阅读说明：本技术 一种用再生铝生产的高导热压铸铝合金材料及其制备方法 (High-thermal-conductivity die-casting aluminum alloy material produced by using secondary aluminum and preparation method thereof ) 是由 范卫忠 高伟全 于 2020-04-30 设计创作，主要内容包括：本发明属于铝合金技术领域,公开了一种用再生铝生产的高导热压铸铝合金材料及其制备方法。其特征在于：(1)所使用的材料以再生料为主；(2)铝合金的主要成分为Si、Mg、Fe、Sr、B和Al,按质量百分比计,所述铝合金各成分为：Si：7.0％～11.0％,Mg：0.3％～1.0％,Fe：0.6％～0.90％,Sr：0.02％～0.06％,B≤0.03％,余量为Al；(3)熔炼炉采用双水口；(4)在生产工艺上,采用了“硼化处理”和延长静置时间,把影响热导率的元素以硼化物的形态沉降至炉底,实现铝液净化。(The invention belongs to the technical field of aluminum alloy, and discloses a high-thermal-conductivity die-casting aluminum alloy material produced by using recycled aluminum and a preparation method thereof. The method is characterized in that: (1) the used materials are mainly reclaimed materials; (2) the main components of the aluminum alloy are Si, Mg, Fe, Sr, B and Al, and the aluminum alloy comprises the following components in percentage by mass: si: 7.0-11.0%, Mg: 0.3% -1.0%, Fe: 0.6-0.90%, Sr: 0.02-0.06%, B is less than or equal to 0.03%, and the balance is Al; (3) the smelting furnace adopts double water gaps; (4) in the production process, the boronizing treatment and the prolonged standing time are adopted, and elements influencing the heat conductivity are settled to the bottom of the furnace in the form of boride to realize the purification of the aluminum liquid.)

1. The high-thermal-conductivity die-casting aluminum alloy material is characterized by comprising the following components in percentage by weight: si: 7.0-11.0%, Mg: 0.3% -1.0%, Fe: 0.6-0.90%, Sr: 0.02-0.06%, B is less than or equal to 0.03%, and the balance is Al.

2. The high thermal conductivity die-cast aluminum alloy material according to claim 1, wherein: 8.0-10.0% of Si, 0.8-1.0% of Mg and 0.6-0.75% of Fe.

3. The high thermal conductivity die-cast aluminum alloy material according to claim 1, wherein: the weight percentage of Mg is 0.7%.

4. The high thermal conductivity die-cast aluminum alloy material according to claim 1, wherein: the raw material of Al is waste aluminum wire or conductive aluminum bus, and the raw material of Mg is waste magnesium.

5. The high thermal conductivity die-cast aluminum alloy material according to claim 1, wherein: the raw material of strontium is an aluminum strontium intermediate alloy, the raw material of boron is an aluminum boron intermediate alloy, and the raw material of iron is an iron additive.

6. The high thermal conductivity die-cast aluminum alloy material according to claim 5, wherein: the iron content of the iron additive is 75%.

7. The method for preparing the high-thermal-conductivity die-casting aluminum alloy material as recited in claim 1, which is characterized by comprising the following steps:

(1) batching the scrap aluminum wire, scrap magnesium, aluminum strontium master alloy, aluminum boron master alloy, iron additive and silicon according to the weight percentage of claim 1;

(2) melting the raw materials, putting 85% of aluminum wires into a furnace, firing for melting, adding silicon at the temperature of 800-850 ℃ of aluminum liquid, fully stirring until the silicon is dissolved, and then sequentially adding an aluminum-boron intermediate alloy and an iron additive, wherein the melting temperature is 750-800 ℃;

(3) adding the rest 15 percent of waste aluminum wire, adjusting the temperature to 720-740 ℃, adding the waste magnesium, and uniformly stirring;

(4) carrying out flux refining on the alloy melt in the step (3), wherein the refining temperature is 720-740 ℃;

(5) after refining, adding the aluminum-strontium intermediate alloy, stirring for 5 minutes after adding, and then standing for 15 minutes;

(6) standing for 15 minutes, and then carrying out gas refining;

(7) preserving heat and standing for one hour;

(8) after the standing is finished, carrying out ingot casting;

(9) when no aluminum liquid flows out, boride is discharged.

8. The method of claim 7, wherein: the refining agent used before the aluminum-strontium intermediate alloy is added is a sodium-free refining agent or a sodium-removing and calcium-removing refining agent.

9. The method of claim 7, wherein: the standing time in the step (8) is more than one hour.

10. The method of claim 7, wherein: and monitoring molten aluminum in the furnace by adopting double water gaps, casting ingots by an upper water gap, and discharging boride by a lower water gap.

Technical Field

The invention belongs to the technical field of aluminum alloy, and particularly relates to a high-thermal-conductivity die-casting aluminum alloy material produced by using reclaimed materials and a preparation method thereof.

Background

With the development of 5G technology, the running speed of a CPU is higher, the heat productivity is higher, if the technology revolution is not carried out on materials, more heat dissipation parts are inevitably added or deformed aluminum alloy is adopted and processed by CNC, the cost is high, and the processing efficiency is low.

In order to adapt to the development of situation, the aluminum alloy material industry adopts pure aluminum ingots and even high-purity aluminum ingots to produce high-heat-conductivity aluminum alloy. The invention uses downstream product (aluminum wire or power supply and distribution aluminum bus) of electrical aluminum as main material, the main material is recycled material, is not a product produced just now, and is obtained by the demolition and elimination of power supply departments. The heat conductivity of the aluminum alloy material is improved by combining a double-water-port device on equipment through 'boronizing treatment' and 'standing treatment' in a casting process, and the fluidity of the aluminum liquid is increased by utilizing silicon, so that the aluminum alloy material is suitable for casting thin-walled parts and complex parts; the demolding performance of the die casting is solved by adding iron; adding boron to eliminate harmful elements affecting the improvement of heat conductivity, combining with boron to form boride, and depositing on the furnace bottom; strontium is added to improve mechanical properties and thermal conductivity. The invention has low cost, energy saving and environmental protection.

Disclosure of Invention

The invention aims to provide a die-casting aluminum alloy material with high thermal conductivity produced by reclaimed materials so as to solve the requirement of the market on 5G materials. The material has the characteristics of die casting, high thermal conductivity, low cost, energy conservation and environmental protection.

The high-thermal-conductivity die-casting aluminum alloy material disclosed by the invention comprises the following components in percentage by weight: si: 7.0-11.0%, Mg: 0.3% -1.0%, Fe: 0.6-0.90%, Sr: 0.02-0.06%, B is less than or equal to 0.03%, and the balance is Al.

Furthermore, the weight percentage of Si is 8.0-10.0%, the weight percentage of Mg is 0.8-1.0%, and the weight percentage of Fe is 0.6-0.75%.

Further, the weight percentage of Mg is 0.7%.

In the element range, silicon is added in consideration of castability of die casting (fluidity of molten aluminum in a die); iron is added in consideration of the demoulding performance of the casting; in consideration of reducing the harm of impurities, boron is added; in consideration of improving mechanical property and thermal conductivity, strontium is added; magnesium is added in view of increasing strength and hardness; the waste aluminum wire is taken into consideration to replace a pure aluminum ingot.

Furthermore, reclaimed materials are used for Al and Mg, the raw material of the Al is waste aluminum wires, and the raw material of the Mg is waste magnesium.

Because the aluminum wires are all produced by using electric aluminum (Al 99.7E and Al 99.6E in the Chinese standard GB/T1196-. The waste aluminum wire (including tapping aluminum wire and overhead wire) can be completely applied to the reproduction of high-heat-conductivity aluminum alloy material. In order to improve the strength and the hardness of the high-thermal-conductivity aluminum alloy material, some magnesium (recycled material) needs to be added, the adding amount is small, and the influence on the thermal conductivity is small.

The strontium raw material is an aluminum strontium intermediate alloy, the boron raw material is an aluminum boron intermediate alloy, the iron raw material is an iron additive, and the iron content of the iron additive is 75%.

The preparation method of the high-thermal-conductivity die-casting aluminum alloy material comprises the following steps of:

(1) mixing the waste aluminum wire, the waste magnesium, the aluminum-strontium intermediate alloy, the aluminum-boron intermediate alloy, the iron additive and the silicon according to the following weight percentage: si: 7.0-11.0%, Mg: 0.3% -1.0%, Fe: 0.6-0.9%, Sr: 0.02-0.06%, B is less than or equal to 0.03%, and the balance is Al;

(2) melting raw materials, putting 85% (by weight) of waste aluminum wires into a furnace, firing for melting, adding silicon at the temperature of 800-850 ℃ of aluminum liquid, fully stirring until the silicon is dissolved, then sequentially adding an aluminum-boron intermediate alloy and an iron additive, wherein the melting temperature is 750-800 ℃;

(3) adding the rest 15 percent of waste aluminum wire, adjusting the temperature to 720-740 ℃, adding the waste magnesium, and uniformly stirring;

(4) carrying out flux refining on the alloy melt in the step (3), wherein the refining temperature is 720-740 ℃;

(5) after refining, adding the aluminum-strontium intermediate alloy, stirring for 5 minutes after adding, and then standing for 15 minutes to fully inoculate the modification effect;

(6) after standing for 15 minutes, gas refining is carried out because flux refining cannot be carried out, so that burning loss of strontium is prevented;

(7) preserving heat and standing;

(8) after the standing is finished, carrying out ingot casting;

(9) when no aluminum liquid flows out, boride is discharged.

Furthermore, the refining agent used before the aluminum-strontium intermediate alloy is added is a sodium-free refining agent or a sodium-removing and calcium-removing refining agent, and the reason that strontium is added later is considered, so that the strontium is prevented from being disturbed to deteriorate.

Further, the standing time in the step (8) is one hour or more. In order to ensure that boride is fully settled so as to improve the purity of molten aluminum, and stirring is not allowed from standing to completion of ingot casting.

And further, monitoring the molten aluminum in the furnace by adopting double water gaps. The smelting furnace adopts double water gaps, an upper water gap ingots, and a lower water gap discharges boride. The two water gaps are in the same launder range, have horizontal and vertical displacement, are arranged in diagonal line on the same plane, and are cast into ingots at the upper water gap and discharged with sediments (borides) at the lower water gap.

The preparation method of the invention adopts the boronizing treatment and prolongs the standing time of the aluminum liquid, and elements influencing the heat conductivity are settled to the bottom of the furnace in the form of boride to realize the purification of the aluminum liquid. The boronizing treatment is adopted to reduce the content of (Mn + Ti + V + Cr), and other three elements except Mn are sensitive to boron, so that boride is easily generated and deposited on the furnace bottom. In order to ensure that the sedimentation is relatively effective, the furnace is kept stand for one hour after the test is qualified, and is fully sedimentated until the casting of the aluminum liquid in the furnace is finished, and the aluminum liquid is not allowed to be stirred again.

The material of the invention is widely applied to terminals (mobile phones) and signal base stations of 5G communication products due to high thermal conductivity and die casting. Compared with the existing high-heat-conduction material produced by pure aluminum, the high-heat-conduction material has the advantages of low cost and environmental protection.

Detailed Description

Preparation of example 1

The high-thermal-conductivity die-casting aluminum alloy material of the embodiment is prepared by the following steps:

(1) mixing the waste aluminum wire, the waste magnesium, the aluminum-strontium intermediate alloy, the aluminum-boron intermediate alloy, the iron additive and the silicon according to the following weight percentage: si: 7.0-11.0%, Mg: 0.3% -1.0%, Fe: 0.6-0.90%, Sr: 0.02-0.06%, B is less than or equal to 0.03%, and the balance is Al;

(2) melting raw materials, putting 85% (by weight) of waste aluminum wires into a furnace, firing for melting, adding silicon at the temperature of 800-850 ℃ of aluminum liquid, fully stirring until the silicon is dissolved, and then sequentially adding an aluminum-boron intermediate alloy and an iron additive, wherein the melting temperature is 750-800 ℃.

(3) Adding the rest 15% (by weight) of waste aluminum wires, adjusting the temperature to 720-740 ℃, adding the waste magnesium, stirring uniformly,

(4) carrying out flux refining on the alloy melt in the step (3), wherein the refining temperature is 720-740 ℃,

(5) after refining, adding the aluminum-strontium intermediate alloy, stirring for 5 minutes after adding, then standing for 15 minutes to fully inoculate the modification effect,

(6) standing for 15 minutes, carrying out gas refining,

(7) sampling, testing, taking off furnace surface slag after the furnace surface slag is qualified,

(8) preserving the temperature and standing the mixture,

(9) after the standing is finished, ingot casting is carried out,

(10) when no aluminum liquid flows out, boride is discharged.

(11) And (4) completely removing the bottom of the furnace and blocking two water gaps.

Preparation of example 2

Preparing a high-thermal-conductivity die-casting aluminum alloy material by the same steps as the preparation example 1, wherein the weight percentages of the elements in the step (1) are as follows: si: 9.0-10.0%, Mg: 0.8% -1.0%, Fe: 0.6 to 0.75 percent of Sr: 0.02-0.06%, B is less than or equal to 0.03%, and the balance is Al.

Preparation of example 3

Preparing a high-thermal-conductivity die-casting aluminum alloy material by the same steps as the preparation example 1, wherein the weight percentages of the elements in the step (1) are as follows: si: 8.0-10.0%, Mg: 0.7%, Fe: 0.6 to 0.75 percent of Sr: 0.02-0.06%, B is less than or equal to 0.03%, and the balance is Al.

Through detection, the thermal conductivity of the aluminum alloy materials prepared in the preparation examples 1-3 is more than or equal to 160 w/m.k. Wherein, when the product of the preparation example 2 is in a die-casting state, the tensile strength is more than or equal to 290MPa, the yield strength is more than or equal to 160MPa, and the elongation is more than or equal to 4 percent. The die casting is subjected to artificial aging (320 ℃ for 3 hours), the thermal conductivity is more than or equal to 180 w/m.k, but the mechanical property is slightly reduced, and the use requirement of the signal base station is still met.