Mg alloy vacuum sealing smelter and method for preventing Mg alloy from oxidation burning

A vacuum sealing, magnesium alloy technology, applied in the fields of metal materials and metallurgy, can solve the problems of equipment and human harm, increase the environment, short life and other problems, achieve the effect of friendly operation interface, economical and environmental protection, and prevention of oxidative combustion

Inactive Publication Date: 2005-08-10
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In order to solve the problem that the current magnesium industry in China uses a large amount of protective gas, which wastes and increases the harm to the environment, equipment and human body; the smelting crucible is seriously oxidized, pollutes the magnesium liquid, and has a short life; Recovery rate, contaminated magnesium liquid and other problems, the present invention proposes a vacuum sealed melting furnace for magnesium alloys, including a melting crucible, a heating furnace for heating the melting crucible, and a protective gas input for filling the protective gas through the gas filling port on the melting crucible The device, as well as the pressure gauge and the overpressure release valve arranged on the melting crucible cover, are characterized in that: the melting crucible includes a lower part of the crucible located in the hearth of the heating furnace for melting magnesium alloys and a lower part of the crucible located outside the heating furnace for containing protective gas The upper part of the crucible, the ratio of the cylindrical volume of the upper part of the crucible to the cross-sectional area of ​​the lower part of the crucible is greater than or equal to 1; A gas concentration analyzer used to detect the concentration of various gases in the melting crucible; the melting crucible and its crucible cover and all other parts connected to the melting crucible are vacuum-sealed to meet the airtightness requirements in the furnace: the pressure rise rate is less than or equal to 20000Pa / Hour

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  • Mg alloy vacuum sealing smelter and method for preventing Mg alloy from oxidation burning

Examples

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Effect test

example 1

[0028] Example 1. Melting magnesium alloy AZ91D, the melting temperature is 720°C, the melting crucible pressure rise rate is 20000Pa / hour, and the protective gas input pipeline is connected for the first time

[0029] Remove the crucible cover 9, put the dried magnesium alloy AZ91D into the lower part 1b of the crucible, and then cover the heat shield 3 and the melting crucible cover 9. Then open the vacuum system to remove the air in the smelting crucible 1; when the pressure in the crucible 1 is less than 1Pa, open the gas charging port and continue pumping for 3 minutes, while using the protective gas input device to fill the melting crucible 1 through the gas charging port 10. Gas, 99.9% N 2 +0.1% SF 6 , to prevent evaporation, oxidation, and combustion during the smelting process of molten magnesium. When the pressure in the melting crucible is 1 atmosphere, close the gas filling port, turn on the power supply of the heating furnace, and start smelting magnesium alloy. ...

example 2

[0031] Example 2. Melting magnesium alloy AZ91D, melting temperature is 720°C, melting crucible pressure rise rate is 200Pa / hour, and there is no air in the protective gas input pipeline

[0032] Remove the crucible cover 9, put the dried magnesium alloy AZ91D into the lower part 1b of the crucible, and then cover the heat shield 3 and the melting crucible cover 9. Then open the vacuum system to remove the air in the melting crucible 1; when the pressure in the crucible 1 is less than 1Pa, close the isolation valve of the vacuum system connected with the melting crucible 1. Open the gas charging port, and use the protective gas input device to fill the melting crucible 1 with protective gas through the gas charging port 10, 99.9% N 2 +0.1% SF 6 , to prevent evaporation, oxidation, and combustion during the smelting process of molten magnesium. When the pressure in the smelting crucible is 80,000Pa, close the gas inlet, turn on the power of the heating furnace, and start smelt...

example 3

[0034] Example 3. Melting magnesium alloy AZ91D, melting temperature is 720°C, melting crucible pressure rise rate is 0.2Pa / hour, and there is no air in the protective gas input pipeline

[0035] Remove the crucible cover 9, put the dried magnesium alloy AZ91D into the lower part 1b of the crucible, and then cover the heat shield 3 and the melting crucible cover 9. Then open the vacuum system to remove the air in the melting crucible 1; when the pressure in the crucible 1 is less than 1Pa, close the isolation valve of the vacuum system connected with the melting crucible 1. Open the gas charging port, and use the protective gas input device to fill the melting crucible 1 with protective gas through the gas charging port 10, 99.5% N 2 +0.5% SF 6 , to prevent evaporation, oxidation, and combustion during the melting of molten magnesium. When the pressure in the melting crucible is 20,000 Pa, close the gas inlet, turn on the power of the heating furnace, and start melting magnes...

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Abstract

The present invention relates to a magnesium alloy vacuum sealed smelting farnace and method for preventing magnesium alloy from being oxidated and burned. Said smelting furnace includes smelting crucible, heating furnace, protective gas input device, vacuum system and gas concentration analyzer. The described smelting crucible includes the crucible lower portion for smelting magnesium alloy and its upper portion for containing protective gas. Besides, said invention also provides the concrete steps of method for preventing magnesium alloy from being oxidated and burned.

Description

technical field [0001] The invention relates to a vacuum-sealed melting furnace for magnesium alloys and a corresponding method for preventing oxidation and combustion of magnesium alloys, belonging to the technical field of metal materials and metallurgy. Background technique [0002] Magnesium and magnesium alloys have significant advantages such as low specific gravity, high specific strength and specific stiffness, and low raw material prices. In the past two decades, the research and application of magnesium alloys have attracted increasing attention from the material science and industry circles. At present, my country's magnesium industry is smelting magnesium and magnesium alloys in open or semi-open furnaces, using continuous feeding of SF 6 or similar gas as shielding gas. This was once the greatest advance in the magnesium industry as it eliminated the previous use of SO 2 and most problems with flux smelting. However, if used in large quantities, it is not onl...

Claims

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Application Information

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IPC IPC(8): C22B26/22F27B14/04F27B14/20
Inventor 聂书红柳百成熊守美
Owner TSINGHUA UNIV
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