Zinc solution iron removing method before production of external continuous hot galvanized plate for automobile and production method thereof

A technology of hot-dip galvanized sheet and production method, which is applied in the direction of hot-dip galvanizing process, coating, metal material coating process, etc., can solve the problems that do not have much practical significance and affect the glossiness of the product surface, and achieve control of the surface quality effect

Inactive Publication Date: 2018-09-21
CISDI ENG CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this scheme increases the aluminum in the zinc solution to a very high level. According to the analysis of the solubility curve of iron in the zinc solution, after the effective aluminum in the zinc solution has increased to a level above 0.30wt%, the slope of the curve has already It tends to be flat and has little effect on the solubility of iron. It has no practical significance to raise it to such a level
The production practice shows that when the aluminum content in the zinc solution is too high, a relatively thick oxide film will be produced on the surface of the galvanized sheet, which will affect the surface gloss of the product.

Method used

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  • Zinc solution iron removing method before production of external continuous hot galvanized plate for automobile and production method thereof
  • Zinc solution iron removing method before production of external continuous hot galvanized plate for automobile and production method thereof
  • Zinc solution iron removing method before production of external continuous hot galvanized plate for automobile and production method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0055] In this embodiment, the following operating process is adopted, and the temperature of the whole process zinc liquid and the theoretical curve of composition control are as follows: Figure 4 Shown:

[0056] 1) Before the production and maintenance of automobile outer panels, gradually reduce the zinc liquid level in the zinc pot; after the unit is shut down, add 2-3 pieces of zinc-aluminum composite ingots with an aluminum content of 5wt% to the zinc pot, and the aluminum content extracted from the zinc pot Higher zinc ingots (partial step 2 was taken out during production before to obtain zinc ingots cast from molten zinc) were allowed to melt naturally, and the aluminum contained in the molten zinc rose to 0.32wt%, while the temperature dropped to 440°C;

[0057] 2) Carry out iron removal treatment, insert a high-pressure nitrogen pipe into the zinc pot, pass high-pressure nitrogen to fully stir the zinc liquid, so that iron and aluminum can fully react, and Fe 2 Al...

Embodiment 2

[0063] In this embodiment, the following operation process is adopted:

[0064] 1) Before the production and maintenance of automobile outer panels, gradually reduce the zinc liquid level in the zinc pot; after the unit is shut down, add 2-3 pieces of zinc-aluminum composite ingots with an aluminum content of 5wt% to the zinc pot, and the aluminum content extracted from the zinc pot Higher zinc ingots (partial step 2 was taken out during production before to obtain zinc ingots cast from molten zinc) were allowed to melt naturally, and the aluminum contained in the molten zinc rose to 0.35wt%, while the temperature dropped to 450°C;

[0065] 2) Carry out iron removal treatment, insert a high-pressure nitrogen pipe into the zinc pot, pass high-pressure nitrogen to fully stir the zinc liquid, so that iron and aluminum can fully react, and Fe 2 Al 5 Precipitation of solid particles; standing for 24 hours to allow the small solid zinc slag particles in the zinc pot to fully collid...

Embodiment 3

[0071] In this embodiment, the following operation process is adopted:

[0072] 1) Before the production and maintenance of automobile outer panels, gradually reduce the zinc liquid level in the zinc pot; after the unit is shut down, add 2-3 pieces of zinc-aluminum composite ingots with an aluminum content of 5wt% to the zinc pot, and the aluminum content extracted from the zinc pot Higher zinc ingots (the zinc liquid obtained from part of step 2) was extracted during production before, and cast into zinc ingots), and allowed to melt naturally, the aluminum contained in the zinc liquid rose to 0.28wt%, and the temperature dropped to 430°C;

[0073] 2) Carry out iron removal treatment, insert a high-pressure nitrogen pipe into the zinc pot, pass high-pressure nitrogen to fully stir the zinc liquid, so that iron and aluminum can fully react, and Fe 2 Al 5 Precipitation of solid particles; standing for 24 hours to allow the small solid zinc slag particles in the zinc pot to full...

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Abstract

The invention provides a Zinc solution iron removing method before the production of an external continuous hot galvanized plate for an automobile and a production method thereof, wherein the iron removing method comprises the following steps: 1) adjusting the aluminum content in the Zinc solution to be between 0.28-0.3wt%, and adjusting the temperature to 430-450 DEG C; 2) introducing inert gas into the zinc solution obtained in the step 1) and stirring, reacting the iron with aluminum, precipitating with Fe2Al5 solid particles, standing, and removing the slag. According to the method, the unreasonable part in the prior art is eliminated, the solubility of Fe in Zinc solution is controlled through the method of reducing the aluminum and the temperature, the slag-free process window for producing the outer plate of the automobile is created, the surface quality is excellently controlled, and the ideal effect is achieved.

Description

technical field [0001] The invention relates to the technical field of continuous hot-dip galvanized sheets for automobiles, in particular to a method for removing iron from zinc liquid before the production of continuous hot-dip galvanized sheets for automobiles and a production method thereof. Background technique [0002] The iron content in the zinc solution is one of the most critical process parameters in the production of outer panels. If the iron content is too high, the defect of "zinc slag particles" may appear, which is a defect that must be strictly controlled for automotive outer panels. A lot of research has been done on this at home and abroad, and a variety of control methods have been formed. For example, a foreign company has adopted a method of greatly increasing the aluminum content of zinc liquid to remove iron. [0003] (1) Lower the zinc liquid level of the zinc pot before maintenance, add high-aluminum ingots, and increase the Al content of the zinc ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C2/06C23C2/40
CPCC23C2/06C23C2/40
Inventor 许秀飞
Owner CISDI ENG CO LTD
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