Method preventing magnesium alloy from oxidative combustion

A magnesium alloy and mixed gas technology, applied in the field of magnesium alloy metallurgy, can solve problems such as large-scale application difficulties, and achieve the effects of preventing oxidative combustion, stable chemical properties, and good protection effects

Inactive Publication Date: 2009-07-15
FUZHOU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method also has obvious disadvantages, such as it is difficult to take into account the flame retardancy and mechanical properties at the same time, so its large-scale application is still difficult.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0012] Magnesium alloy AZ91D was melted in a resistance crucible furnace with a volume of 25 liters and a melting temperature of 680°C using 0.07% HFC-245fa and 99.93% N 2 The mixed gas, the feeding rate of the mixed gas is 2L per minute (about 8% of the closed gas volume above the surface of the magnesium melt), and the magnesium alloy smelting gas protection is carried out.

[0013] Put the dried charge (3 kg) into the crucible of the resistance crucible furnace, and cover the crucible lid. Turn on the melting furnace, heat the crucible, the heating rate is 10°C / min, and feed the mixed gas at 200°C, the mixed gas composition is 0.07% HFC-245fa and 99.93% N 2 The mixed gas, the flow rate of the mixed gas is 2L / min. After heating up to melting, the protective gas quickly forms a dense and well-protective protective film on the surface of the magnesium melt, and continues to heat up to 680°C after melting. Keep warm for 1 hour, then pour. During the whole smelting and heat pr...

Embodiment 2

[0015] Magnesium alloy AM50 is smelted in a resistance crucible furnace, the volume of the smelting furnace is 25 liters, the melting temperature is 700 ° C, a mixed gas of 0.15% HFC-245fa and 99.85% dry compressed air is used, and the feeding rate of the mixed gas is 2.0 L per minute (approx. 8% of the closed gas volume above the surface of the magnesium melt), the magnesium alloy smelting gas protection is carried out.

[0016] Put the dried charge (3 kg) into the crucible of the resistance crucible furnace, and cover the crucible lid. Turn on the melting furnace, heat the crucible, the temperature rise rate is 10°C / min, and feed the mixed gas at 200°C, the mixed gas composition is 0.15% HFC-245fa and 99.85% dry compressed air, the flow rate of the mixed gas is 1.0L / min, heat up After melting, the protective gas quickly forms a dense and well-protective protective film on the surface of the magnesium melt. After melting, continue to heat up to 700°C, keep it warm for 1 hour,...

Embodiment 3

[0018] Pure magnesium is smelted in a resistance crucible furnace with a volume of 25 liters and a melting temperature of 730°C. A mixed gas of 0.3% HFC-245fa and 99.7% dry compressed air is used. 8% of the closed gas volume above the surface of the magnesium melt), and carry out gas protection for magnesium alloy smelting.

[0019] Put the dried charge (3 kg) into the crucible of the resistance crucible furnace, and cover the crucible lid. Turn on the melting furnace, heat the crucible, the heating rate is 10°C / min, and feed the mixed gas at 200°C, the mixed gas composition is 0.3% HFC-245fa and 99.7% dry compressed air, the flow rate of the mixed gas is 2.0L / min, heat up After melting, the protective gas quickly forms a dense and well-protective protective film on the surface of the magnesium melt. After melting, continue to heat up to 730°C, keep it warm for 1 hour, and then pour. During the whole smelting and heat preservation process, the mixed gas containing HFC-245fa h...

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Abstract

The invention provides a method for preventing magnesium alloy from oxidizing and combusting while the magnesium alloy is smelted. The method comprises the following steps: leading mixed gases comprising HFC-245fa gas and diluent gas to a magnesium alloy smelting furnace so as to protect the smelting of the magnesium alloy; and when the magnesium alloy is smelted, drying and mixing the gases, and conveying the gases to the magnesium alloy surface to be protected to provide the protection. The HFC-245fa (1,1,1,3,3-Pentafluoropropane with the structural formula of C3F5H3) gas adopted by the invention has low greenhouse effect with extremely low toxicity in the working concentration, thereby hardly affecting the human body; the method has the advantages of high quality, high efficiency, environmental protection, low cost and easy and feasible operation, solves the problems in the aspects of environment, equipment, harm to human health and the like caused by the SF6 gas having high greenhouse effect and the toxic SO2 gas for preventing the smelting of the magnesium alloy in the current international magnesium industrial community, and has remarkable value of environmental protection and economic benefit, therefore, the method is suitable for large-scale industrialized popularization.

Description

technical field [0001] The invention belongs to the technical field of magnesium alloy metallurgy, and more specifically relates to a method for preventing oxidation and combustion of magnesium alloy during smelting. Background technique [0002] Magnesium alloy not only has low density, high specific strength and high specific stiffness, but also has the advantages of good damping performance, good cutting performance, good electrical conductivity, stable size, low cost, no pollution, and easy recycling. It has been widely used in fields such as aviation and aerospace, and is one of the important lightweight and high-strength materials in the 21st century. However, some key technologies that hinder the large-scale application of magnesium alloys have not been resolved, such as magnesium alloys are prone to oxidative combustion during smelting, processing and heat treatment. For many years, people have been looking for ways to prevent oxidative combustion during the melting...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C1/02C22C23/00
Inventor 陈晓朱立生林银山
Owner FUZHOU UNIV
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