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Solidification structure refinement and purification method of thick-walled steel castings and thick-walled steel castings

A technology for solidification structure and steel castings, which is applied in the refinement and purification of solidification structure of thick-walled steel castings, and in the field of solidification structure refinement and purification of steel castings. The performance of thick-walled steel castings cannot be greatly improved, etc., to achieve obvious refinement and purification effects, simple process, and high production efficiency

Inactive Publication Date: 2017-05-17
BEIJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] However, the above-mentioned methods for refining and purifying the cast steel structure have complex processes, and for thick-walled steel castings, the refinement and purification effects are not obvious, resulting in that the performance of thick-walled steel castings cannot be greatly improved.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] A method for refining and purifying the solidified structure of a carbon steel casting with a carbon content of 0.45% and a wall thickness of 260mm, which is characterized in that ferrosilicon, ferromanganese and silicon-calcium-barium alloy are used for pre-deoxidation in an electric furnace, and the final deoxidation and fine Combined with chemical solidification process, carried out in the ladle, the specific process steps are:

[0029] ①Melting the cast steel material in a 3 ton electric furnace first, when the temperature of the molten steel rises to 1563°C, add respectively 0.3% of the mass fraction of the molten steel in the furnace to ferrosilicon (the chemical composition mass fraction of ferrosilicon is: 72.54% Si, 0.11 %C, 0.014% S, 0.027% P, the balance being Fe) and 0.7% ferromanganese (the chemical composition mass fraction of ferromanganese is: 1.37%C, 81.50%Mn, 1.66%Si, 0.15%P , 0.017% S, and the balance is Fe) pre-deoxidation, when the molten steel temp...

Embodiment 2

[0033] A method for refining and purifying the solidified structure of a carbon steel casting with a carbon content of 0.29% and a wall thickness of 290mm, which is characterized in that ferrosilicon, ferromanganese and silicon-calcium-barium alloy are used for pre-deoxidation in an electric furnace, and the final deoxidation and fine Combined with chemical solidification process, carried out in the ladle, the specific process steps are:

[0034] ①Smelt the cast steel material in a 5-ton electric furnace first, and when the molten steel temperature rises to 1587°C, respectively add ferrosilicon which accounts for 0.6% of the molten steel mass fraction in the furnace (the chemical composition mass fraction of ferrosilicon is: 79.57% Si, 0.15% %C, 0.009% S, 0.021% P, the balance being Fe) and 0.5% ferromanganese (the chemical composition mass fraction of ferromanganese is: 0.59%C, 75.42%Mn, 2.07%Si, 0.12%P , 0.012% S, the balance being Fe) pre-deoxidation, when the molten steel ...

Embodiment 3

[0038] A method for refining and purifying the solidification structure of low-alloy steel castings with a carbon content of 0.36% and a wall thickness of 340mm, which is characterized in that ferrosilicon, ferromanganese and silicon-calcium-barium alloy are used for pre-deoxidation in an electric furnace, and the final deoxidation and The process of refining and solidifying structure is combined together and carried out in the ladle. The specific process steps are:

[0039] ①Melting the cast steel material in a 3 ton electric furnace first, when the temperature of the molten steel rises to 1581°C, respectively add ferrosilicon which accounts for 0.5% of the mass fraction of the molten steel in the furnace (the chemical composition mass fraction of ferrosilicon is: 75.37% Si, 0.12 %C, 0.013% S, 0.025% P, the balance being Fe) and 0.6% ferromanganese (the chemical composition mass fraction of ferromanganese is: 0.78%C, 78.41%Mn, 1.06%Si, 0.10%P , 0.015% S, the balance being Fe)...

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Abstract

The invention discloses a thick-wall steel casting solidification structure refining and purifying method, and belongs to the technical field of steel casting. In the molten steel smelting process, firstly, the pre-deoxidation is performed in a furnace by ferrosilicon, ferromanganese and silicon calcium barium alloys; when the temperature of molten steel is increased to 1620-1650 DEG C, the alloys are discharged to a steel ladle from the furnace; multielement aluminum iron alloy blocks are added in the steel ladle for deoxidation; then, aluminum-wrapped alloy wires are added in the steel ladle by a wire feeding machine, and consist of two parts of outer metal aluminum strips and powder core materials; after the slag removal and the standing are performed for the molten steel in the steel ladle, and the temperature is reduced to 1490-1520 DEG C, the molten steel is poured into a large casting mold; after the molten steel is poured by 24-48 hours, the casting is fed into a slow cooling pit after opening the ladle; and after the temperature of the casting is lower than 120 DEG C, the casting is discharged from the pit for cutting out a gate and a riser so as to obtain a thick-wall steel casting with fine solidification structures and few inclusions.

Description

technical field [0001] The invention discloses a method for refining and purifying the solidification structure of a steel casting, in particular to a method for refining and purifying the solidification structure of a thick-walled steel casting, and belongs to the technical field of steel casting. Background technique [0002] With the rapid development of my country's industrial technology, the demand for large ball mills, slurry pumps, rolling mills, etc. continues to increase, resulting in increasing demand for large ball mill end covers, rolling mill archways, slurry pump shells, and large cast steel rolls. Due to the large wall thickness and long solidification time of the above-mentioned steel castings, in the past, there were many inclusions and coarse solidification structures in the casting and forming process of these large steel castings, which resulted in a significant decrease in the mechanical properties of the above-mentioned steel castings and a decline in the...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22D1/00C21C7/00C21C7/06
CPCB22D1/00C21C7/0056C21C7/06
Inventor 符寒光鞠江魏世忠符定梅雷永平李耳周向阳成小乐屈银虎
Owner BEIJING UNIV OF TECH