A low-cost, high-formability, low-carbon aluminum-killed clean steel process for continuous casting of thin slabs

A thin slab continuous casting, low-cost technology, applied in the field of iron and steel metallurgy, can solve the problems of limiting thin slab continuous casting production efficiency, affecting the formability of steel plates, CaS inclusions, etc., to meet the requirements of cleanliness and pourability, and to save calcium Treatment cost, obvious effect of adsorption

Active Publication Date: 2020-03-20
RIZHAO STEEL HLDG GROUP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] However, in actual production, using the above-mentioned calcium treatment process, the yield of calcium is often about 20%. At the smelting temperature, most of the calcium remains in the metal molten pool. The main forms are as follows (1) oxide inclusions, solid calcium aluminum (C.6A, C.2A, C.A); (2) CaS inclusions in molten steel, and the existence of these calcium forms can easily cause nozzle blockage, affecting and limiting the production efficiency of thin slab continuous casting; and, high melting point aluminum in molten steel Calcium acid inclusions affect the formability of the steel plate and are prone to cold bending cracking

Method used

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  • A low-cost, high-formability, low-carbon aluminum-killed clean steel process for continuous casting of thin slabs
  • A low-cost, high-formability, low-carbon aluminum-killed clean steel process for continuous casting of thin slabs
  • A low-cost, high-formability, low-carbon aluminum-killed clean steel process for continuous casting of thin slabs

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] (1) Hot metal: Reduce the sulfur content of hot metal to less than 0.02% through hot metal pretreatment and other methods;

[0043] (2) Oxygen top-bottom combined blowing converter: using sub-lance technology and bottom argon blowing technology, control the end-point molten steel [O] of the converter 2 O 3 The total amount of deoxygenated inclusions.

[0044] (3) LF refining: refining molten steel [Al] 0.020-0.03% in the station, molten steel temperature ≥ 1550℃; adding lime at 6-7Kg / ton, controlling the slag composition to be CaO 55-60%; 2 O 3 25~30%; SiO 2 7~8%; MgO 5~7%, alkalinity CaO / SiO 2 The value is 7-8; white slag is refined; the aluminum composition of molten steel is adjusted, and the number of aluminum allocation is strictly controlled to be less than 3 times. This embodiment is specifically twice; the mass percentage of molten steel composition is controlled as follows: C: 0.038 to 0.045%, Si: 0.15~0.25%, Mn: 0.50~0.60%, P≤0.015%, S≤0.003%, Alt: 0.008~0.020%, t...

Embodiment 2

[0050] (1) Hot metal: Reduce the sulfur content of hot metal to less than 0.02% through hot metal pretreatment and other methods;

[0051] (2) Oxygen top-bottom combined blowing converter: using sub-lance technology and bottom argon blowing technology to control the final molten steel [O] of the converter 2 O 3 The total amount of deoxygenated inclusions.

[0052] (3) LF refining: Refining the molten steel [Al] 0.035~0.050% in the station, the temperature of the molten steel is 1550~1650℃; adding lime at 6~7Kg / ton, control the slag composition to CaO 54~58%; Al 2 O 3 26~28%; SiO 2 7~8%; MgO 5~6%, alkalinity CaO / SiO 2 Value 6~8; refining white slag; adjusting the aluminum composition of molten steel, feeding aluminum 3 times, feeding aluminum, iron, and rare earth cored wire; making the silicon content of molten steel 0.15 to 0.25%; controlling the mass percentage of molten steel composition out of the station as :C: 0.038~0.045%, Si: 0.15~0.25%, Mn: 0.50~0.60%, P≤0.015%, S≤0.003%,...

Embodiment 3

[0057] (1) Hot metal: Reduce the sulfur content of hot metal to less than 0.02% through hot metal pretreatment and other methods;

[0058] (2) Oxygen top-bottom combined blowing converter: using sub-lance technology and bottom argon blowing technology, control the final molten steel [O] of the converter 2 O 3 The total amount of deoxygenated inclusions.

[0059] (3) LF refining: adjust the refining incoming molten steel [Al] 0.02~0.04%, the molten steel temperature ≥1550℃; add lime at 6~7Kg / ton, control the slag composition to CaO 54~56%, Al 2 O 3 25~30%; SiO 2 6~7%; MgO 5~7%, basicity CaO / SiO 2 Value 8-9; white slag refining; adjustment of the aluminum composition of molten steel, the number of times of aluminum distribution is 2 times, 400 meters of limestone cored wire feeding; the silicon content of molten steel is 0.15 to 0.25%; the mass percentage control of the refined molten steel composition is: C :0.038~0.045%, Si: 0.15~0.25%, Mn: 0.50~0.60%, P≤0.015%, S≤0.003%, Alt: 0.0...

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Abstract

The invention discloses a low-cost thin slab continuous casting process for producing high-formability low-carbon aluminum killed clean steel, which belongs to the technical field of iron and steel metallurgy, and is characterized in that: molten iron→oxygen top-bottom combined blowing converter→LF refining→argon gas at the bottom of the ladle Soft blowing→continuous casting→continuous rolling process. Compared with the existing technology, the calcium treatment process is not used, which saves the cost of calcium treatment, avoids the problem of flocculation of high melting point aluminate, improves the formability of the steel plate, and reduces the probability of cold bending cracking.

Description

Technical field [0001] The invention relates to the technical field of iron and steel metallurgy, in particular to the production technology of thin slab continuous casting low-cost production of low-carbon aluminum killed clean steel with high formability. Background technique [0002] Thin slab continuous casting refers to a short-flow hot steel coil production process with a continuous casting billet thickness of 70-120mm and a continuous casting speed of 3-6m / min. Its typical steel grade is low carbon (silicon or silicon-containing) aluminum killed steel. [0003] Thin slabs produce low-carbon (silicon-containing or silicon-controlled) aluminum killed steel. The production process generally adopts molten iron → oxygen top and bottom combined blowing converter → LF refining → soft argon blowing at the bottom of the ladle → calcium treatment → soft argon blowing at the bottom of the ladle → The process flow of thin slab continuous casting→continuous rolling. The calcium treatme...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/06C21C7/06C21C7/064C21C7/00
CPCC21C7/0006C21C7/0056C21C7/072C22C33/04C22C38/002C22C38/02C22C38/04C22C38/06
Inventor 乔继纲
Owner RIZHAO STEEL HLDG GROUP
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