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Blank steel plate hydrogen-induced crack control method for electric arc furnace short-process steelmaking

A control method, hydrogen-induced cracking technology, applied in the direction of electric furnace, furnace, furnace type, etc., can solve the problems of slow hydrogen diffusion, increase of production cost, non-compliance of steel plate flaw detection, etc., to reduce the absorption of molten steel and promote the growth of collision , The effect of improving the cleanliness of molten steel

Pending Publication Date: 2022-04-12
WUYANG IRON & STEEL +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] The initial hydrogen content of electric arc furnace short-process steelmaking is generally 2-4ppm higher than that of converter steelmaking, and hydrogen is one of the important elements harmful to the internal quality of medium and thick plates, especially for steel plates with a thickness ≥ 30mm, the hydrogen diffusion rate is slow, when the steel plate When the accumulated hydrogen content exceeds 1.0ppm, the steel plate will produce hydrogen white spots. Once this kind of hazard occurs, it cannot be eliminated, and the hazard is extremely serious. The most common one is the crack defect in the entire steel plate after rolling, which causes the steel plate to fail to detect flaws and the product Scrap, seriously increase production cost

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] In this example, 20 Q355NB steel plates are produced, with a thickness of 50mm. The hydrogen-induced crack control method includes controlling the moisture content of scrap steel entering the electric arc furnace, the composition of LF slag, the time of VD high vacuum, the intensity of argon blowing at VD high vacuum, and the hierarchical control of the pile of slabs. Stack slow cooling, as follows:

[0021] (1) 45t of steel scrap is put into the electric arc furnace, all of which are preheated by the electric arc furnace flue for 15 minutes, the temperature of the flue is 518°C, fully baked and dried, and then added to the furnace;

[0022] (2) Refining slagging: add 450kg of pre-melted slag, Al in pre-melted slag 2 o 3 Content 42.38%, refining slag Al 2 o 3 Content 27.33%;

[0023] (3) Vacuum dehydrogenation: 60Pa vacuum holding time for 15min, 60Pa vacuum argon flow rate 250L / min, strong stirring for 10min;

[0024] (4) Slow cooling and hydrogen expansion of bil...

Embodiment 2

[0027] In this example, 20 pieces of Q355NC steel plates are produced, with a thickness of 40mm. The hydrogen-induced crack control method includes controlling the water content of scrap steel in the electric arc furnace, the composition of LF slag, the time of VD high vacuum degree, the intensity of argon blowing at VD high vacuum degree, and the graded control of the pile of slabs. Stack slow cooling, as follows:

[0028] (1) 40t of scrap steel is put into the electric arc furnace, all of which are preheated by the electric arc furnace flue for 17 minutes, the temperature of the flue is 528°C, fully baked and dried, and then added to the furnace;

[0029] (2) Refining slagging: add 400kg pre-melted slag, Al in pre-melted slag 2 o 3 Content 35.88%, refining slag Al 2 o 3 Content 20.46%;

[0030] (3) Vacuum dehydrogenation: 38Pa vacuum holding time for 15min, 38Pa vacuum argon flow rate 230L / min strong stirring for 11min;

[0031] (4) Slow cooling and hydrogen expansion o...

Embodiment 3

[0034] In this example, 12 pieces of Q345D steel plates are produced, with a thickness of 38 mm. The hydrogen-induced crack control method includes controlling the water content of scrap steel in the electric arc furnace, the composition of LF slag, the time of VD high vacuum degree, the intensity of argon blowing at VD high vacuum degree, and the hierarchical control of the pile of slabs. Stack slow cooling, as follows:

[0035] (1) 40t of scrap steel is put into the electric arc furnace, all of which are preheated by the electric arc furnace flue for 15 minutes, the flue temperature is 501°C, fully baked and dried, and then added to the furnace;

[0036] (2) Refining slagging: add 400kg pre-melted slag, Al in pre-melted slag 2 o 3 Content 41.22%, refining slag Al 2 o 3 Content 23.92%;

[0037] (3) Vacuum dehydrogenation: 58Pa vacuum holding time for 15min, 58Pa vacuum argon flow rate 250L / min strong stirring for 11min;

[0038] (4) Slow cooling and hydrogen expansion of...

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Abstract

The invention discloses a method for controlling hydrogen-induced cracks of a billet steel plate in short-process steelmaking of an electric arc furnace. The method comprises the following steps: controlling the moisture of scrap steel entering the electric arc furnace, components of an LF slag system, VD high-vacuum-degree time, VD high-vacuum-degree argon blowing strength and staged control of casting blank stacking and slow cooling. According to the method, the initial hydrogen content of the molten steel can be reduced, the dehydrogenation degree of the molten steel in the refining process is increased, residual hydrogen in the casting blank is fully discharged, and the residual hydrogen in the final rolled blank-material steel plate reaches the safety range. The operation method is convenient and effective, the purpose of fully eliminating hydrogen-induced crack hazards can be achieved with low cost, and the rolled blank-material has no defects such as white spots and internal cracks. According to the blank-material steel plate with the thickness larger than or equal to 30 mm, the flaw detection qualification rate of the rolled steel plate is larger than or equal to 99.51%, and the hydrogen content of the rolled steel plate is detected to be smaller than or equal to 0.9 ppm.

Description

technical field [0001] The invention belongs to the category of clean steel production technology, and in particular relates to a method for controlling hydrogen-induced cracks in blank finished steel plates for electric arc furnace short-process steelmaking. Background technique [0002] The initial hydrogen content of electric arc furnace short-process steelmaking is generally 2-4ppm higher than that of converter steelmaking, and hydrogen is one of the important elements harmful to the internal quality of medium and thick plates, especially for steel plates with a thickness ≥ 30mm, the hydrogen diffusion rate is slow, when the steel plate When the accumulated hydrogen content exceeds 1.0ppm, the steel plate will produce hydrogen white spots. Once this kind of hazard occurs, it cannot be eliminated, and the hazard is extremely serious. The most common one is the crack defect in the entire steel plate after rolling, which causes the steel plate to fail to detect flaws and the...

Claims

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Application Information

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IPC IPC(8): C21C5/52C21C7/072C21C7/076C21C7/10
CPCY02P10/20
Inventor 陈家超董亚楠
Owner WUYANG IRON & STEEL
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