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Secondary refining method capable of improving cleanliness of molten steel

A technology of secondary refining and cleanliness, which is applied in the field of metallurgy and can solve problems such as not being universally applicable

Inactive Publication Date: 2018-06-29
ANGANG STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the continuous expansion of production of high-quality steel in recent years, conventional methods cannot be generally applied to some steel types that require high-grade inclusions, such as heavy rail steel and bearing steel.

Method used

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  • Secondary refining method capable of improving cleanliness of molten steel
  • Secondary refining method capable of improving cleanliness of molten steel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] Embodiment 1 (the 1st pot of pouring order):

[0014] (1) The carbon content at the control end point of converter tapping is 0.35%, the phosphorus content is 0.012%, and the sulfur content is 0.026%. Add recarburizer, ferrosilicon manganese and high-carbon ferromanganese when tapping the steel, the tapping temperature is 1658°C, and add 230kg of lidded lime after tapping;

[0015] (2) The steel ladle is transported to the LF station, and the entry temperature is 1577°C. The LF process performs desulfurization, alloying, heating and stirring operations according to the requirements of the steel type. After the temperature and alloy are all adjusted, slaked lime is added from the high-level silo at one time. 800kg, followed by a weak argon blowing operation for 4 minutes, after the argon blowing is completed, add 320kg of thick slag lime, after adding, hoist from the LF station to the VD station;

[0016] (3) After entering the VD, vacuumize the furnace to degas the fur...

Embodiment 2

[0017] Embodiment 2 (pouring the 6th can):

[0018] (1) The carbon content at the end point of converter tapping control is 0.39%, the phosphorus content is 0.013%, and the sulfur content is 0.029%. Add recarburizer, silicomanganese ferromanganese and high carbon ferromanganese when tapping, the tapping temperature is 1655℃, after tapping, add 240kg of lid can lime;

[0019] (2) The ladle is transported to the LF station, and the entry temperature is 1572°C. The LF process performs desulfurization, alloying, heating and stirring operations according to the requirements of the steel type. After the temperature and alloy are all adjusted, slaked lime is added from the high-level silo at one time. 860kg, followed by a weak argon blowing operation for 4 minutes, after the argon blowing is completed, add 350kg of thick slag lime, after adding, hoist from the LF station to the VD station;

[0020] (3) After entering the VD, vacuumize the furnace for degassing. The pressure holding ...

Embodiment 3

[0021] Embodiment 3 (the 7th pot of pouring time):

[0022] (1) The carbon content at the control end point of converter tapping is 0.42%, the phosphorus content is 0.015%, and the sulfur content is 0.027%. Add recarburizer, silicomanganese ferromanganese and high carbon ferromanganese when tapping, the tapping temperature is 1654℃, after tapping, add 280kg of lid can lime;

[0023] (2) The steel ladle is transported to the LF station, and the entry temperature is 1571°C. The LF process performs desulfurization, alloying, heating and stirring operations according to the requirements of the steel type. After the temperature and alloy are all adjusted, slaked lime is added from the high-level silo at one time. 870kg, followed by weak argon blowing operation for 5 minutes, after argon blowing, add 380kg of thick slag lime, after adding, hoist from LF station to VD station;

[0024] (3) After entering the VD, vacuumize the furnace to degas the furnace. The pressure holding time o...

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Abstract

The invention discloses a secondary refining method capable of improving cleanliness of molten steel. The secondary refining method capable of improving the cleanliness of the molten steel comprises the steps of controlling the steel tapping temperature above 1650 DEG C and adding cover can lime at a ratio of 2-3 kg / t to steel after steel tapping; then conveying the steel ladle to an LF station and ensuring the inlet temperature be above 1570 DEG C, then adding hydrated lime at a ratio of 5-10 kg / t to steel from an overhead bunker at one time after the temperature and alloys are all adjusted,wherein the granularity of the hydrated lime is 0.2-0.5 mm, and conducting soft argon blowing operation for 3-5 min, and adding sluggish slag lime at a ratio of 3-4 kg / t to steel after argon blowing;and conducting vacuumizing operation for degassing a furnace after the steel ladle gets into a VD furnace and ensuring the dwell time, which is lower than 67 Pa, of the VD furnace be not shorter than25 min, then enabling inclusion in the molten steel to be taken out and float upward by bubbles generated by the hydrated lime, and conducting hydrogen determination, and directly pouring with a machine after soft argon blowing for longer than 5 min. By means of the method, the melting time would not be increased, the raw materials are low-cost and the operation is simple and practicable.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a secondary refining method for improving the cleanliness of molten steel. Background technique [0002] At present, steel users have increasingly stringent requirements on steel quality. In order to improve the quality of steel, the cleanliness of molten steel must be improved. Therefore, cleanliness is the main trend in the development of modern steel materials, and clean steel production is an important direction for the development of contemporary steelmaking technology. In addition, the world's steel market has become saturated and the competition is fierce. In order to occupy the steel market, some domestic and foreign steel factories have adopted technical measures to produce high value-added products, such as high-quality deep-drawing steel and ultra-low sulfur steel. The key to improving steel quality and producing clean steel is to control inclusions. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C7/10C21C7/068C21C7/076
CPCC21C7/068C21C7/076C21C7/10Y02P10/20
Inventor 朱晓雷李德军王爽刘祥李晓伟赵成林许孟春彭春霖栾花冰王晗桐
Owner ANGANG STEEL CO LTD
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