Smelting method for sulfur-containing and aluminum-containing steel

A smelting method and technology for aluminum steel, applied in the direction of improving process efficiency, etc., can solve problems such as affecting production rhythm, blocking nozzles, how much calcium is added, and difficult to control the timing of calcium treatment.

Inactive Publication Date: 2020-01-24
DONGBEI SPECIAL STEEL GROUP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

During the pouring process of molten steel, CaS or Al with high melting point 2 o 3 Attached to the inner wall of the nozzle to form nodules, which will cause blockage of the continuous casting nozzle and affect the smooth flow of pouring. When the tumor falls off and enters the molten steel, it will become a large particle inclusion in the steel, seriously affecting the quality of the steel and reducing the quality of the cast slab
[0005] At present, the smelting method of sulfur-containing and aluminum-containing steel mainly adopts the traditional deoxidation and desulfurization → calcium treatment → sulfur-increasing treatment method, which can improve the castability of sulfur-containing and aluminum-containing steel, but it is very difficult to control the intensity of calcium treatment, and the amount of calcium added The amount and timing of calcium treatment are difficult to control. Traditional calcium treatment is carried out during or after vacuum treatment. Sulfur feeding is carried out before hanging the ladle to continuous casting. This process will easily lead to the reaction of calcium and sulfur in the steel [Ca ]+[S]=(CaS), it is very easy to cause nodulation at the nozzle
Therefore, the production of sulfur-containing and aluminum-containing steel has been facing poor pourability of molten steel, the purity of molten steel is affected, and the quality of casting slabs and production efficiency are reduced.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] 1. Using electric furnace steelmaking-LF refining-VD vacuum smelting-continuous casting process route to produce sulfur-containing aluminum steel, the steel melting composition (%) is carbon: 0.32%~0.34%, silicon: 0.20%~0.30%, manganese: 1.25%~1.32%, sulfur: 0.015%~0.025%, phosphorus not more than 0.030%, chromium: 0.34%~0.39%, aluminum: 0.010%~0.030%, boron: 0.0010%~0.0018%, titanium: 0.020%~0.040 %, nitrogen not more than 75×10 -6 ;

[0026] Product testing:

[0027] Carbon: 0.33%, silicon: 0.26%, manganese: 1.28%, sulfur: 0.020%, phosphorus: 0.020, chromium: 0.35%, aluminum: 0.026%, boron: 0.0016%, titanium: 0.027%, nitrogen: 55×10 -6 .

[0028] 2. Electric furnace steelmaking

[0029] ⑴The tapping quantity of the electric furnace is controlled between 50t and 55t, the tapping end point C: 0.07%~0.25%, and the tapping temperature is controlled at 1630℃±20℃;

[0030] (2) Ferrosilicon and aluminum are used for co-deoxidation during tapping, 70kg of ferrosilicon is added for ab...

Embodiment 2

[0050] 1. The process route of electric furnace steelmaking-LF refining-VD vacuum smelting-continuous casting is adopted to produce sulfur-containing aluminum steel. The melting composition (%) of steel is carbon: 0.38%~0.41%, silicon: 0.20%~0.35%, manganese: 0.65%~0.75%, sulfur: 0.015%~0.030%, phosphorus not more than 0.025%, chromium: 0.90%~1.00%, aluminum: 0.015%~0.035%, boron: 0.0010%~0.0018%, oxygen not more than 15×10 -6 , Nitrogen is not more than 75×10 -6 ;

[0051] Product testing:

[0052] Carbon: 0.40%, silicon: 0.30%, manganese: 0.68%, sulfur: 0.028%, phosphorus: 0.015%, chromium: 0.93%, aluminum: 0.020%, boron: 0.0013%, oxygen: 15×10 -6 , Nitrogen: 50×10 -6 .

[0053] 2. Electric furnace steelmaking

[0054] ⑴The tapping quantity of the electric furnace is controlled between 50t and 55t, the tapping end point C: 0.07%~0.25%, and the tapping temperature is controlled at 1630℃±20℃;

[0055] ⑵The steel tapping adopts ferrosilicon and aluminum to deoxidize together. In the ear...

Embodiment 3

[0075] 1. Using converter steelmaking-LF refining-VD vacuum smelting-continuous casting process route to produce sulfur-containing aluminum-containing steel, the melting composition is carbon: 0.32%~0.34%, silicon: 0.20%~0.30%, manganese: 1.25%~ 1.32%, sulfur: 0.015%~0.025%, phosphorus not more than 0.030%, chromium: 0.34%~0.39%, aluminum: 0.010%~0.030%, boron: 0.0010%~0.0018%, titanium: 0.020%~0.040%, nitrogen Not more than 75×10 -6 ;

[0076] Product testing:

[0077] Carbon: 0.33%, silicon: 0.24%, manganese: 1.20%, sulfur: 0.020%, phosphorus: 0.015%, chromium: 0.37%, aluminum: 0.020%, boron: 0.0013%, titanium: 0.025%, nitrogen: 50×10 -6 .

[0078] 2. Converter steelmaking

[0079] ⑴The tapping volume of the converter is controlled between 50t and 55t, the end carbon of tapping is not less than 0.07%, and the tapping temperature is controlled at 1610℃±20℃;

[0080] ⑵The tapping adopts ferrosilicon and aluminum to deoxidize, 75kg ferrosilicon is added per ton of steel when the tappin...

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Abstract

The invention discloses a smelting method for sulfur-containing and aluminum-containing steel. In the LF refining process, high-alkalinity slag is prepared from lime and pre-molten refining slag to assist in aluminum wire precipitation deoxidization and calcium carbide diffusion deoxidization, it is required that the sulfur content is not larger than 0.008% before LF station leaving, the content of sulfur in the steel is reduced, the content of sulfur entering VD / RH steel is stabilized, and it is avoided that Al2O3 and CaS impurities are generated during calcium treatment; and calcium treatment is performed ahead of VD / RH vacuum treatment. By means of the method, the Al2O3 impurities and calcium in the steel can react to generate low-melting-point liquid-state 12CaO.7Al2O3 and 3CaO.Al2O3;after vacuum breaking, sulfur feeding is performed, and since the time interval between the calcium feeding procedure and the sulfur feeding procedure is long, it can be avoided that the calcium and the sulfur react to generate CaS impurities. The method mainly has the advantages that the cleanliness of molten steel can be improved, the formation of the Al2O3 and CaS impurities is reduced, the cleanliness of the molten steel is improved, scaffolding of a continuous casting nozzle is reduced, the continuous casting and continuous pouring ratio is increased, and production cost is reduced.

Description

Technical field [0001] The invention belongs to the technical field of metallurgy, and relates to a method for smelting sulfur-containing aluminum-containing steel, which can improve the cleanliness of molten steel and reduce Al 2 O 3 The formation of CaS and CaS inclusions can reduce continuous casting nozzle nodules, increase continuous casting and continuous casting ratio and reduce production costs. Background technique [0002] Calcium treatment transforms high melting point Al 2 O 3 The key to inclusions is to control the calcium content at a certain level to ensure that the resulting calcium aluminate composite inclusions are low melting point 12CaO·7Al 2 O 3 And 3CaO·Al 2 O 3 . Although calcium treatment can improve the continuous casting ability of aluminum killed steel, the effect of calcium treatment is closely related to the composition of steel. Because the molten steel contains aluminum and sulfur at the same time, the reactions of aluminum, sulfur and calcium are mu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C7/00C21C7/06C21C7/076C21C7/10
CPCC21C7/0006C21C7/06C21C7/076C21C7/10Y02P10/20
Inventor 周伟基刘建张志兴陈修君马玉民刘丙旭冯荣鹏毕胜路辉姜盛鑫林立民张彤王金国李周强
Owner DONGBEI SPECIAL STEEL GROUP
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