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Method for refining continuous casting billet solidification structure by blowing magnesium powder through submerged nozzle

A solidification structure and immersion technology, which is applied to casting equipment, casting melt containers, manufacturing tools, etc., to achieve the effects of low cost, good grain refinement, and short interval time

Active Publication Date: 2020-07-28
SUZHOU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In order to solve the problem of obtaining nano-scale second phase particles in industrial production, the present invention provides a method for refining the solidification structure of continuous casting slabs by spraying magnesium powder into the submerged nozzle. During the casting process, the magnesium powder is continuously sprayed into the submerged nozzle. In the inner cavity of the nozzle, the magnesium powder mixes with the molten steel flowing downward in the submerged nozzle, and enters the crystallizer with the steel flow, dissolves evenly in the molten steel, and combines with [O] and [S] in the molten steel to form a large number of dispersed nano Grade MgO or MgS particles, promote the nucleation of grains, inhibit the growth of grains, and refine the solidification structure of continuous casting slabs

Method used

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  • Method for refining continuous casting billet solidification structure by blowing magnesium powder through submerged nozzle

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Embodiment 1

[0031] The present invention is applied in the continuous casting process of 250mm×350mm billet. The submerged nozzle is a straight-through type. Two slit nozzles 2 are arranged on the inner wall of the submerged nozzle 1, which are symmetrically distributed, and the width of each slit is 1mm. , the length is 10mm, the length direction of the slit is parallel to the axial direction of the submerged nozzle, the slit nozzle is connected with the existing argon blowing powder injection system 3 through the powder delivery pipeline 4, see figure 1 , the two slit nozzles are consistent, and one place is marked in the attached drawing.

[0032] When casting 45# steel, 200 mesh magnesium powder is sprayed to the steel flow through the submerged nozzle. The flow rate of molten steel in the submerged nozzle is 0.5t / min during the casting process. is 0.0025kg / min, and the amount of magnesium powder added per ton of steel is 0.01kg; the specific processing steps are as follows:

[0033]...

Embodiment 2

[0043] The present invention is applied in the 220mm×1680mm slab continuous casting process. The submerged nozzle is double-sided hole type, with two side holes, and the outlet inclination angle is 16°. Two slit nozzles are arranged on the inner wall surface of the submerged nozzle. The length direction of the slit is parallel to the axial direction of the submerged nozzle. The width of each slit is 1mm and the length is 30mm. The slit nozzle is connected to the existing argon blowing powder injection system through the pipeline, and the two slit nozzles are consistent. .

[0044] When casting Q345 steel, spray 300-mesh magnesium powder to the steel flow through the submerged nozzle. During the casting process, the flow rate of molten steel in the submerged nozzle is 3t / min, and the flow rate of magnesium powder sprayed by each slit nozzle is 0.015kg. / min, the amount of magnesium powder added per ton of steel is 0.01kg, the specific processing steps are as follows:

[0045] ...

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Abstract

The invention belongs to the technical field of molten steel continuous casting, and relates to a method for refining a continuous casting billet solidification structure by blowing magnesium powder through a submerged nozzle. In the molten steel casting process, the magnesium powder is continuously blown into the inner cavity of the submerged nozzle and mixed with the molten steel flowing downwards in the submerged nozzle, then enters a crystallizer along with the steel flow, and is uniformly dissolved in the molten steel and combined with [O] and [S] in the molten steel so as to generate a large amount of dispersedly distributed nanoscale MgO or MgS particles, so that the nucleation of grains is promoted, the growth of the grains is inhibited, and the continuous casting billet solidification structure is refined. According to the method, the low-price magnesium powder is blown into the molten steel before solidification, the nanoscale second-phase particles are obtained with high efficiency and low cost, the continuous casting billet solidification structure is refined, and the performance of steel is improved.

Description

technical field [0001] The invention belongs to the technical field of continuous casting of molten steel, and mainly relates to a method for refining the solidification structure of continuous casting slabs by using a submerged nozzle to spray magnesium powder. Background technique [0002] Grain refinement can significantly improve the strength and toughness of iron and steel materials. How to refine grains is one of the important directions in the research and development of iron and steel materials. Production practice and research have shown that the fine and dispersed second phase particles in steel can be used as the core of grain nucleation, and inhibit the growth of grains by pinning grain boundaries, so as to achieve the effect of refining grains and improving the performance of steel . At present, the second phase particles are mainly obtained by precipitation of inclusions in molten steel, but it is difficult to meet the conditions for obtaining fine and dispers...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22D11/108B22D41/58
CPCB22D11/108B22D41/58
Inventor 胡绍岩屈天鹏王德永王慧华田俊侯栋
Owner SUZHOU UNIV