Design method of refining slag system for removal of magnesium aluminum spinel inclusions

A technology of magnesium aluminum spinel, design method, applied in the field of metallurgy

Active Publication Date: 2021-04-30
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Most of the existing technical solutions fail to propose specific indicators for removing large-size magnesia-aluminum spinel inclusions based on the mechanism

Method used

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  • Design method of refining slag system for removal of magnesium aluminum spinel inclusions
  • Design method of refining slag system for removal of magnesium aluminum spinel inclusions
  • Design method of refining slag system for removal of magnesium aluminum spinel inclusions

Examples

Experimental program
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Effect test

Embodiment 1

[0077] A factory produces aluminum-deoxidized molten steel, which is treated with magnesium in the late stage of the refining process, and the inclusions are mainly magnesium-aluminum spinel. The main component of refining slag is Al 2 o 3 -CaO-SiO 2 .

[0078] The relationship between the inclusion displacement Z and the time t is calculated by the following formulas (1)-(8).

[0079] (1)

[0080] in, is the driving force on the inclusion, N; R is the radius of the inclusion, m; G is the acceleration due to gravity, 9.81m / s 2 ; is fluid density, kg / m 3 ; ——inclusion density, kg / m 3 ;

[0081] (2)

[0082] in, is the characteristic viscosity of the fluid, Pa·s; is the floating speed of inclusions, m / s; F d is the fluid drag force on the uplift of the inclusions, N; Re is the Reynolds number of the uplift of the inclusions;

[0083] (3)

[0084] in, F m is the additional mass force, N; is the acceleration during the movement of inclusions, m / s ...

Embodiment 2

[0109] The same process conditions as in Example 1, the refining slag system is required to be able to absorb magnesium-aluminum spinel inclusions with a radius greater than 10 μm, according to figure 2 , the viscosity range of the selected slag system is less than 0.12 Pa•s, the cosine value of the three-phase wetting angle cosθ of steel-slag inclusions is greater than 0.7, and the calculated surface tension coefficient of the corresponding refining slag is less than 0.53 N / m. The composition of the first refining slag system corresponding to the viscosity calculated by FactSage software is 20-35%Al 2 o 3 , 55-60%CaO, 10-15%SiO 2 , according to the equivalent diagram of the surface tension of the ternary system ( image 3 ) The composition of the first refining slag system and the composition of the second refining slag system corresponding to the surface tension coefficient are 10-40%Al 2 o 3 , 50-80%CaO, 0-15%SiO 2 . The ratio (mass fraction) of the slag-based compos...

Embodiment 3

[0111] The same algorithm as in Embodiment 1 is used.

[0112] A factory produces low-carbon steel. In the refining process, aluminum-magnesium composite deoxidation is used, and the inclusions are mainly magnesium-aluminum spinel. The main component of refining slag is Al 2 o 3 -CaO binary slag system. The upper limit of the size of the predetermined inclusions is 15 μm, and the advantageous area diagram of the inclusion removal physical properties is obtained through the calculation of the dynamic force analysis model, as shown in Figure 5 shown. The selected viscosity range is less than 0.09 Pa•s, the cosine value of the three-phase wetting angle cosθ of steel-slag inclusions is in the range of 0.65-0.85, and the calculated surface tension coefficient corresponding to the refining slag is 0.55-0.8 N / m. Use the FactSage thermodynamic database software to calculate or query the slag atlas to obtain the composition of the first refining slag system corresponding to the vi...

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Abstract

The invention provides a method for designing a refining slag system for removing magnesium-aluminum spinel inclusions. The design method includes: establishing a motion model of magnesium-aluminum spinel inclusions, obtaining the relationship between the displacement and time of magnesium-aluminum spinel inclusions, and judging the state of magnesium-aluminum spinel inclusions; calculating the removal of inclusions of different sizes should meet The viscosity and interface characteristic conditions of the refining slag system; draw the removal advantage zone map; obtain the maximum size of the inclusions in the steel that have not been removed according to the requirements of the steel type, and select the target slag viscosity and surface tension coefficient according to the removal advantage zone map; according to the target slag viscosity The composition of the first refining slag system and the composition of the second refining slag system are obtained by calculating the surface tension coefficient respectively, and their intersection is taken to determine the composition of the target refining slag system. The design method provided by this application can obtain a slag system that efficiently removes inclusions.

Description

technical field [0001] The invention relates to the field of metallurgy, in particular to a method for designing a refining slag system for removing inclusions of magnesium-aluminum spinel. Background technique [0002] In the modern steelmaking process, except for steel types with special requirements, aluminum deoxidation is mostly used in the refining process, so the deoxidation product is mostly alumina. At the same time, since the refining ladle and continuous casting tundish mostly use magnesia refractory materials, it is easy to react with alumina inclusions to form magnesia-alumina spinel inclusions, which have become one of the common inclusions under modern steelmaking process conditions. . [0003] MgAl 2 o 4 The main shapes of inclusions are spherical, cubic and irregular. Most of them exist alone in the steel matrix. The melting point is high and it is easy to deposit at the nozzle and cause production accidents such as nozzle nodules. The inclusions in molt...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21C7/076G06F30/20G06F119/14
CPCC21C7/076Y02P10/20
Inventor 刘威杨树峰刘杰王田田杨曙磊赵朋赵梦静
Owner UNIV OF SCI & TECH BEIJING
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