CN113174506A - Refining flux suitable for magnesium-lithium alloy and preparation method thereof - Google Patents

Refining flux suitable for magnesium-lithium alloy and preparation method thereof Download PDF

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CN113174506A
CN113174506A CN202110378615.8A CN202110378615A CN113174506A CN 113174506 A CN113174506 A CN 113174506A CN 202110378615 A CN202110378615 A CN 202110378615A CN 113174506 A CN113174506 A CN 113174506A
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melt
lithium
flux
magnesium
refining
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CN113174506B (en
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徐仕豪
刘文才
吴国华
温璐
丁文江
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Shanghai Jiaotong University
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    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C1/00Making non-ferrous alloys
    • C22C1/06Making non-ferrous alloys with the use of special agents for refining or deoxidising
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22BPRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B9/00General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
    • C22B9/006General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals with use of an inert protective material including the use of an inert gas
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22BPRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B9/00General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
    • C22B9/10General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals with refining or fluxing agents; Use of materials therefor, e.g. slagging or scorifying agents
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C1/00Making non-ferrous alloys
    • C22C1/02Making non-ferrous alloys by melting
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C1/00Making non-ferrous alloys
    • C22C1/02Making non-ferrous alloys by melting
    • C22C1/03Making non-ferrous alloys by melting using master alloys
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C23/00Alloys based on magnesium

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  • Engineering & Computer Science (AREA)
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Abstract

The invention provides a refining flux suitable for a magnesium-lithium alloy and a preparation method thereof, wherein the flux comprises the following components in percentage by mass: 40-70% of lithium bromide (LiBr), 15-40% of lithium chloride (LiCl), 10-40% of potassium chloride (KCl), 0-10% of lithium fluoride (LiF), and 0-10% of calcium fluoride (CaF)2) 1-10% of carbonate gas-making agent and 1-5% of carbonate gas-making agent; the carbonate gas-generating agent comprises one of magnesium carbonate and calcium carbonate. The flux of the invention optimizes the proportion of each component and has better melting pointThe magnesium-lithium alloy melt is prevented from being oxidized and burnt, the dosage of the flux is reduced, alloy liquid is not easy to mix, the magnesium-lithium alloy melt is favorably separated from the melt, and the quality of cast ingots is ensured.

Description

Refining flux suitable for magnesium-lithium alloy and preparation method thereof
Technical Field
The invention relates to a refining flux suitable for a magnesium-lithium alloy and a preparation method thereof, in particular to a magnesium-lithium alloy refining flux which has good wettability and viscosity and an adsorption and agglomeration effect, is used for purifying a magnesium-lithium alloy melt, has a grain refining effect, and belongs to the field of metal materials and metallurgy.
Background
With the increasing shortage of global energy and resources, the light weight and recycling capability of materials are of great importance. The magnesium-lithium alloy is the lightest metal structure material so far, and the density is usually 1.3-1.65 g/cm according to the lithium content3But not limited to 1/2-2/3 of the density of the magnesium alloy. The magnesium-lithium alloy can not only greatly reduce weight of national defense industries such as rockets, missiles, satellites, space stations, lunar landing mechanisms, military aircraft, radars and the like in China, but also solve the bottleneck problem that the development of weapons and satellites in China is restricted by light materials; the damping material can also be applied to the fields of civil industries such as automobiles, electrical appliances, electronics, medical treatment and the like, and the advantages of low density, good damping performance, 100 percent recoverability and the like are utilized to reduce weight, improve product quality and greatly promote the cyclic utilization of resources.
Most of the currently adopted magnesium-lithium alloy components are produced by adopting a casting method due to complex structure and large size, and are generally smelted and cast in an atmospheric environment aiming at complex structural parts, and at the moment, magnesium and lithium in the alloy are easy to chemically react with substances such as air, oxygen and water in smelting equipment or raw materials, so that the oxidation and even combustion loss of alloy elements are caused, and impurities such as oxides, carbides and the like of magnesium and lithium elements are introduced to pollute a melt. Therefore, the melt is protected and refined in the smelting process of the magnesium-lithium alloy, and the purpose of protection treatment is to isolate the melt from the outside air and prevent the oxidation and burning loss of elements. The refining treatment aims to purify the melt, remove impurities in the melt and prevent the impurities from influencing the quality of the cast ingot. The refining process of the currently researched magnesium-lithium alloy is mainly flux refining, and the used refining flux is mainly lithium chloride and lithium fluoride series flux [ as described in the literature' research on melting and casting process and organizational performance of magnesium-lithium alloy, [ Yaxinzhao, the treatise on Master academic degree of the institute of materiel science and engineering institute of Hunan university 2006, P1-32) ], but the flux is inconvenient to separate from the melt in the refining process, so that the inclusion of the flux is easily formed, the pollution to the melt is increased, and the quality of cast ingots is influenced; if a common magnesium alloy system flux is adopted [ as described in the research progress of magnesium alloy melt purification technology in the literature, [ Liuwangbo et al, 2015 64 th volume 6 th period P521-527) ], lithium reacts with magnesium chloride which is the main component of the flux, lithium element in the melt is consumed, and ingot components are unstable; meanwhile, the flux can decompose and release harmful gases such as hydrogen chloride, chlorine and the like at high temperature, so that the corrosion to equipment and the damage to operators are increased, and the pollution to the atmosphere is further increased.
In conclusion, in order to improve the refining effect of magnesium-lithium alloy smelting, the development of a novel magnesium-lithium alloy refining flux which is effective in refining, low in cost, small in pollution to a melt and atmosphere and beneficial to separation from the melt is an urgent task of expanding the production application of magnesium-lithium alloy castings and improving the quality of the castings.
Disclosure of Invention
The invention aims to overcome the defects of the existing magnesium-lithium alloy refining flux and provides a refining flux suitable for magnesium-lithium alloy and a preparation method thereof. The invention provides a novel magnesium-lithium alloy refining agent which does not react with lithium element and has an adsorption effect in the using process, and in the using process, gas-making substances in the refining agent are heated and decomposed to continuously release tiny inert gas bubbles, so that a liquid flux floats on the surface of a melt in a foam shape, magnesium, lithium and other elements in the melt are better protected, the refining effect is stable, and the magnesium-lithium alloy refining agent is easy to separate from an alloy liquid and is convenient to remove slag.
In order to achieve the aim, the chemical components of the magnesium-lithium alloy refining flux provided by the invention reduce the content of calcium fluoride which can generate a replacement reaction with lithium, and magnesium chloride which consumes lithium element and causes inaccurate alloy components is not added, and a certain amount of alkali carbonate is added instead, wherein the alkali carbonate comprises one of magnesium carbonate and calcium carbonate; the air can be effectively isolated, and the melt is fully protected; meanwhile, the magnesium-lithium alloy refining flux provided by the invention optimizes the component ranges of lithium bromide, lithium chloride, potassium chloride, lithium fluoride and calcium fluoride, and has a better purification effect under the action of gas-making substances. Compared with the common refining agent, the added lithium bromide plays a role of a thickening agent, and the viscosity of the liquid flux is improved; the added potassium chloride has the function of improving the spreadability of the fusing agent; the dosage of calcium fluoride is reduced, the loss of a large amount of lithium is avoided, and meanwhile, calcium element for refining grains can be introduced by virtue of the reaction of lithium and a small amount of calcium fluoride, so that the strength of the alloy is improved.
The purpose of the invention is realized by the following scheme:
in a first aspect, the invention provides a refining flux suitable for magnesium-lithium alloy and a preparation method thereof, wherein the flux comprises the following components in percentage by mass: 40-70% of lithium bromide (LiBr), 15-40% of lithium chloride (LiCl), 10-40% of potassium chloride (KCl), 0-10% of lithium fluoride (LiF), and 0-10% of calcium fluoride (CaF)2) 1-10% of carbonate gas-making agent and 1-5% of carbonate gas-making agent.
As an embodiment of the present invention, the carbonate gas generating agent is an alkali metal carbonate; including calcium carbonate or magnesium carbonate.
As an embodiment of the present invention, the particle size of the alkali metal carbonate should be 0.1 to 1 μm.
As one embodiment of the invention, the fusing agent comprises the following components in percentage by mass: 40-50% of lithium bromide (LiBr), 20-22% of lithium chloride (LiCl), 20-22% of potassium chloride (KCl), 0-10% of lithium fluoride (LiF), and 0-10% of calcium fluoride (CaF)2) 3-5% of carbonate gas-making agent and 3-5% of carbonate gas-making agent.
As an embodiment of the invention, the flux comprises the following components in percentage by mass: 50% lithium bromide (LiBr), 22% lithium chloride (LiCl), 22% potassium chloride (KCl), 3% calcium fluoride (CaF)2) 3% magnesium carbonate (MgCO)3)。
In a second aspect, the present invention provides a method of preparing a refining flux suitable for magnesium-lithium alloys, comprising the steps of:
preheating a crucible, and adding lithium bromide, lithium chloride, lithium fluoride and potassium chloride; heating to partially melt, adding calcium fluoride, heating to 650-750 ℃ to completely melt, uniformly stirring, and casting into blocks; crushing and grinding the block sample to obtain a powdery sample, sieving the powdery sample, adding a carbonate gas generating agent, and performing ball milling and mixing to obtain the refining flux.
As an embodiment of the invention, a sieve with the number of 20-40 is adopted for sieving.
In a third aspect, the present invention provides a method of using a refining flux suitable for magnesium lithium alloys, comprising the steps of:
a. when in use, an industrial pure magnesium or magnesium alloy ingot is added into a smelting furnace, a little refining flux is scattered on the surface of the magnesium ingot before melting, the flux is melted into liquid state at high temperature (higher than 600 ℃), and the liquid state is spread on the surface of the melt or the magnesium ingot (playing a role of isolating air); after all alloy raw materials except lithium are melted, adding a refining flux to completely cover the melt (preferably without obvious flame);
b. when the temperature of the melt rises to 670-690 ℃, pressing lithium below the liquid level of the melt (2/3) by using a lithium adding cover to completely melt the lithium;
c. when the temperature of the melt mixture in the step b is raised back to 690-700 ℃, vertically stirring for 1-3 minutes (fully diffusing and homogenizing elements of the melt to prevent segregation) below the melt liquid level (2/3) by using a lithium adding cover;
d. c, when the temperature of the melt mixture in the step c rises to 710-720 ℃, scattering a refining flux into the melt for multiple times, wherein the flux needs to be basically melted and stirred for 1-3 minutes each time the flux is scattered;
e. after all the refining flux is added, vertically stirring for 3-5 minutes below the melt liquid level (2/3) by using a lithium adding cover (so that the melt circularly flows, the stroke of the flux is prolonged, and the chance of fully contacting the flux with inclusions is increased), and then standing the melt.
f. And after refining treatment, slagging off, and standing the melt until the liquid level is a bright mirror surface, thus pouring.
In one embodiment of the present invention, in step a, the flux is added in an amount of 2 to 10% by mass based on the mass of the melt.
In step b, a step of adding a small amount of refining flux (reducing the loss of lithium) depending on the surface condition of the melt is further included after melting; and the supplementary flux accounts for 0-1% of the mass of the melt.
In one embodiment of the present invention, in the step d, the total addition amount of the flux is 2 to 5% by mass of the melt.
In one embodiment of the invention, in the step d, the flux is added in 2-5 times.
In one embodiment of the invention, in the step e, the standing time is 8 to 15 minutes.
Compared with the prior art, the invention has the following beneficial effects:
compared with the existing flux, the flux provided by the invention has the advantages that substances such as magnesium chloride and the like which can react with lithium are not added in the components, so that the loss of lithium can be reduced, and the yield of lithium elements is ensured;
compared with the existing flux, the flux has better melting point, density and wettability by optimizing the component ranges of lithium bromide, lithium chloride, lithium fluoride, potassium chloride and calcium fluoride, has the functions of a refining agent and a covering agent, can effectively isolate air when used as the covering agent, provides sufficient protection for a melt, and simultaneously releases protective gas to dilute harmful gas such as hydrogen chloride and the like, remarkably reduces the emission of the harmful gas in the smelting process, and achieves the purpose of no pollution; when the refining agent is used as a refining agent, the refining agent can be fully contacted with the impurities in the melt to remove the impurities, so that the refining effect is ensured;
compared with the existing flux, the flux is added with a certain amount of alkali carbonate, in the using process, the adsorbed substances in the refining agent are heated and decomposed to continuously release tiny inert gas bubbles, and the bubbles can adsorb nonmetallic inclusions in the floating process to enable the nonmetallic inclusions to be agglomerated into large particles, so that the removal rate of various inclusions is greatly improved, the refining effect is stable, and the flux is easy to separate from alloy liquid and is convenient for slag skimming;
compared with the existing flux, the flux of the invention is added with a certain amount of calcium fluoride, and calcium element reduced in the smelting process has the functions of improving the ignition point of the magnesium alloy and refining crystal grains;
compared with the existing flux, the preparation method of the flux has the advantages of simple process and convenient operation.
Detailed Description
The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention. All falling within the scope of the present invention.
Example 1
The embodiment provides a refining flux suitable for magnesium-lithium alloy, which comprises the following chemical components in percentage by mass: 50% lithium bromide (LiBr), 22% lithium chloride (LiCl), 22% potassium chloride (KCl), 3% calcium fluoride (CaF)2) 3% magnesium carbonate (MgCO)3)。
Weighing the raw materials according to the mass percentage of the raw materials, preheating a crucible, and adding lithium bromide, lithium chloride and potassium chloride; heating to partially melt, adding calcium fluoride, heating to 750 deg.C to completely melt, stirring, and casting into blocks; crushing and grinding the block sample to obtain a powdery sample, sieving the powdery sample by a No. 20 sieve, adding magnesium carbonate, performing ball milling and mixing to obtain a refined flux, and placing the refined flux in a closed container for later use.
Before use, a refining flux of about 6% by mass of the melt was prepared. When the magnesium alloy is used as a covering agent, industrial pure magnesium is added into a crucible, a little flux (accounting for about 2% of the mass of the melt) is scattered on the surface of a magnesium ingot before melting, alloy raw materials except lithium are added in batches, refined flux is added after all the raw materials are completely melted, the surface layer of the melt is completely covered by the flux in a foam-liquid state, and the adding amount of the total flux is about 4% of the mass of the melt. And then, when the temperature of the melt rises to 680 ℃, adding subsequent raw material lithium and completely melting, wherein a protective layer on the surface of the melt is intact in the lithium adding process, the flux covers the surface of the melt in a foam shape, and a lithium adding cover is used for stirring for 2 minutes at 2/3 below the liquid level of the melt. When the temperature of the melt mixture rises to 720 ℃, adding a flux with the mass of 2 percent of the melt in batches, stirring for 1 minute after the flux is basically melted each time, and vertically stirring for 5 minutes below the melt liquid level 2/3 by using a lithium adding cover after all the flux is melted so as to ensure that the melt flows fully and increase the contact chance of the flux and inclusions; and after the refining treatment is finished, slagging off is carried out, the melt is kept stand for 10 minutes until the surface of the melt is a bright mirror surface, and then pouring is carried out.
The Mg-8Li-1Al-4Zn magnesium lithium alloy prepared by the flux has the inclusion content of 0.17 percent by volume, and the inclusions with the grain diameter of more than 15 mu m in the alloy are basically removed; the tensile strength of the as-cast alloy is 156.4MPa, the yield strength is 121.5MPa, and the elongation is 46.3%; the solid solution alloy has tensile strength of 278.6MPa, yield strength of 235.3MPa and elongation of 15.2%.
The Mg-8Li-3Al-2Zn-0.5Y magnesium-lithium alloy prepared by the flux has the alloy inclusion content of 0.10 percent, the tensile strength of 247.2MPa, the yield strength of 186.3MPa and the elongation of 25.1 percent.
Example 2
The embodiment provides a refining flux suitable for magnesium-lithium alloy, which comprises the following chemical components in percentage by mass: 45% lithium bromide (LiBr), 20% lithium chloride (LiCl), 5% lithium fluoride (LiF), 20% potassium chloride (KCl), 5% calcium fluoride (CaF)2) 5% calcium carbonate (CaCO)3)。
Weighing the raw materials according to the mass percentage of the raw materials, preheating a crucible, and adding lithium bromide, lithium chloride, lithium fluoride and potassium chloride; heating to partially melt, adding calcium fluoride, heating to 730 ℃ to completely melt, uniformly stirring, and casting into blocks; crushing and grinding the block sample to obtain a powdery sample, sieving the powdery sample by a No. 30 sieve, adding calcium carbonate, performing ball milling and mixing to obtain a refined flux, and placing the refined flux in a closed container for later use.
Before use, a refining flux of about 7% by mass of the melt was prepared. When the magnesium alloy covering flux is used as a covering agent, an industrial pure magnesium or magnesium alloy ingot is added into a crucible, a little flux (accounting for about 3% of the mass of a melt) is scattered on the surface of the magnesium ingot before melting, alloy raw materials except lithium are added in batches, a refining flux is added after all the raw materials are completely melted, the surface layer of the melt is completely covered by the flux in a foam-liquid state, and the adding amount of the total flux is about 5% of the mass of the melt. And then, when the temperature of the melt rises to 680 ℃, adding subsequent raw material lithium and completely melting, wherein a protective layer on the surface of the melt is intact in the lithium adding process, the flux covers the surface of the melt in a foam shape, and a lithium adding cover is used for stirring for 2 minutes at 2/3 below the liquid level of the melt. When the temperature of the melt mixture rises to 720 ℃, adding a flux with the mass of 2 percent of the melt in batches, stirring for 1 minute after the flux is basically melted each time, and vertically stirring for 4 minutes below the melt liquid level 2/3 by using a lithium adding cover after all the flux is melted so as to ensure that the melt flows fully and increase the contact chance of the flux and inclusions; and after the refining treatment is finished, slagging off is carried out, the melt is kept stand for 12 minutes until the surface of the melt is a bright mirror surface, and then pouring is carried out.
The Mg-8Li-1Al-4Zn magnesium lithium alloy prepared by the flux has the inclusion content of 0.21 percent by volume and basically removes the inclusions with the grain diameter of more than 20 mu m in the alloy; the tensile strength of the as-cast alloy is 155.7MPa, the yield strength is 120.5MPa, and the elongation is 45.2%; the solid solution alloy has the tensile strength of 275.2MPa, the yield strength of 233.9MPa and the elongation of 14.3 percent.
Example 3
The embodiment provides a refining flux suitable for magnesium-lithium alloy, which comprises the following chemical components in percentage by mass: 40% lithium bromide (LiBr), 21% lithium chloride (LiCl), 10% lithium fluoride (LiCl), 21% potassium chloride (KCl), 5% calcium fluoride (CaF)2) 3% calcium carbonate (CaCO)3)。
Weighing the raw materials according to the mass percentage of the raw materials, preheating a crucible, and adding lithium bromide, lithium chloride, lithium fluoride and potassium chloride; heating to partially melt, adding calcium fluoride, heating to 730 ℃ to completely melt, uniformly stirring, and casting into blocks; crushing and grinding the block sample to obtain a powdery sample, sieving the powdery sample by a No. 40 sieve, adding calcium carbonate, performing ball milling and mixing to obtain a refined flux, and placing the refined flux in a closed container for later use.
Before use, a refining flux of about 10% by mass of the melt is prepared. When the magnesium alloy covering flux is used as a covering agent, an industrial pure magnesium or magnesium alloy ingot is added into a crucible, a little flux (accounting for about 3% of the mass of a melt) is scattered on the surface of the magnesium ingot before melting, alloy raw materials except lithium are added in batches, a refining flux is added after all the raw materials are completely melted, the surface layer of the melt is completely covered by the flux in a foam-liquid state, and the adding amount of the total flux is about 6% of the mass of the melt. And then, when the temperature of the melt rises to 680 ℃, adding subsequent raw material lithium and completely melting, wherein a protective layer on the surface of the melt is intact in the lithium adding process, the flux covers the surface of the melt in a foam shape, and a lithium adding cover is used for stirring for 2 minutes at 2/3 below the liquid level of the melt. When the temperature of the melt mixture rises to 710 ℃, adding 4% flux by mass of the melt in batches, stirring for 1 minute after the flux is basically melted each time, and vertically stirring for 3 minutes below the melt liquid level 2/3 by using a lithium adding cover after all the flux is melted so as to ensure that the melt flows fully and circularly and increase the contact chance of the flux and inclusions; and after the refining treatment is finished, slagging off is carried out, the melt is kept stand for 15 minutes until the surface of the melt is a bright mirror surface, and then pouring is carried out.
The Mg-8Li-1Al-4Zn magnesium lithium alloy prepared by the flux has the inclusion content of 0.25 percent by volume, and the inclusions with the grain diameter of more than 25 mu m in the alloy are basically removed; the tensile strength of the as-cast alloy is 154.6MPa, the yield strength is 121.3MPa, and the elongation is 45.4%; the solid solution alloy has the tensile strength of 275.4MPa, the yield strength of 234.2MPa and the elongation of 13.8 percent.
Comparative example 1
The comparative example provides a magnesium-lithium alloy refining flux which comprises the following chemical components in percentage by mass: 60% lithium chloride (LiCl), 20% lithium fluoride (LiCl), 20% calcium fluoride (CaF)2)。
Weighing the raw materials according to the mass percentage of the raw materials, preheating a crucible, and adding lithium chloride and lithium fluoride; heating to partially melt, adding calcium fluoride, heating to 700 ℃ to completely melt, uniformly stirring, and casting into blocks; crushing and grinding the block sample to obtain a powdery sample, sieving the powdery sample by a No. 20 sieve to obtain a refining flux, and placing the refining flux in a closed container for later use.
Before use, a refining flux of about 14% by mass of the melt was prepared. When the covering agent is used, industrial pure magnesium or magnesium alloy ingot is added into a crucible, a little flux (accounting for about 3% of the mass of the melt) is scattered on the surface of the magnesium ingot before melting, alloy raw materials are added in batches, the flux is supplemented according to the condition of the surface of the melt (no obvious flame is suitable) after the raw materials except lithium are completely melted, and the total flux addition amount is about 5% of the mass of the melt. And then, when the temperature of the melt rises to 680 ℃, adding subsequent raw material lithium and completely melting, slightly damaging the protective layer on the surface of the melt in the lithium adding process, supplementing a flux with the mass of about 1 percent of the melt, and stirring for 2 minutes at 2/3 below the liquid level of the melt by using a lithium adding cover. When a protective layer is formed on the surface of the melt again and the temperature of the melt mixture rises to 710 ℃, adding a flux with the mass of 8 percent of the melt for multiple times, and vertically stirring for 5 minutes below the melt liquid level 2/3 by utilizing a lithium adding cover to ensure that the melt flows fully and circularly; and after the refining treatment is finished, slagging off is carried out, the melt is kept stand for 10 minutes until the surface of the melt is a bright mirror surface, and then pouring is carried out.
The Mg-8Li-1Al-4Zn magnesium lithium alloy prepared by the flux has the inclusion content of 0.66 percent by volume, and the inclusions with the grain diameter of more than 50 mu m in the alloy are not completely removed; the tensile strength of the as-cast alloy is 151.9MPa, the yield strength is 122.3MPa, and the elongation is 40.3%; the solid solution alloy has the tensile strength of 265.1MPa, the yield strength of 233.7MPa and the elongation of 10.5 percent.
The Mg-8Li-3Al-2Zn-0.5Y magnesium-lithium alloy is prepared by adopting the flux, the content of alloy inclusions is 0.14 wt.%, the tensile strength is 241MPa, the yield strength is 186MPa, and the elongation is 21%.
Comparative example 2
The comparative example provides a magnesium-lithium alloy refining flux which comprises the following chemical components in percentage by mass: 65% lithium bromide (LiBr), 20% lithium chloride (LiCl), 5% lithium fluoride (LiF), 5% calcium fluoride (CaF)2) 5% calcium carbonate (CaCO)3)。
Weighing the raw materials according to the mass percentage of the raw materials, preheating a crucible, and adding lithium bromide, lithium chloride and lithium fluoride; heating to partially melt, adding calcium fluoride, heating to 720 ℃ to completely melt, uniformly stirring, and casting into blocks; crushing and grinding the block sample to obtain a powdery sample, sieving the powdery sample by a No. 30 sieve, adding calcium carbonate, performing ball milling and mixing to obtain a refined flux, and placing the refined flux in a closed container for later use.
Before use, a refining flux of about 7% by mass of the melt was prepared. When the magnesium alloy covering flux is used as a covering agent, an industrial pure magnesium or magnesium alloy ingot is added into a crucible, a little flux (accounting for about 3% of the mass of a melt) is scattered on the surface of the magnesium ingot before melting, alloy raw materials except lithium are added in batches, a refining flux is added after all the raw materials are completely melted, the surface layer of the melt is completely covered by the flux in a foam-liquid state, and the adding amount of the total flux is about 5% of the mass of the melt. And then, when the temperature of the melt rises to 680 ℃, adding subsequent raw material lithium and completely melting, wherein a protective layer on the surface of the melt is intact in the lithium adding process, the flux covers the surface of the melt in a foam shape, and a lithium adding cover is used for stirring for 2 minutes at 2/3 below the liquid level of the melt. When the temperature of the melt mixture rises to 710 ℃, adding a flux with the mass of 2 percent of the melt for multiple times, and vertically stirring for 5 minutes below the melt liquid level 2/3 by utilizing a lithium adding cover to ensure that the melt flows fully and circularly; and after the refining treatment is finished, slagging off is carried out, the melt is kept stand for 9 minutes until the surface of the melt is a bright mirror surface, and then pouring is carried out.
The Mg-8Li-1Al-4Zn magnesium lithium alloy prepared by the flux has the inclusion content of 0.52 percent by volume, large-particle inclusions in the alloy are basically removed, but the inclusions with the particle size of more than 30 mu m are not completely removed; the tensile strength of the as-cast alloy is 151.7MPa, the yield strength is 121.5MPa, and the elongation is 40.1%; the solid solution alloy has tensile strength of 267.8MPa, yield strength of 232.8MPa and elongation of 11.6%.
Comparative example 3
The comparative example provides a magnesium-lithium alloy refining flux which comprises the following chemical components in percentage by mass: 61% lithium chloride (LiCl), 10% lithium fluoride (LiCl), 21% potassium chloride (KCl), 5% calcium fluoride (CaF)2) 3% calcium carbonate (CaCO)3)。
Weighing the raw materials according to the mass percentage of the raw materials, preheating a crucible, and adding lithium chloride, potassium chloride and lithium fluoride; heating to partially melt, adding calcium fluoride, heating to 720 ℃ to completely melt, uniformly stirring, and casting into blocks; crushing and grinding the block sample to obtain a powdery sample, sieving the powdery sample by a No. 40 sieve, adding magnesium carbonate, performing ball milling and mixing to obtain a refined flux, and placing the refined flux in a closed container for later use.
Before use, a refining flux of about 10% by mass of the melt is prepared. When the magnesium alloy covering flux is used as a covering agent, an industrial pure magnesium or magnesium alloy ingot is added into a crucible, a little flux (accounting for about 3% of the mass of a melt) is scattered on the surface of the magnesium ingot before melting, alloy raw materials except lithium are added in batches, a refining flux is added after all the raw materials are completely melted, the surface layer of the melt is completely covered by the flux in a foam-liquid state, and the adding amount of the total flux is about 6% of the mass of the melt. And then, when the temperature of the melt rises to 680 ℃, adding subsequent raw material lithium and completely melting, wherein a protective layer on the surface of the melt is intact in the lithium adding process, the flux covers the surface of the melt in a foam shape, and a lithium adding cover is used for stirring for 2 minutes at 2/3 below the liquid level of the melt. When the temperature of the melt mixture rises to 710 ℃, adding a flux with the mass of 4 percent of the melt for multiple times, and vertically stirring for 5 minutes below the melt liquid level 2/3 by utilizing a lithium adding cover to ensure that the melt flows fully and circularly; and after the refining treatment is finished, slagging off is carried out, the melt is kept stand for 10 minutes until the surface of the melt is a bright mirror surface, and then pouring is carried out.
The Mg-8Li-1Al-4Zn magnesium lithium alloy prepared by the flux has the inclusion content of 0.72 percent by volume, a small amount of large-particle inclusions exist in the alloy, and the as-cast alloy grains are slightly coarse; the tensile strength of the as-cast alloy is 151.1MPa, the yield strength is 120.3MPa, and the elongation is 36.2%; the solid solution alloy has the tensile strength of 260.4MPa, the yield strength of 233.7MPa and the elongation of 10.8 percent.
Comparative example 4
The comparative example provides a magnesium-lithium alloy refining flux which comprises the following chemical components in percentage by mass: 50% lithium bromide (LiBr), 22% lithium chloride (LiCl), 22% potassium chloride (KCl), 3% calcium fluoride (CaF)2) 3% Yttrium carbonate (Y)2(CO3)3)。
Weighing the raw materials according to the mass percentage of the raw materials, preheating a crucible, and adding lithium bromide, lithium chloride, potassium chloride and lithium fluoride; heating to 720 ℃ to completely melt the mixture, uniformly stirring and casting the mixture into blocks; crushing and grinding the block sample to obtain a powdery sample, sieving the powdery sample by a No. 30 sieve, adding calcium carbonate, performing ball milling and mixing to obtain a refined flux, and placing the refined flux in a closed container for later use.
Before use, a refining flux of about 12% by mass of the melt is prepared. When the covering agent is used as a covering agent, an industrial pure magnesium or magnesium alloy ingot is added into a crucible, a little flux (accounting for about 3% of the mass of the melt) is scattered on the surface of the magnesium ingot before melting, alloy raw materials except lithium are added in batches, refined flux is supplemented after all the raw materials are completely melted, a little foam appears in the liquid flux on the surface layer of the melt, and the adding amount of the total flux is about 6% of the mass of the melt. And then, when the temperature of the melt rises to 680 ℃, adding the subsequent raw material lithium and completely melting, slightly damaging the protective layer on the surface of the melt in the lithium adding process, supplementing a flux accounting for 1 percent of the mass of the melt, and stirring for 2 minutes at 2/3 below the liquid level of the melt by using a lithium adding cover. When a protective layer is formed on the surface of the melt again and the temperature of the melt mixture rises to 710 ℃, adding a flux with the mass of 5 percent of the melt for multiple times, and vertically stirring for 5 minutes below the melt liquid level 2/3 by utilizing a lithium adding cover to ensure that the melt flows fully and circularly; and after the refining treatment is finished, slagging off is carried out, the melt is kept stand for 10 minutes until the surface of the melt is a bright mirror surface, and then pouring is carried out.
The Mg-8Li-1Al-4Zn magnesium lithium alloy prepared by the flux has the inclusion content of 0.57 percent by volume and basically removes the inclusions with the grain diameter of more than 30 mu m in the alloy; the tensile strength of the as-cast alloy is 153.1MPa, the yield strength is 122.9MPa, and the elongation is 40.2%; the solid solution alloy has the tensile strength of 266.2MPa, the yield strength of 234.6MPa and the elongation of 11.3 percent.
The Mg-8Li-3Al-2Zn-0.5Y magnesium-lithium alloy prepared by the flux has the alloy inclusion content of 0.52 percent, the tensile strength of 242.2MPa, the yield strength of 184.3MPa and the elongation of 20.3 percent.
The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes or modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention. The embodiments and features of the embodiments of the present application may be combined with each other arbitrarily without conflict.

Claims (10)

1. The refining flux suitable for the magnesium-lithium alloy is characterized by comprising the following components in percentage by mass: 40-70% of lithium bromide, 15-40% of lithium chloride, 10-40% of potassium chloride, 0-10% of lithium fluoride, 1-10% of calcium fluoride and 1-5% of carbonate gas-making agent.
2. A refining flux for magnesium lithium alloys according to claim 1, characterised in that the carbonate gassing agent comprises magnesium or calcium carbonate.
3. A refining flux suitable for a magnesium-lithium alloy according to claim 1, characterized in that said flux is as follows in specific mass percentages: 50% of lithium bromide, 22% of lithium chloride, 22% of potassium chloride, 3% of calcium fluoride and 3% of magnesium carbonate.
4. A method of preparing a refining flux for a magnesium lithium alloy according to claim 1, 2 or 3, characterised in that the method comprises the steps of:
preheating a crucible, and adding lithium bromide, lithium chloride, lithium fluoride and potassium chloride; heating to partially melt, adding calcium fluoride, heating to 650-750 ℃ to completely melt, uniformly stirring, and casting into blocks; crushing and grinding the block sample to obtain a powdery sample, sieving the powdery sample, adding a carbonate gas generating agent, and performing ball milling and mixing to obtain the refining flux.
5. A method of using a refining flux for a magnesium lithium alloy according to claim 1, 2 or 3, characterised in that the method comprises the steps of:
a. when in use, adding an industrial pure magnesium or magnesium alloy ingot into a smelting furnace, scattering a little refining flux on the surface of the magnesium ingot before melting, melting the flux into a liquid state at high temperature, and spreading the liquid on the surface of the melt or the magnesium ingot; after all alloy raw materials except lithium are melted, replenishing a refining flux to completely cover the melt;
b. when the temperature of the melt rises to 670-690 ℃, pressing lithium below the liquid level of the melt by using a lithium adding cover to completely melt the lithium;
c. when the temperature of the melt mixture in the step b is raised back to 690-700 ℃, vertically stirring for 1-3 minutes below the melt liquid level by using a lithium adding cover;
d. c, when the temperature of the melt mixture in the step c rises to 710-720 ℃, scattering a refining flux into the melt for multiple times, wherein the flux needs to be basically melted and stirred for 1-3 minutes each time the flux is scattered;
e. after all refining flux is added, vertically stirring for 3-5 minutes below the melt liquid level 2/3 by using a lithium adding cover, and then standing the melt;
f. and after refining treatment, slagging off, and standing the melt until the liquid level is a bright mirror surface, thus pouring.
6. A method of using a refining flux for a magnesium lithium alloy according to claim 5, wherein in the step a, the amount of the flux is 2 to 10% by mass of the melt.
7. A method of using a refining flux for magnesium lithium alloy according to claim 5, wherein the step b further comprises the step of adding a small amount of refining flux depending on the surface condition of the melt after melting; and the supplementary flux accounts for 0-1% of the mass of the melt.
8. The use method of a refining flux suitable for a magnesium-lithium alloy according to claim 5, wherein in the step d, the total addition amount of the flux is 2-5% by mass of the melt.
9. The use method of the refining flux suitable for the magnesium-lithium alloy according to claim 5, wherein in the step d, the flux is added in 2 to 5 times.
10. A use method of a refining flux suitable for a magnesium lithium alloy according to claim 5, wherein in the step e, the standing time of the melt is 8 to 15 minutes.
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CN115852183A (en) * 2022-12-07 2023-03-28 上海云铸三维科技有限公司 Smelting purification method of Mg-Li-Al-Zn-Y alloy for three-dimensional printing
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CN116043048A (en) * 2022-12-08 2023-05-02 上海云铸三维科技有限公司 Magnesium lithium zinc erbium calcium alloy wire and preparation method thereof, and preparation method of magnesium lithium zinc erbium calcium alloy member
CN116144969A (en) * 2022-12-08 2023-05-23 上海云铸三维科技有限公司 Magnesium-lithium-zinc-erbium-ytterbium alloy wire, preparation method thereof and application thereof in arc additive manufacturing

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