Method for increasing AZ91D magnesium alloy corrosion-resistant property

A magnesium alloy and corrosion-resistant technology, applied in the field of improving the corrosion resistance of AZ91D magnesium alloy, can solve the problems of material consumption, high cost, time consumption, etc., and achieve the effects of abundant resources, simple installation, and convenient operation and control.

Inactive Publication Date: 2008-09-17
WUHAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

It is a kind of non-contact stirring, which not only overcomes the shortcomings of direct contact with molten metal caused by mechanical stirring, which causes defects such as gas slag, but also overcomes the shortcomings of material consumption, time consumption and high cost of adding the third component. Attention, great industrial potential

Method used

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  • Method for increasing AZ91D magnesium alloy corrosion-resistant property
  • Method for increasing AZ91D magnesium alloy corrosion-resistant property
  • Method for increasing AZ91D magnesium alloy corrosion-resistant property

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Place the magnesium alloy AZ91D in a crucible, put it in a graphite crucible, heat and smelt in a well-type crucible resistance furnace, when the furnace cavity temperature rises to 600 ℃, pass in CO 2 +SF 6 The mixed gas is protected. When the temperature continues to rise to 720°C, add 0.02% B in the form of an Al-4B (mass fraction, %) master alloy to the alloy liquid, stir it evenly and keep it for 10 minutes, and wait for the temperature to drop. At 685°C, the magnesium alloy is cast into a metal mold (preheated to 350°C), and the mold is placed in a rotating magnetic field generator. After casting, immediately turn on the electricity to start the rotating magnetic field, the current frequency is 50HZ, and the excitation voltage is adjusted to 50V. The alloy is solidified under the action of the rotating magnetic field and cooled at room temperature. After solidification, the rotating magnetic field generator is turned off and the mold is released. The chemical composit...

Embodiment 2

[0033] Put the AZ91D magnesium alloy in a crucible, put it in a graphite crucible, heat and melt in a well-type crucible resistance furnace, when the furnace cavity temperature rises to 600 ℃, let CO 2 +SF 6 The mixed gas is protected. When the temperature continues to rise to 730℃, add 0.05% of B mass fraction to the alloy liquid in the form of Al-4B (mass fraction, %) master alloy, stir it evenly and keep it for 15 minutes, and wait for the temperature to drop. At 690°C, the magnesium alloy is cast into a metal mold (preheated to 300°C), and the mold is placed in a rotating magnetic field generator. After casting, immediately turn on the power to start the rotating magnetic field, the current frequency is 50HZ, and the excitation voltage is adjusted to 100V. The alloy is solidified under the action of the rotating magnetic field and cooled at room temperature. After solidification, the rotating magnetic field generator is turned off and the mold is released.

[0034] Potential p...

Embodiment 3

[0035] Example 3: Put AZ91D magnesium alloy in a crucible, put it in a graphite crucible, and heat and melt in a pit crucible resistance furnace. When the temperature of the furnace chamber rises to 590°C, let CO 2 +SF 6The mixed gas is protected. When the temperature continues to rise to 730°C, add 0.03% of B in the form of Al-4B (mass fraction, %) master alloy to the alloy liquid, stir it evenly and keep it for 20 minutes, and wait for the temperature to drop. At 690°C, the magnesium alloy is cast into a metal mold (preheated to 300°C), and the mold is placed in a rotating magnetic field generator. After casting, immediately turn on the electricity to start the rotating magnetic field, the current frequency is 50HZ, and the excitation voltage is adjusted to 120V. The alloy is solidified under the action of the rotating magnetic field and cooled at room temperature. After solidification, the rotating magnetic field generator is turned off and the mold is released.

[0036] The el...

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Abstract

The invention relates to a method for improving corrosion-resistant performance of AZ91D magnesium alloy, comprising the steps of: heating to melt AZ91D magnesium alloy ingot, introducing protective CO2 and SF6 mixed gas at 590-610 DEG C, heating to 720-740 DEG C, adding boron to the magnesium alloy liquid in the Al-4B intermediate alloy form, stirring, standing to obtain boron-magnesium complex liquid, cooling to 680-700 DEG C, pouring the boron-magnesium complex liquid into a preheated metal mould (200-400 DEG C), and placing the mould into a rotating magnetic field; and powering on to start up a rotating magnetic field generating device, allowing the boron-magnesium complex liquid to solidify under the action of rotating magnetic field, cooling at room temperature, powering off the rotating magnetic field generating device, and demoulding. The inventive method can improve the corrosion-resistant performance of AZ91D magnesium alloy; and has the advantages of no pollution, low energy consumption, and remarkably refined magnesium alloy crystal grains.

Description

Technical field [0001] The invention relates to metal materials, in particular to a method for improving the corrosion resistance of AZ91D magnesium alloy by using a rotating magnetic field and a boron composite treatment process. Background technique [0002] Magnesium alloy is one of the lightest structural materials. It has high specific strength, specific stiffness, excellent shock absorption and casting performance. It has been widely used in aviation, automotive, electronics and other fields, and has shown a strong development momentum. . AZ91D magnesium alloy has excellent casting properties and good mechanical properties at room temperature. It is the most widely used type of magnesium alloy, accounting for 90% of the consumption of die-cast magnesium alloys. However, the corrosion resistance of magnesium and magnesium alloys is very low, so it is used The range is greatly limited, therefore, it becomes more and more urgent to further improve the corrosion resistance of m...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C1/02C22F3/02
Inventor 华林许小芳金亚旭李继高
Owner WUHAN UNIV OF TECH
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