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Method for controlling phosphorus content of molten steel in tapping weak deoxidation mode

A technology of phosphorus content and molten steel, applied in the direction of manufacturing converters, improving process efficiency, etc., can solve the problems of reducing the oxidation of molten steel, not suitable for low nitrogen steel grades, and the impact of production rhythm.

Pending Publication Date: 2021-12-31
SHANDONG IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The above-mentioned "nitrogen stirring" process reduces the oxidation of molten steel, but it is not suitable for low-nitrogen steel types, and it will also have a certain impact on the production rhythm

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] 1) Converter blowing

[0029] According to the composition of molten iron, the amount of light-burned lime, light-burned dolomite, and coolant (iron ore) added to the slagging process per ton of steel is 30kg, 6kg, and 10kg, respectively.

[0030] Oxygen top-bottom double-blowing converter is used, the blowing process is controlled by reasonable gun position and feeding mode, reasonable addition of slag forming material and coolant, and uniform and slow temperature rise of the molten pool are controlled to ensure good fluidity and foaming of the slag to avoid Splash and dry back, control the molten steel w(P) at a low level. The converter blowing process is controlled smoothly, and the sub-gun TSC results: temperature 1575°C, carbon content 0.32wt%, phosphorus content test results 0.036wt%;

[0031] 2) pull carbon

[0032] The position of the carbon gun at the end of blowing is kept for 23s, and the end point is hit once: the basicity of slag is R=3.8, the end point t...

Embodiment 2

[0043] 1) Converter blowing

[0044] According to the composition of molten iron, the amount of light-burned lime, light-burned dolomite, and coolant (iron ore) added to the slagging process per ton of steel are 28kg, 10kg, and 12kg, respectively;

[0045] Oxygen top-bottom combined blowing converter is adopted, the converter blowing process is controlled with reasonable lance position and feeding mode, no splashing and back-drying phenomenon, the process control is stable, and the sub-lance TSC results: temperature 1582 ℃, carbon content 0.26wt%, phosphorus The content test result is 0.028wt%;

[0046] 2) pull carbon

[0047] The position of the carbon gun at the end of blowing is maintained for 20s, and the end point is hit once: slag basicity R=3.6, end point temperature T=1628°C, carbon content is 0.046wt%, oxygen content is 500ppm;

[0048] 3) Preparation before tapping

[0049] The tapping ladle, the condition of the tapping hole, the alloy and the additives of the la...

Embodiment 3

[0058] 1) Converter blowing

[0059] According to the composition of molten iron, the amount of light-burned lime, light-burned dolomite, and coolant (iron ore) added to the slagging process per ton of steel is 27kg, 7kg, and 11kg, respectively;

[0060] Oxygen top-bottom double-blowing converter is adopted, and the converter blowing process controls reasonable lance position and feeding mode. The slag in the process has good fluidity and foaming, no splashing and back-drying phenomenon, sub-lance TSC result: temperature 1572 ℃, Carbon content 0.36wt%, phosphorus content test result 0.038wt%;

[0061] 2) pull carbon

[0062] The position of the carbon gun at the end of blowing is maintained for 22s, and the end point is hit once: slag basicity R=3.5, end point temperature T=1642°C, carbon content is 0.040wt%, and oxygen content is 560ppm;

[0063] 3) Preparation before tapping

[0064] The tapping ladle, the condition of the tapping hole, the alloy and the additives of the ...

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Abstract

The invention discloses a method for controlling the phosphorus content of molten steel in a tapping weak deoxidation mode. By controlling the basicity, oxidability and temperature of the slag in the converter blowing process and at the blowing end point (the basicity R of the slag at the blowing end point is 3.2-4.0, the end point temperature T is 1620-1650 DEG C, the carbon content is 0.04-0.06 wt%, and the oxygen content in the molten steel at the end point is 500 ppm-700 ppm), process dephosphorization is achieved to the maximum extent, later rephosphorization is prevented, P in the molten steel is controlled to be at a low level, double-slag-stopping operation is adopted during tapping, weak deoxidation alloying (the adding amount of aluminum blocks is about 2 / 3 of the target using amount of steel types) is conducted in the later period of tapping, high argon is used for intense stirring and high oxygen partial pressure is used for flushing and mixing dephosphorization, the good flowability of top slag is kept, and steel ladle dephosphorization is achieved as much as possible; and slagging-off is conducted after tapping, so that the rephosphorization probability and the total mass of phosphorus are further reduced, and the cleanliness of molten steel and the quality of casting blanks are improved.

Description

technical field [0001] The invention relates to a method for controlling the phosphorus content of molten steel in a weak deoxidation mode for tapping, and belongs to the technical field of converter steelmaking. Background technique [0002] The cleanliness of steel is an important symbol reflecting the overall quality level of steel and an important indicator to ensure the internal quality of steel. At present, the cleanliness of steel is generally evaluated by the content of harmful elements in steel and the type, quantity, size, distribution and shape of non-metallic inclusions. The harmful elements in steel are mainly O, S, P, H, and N. Impurity elements and low-content Pb, As, Cu, Zn, etc., especially because P has the problem of "high proportion, large base, difficult to remove in the smelting process, easy to cause phosphorus return, and difficult to control", It restricts the improvement of the cleanliness of steel. [0003] Phosphorus is harmful in most steel typ...

Claims

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Application Information

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IPC IPC(8): C21C5/35C21C7/00C21C7/06C21C7/072C21C7/076
CPCC21C5/35C21C7/06C21C7/072C21C7/076C21C7/0006Y02P10/20
Inventor 王念欣苗振鲁曾晖董德明李海峰张戈栾吉益陈万福董洪壮袁宇皓李长新董慧孙宗辉
Owner SHANDONG IRON & STEEL CO LTD
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