 10%≤Al 2 o 3 ≤15%, 5%≤CaF 2 ≤10%, and other unavoidable impurities, cir...

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Abstract

The invention discloses a low-nitrogen boron-containing steel smelting method for improving the boron element yield. Converter end point boiling tapping is conducted, the frequency that molten steel absorbs nitrogen from air is reduced, a slag modifier and lime are added after converter tapping is finished for adjusting slag oxygen potentials and components, and in the tapping process, a steel ladle is subjected to bottom blowing and stirring in the whole process; after tapping is finished, molten steel is conveyed to be subjected to RH treatment, after the steel ladle is conveyed in place, vacuum pumping is conducted, C in the molten steel is utilized for deoxygenation, and after the oxygen content is reduced to be 0.02% or below, aluminum is added for deoxygenation and alloying, the 1.0-3.5 kg / t of slag modifier is added in the slag face of the steel ladle, and after all the alloy and the slag modifier are added, clean circulation is conducted for 5 min or longer time, T.O in the molten steel is smaller than or equal to 0.002%, the steel slag T.Fe+MnO is smaller than or equal to 2.0%; then, a boron-iron alloy is added, clean circulation is conducted for 8 min or longer time, andvacuum breaking and tapping are conducted. During RH tapping, the boron yield reaches 89% or above, the content and the yield of the boron element in the molten steel are stably controlled, BN precipitation in the later continuous casting process can be reduced, and important significance is achieved for stabilizing the mass and performance of the boron containing steel.

Description

technical field [0001] The invention belongs to the technical field of steelmaking, and in particular provides a method for smelting low-nitrogen boron-containing steel that improves the yield of boron element. Background technique [0002] Boron can significantly improve the performance of steel, and a small amount of boron can double the hardenability of steel. Boron steel has good mechanical properties and process performance, simple heat treatment process, and low price. Boron has a lot of resources and a small amount of consumption. From the perspective of solving a large number of expensive alloying elements, such as nickel, chromium, and molybdenum, the research and development and production of boron steel are of great significance. Trace amounts of boron can change the hardenability of steel, which is the biggest advantage of boron, but also a major disadvantage, because steel is very sensitive to small changes in boron content. [0003] Therefore, the steelmaking...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C33/06C21C5/28C21C7/10C21C7/06C21C7/00
CPCC21C5/28C21C7/0006C21C7/0087C21C7/06C21C7/10C21C2007/0018C22C33/06
Inventor 赵家七邹长东蔡小锋皇祝平
Owner INST OF RES OF IRON & STEEL JIANGSU PROVINCE
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