阅读说明：本技术 一种高性能稀土Al-Mg-Si铝合金挤压材料及其制备方法 (High-performance rare earth Al-Mg-Si aluminum alloy extrusion material and preparation method thereof ) 是由 冯艳飞 孙巍 谢方亮 杨路 冯枭 王克 张宇 郑建 吴楠 于 2019-10-31 设计创作，主要内容包括：本发明属于铝合金材料技术领域,涉及一种高性能稀土Al-Mg-Si铝合金挤压材料及其制备方法,铝合金挤压材料由以下元素组分按照重量百分比配制而成：Si：0.4～0.7％,Mg：0.5～0.7％,Cu：0.01～0.2％,Mn：0.05～0.45％,Cr：0.01～0.3％,Ti：0.01～0.02％,稀土元素0.05～0.30％,Zn≤0.1％,Fe≤0.15％,其余单个杂质含量≤0.05％,杂质合计≤0.15％,余量为Al,稀土元素为Er、Sc中的任意一种或两种混合,制备方法可以显著优化合金成分、均匀细化晶粒、熔液净化除杂、减少铸造缺陷、大幅度提高铸锭质量,另外还可以较好地改善了挤压型材表面质量,提高挤压速度及挤压型材产品的热处理综合力学性能。(The invention belongs to the technical field of aluminum alloy materials, and relates to a high-performance rare earth Al-Mg-Si aluminum alloy extrusion material and a preparation method thereof, wherein the aluminum alloy extrusion material is prepared from the following element components in percentage by weight: si: 0.4-0.7%, Mg: 0.5-0.7%, Cu: 0.01 to 0.2%, Mn: 0.05-0.45%, Cr: 0.01-0.3%, Ti: 0.01-0.02%, rare earth elements 0.05-0.30%, Zn less than or equal to 0.1%, Fe less than or equal to 0.15%, the content of other single impurities less than or equal to 0.05%, the total amount of the impurities less than or equal to 0.15%, and the balance of Al, wherein the rare earth elements are Er and Sc or a mixture of the Er and the Sc.)

1. A high-performance rare earth Al-Mg-Si aluminum alloy extrusion material is characterized by being prepared from the following element components in percentage by weight: si: 0.4-0.7%, Mg: 0.5-0.7%, Cu: 0.01 to 0.2%, Mn: 0.05-0.45%, Cr: 0.01-0.3%, Ti: 0.01-0.02 percent of rare earth elements, 0.05-0.30 percent of rare earth elements, less than or equal to 0.1 percent of Zn, less than or equal to 0.15 percent of Fe, less than or equal to 0.05 percent of the content of other single impurities, less than or equal to 0.15 percent of total impurities, and the balance of Al, wherein the rare earth elements are any one or two of Er and Sc.

2. The method for producing an Al-Mg-Si aluminum alloy extruded material according to claim 1, comprising the steps of:

A. calculating the use amount of each aluminum alloy raw material, respectively transferring the prepared aluminum-chromium intermediate alloy, aluminum-copper intermediate alloy, aluminum-manganese intermediate alloy, industrial silicon block and aluminum ingot into a smelting furnace, placing the aluminum-chromium intermediate alloy, the aluminum-copper intermediate alloy, the aluminum-manganese intermediate alloy and the industrial silicon block at the upper layer in the smelting furnace, covering the aluminum ingot at the uppermost layer in the smelting furnace, and controlling the smelting temperature to be 720-760 ℃;

B. after furnace burden is completely melted, sequentially adding aluminum-titanium intermediate alloy and rare earth-aluminum intermediate alloy small blocks wrapped by aluminum foil to the center of the melt in the furnace to prevent the aluminum-titanium intermediate alloy and the rare earth-aluminum intermediate alloy from being oxidized and burnt by contacting with air, wherein the melting temperature is 720-740 ℃; after the furnace burden is melted completely, adding a magnesium ingot wrapped by an aluminum foil into the center of the melt, pressing the magnesium ingot to be deposited below the liquid level of the aluminum liquid, and preventing the magnesium ingot from being oxidized and burnt by contacting with air, wherein the melting temperature is 720-740 ℃;

C. after the melt in the smelting furnace is completely melted, stirring and slagging off at the smelting temperature of 720-740 ℃, performing front component detection on the melt in the furnace, if the components are unqualified, correspondingly supplementing corresponding intermediate alloy, after the components are qualified, performing furnace refining treatment, introducing argon and a refining agent into the melt in the furnace after the components are qualified, performing furnace refining at the refining temperature of 710-730 ℃ for 15-30 min, slagging off after the refining treatment, and standing for 15-30 min to obtain semi-continuously cast aluminum alloy melt;

D. in the semi-continuous casting process, uniformly and online adding 0.005-0.01% of aluminum-titanium-boron wires into aluminum alloy liquid, wherein the casting temperature is 710-730 ℃, the casting speed is 35-85 mm/min, and the cooling water pressure is 0.05-0.10 MPa, so as to obtain a high-performance rare earth aluminum alloy material casting bar;

E. after the rare earth aluminum alloy cast rod is subjected to homogenizing annealing treatment, removing the head and the tail, cutting the head and the tail into 400-610 mm aluminum alloy short cast ingots with fixed length, and extruding the aluminum alloy short cast ingots after turning the skin, wherein the extrusion parameters are as follows: heating the cast ingot at 465-520 ℃, extruding at 3.5-5.5 m/min at the temperature of not less than 485 ℃ before quenching, and finally extruding into the required thin-walled hollow pipe by adopting a water tank online quenching mode;

F. standing the extruded thin-wall hollow pipe at room temperature for 24 hours, then carrying out artificial aging at 170-210 ℃ for 4-8 hours, and then air-cooling to room temperature to obtain the high-performance rare earth Al-Mg-Si aluminum alloy extruded section.

3. The method for producing an Al-Mg-Si aluminum alloy extruded material according to claim 2, wherein the purity of the industrial silicon ingot in the step A is 99.9% or more and the volume range of each small ingot is less than 50cm³The purity of the aluminum ingot is more than 99.9 percent.

4. The method for producing an Al-Mg-Si aluminum alloy extruded material according to claim 2, wherein the aluminum foil-wrapped Al-Ti master alloy and rare earth-Al master alloy in the step B are in a volume range of less than 50cm³。

5. The method of producing an Al-Mg-Si aluminum alloy extruded material according to claim 2, wherein the purity of argon gas in the step C is 99.9%.

6. The method for preparing an Al-Mg-Si aluminum alloy extruded material according to claim 2, wherein the temperature of the homogenizing annealing treatment in the step E is 550 to 580 ℃ and the holding time is 8 to 10 hours.

7. The method of producing an Al-Mg-Si aluminum alloy extruded material according to claim 2, wherein the thin-walled hollow tube after extrusion in step E has a wall thickness of 1.5mm or 3 mm.

Technical Field

The invention belongs to the technical field of aluminum alloy materials, and relates to a high-performance rare earth Al-Mg-Si aluminum alloy extrusion material and a preparation method thereof.

Background

Along with the increase of the demand of high-end technical fields such as national defense and military industry, rail traffic, aerospace and the like on the aluminum alloy extruded section, higher requirements are also put forward on the performance of the aluminum alloy extruded section. The requirements of high speed, safety, energy conservation, comfort, environmental protection and the like proposed by rail transit and vehicles are one of the major problems faced by the domestic modern construction. The Al-Mg-Si series aluminum alloy has medium strength, good weldability and extrusion formability, is widely applied to the manufacturing of rail transit and vehicles, and can be used for extruding hollow sections with different thicknesses and thin walls and complicated section shapes. At present, various researches on Al-Mg-Si series aluminum alloy are widely reported, but the researches are mostly concentrated on the aspects of extrusion performance, welding performance, corrosion performance and the like, the researches are less in the aspect of casting process, and the addition of trace rare earth elements in the alloy is more rarely reported. In the prior art, cast ingots produced by mainly adopting the traditional semi-continuous casting method for aluminum alloy generally have the problems of large grains, uneven structure, obvious casting defects, poor cast ingot quality and the like.

As the mechanical property of the metal is determined to a great extent by the solidification structure of the metal, the mechanical property of the ingot can be effectively improved by the refinement of the ingot grains. The prior art mainly comprises: adding a refiner and microalloy, optimizing a casting process and the like to refine crystal grains and improve the mechanical property of the cast ingot. However, with the increasing requirements of high-end products on the quality of materials, higher requirements are provided for the refinement degree and the mechanical property of crystal grains, and the current control method cannot meet the requirements of the materials on higher properties.

Disclosure of Invention

In view of the above, the present invention provides a high performance rare earth Al-Mg-Si aluminum alloy extrusion material and a preparation method thereof, which can significantly optimize alloy components, homogenize and refine crystal grains, reduce casting defects, and greatly improve the comprehensive mechanical properties of ingot casting and extrusion section heat treatment, in order to solve the problems existing in the refinement of the crystal grains of the Al-Mg-Si aluminum alloy ingot.

In order to achieve the aim, the invention provides a high-performance rare earth Al-Mg-Si aluminum alloy extrusion material which is prepared from the following element components in percentage by weight: si: 0.4-0.7%, Mg: 0.5-0.7%, Cu: 0.01 to 0.2%, Mn: 0.05-0.45%, Cr: 0.01-0.3%, Ti: 0.01-0.02 percent of rare earth elements, 0.05-0.30 percent of rare earth elements, less than or equal to 0.1 percent of Zn, less than or equal to 0.15 percent of Fe, less than or equal to 0.05 percent of the content of other single impurities, less than or equal to 0.15 percent of total impurities, and the balance of Al, wherein the rare earth elements are any one or two of Er and Sc.

A preparation method of a high-performance rare earth Al-Mg-Si aluminum alloy extrusion material comprises the following steps:

A. calculating the use amount of each aluminum alloy raw material, respectively transferring the prepared aluminum-chromium intermediate alloy, aluminum-copper intermediate alloy, aluminum-manganese intermediate alloy, industrial silicon block and aluminum ingot into a smelting furnace, placing the aluminum-chromium intermediate alloy, the aluminum-copper intermediate alloy, the aluminum-manganese intermediate alloy and the industrial silicon block at the upper layer in the smelting furnace, covering the aluminum ingot at the uppermost layer in the smelting furnace, and controlling the smelting temperature to be 720-760 ℃;

B. after furnace burden is completely melted, sequentially adding aluminum-titanium intermediate alloy and rare earth-aluminum intermediate alloy small blocks wrapped by aluminum foil to the center of the melt in the furnace to prevent the aluminum-titanium intermediate alloy and the rare earth-aluminum intermediate alloy from being oxidized and burnt by contacting with air, wherein the melting temperature is 720-740 ℃; after the furnace burden is melted completely, adding a magnesium ingot wrapped by an aluminum foil into the center of the melt, pressing the magnesium ingot to be deposited below the liquid level of the aluminum liquid, and preventing the magnesium ingot from being oxidized and burnt by contacting with air, wherein the melting temperature is 720-740 ℃;

C. after the melt in the smelting furnace is completely melted, stirring and slagging off at the smelting temperature of 720-740 ℃, performing front component detection on the melt in the furnace, if the components are unqualified, correspondingly supplementing corresponding intermediate alloy, after the components are qualified, performing furnace refining treatment, introducing argon and a refining agent into the melt in the furnace after the components are qualified, performing furnace refining at the refining temperature of 710-730 ℃ for 15-30 min, slagging off after the refining treatment, and standing for 15-30 min to obtain semi-continuously cast aluminum alloy melt;

D. in the semi-continuous casting process, uniformly and online adding 0.005-0.01% of aluminum-titanium-boron wires into aluminum alloy liquid, wherein the casting temperature is 710-730 ℃, the casting speed is 35-85 mm/min, and the cooling water pressure is 0.05-0.10 MPa, so as to obtain a high-performance rare earth aluminum alloy material casting bar;

E. after the rare earth aluminum alloy cast rod is subjected to homogenizing annealing treatment, removing the head and the tail, cutting the head and the tail into 400-610 mm aluminum alloy short cast ingots with fixed length, and extruding the aluminum alloy short cast ingots after turning the skin, wherein the extrusion parameters are as follows: heating the cast ingot at 465-520 ℃, extruding at 3.5-5.5 m/min at the temperature of not less than 485 ℃ before quenching, and finally extruding into the required thin-walled hollow pipe by adopting a water tank online quenching mode;

F. standing the extruded thin-wall hollow pipe at room temperature for 24 hours, then carrying out artificial aging at 170-210 ℃ for 4-8 hours, and then air-cooling to room temperature to obtain the high-performance rare earth A1-Mg-Si aluminum alloy extruded section.

Further, the purity of the industrial silicon block in the step A is more than 99.9 percent, and the volume range of each small block is less than 50cm³The purity of the aluminum ingot is more than 99.9 percent.

Further, in the step B, the volume range of each small piece of the aluminum-titanium intermediate alloy and the rare earth-aluminum intermediate alloy wrapped by the aluminum foil is less than 50cm³。

Further, the purity of argon in step C was 99.9%.

Further, in the step E, the temperature of the homogenizing annealing treatment is 550-580 ℃, and the heat preservation time is 8-10 hours.

And furthermore, the wall thickness of the thin-wall hollow pipe extruded in the step E is 1.5mm or 3 mm.

The invention has the beneficial effects that:

1. the high-performance rare earth Al-Mg-Si aluminum alloy extrusion material and the preparation method thereof disclosed by the invention develop the high-performance rare earth Al-Mg-Si aluminum alloy extrusion material by reasonably optimizing the component design and adding rare earth elements. The rare earth elements Er and Sc can play a role in improving the performance in the aluminum alloy. A large number of researches show that Er and Sc can form a binary intermetallic compound Al in an aluminum alloy system₃Er、Al₃Sc, the compounds have the same space lattice type with an aluminum matrix and close lattice constant, not only can play a role in grain refinement in the solidification process, but also can uniformly precipitate a large amount of precipitates after T6 treatment, and play a strong role in precipitation strengthening. Through the above effects, the rare earth elements Er and Sc have a relatively obvious effect of improving the comprehensive performance of the aluminum alloy. The invention scientifically and reasonably optimizes the alloy components, and adds rare earth elements Er and Sc to form a binary intermetallic compound Al in an aluminum alloy system₃Er、Al₃Sc not only can play a role in grain refinement in the solidification process, but also can uniformly separate out a large amount of precipitates after T6 treatment, and plays a strong precipitation strengthening role, thereby obviously improving the performance of the aluminum alloy. In addition, the high-performance rare earth Al-Mg-Si aluminum alloy extrusion material and the preparation method thereof are simple, cost is saved, and the process is convenient and fast.

2. The invention discloses a high-performance rare earth Al-Mg-Si aluminum alloy extrusion material and a preparation method thereof, wherein rare earth elements Er and Sc have strong tissue refining and mechanical property improving effects on the tissue of Al-Mg-Si alloy, mainly because the binding energy of the Er and Sc elements and vacancies is higher than that of other elements, the generated Al₃Er、Al₃The rare earth phases such as Sc and the like can effectively prevent the crystal grains from growing, improve the nucleation rate and further refine the crystal grains. But also can refine the dendritic crystal spacing, refine the crystal grains, have certain modification effect on the form of eutectic Si, and convert coarse massive or flaky spheroidization into round grains or granules. In addition, the rare earth elements Er and Sc are doped with Al-The Mg-Si alloy also has the functions of degassing and deslagging. The rare earth compound is combined to spheroidize and purify the grain boundary, particularly, the plastic processability is obviously improved, the toughness of the alloy is improved, the intergranular brittle fracture is changed into crystal-crossing and intergranular mixed fracture, and the size of a dimple is also refined. In addition, because rare earth elements Er and Sc are added into the molten aluminum, the strength, the fracture toughness and the fatigue performance of the cast ingot and the extruded section are improved more obviously, particularly, the anti-corrosion performance and the extrusion speed are improved, and the surface smoothness and the extrusion yield of the extruded product are improved. The strengthening action mechanism of the rare earth elements Er and Sc in the Al-Mg-Si aluminum alloy mainly comprises the mechanisms of fine crystal strengthening, limited solid solution strengthening, second phase strengthening of rare earth compounds and the like.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the means of the instrumentalities and combinations particularly pointed out hereinafter.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.

The raw materials selected by the invention comprise an aluminum ingot, an aluminum-chromium intermediate alloy, an aluminum-copper intermediate alloy, an aluminum-manganese intermediate alloy, an aluminum-titanium intermediate alloy, an industrial silicon block and a pure magnesium block. The argon used was 99.9% high purity argon.