Smelting technology of ultralow boron steel

An ultra-low boron, process technology, applied in the direction of improving process efficiency, manufacturing converters, etc., can solve the problems affecting the low-temperature impact performance of steel, affecting the surface quality of steel, etc., and achieve the effect of excellent comprehensive performance

Active Publication Date: 2018-03-27
NANYANG HANYE SPECIAL STEEL CO LTD
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  • Abstract
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  • Application Information

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Problems solved by technology

And part of the steel smelting process needs to add boron, mainly because boron can improve the hardenability of steel during normalizing, which is conducive to the formation of some high-strength steel structures, but theoretical research shows that high boron content not only affects the surface quality of steel, And affect the low temperature impact properties of steel

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  • Smelting technology of ultralow boron steel

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Comparison scheme
Effect test

Embodiment 1

[0038] A smelting process for ultra-low boron steel, comprising the following steps:

[0039] (1) Pretreatment of KR molten iron: the molten iron entering the furnace is pretreated by desulfurization and cleaned of slag, and the sulfur content of the molten iron after desulfurization is controlled to be ≤0.003%;

[0040] The mass percentage of the chemical composition of the desulfurizer is: SiO 2 7.04%, CaO 79.68%, CaF 2 8.05%, S0.050%, desulfurizer particle size (0.3-2mm) ≥ 85%;

[0041](2) Converter smelting: add 100 tons of molten iron and 20 tons of steel scrap to the top-bottom combined blowing converter, add lime 41Kg / ton steel and light-burned dolomite 18Kg / ton steel during the converter smelting process, add low-carbon manganese when tapping Iron alloy 17Kg / ton steel, lime 1.8Kg / ton steel and aluminum grain 0.25Kg / ton steel, control the end temperature of converter smelting above 1650°C, control the carbon content of converter tapping to 0.035%, phosphorus ≤ 0.025...

Embodiment 2

[0055] A smelting process for ultra-low boron steel, comprising the following steps:

[0056] (1) Pretreatment of KR molten iron: the molten iron entering the furnace is pretreated by desulfurization and cleaned of slag, and the sulfur content of the molten iron after desulfurization is controlled to be ≤0.003%;

[0057] The mass percentage of the chemical composition of the desulfurizer is: SiO 2 7.04%, CaO 79.68%, CaF 2 8.05%, S0.050%, desulfurizer particle size (0.3-2mm) ≥ 85%;

[0058] (2) Converter smelting: add 100 tons of molten iron and 20 tons of steel scrap to the top-bottom combined blowing converter, add lime 42Kg / ton steel and light-burned dolomite 20Kg / ton steel during the converter smelting process, add low-carbon manganese when tapping Iron alloy 18Kg / ton steel, lime 2Kg / ton steel and aluminum grain 0.3Kg / ton steel, control the end temperature of converter smelting above 1650°C, control the carbon content of converter tapping to 0.04%, phosphorus ≤ 0.025%, ...

Embodiment 3

[0072] A smelting process for ultra-low boron steel, comprising the following steps:

[0073] (1) Pretreatment of KR molten iron: the molten iron entering the furnace is pretreated by desulfurization and cleaned of slag, and the sulfur content of the molten iron after desulfurization is controlled to be ≤0.003%;

[0074] The mass percentage of the chemical composition of the desulfurizer is: SiO 2 7.04%, CaO 79.68%, CaF 2 8.05%, S0.050%, desulfurizer particle size (0.3-2mm) ≥ 85%;

[0075] (2) Converter smelting: add 100 tons of molten iron and 20 tons of steel scrap to the top-bottom combined blowing converter, add lime 43Kg / ton steel and light-burned dolomite 19Kg / ton steel during the converter smelting process, add low-carbon manganese when tapping Iron alloy 19Kg / ton steel, lime 1.9Kg / ton steel and aluminum grain 0.35Kg / ton steel, control the end temperature of converter smelting above 1650°C, control the carbon content of converter tapping to 0.05%, phosphorus ≤ 0.025...

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Abstract

The invention discloses a smelting technology of ultralow boron steel, and belongs to the technical field of steel smelting. The smelting technology specifically comprises the stages of KR molten ironpretreatment, converter smelting, LF refining, pouring, cast blank stack cooling and cleaning, heating and rolling and steel plate stack cooling. According to the smelting technology, the boron content in molten steel can be controlled to be 0.0005% or below, the smelting requirements of the ultralow boron steel can be completely met, according to a prepared steel plate, the yield strength is higher than or equal to 462 MPa, the tensile strength is higher than or equal to 560 MPa, the ductility is higher than or equal to 25%, the impact strength at the temperature of minus 40 DEG C can reach186 J or above, and the overall performance is excellent.

Description

technical field [0001] The invention relates to a steel smelting process, in particular to an ultra-low boron steel smelting process. Background technique [0002] Boron mainly exists in molten iron, alloys such as silicon-manganese for steelmaking, and various auxiliary materials for steelmaking, and it is an easily oxidizable element. And part of the steel smelting process needs to add boron, mainly because boron can improve the hardenability of steel during normalizing, which is conducive to the formation of some high-strength steel structures, but theoretical research shows that high boron content not only affects the surface quality of steel, And affect the low temperature impact properties of steel. At present, the boron content is not deliberately controlled in the steelmaking process, and the boron content of the steel produced is basically around 8ppm. However, the newly issued national bridge steel standard specifies that the boron content is below 0.0005%, and i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/12C21C5/28C21C7/00C21C7/064C21C7/076C22C33/04C22C38/02C22C38/04C22C38/06
CPCC21C5/28C21C7/0006C21C7/064C21C7/076C22C33/04C22C38/02C22C38/04C22C38/06C22C38/12Y02P10/20
Inventor 朱书成刘丹许少普赵迪高照海李红阳郭艳芳康文举黄红乾
Owner NANYANG HANYE SPECIAL STEEL CO LTD
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