Treatment method for cracks at corners of nickel-containing continuous casting slab

A treatment method and a technology for corners, which are applied in the direction of aluminothermic welding equipment, welding equipment, metal processing equipment, etc., can solve the problems of reducing the cleaning area and surrounding steel base, affecting the quality and performance of steel, and waste of blanks, etc., to achieve improvement Processing efficiency and stability, optimization of crack processing effect, and improvement of billet yield

Inactive Publication Date: 2018-10-26
武汉钢铁有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there are many problems in the existing flame cleaning technology: 1) The cracks at the corners of the continuous casting slab are generally irregular, and the depth often fluctuates in a large range of 2-20mm, and the heat generated by flame combustion is not enough Ensure that the molten metal penetrates deep. Since the thickness of the defect layer cannot be effectively detected, if cracks are to be completely eliminated, it is necessary to remove the surface layer of the billet as thick as possible, which will cause a great waste of billets; 2) at the opposite corner In the process of deep cleaning of cracks, more molten oxides will be produced to cover the corner area, and partially oxidized metal liquid will even penetrate into the depth of micro cracks, because the metal liquid containing nickel oxide will combine with the steel base after cooling Therefore, during the heating process of the slab, these oxides further deteriorate into serious nickel-containing iron oxide scale deposits. After the slab is released from the furnace, it is difficult for general high-pressure descaling equipment to remove such thick and dense oxide scales. The iron sheet is removed cleanly, resulting in the formation of iron oxide surface defects in the subs

Method used

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  • Treatment method for cracks at corners of nickel-containing continuous casting slab
  • Treatment method for cracks at corners of nickel-containing continuous casting slab
  • Treatment method for cracks at corners of nickel-containing continuous casting slab

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0061] The conditions for applying this method to medium and high alloy continuous casting slabs are as follows:

[0062]

[0063] Based on the above conditions, the composition of thermite used is as follows:

[0064]

[0065]

[0066] It takes 6 minutes to fabricate the cracked area at the corner. When the magnesium strip is ignited, the surface temperature of the slab is 484°C. After the reaction is self-sustaining and the surface of the reaction area is purged, the cracked area is well fused. The total treatment time is 13 minutes. After slow cooling No secondary cracks were seen, and the metal sample after the reaction was taken for detection, and the composition was as follows:

[0067]

[0068] It can be seen from the above table that after the aluminothermic reaction, the cost of the reaction product is basically the same as that of the steel base, and meets the requirements of the steel composition. It is consistent with the thermite reaction design princ...

Embodiment 2

[0071] The conditions for applying this method to medium and high alloy continuous casting slabs are as follows:

[0072]

[0073] Based on the above conditions, the composition of thermite used is as follows:

[0074]

[0075] It takes 8 minutes to fabricate the cracked area at the corner. When the magnesium strip is ignited, the surface temperature of the slab is 271°C. After the reaction is self-sustaining and the surface of the reaction area is purged, the cracked area is well fused. The total treatment time is 13 minutes. After slow cooling No secondary cracks were found, and the reacted metal sample was taken for testing. The composition is as follows:

[0076]

[0077]

[0078] It can be seen from the above table that after the aluminothermic reaction, the cost of the reaction product is basically the same as that of the steel base, and meets the composition requirements of the steel type. The contents of Mn and Ni in the reactant are slightly higher than th...

Embodiment 3

[0081] The conditions for applying this method to medium and high alloy continuous casting slabs are as follows:

[0082]

[0083] Based on the above conditions, the composition of thermite used is as follows:

[0084]

[0085] It takes 7 minutes to fabricate the cracked area at the corner. When the magnesium strip is ignited, the surface temperature of the slab is 425°C. After the reaction is self-sustaining and the surface of the reaction area is purged, the cracked area is well fused. The total treatment time is 15 minutes. After slow cooling No secondary cracks were found, and the reacted metal sample was taken for testing. The composition is as follows:

[0086]

[0087] It can be seen from the above table that after the aluminothermic reaction, the cost of the reaction product is basically the same as that of the steel base, and meets the steel composition requirements, and the carbon content meets the minimum requirements

[0088] The continuous casting slab w...

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PUM

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Abstract

The invention discloses a treatment method for cracks at corners of a nickel-containing continuous casting slab. The method comprises the following steps: (1) proportioning: uniformly mixing components of a thermit, wherein the components of the thermit comprise Al, Fe2O3, MnO2, Fe, Si and other micro component powder, the grain sizes of which are 100[mu]m; (2) feeding: calculating the amount of the thermit needed for a 10mm thick thermit covering layer, wherein the actual feeding amount is 1.2-1.5 times of the calculated amount; and (3) igniting to react: after feeding, putting a magnesium rod on the end part of the thermit as an ignition substance, approaching the end part of the thermit on the surface of the nickel-containing continuous casting slab with an ignited flue gas spray gun flame slowly step by step, and quickly combusting the magnesium rod embedded onto the end to lead to a self-maintaining reaction of the thermit. The method disclosed by the invention can optimize the treatment effect of the cracks at the corners of the slab, improves the treatment efficiency and stability, and reduces the surface defect occurrence rate of a finished product steel plate caused by thecracks at the corners on the surface of the slab.

Description

technical field [0001] The invention relates to the technical field of continuous casting and steel casting, in particular to a method for treating cracks at the edges and corners of nickel-containing continuous casting slabs. Background technique [0002] Corner cracks are common surface defects of continuous casting slabs, which mainly occur at or near the corners of the upper surface of the continuous casting slab. Since the cracks at the corners of the slab are related to the state of the mold, the quality of the mold flux, the casting speed, the secondary cooling intensity and the mode, etc. Fit or blockage of the nozzle may cause cracks at the corners of the continuous casting slab. For continuous casting slabs of medium and high alloys containing nickel alloy elements ≥ 1% (the total alloy content ranges from 5% to 10%), due to the difference in physical parameters such as latent heat and shrinkage coefficient of higher alloy elements in the cooling process, and the ...

Claims

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Application Information

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IPC IPC(8): B23K23/00
CPCB23K23/00
Inventor 杨治争洪霞陈昊严翔朱丛茂官计生罗毅
Owner 武汉钢铁有限公司
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