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Method for desulfurizing ultra-low carbon pure steel in circulating vacuum degassing method

A vacuum degassing and pure steel technology, applied in the manufacture of converters, etc., can solve the problems of fast slagging, high desulfurization cost, and environmental pollution, and achieve the effect of reducing desulfurization cost and reducing erosion

Inactive Publication Date: 2011-04-27
SHANXI TAIGANG STAINLESS STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The desulfurization effect of this desulfurizer is ideal, but the fluorite in the component seriously corrodes the refractory material of the RH tank and the insertion pipe, and also pollutes the environment; the other type is CaO-Al 2 o 3 - SiO 2 Slag system, mainly composed of lime and bauxite, is melted into calcium aluminate by electric furnace, and its melting point is greatly reduced. The agent is melted in an electric furnace and has high carbon content, which is not suitable for smelting ultra-low carbon steel. At the same time, the alkalinity of the pre-melted calcium aluminate is very low. After the lime is melted, the reactivity decreases, and lime needs to be added during the RH desulfurization process. , higher cost of desulfurization

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] In this embodiment, a 180-ton converter + RH refining furnace is used to produce ultra-low carbon IF steel, and the actual processing capacity is 195 tons.

[0025] The mass percentage ratio of the composition of the ultra-low carbon steel IF steel smelted in this embodiment is:

[0026] C 0.0022% Si 0.02% Mn 0.15%

[0027] P 0.008% S 0.0036% Al 0.04% N 0.0025%

[0028] The rest is Fe and unavoidable impurities.

[0029] The steps of this embodiment are as follows: 180 tons of hot metal pretreatment desulfurization → 180 tons of top-bottom combined blowing converter decarburization, dephosphorization → 180 tons of RH deep decarburization, desulfurization, deoxidation → continuous casting.

[0030] The specific steps of this embodiment are as follows:

[0031] (1) Hot metal pretreatment desulfurization

[0032] Use 85kg of granular magnesium for desulfurization. After desulfurization, the sulfur content reaches 0.0025%.

[0033] (2) Decarburization and dephosphoriza...

Embodiment 2

[0046] In this embodiment, a 180-ton converter+RH refining furnace is used to smelt pure iron, and the actual processing capacity is 190 tons.

[0047] The mass percentage ratio of the composition of the ultra-low carbon steel pure iron smelted in this embodiment is:

[0048] C 0.0022% Si 0.04% Mn 0.06%

[0049] P 0.008% S 0.0043% Al 0.040% N 0.0022%

[0050] The rest is Fe and unavoidable impurities.

[0051] The steps in this embodiment are as follows: 180 tons of hot metal pretreatment desulfurization → 180 tons of top-bottom combined blowing converter decarburization, dephosphorization → 180 tons of RH deep decarburization, desulfurization → continuous casting.

[0052] The specific steps of this embodiment are as follows:

[0053] (1) Hot metal pretreatment desulfurization

[0054] Use 90kg of granular magnesium for desulfurization. After desulfurization, the sulfur content reaches 0.002%. After desulfurization, carry out slag removal treatment to remove most of the des...

Embodiment 3

[0068] In this embodiment, an 80-ton converter+RH refining furnace is used to produce ultra-low carbon IF steel, with a processing capacity of 82 tons.

[0069] The mass percentage ratio of the composition of the ultra-low carbon steel IF steel smelted in this embodiment is

[0070] C 0.0022% Si 0.02% Mn 0.16%

[0071] P 0.008% S 0.0040% Al 0.04% N 0.003%

[0072] The rest is Fe and unavoidable impurities.

[0073] The steps in this embodiment are as follows: 80 tons of hot metal pretreatment desulfurization → 80 tons of top-bottom combined blowing converter decarburization, dephosphorization → 80 tons of RH deep decarburization, desulfurization → continuous casting.

[0074] (1) Hot metal pretreatment desulfurization

[0075] 40kg of granular magnesium is used for desulfurization. After desulfurization, the sulfur content reaches 0.003%. After desulfurization, slag removal is performed to remove most of the desulfurization slag, and 90% of the desulfurization slag is remov...

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Abstract

A method for desulfurizing ultra-low carbon pure steel in a circulating vacuum degassing method comprises the following steps: 1. molten iron pretreatment desulfurization: blast-furnace molten iron is desulfurized by injecting and blowing granular magnesium, and slag skimming is carried out after desulfurization to skim most desulfurized slag; 2. decarbonization and dephosphorization in a top and bottom combined blown converter: the desulfurized molten iron is added into the top and bottom combined blown converter to carry out converting and decarbonization and dephosphorization, when tapping, alloying is not carried out, and synthetic slag is added in the tapping process; 3. RH deep decarbonization and desulfurization: a. a ladle which is filled with poured molten steel is moved to an RH work station to carry out vacuum carbon-oxygen reaction deep decarbonization, and carbon reaches 0.001 percent to 0.0025 percent; b. after RH decarbonization is finished, aluminum deoxidation is carried out, and dissolved oxygen is not more than 0.0005 percent; and c. after the deoxidation for 2 to 3min, desulfurater is added, and low-carbon active lime is desulfurized; and 4. continuous casting. The method for desulfurizing ultra-low carbon pure steel in the circulating vacuum degassing method has low cost and high desulfurization rate.

Description

technical field [0001] The invention relates to a method for RH desulfurization of ultra-low-carbon pure steel, that is, a method for desulfurizing ultra-low-carbon pure steel by a circular vacuum degassing method. Background technique [0002] In addition to free-cutting steel, sulfur is usually a harmful element in steel. Sulfur forms sulfide inclusions in steel, which reduces the ductility and toughness of steel, especially impact toughness. High sulfur content will lead to the occurrence of hydrogen-induced cracks in steel, and the corrosion resistance of steel will be greatly reduced, especially for oil pipelines. Welding performance is one of the most important performances of steel. When sulfur content is high, it is unfavorable to the welding performance of steel. When sulfur exists in the form of iron sulfide, it will cause hot embrittlement and significantly reduce the hot workability of steel. Therefore, improving the purity of steel and reducing sulfur content i...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21C5/30C21C7/064C21C1/02C21C7/10C21C7/068
Inventor 段建平王建昌秦瑛张永亮
Owner SHANXI TAIGANG STAINLESS STEEL CO LTD