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 acc

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0019] Example 1:

[0020] In this example, 20 Q355NB steel plates, a thickness of 50 mm, hydrogen-caled control method including control of the electric arc furnace induction steel, LF slag system, VD high vacuum time, VD high vacuum blowing argon, hierarchical control Slips, as follows:

[0021] (1) The electric arc furnace is injected 45T, all over the electric arc furnace to flue, 518 ° C, sufficiently bake, and dry after drying;

[0022] (2) Refining Standard: Add 450kg pre-measuring slag, pre-melt residue Al 2 O 3 Cost 42.38%, refined slag Al 2 O 3 The content is 27.33%;

[0023] (3) Vacuum dehydrogenation: 60Pa vacuum maintenance time 15 min, 60Pa vacuum argon flow 250 l / min, stirred for 10 min;

[0024] (4) Strip Clever Cooling Hands: 2.36 ppm in the middle, and the slab is underlined at 12h.

[0025] In this example, the control method is rolled after the steel sheet detected 0.76 ppm, no internal crack defect, and the test rate is 100%.

Example Embodiment

[0026] Example 2:

[0027] In this example, 20 Q355NC steel sheets, thickness 40 mm, hydrogen caison control method include controlling the electric arc furnace induction steel, LF slag system, VD high vacuum time, VD high vacuum brake strength, hierarchical control Slips, as follows:

[0028] (1) The electric arc furnace is 40t, all over the electric arc furnace to the flue of 17 min, the flue temperature is 528 ° C, fully baked, and then add the furnace after drying;

[0029] (2) Refining Standard: Add 400kg pre-melt slag, pre-melt residue Al 2 O 3 35.88% content, refined slag Al 2 O 3 The content is 20.46%;

[0030] (3) Vacuum dehydrogenation: 38Pa vacuum retention time 15 min, 38Pa vacuum argon flow 230 l / min is strongly stirred 11min;

[0031] (4) Clever cooled hydrogenation: 1.83 ppm in the middle, and the slab is underestined.

[0032] In this example, the control method is rolled after the steel sheet detected 0.72 ppm, no internal crack defect, and the test rate is 100%...

Example Embodiment

[0033] Example 3:

[0034] In this example, 12 Q345D steel plates, thickness of 38 mm, hydrogen caison control method include controlling the electric arc furnace induction steel, LF slag system, VD high vacuum time, VD high vacuum blowing argon, hierarchical control Slips, as follows:

[0035] (1) The electric arc furnace is 40t, all over the electric arc furnace to be preheated by 15 min, the flue temperature is 501 ° C, fully bake, and then add the furnace;

[0036] (2) Refining Standard: Add 400kg pre-melt slag, pre-melt residue Al 2 O 3 Content 41.22%, refined slag Al 2 O 3 The content is 23.92%;

[0037] (3) Vacuum dehydrogenation: 58Pa vacuum retention time 15 min, 58Pa vacuum argon flow 250 l / min is strongly stirred 11min;

[0038] (4) Clever hydrogenation of the slab: 2.5 ppm in the middle, and the slab is closed.

[0039] In this example, the control method rolled the steel sheet to detect 0.56 ppm, no internal crack defect, and the test rate was 100%.

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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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