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CN-121992233-A - Low-cost vacuum smelting magnesium-lithium alloy and high-purity purifying casting method thereof

CN121992233ACN 121992233 ACN121992233 ACN 121992233ACN-121992233-A

Abstract

The invention discloses a low-cost vacuum smelting magnesium-lithium alloy and a high-purity purifying casting method thereof, belonging to the technical field of alloy casting. The method comprises the steps of material preparation quality inspection, preheating and air extraction of a vacuum furnace, argon gas introduction, stirring and slag dragging after medium-frequency segmented melting of a melt, pouring the melt into a mold (a built-in ceramic filter screen and a circulating water cooling disc below) with a pouring channel and a slag removing ladle after standing, cooling, demoulding, machining, descaling and the like. The problems of uneven components, more inclusions, low availability ratio of cast ingots and the like of the magnesium-lithium alloy in the prior art are solved by optimizing the technological parameters and the structural design, the obtained alloy cast ingots are uniform in structure, high in purity and stable in performance, the problems of uneven components, more inclusions, low availability ratio, serious dead head shrinkage cavity burning loss and the like in the process of vacuum smelting the magnesium-lithium alloy are effectively solved, and the method is simple in process, convenient to operate, controllable in cost and suitable for the requirements of the fields of aerospace, 3C electronics, weapon industry and the like on ultra-light high-strength materials.

Inventors

  • YANG YAN
  • JIANG BIN
  • PENG XIAODONG
  • PAN FUSHENG
  • LIU WEIHAO
  • FU RUIHAO
  • YANG CHUBIN
  • WU SHIMING
  • LIU QIHANG
  • Lan xinyi
  • ZENG YU
  • LONG XIN

Assignees

  • 重庆大学
  • 湖州天使镁新材料科技有限公司
  • 重庆新型储能材料与装备研究院

Dates

Publication Date
20260508
Application Date
20260205

Claims (10)

  1. 1. The high-purity purification casting method for low-cost vacuum smelting of the magnesium-lithium alloy is characterized by comprising the following steps of: 1) Preparing materials, namely selecting pure magnesium ingots, pure zinc ingots, magnesium-lithium intermediate alloys, magnesium-calcium intermediate alloys and magnesium-yttrium intermediate alloys as raw materials, and performing quality inspection on the raw materials; 2) Charging, namely charging qualified raw materials into a vacuum smelting furnace; 3) Preheating and vacuumizing, namely preheating a vacuum smelting furnace, vacuumizing and then introducing argon; 4) Melting and deslagging, namely starting an intermediate frequency power supply to heat the metal in a segmented mode until the metal is melted, stirring the melt after power is reduced, and then carrying out slag dragging from bottom to top; 5) Standing and pouring, namely, after slag is fished out, standing, closing an intermediate frequency power supply, pouring a melt into a pouring mould with a pouring channel and a slag removing ladle, and arranging a circulating water cooling disc below the mould; 6) Cooling and demoulding, namely closing the vacuum system, cooling along with the furnace and demoulding; 7) And (3) post-processing, namely machining to remove a riser and surface oxide skin, and obtaining the magnesium-lithium alloy cast ingot.
  2. 2. The method for high purity casting of low cost vacuum melted magnesium lithium alloy according to claim 1, wherein in step 3), the preheating power is 5-8KW, the vacuum degree is 5X 10 -2 Pa, and then argon gas is introduced to the furnace pressure of 0.05MPa.
  3. 3. A high purity purification casting method for low cost vacuum melting magnesium lithium alloy as set forth in claim 1 wherein in step 4) the initial power of the staged heating is 5kW, and 5kW is increased every 5 minutes until the metal is completely melted.
  4. 4. The method for high purity casting of low cost vacuum melted magnesium lithium alloy according to claim 1, wherein in step 4), stirring temperature is 680-750 ℃ and stirring time is 3-6min.
  5. 5. The method for high purity casting of low cost vacuum melted magnesium lithium alloy according to claim 1, wherein in step 5), the casting temperature is 720-750 ℃ and the casting time is 30s.
  6. 6. The high-purity purification casting method for low-cost vacuum smelting of magnesium-lithium alloy according to claim 1, wherein in step 5), the inner diameter of the casting mold is 90-200mm, the height is 200-600mm, and the ceramic filter screen is placed in the casting mold.
  7. 7. The method for high purity casting of low cost vacuum melted magnesium lithium alloy according to claim 1, wherein in step 6), the cooling time is 1-1.5h.
  8. 8. A low-cost vacuum smelting magnesium-lithium alloy is characterized in that the magnesium-lithium alloy is obtained by adopting the casting method according to any one of claims 1 to 7.
  9. 9. The low-cost vacuum-smelted magnesium-lithium alloy according to claim 8, wherein the chemical element composition of the magnesium-lithium alloy comprises, by mass fraction, 1-20wt.% of Li, 0.1-4wt.% of Zn, 0-3wt.% of Ca, 0.1-5wt.% of Y, and the balance of magnesium and unavoidable impurities, wherein the total content of impurities is less than or equal to 0.3%.
  10. 10. The low-cost vacuum-smelted magnesium-lithium alloy according to claim 9, wherein the chemical element composition of the magnesium-lithium alloy comprises, by mass fraction, 5-15wt.% of Li, 0.1-3wt.% of Zn, 0-2wt.% of Ca, 0.1-4wt.% of Y, and the balance of magnesium and unavoidable impurities, wherein the total content of impurities is less than or equal to 0.3%.

Description

Low-cost vacuum smelting magnesium-lithium alloy and high-purity purifying casting method thereof Technical Field The invention relates to the technical field of alloy casting, in particular to a low-cost vacuum smelting magnesium-lithium alloy and a high-purity purifying casting method thereof. Background The magnesium alloy has the advantages of low density, high specific strength, good cutting processability and the like, but is of a HCP structure (close-packed hexagonal structure), c/a is about 1.62, the sliding system is only three, the room temperature deformability is poor, the strong basal plane texture is easily formed in the magnesium alloy plate by conventional extrusion deformation or rolling deformation, and the anisotropy is obvious. The c/a ratio of the magnesium alloy can be reduced by adding the lithium element into the magnesium alloy, so that the non-basal sliding system of the magnesium alloy is increased, the basal texture is weakened, the anisotropism is reduced, and the room temperature deformability is improved. Meanwhile, the density of the magnesium-lithium alloy is the smallest in the used alloy system, which is only 2/3-3/4 of that of the general magnesium alloy and is 1/3-1/2 lighter than most aluminum alloys, so the magnesium-lithium alloy is also called as super light alloy. The composite material also has the advantages of excellent plasticity and toughness, high specific strength, high specific rigidity, good formability and the like, and has wide application prospect in the industries of military, aerospace and aviation, weapon industry, 3C (computer, intelligent wearing and communication) and the like. However, the industrial application of the magnesium-lithium alloy is limited by the defects of complex smelting process of large-smelting high-quality magnesium-lithium alloy, lack of melt purification technology, poor heat resistance, low absolute strength, poor corrosion resistance and the like of the alloy. In the casting process of the magnesium-lithium alloy, the components and the ingot tissue are greatly influenced by a smelting process, and if the quality of the ingot is unqualified, the strength of a structural member obtained by subsequent plastic deformation is difficult to reach the standard. In addition, the alloy elements are easy to burn in the magnesium-lithium alloy casting process, and the risks of fire or explosion and the like can be caused when the alloy elements are serious, and a covering agent or inert gas is generally required to protect the melt. In the prior art, the mixing and melting-pair doping method has the problems of uneven mixing of lithium elements, difficult control of components, serious burning loss of other alloy elements and the like, and the mainstream vacuum melting method can avoid oxidation burning loss to a certain extent, but has the defects of uneven tissue components, more internal inclusions, low ingot casting use rate and the like, and seriously influences the mechanical property and subsequent plastic deformation of the alloy. Therefore, a novel low-cost and high-purity magnesium-lithium alloy casting method is developed, the defects of the prior art are overcome, and the method has important significance. Disclosure of Invention The invention aims to provide a low-cost vacuum smelting magnesium-lithium alloy and a high-purity purifying casting method thereof, which are used for obtaining magnesium-lithium alloy cast ingots with uniform tissue components, high purity purification and high availability through optimizing technological parameters, improving deslagging and casting structures, strengthening melt purification and solidification control, reducing production cost, improving product quality stability and solving the problems in the background art. In order to achieve the above purpose, the invention provides a high-purity purification casting method for vacuum smelting a magnesium-lithium alloy with low cost, which comprises the following steps: 1) Preparing materials, namely selecting pure magnesium ingots, pure zinc ingots, magnesium-lithium intermediate alloys, magnesium-calcium intermediate alloys and magnesium-yttrium intermediate alloys as raw materials, and performing quality inspection on the raw materials; 2) Charging, namely charging qualified raw materials into a vacuum smelting furnace; 3) Preheating and vacuumizing, namely preheating a vacuum smelting furnace, vacuumizing and then introducing argon; 4) Melting and deslagging, namely starting an intermediate frequency power supply to heat the metal in a segmented mode until the metal is melted, stirring the melt after power is reduced, and then carrying out slag dragging from bottom to top; 5) Standing and pouring, namely, after slag is fished out, standing, closing an intermediate frequency power supply, pouring a melt into a pouring mould with a pouring channel and a slag removing ladle, and arranging a circulating water cooling disc below the mould;