阅读说明：本技术 高强韧压铸铝合金材料的制备方法、热处理方法和压铸方法 (Preparation method, heat treatment method and die-casting method of high-strength and high-toughness die-casting aluminum alloy material ) 是由 李新豪 陈苏坚 李升� 李旭涛 王永科 于 2020-11-27 设计创作，主要内容包括：本发明提供一种抗拉强度、屈服强度及伸长率较好的高强韧压铸铝合金材料的制备方法、热处理方法和压铸方法。本发明提供的高强韧压铸铝合金材料的制备方法,包括如下步骤：加入部分铝锭和硅；加入锰添加剂、钛添加剂；加入剩余铝锭使其熔化；加入已经预热的镁,并控制Mg/Si≥2.5；加入经过预热的铝铍中间合金；加入无钠精炼剂进行精炼；加入经过预热的铝钛碳硼晶种材料；取样检验成分,按重量百分比计,保证成分在如下范围内：Mg：4％-7％；Si：1.6％-2.8％；Mn：0.4％-0.9％；Ti：0.1％-0.3％；Be：0.002％-0.010％；铝钛碳硼晶种材料：0.3％-2％,Fe：≤0.2％,Mg/Si≥2.5；成分合格后,温度在690℃-740℃时浇铸。(The invention provides a preparation method, a heat treatment method and a die-casting method of a high-strength and high-toughness die-casting aluminum alloy material with good tensile strength, yield strength and elongation. The preparation method of the high-strength and high-toughness die-casting aluminum alloy material provided by the invention comprises the following steps of: adding part of aluminum ingot and silicon; adding a manganese additive and a titanium additive; adding the rest aluminum ingot to melt; adding preheated magnesium, and controlling Mg/Si to be more than or equal to 2.5; adding preheated aluminum-beryllium intermediate alloy; adding a sodium-free refining agent for refining; adding a preheated aluminum titanium carbon boron seed crystal material; sampling and inspecting components, wherein the components are ensured to be in the following ranges in percentage by weight: mg: 4% -7%; si: 1.6% -2.8%; mn: 0.4% -0.9%; ti: 0.1% -0.3%; be: 0.002% -0.010%; aluminum titanium carbon boron seed crystal material: 0.3% -2%, Fe: less than or equal to 0.2 percent, and Mg/Si is more than or equal to 2.5; after the components are qualified, casting at the temperature of 690-740 ℃.)

1. The preparation method of the high-strength and high-toughness die-casting aluminum alloy material is characterized by comprising the following steps of:

(1) adding part of aluminum ingot and silicon, and heating to 830-860 ℃;

(2) when the temperature is 830-860 ℃ and the silicon is melted uniformly, adding a manganese additive and a titanium additive;

(3) sampling and inspecting components, wherein the components are ensured to be in the following ranges in percentage by weight: si: 1.6% -2.8%; mn: 0.4% -0.9%; ti: 0.1% -0.3%;

(4) adding the rest aluminum ingot to melt;

(5) adding preheated magnesium at 740-760 ℃, pressing into a molten pool, melting in aluminum liquid, and controlling Mg/Si to be more than or equal to 2.5;

(6) adding preheated aluminum-beryllium intermediate alloy, pressing into a molten pool, and rapidly melting;

(7) and (3) adopting nitrogen or argon as a carrier gas, adding a sodium-free refining agent for refining, and after the refining reaction is finished, standing for 5-10 minutes to remove dross on the surface of the aluminum liquid.

(8) Adding preheated aluminum titanium carbon boron seed crystal material at the temperature of 700-750 ℃;

(9) sampling and inspecting components, wherein the components are ensured to be in the following ranges in percentage by weight: mg: 4% -7%; si: 1.6% -2.8%; mn: 0.4% -0.9%; ti: 0.1% -0.3%; be: 0.002% -0.010%; aluminum titanium carbon boron seed crystal material: 0.3% -2%, Fe: less than or equal to 0.2 percent, and Mg/Si is more than or equal to 2.5;

(10) and after the components are qualified, casting at the temperature of 690-740 ℃ to obtain an alloy ingot.

2. The preparation method of the high-strength high-toughness die-casting aluminum alloy material as claimed in claim 1, wherein the alloy ingot comprises the following components in percentage by weight: mg: 4% -7%; si: 1.6% -2.8%; mn: 0.4% -0.9%; ti: 0.1% -0.3%; be: 0.002% -0.010%; aluminum titanium carbon boron seed crystal material: 0.3% -2%; fe: less than or equal to 0.2 percent; cu: less than or equal to 0.2 percent; zn: less than or equal to 0.3 percent; pb: less than or equal to 0.1 percent; sn: less than or equal to 0.01 percent; cd: less than or equal to 0.01 percent, and the sum of other inevitable impurity elements: less than or equal to 0.2 percent; the balance of Al, wherein the ratio of Mg to Si is satisfied: Mg/Si is more than or equal to 2.5.

3. The method for preparing the high-strength high-toughness die-casting aluminum alloy material according to claim 1, wherein the aluminum-titanium-carbon-boron seed crystal material is a submicron aluminum-titanium-carbon-boron seed crystal material.

4. The method for preparing the high-strength high-toughness die-cast aluminum alloy material according to claim 3, wherein the submicron-order aluminum-titanium-carbon-boron seed crystal material contains 2-4% of seed crystals.

5. The preparation method of the high-strength high-toughness die-cast aluminum alloy material as claimed in claim 1, wherein the addition amount of the sodium-free refining agent is 0.2% -0.4%.

6. The method for producing a high-toughness die-cast aluminum alloy material according to claim 1, wherein the composition of the sodium-free refining agent includes Ba.

7. The method for preparing the high-strength high-toughness die-cast aluminum alloy material according to claim 6, wherein the sodium-free refining agent further comprises K, Cl, F and Mg.

8. The preparation method of the high-strength high-toughness die-cast aluminum alloy material according to claim 7, wherein the sodium-free refining agent is an aluminum magnesium sodium-free refining agent, and the aluminum magnesium sodium-free refining agent comprises the following components in percentage by mass: 10 to 16 percent; na: less than or equal to 3 percent; si: less than or equal to 8 percent; cl: 40-55 percent; f: 3 to 6 percent; mg: 8 to 12 percent; ba: 2 to 8 percent; ca: 1 to 3 percent.

9. A heat treatment method of a high-strength and high-toughness die-cast aluminum alloy material is characterized in that when a casting of the high-strength and high-toughness die-cast aluminum alloy material prepared by the preparation method of the high-strength and high-toughness die-cast aluminum alloy material according to any one of claims 1 to 8 is subjected to heat treatment, the heat treatment steps are as follows:

putting the casting into a heat treatment furnace, heating the casting to 320-380 ℃ from 20-30 ℃, then preserving the heat, taking out the casting after the heat preservation lasts for 80-100 minutes, and cooling the casting in air;

or putting the casting into a heat treatment furnace, heating the temperature from 20-30 ℃ to 220-280 ℃, then preserving the heat, taking out the casting after the heat preservation lasts for 80-100 minutes, and cooling by water.

10. A die-casting forming method of high-strength and high-toughness die-casting aluminum alloy material is characterized in that when an alloy ingot prepared by the preparation method of the high-strength and high-toughness die-casting aluminum alloy material according to any one of claims 1 to 8 is subjected to remelting die-casting forming, the die-casting temperature is 690-730 ℃; the temperature of the die-casting mould is 200-300 ℃; the die casting shrinkage rate is 0.6-1.1%; the demoulding inclination is controlled to be more than or equal to 1.5⁰。

Technical Field

The invention belongs to the technical field of die-casting aluminum alloys, and particularly relates to a preparation method, a heat treatment method and a die-casting method of a high-strength and high-toughness die-casting aluminum alloy material.

Background

With the continuous improvement of the performance requirements of the aluminum alloy structural member, particularly with the promotion of replacing steel with aluminum to realize the lightweight of an automobile, higher requirements are provided for the performance of the aluminum alloy die casting in the aspects of simultaneously realizing high strength and high toughness. In response to the demand, in recent years, development and upgrading are mainly performed in Al-Si-Mg series die-cast aluminum alloy materials, and, for example, AlSi10MnMg is a relatively representative high-strength die-cast aluminum alloy material. It realizes different performances by adjusting and controlling different contents of magnesium in 0.1-0.5%. In order to actually exert its high toughness, Al-Si-Mg series die casting aluminum alloys must be subjected to heat treatment including solution treatment, such as T4, T5, T6, T7, etc. If the required heat treatment is not performed, good high toughness performance cannot be obtained. Such a heat treatment process, particularly for large and thin-walled die-cast parts, is likely to deform and cause dimensional changes, and after the heat treatment, a correction operation is necessary. Meanwhile, heat treatment equipment needs to be put into the furnace, so that the flow operation time of heat treatment is prolonged, the production efficiency is reduced, and the cost of heat treatment is increased. Therefore, the die-casting aluminum alloy material which can remove the heat treatment link and can achieve high strength and toughness is developed, the requirement of social development on high strength and toughness aluminum alloy structural parts is met, and the die-casting aluminum alloy material has urgency and wide application prospect.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a preparation method, a heat treatment method and a die-casting method of a high-strength and high-toughness die-casting aluminum alloy material with good tensile strength, yield strength and elongation.

The invention provides a preparation method of a high-strength and high-toughness die-casting aluminum alloy material, which comprises the following steps of:

(1) adding part of aluminum ingot and silicon, and heating to 830-860 ℃;

(2) when the temperature is 830-860 ℃ and the silicon is melted uniformly, adding a manganese additive and a titanium additive;

(3) sampling and testing the components, wherein the components are calculated according to the weight percentage, and the calculation of the components is ensured to fall within the following range under the condition of including the later required added materials: si: 1.6% -2.8%; mn: 0.4% -0.9%; ti: 0.1% -0.3%;

(4) adding the rest aluminum ingot to melt;

(5) adding preheated magnesium at 740-760 ℃, pressing into a molten pool, melting in aluminum liquid, and controlling Mg/Si to be more than or equal to 2.5;

(6) adding preheated aluminum-beryllium intermediate alloy, pressing into a molten pool, and rapidly melting;

(7) and (3) adopting nitrogen or argon as a carrier gas, adding a sodium-free refining agent for refining, and after the refining reaction is finished, standing for 5-10 minutes to remove dross on the surface of the aluminum liquid.

(8) Adding preheated aluminum titanium carbon boron seed crystal material at the temperature of 700-750 ℃;

(9) sampling and inspecting components, wherein the components are ensured to be in the following ranges in percentage by weight: mg: 4% -7%; si: 1.6% -2.8%; mn: 0.4% -0.9%; ti: 0.1% -0.3%; be: 0.002% -0.010%; aluminum titanium carbon boron seed crystal material: 0.3% -2%, Fe: less than or equal to 0.2 percent, and Mg/Si is more than or equal to 2.5;

(10) and after the components are qualified, casting at the temperature of 690-740 ℃ to obtain an alloy ingot.

Preferably, the alloy ingot comprises the following components in percentage by weight: mg: 4% -7%; si: 1.6% -2.8%; mn: 0.4% -0.9%; ti: 0.1% -0.3%; be: 0.002% -0.010%; aluminum titanium carbon boron seed crystal material: 0.3% -2%; fe: less than or equal to 0.2 percent; cu: less than or equal to 0.2 percent; zn: less than or equal to 0.3 percent; pb: less than or equal to 0.1 percent; sn: less than or equal to 0.01 percent; cd: less than or equal to 0.01 percent, and the sum of other inevitable impurity elements: less than or equal to 0.2 percent; the balance of Al, wherein the ratio of Mg to Si is satisfied: Mg/Si is more than or equal to 2.5.

Preferably, the aluminum titanium carbon boron seed material is a submicron aluminum titanium carbon boron seed material.

Preferably, the sub-micron aluminum titanium carbon boron seed material contains 2-4% of seed crystal.

Preferably, the sodium-free refining agent is added in an amount of 0.2-0.4%.

Preferably, the sodium free refining agent comprises Ba.

Preferably, the sodium-free refining agent further comprises K, Cl, F and Mg.

Preferably, the sodium-free refining agent is an aluminum magnesium sodium-free refining agent, and the aluminum magnesium sodium-free refining agent comprises the following components in percentage by mass: 10 to 16 percent; na: less than or equal to 3 percent; si: less than or equal to 8 percent; cl: 40-55 percent; f: 3 to 6 percent; mg: 8 to 12 percent; ba: 2 to 8 percent; ca: 1 to 3 percent.

The invention also provides a heat treatment method of the high-strength and high-toughness die-casting aluminum alloy material, when the casting of the high-strength and high-toughness die-casting aluminum alloy material prepared by the preparation method of the high-strength and high-toughness die-casting aluminum alloy material is subjected to heat treatment, the heat treatment steps are as follows:

putting the casting into a heat treatment furnace, heating the casting to 320-380 ℃ from 20-30 ℃, then preserving the heat, taking out the casting after the heat preservation lasts for 80-100 minutes, and cooling the casting in air;

or putting the casting into a heat treatment furnace, heating the temperature from 20-30 ℃ to 220-280 ℃, then preserving the heat, taking out the casting after the heat preservation lasts for 80-100 minutes, and cooling by water.

The invention also provides a die-casting forming method of the high-strength and high-toughness die-casting aluminum alloy material, when the alloy ingot prepared by the preparation method of the high-strength and high-toughness die-casting aluminum alloy material is subjected to remelting die-casting forming, the die-casting temperature is 690-730 ℃; the temperature of the die casting mold is 200-300 ℃; the die-casting shrinkage factor considered during the design of the die-casting die is 0.6-1.1%; the demoulding inclination is controlled to be more than or equal to 1.5⁰。

The high-strength and high-toughness die-casting aluminum alloy material prepared by the preparation method, the heat treatment method and the die-casting method of the high-strength and high-toughness die-casting aluminum alloy provided by the invention has better tensile strength, yield strength and elongation.

Detailed Description

The technical solutions of the present invention are further described in detail with reference to specific examples so that those skilled in the art can better understand the present invention and can implement the present invention, but the examples are not intended to limit the present invention.

The embodiment of the invention provides a preparation method of a high-strength and high-toughness die-casting aluminum alloy material, which comprises the following steps:

(1) adding 85-90% aluminum ingot and all silicon, melting and heating to 830-860 deg.C.

(2) When the temperature is 830-860 ℃ and the silicon is melted evenly, adding the manganese additive and the titanium additive, stirring and melting, and then standing for 10-20 minutes.

(3) Sampling and testing the components, wherein the components are calculated according to the weight percentage, and the calculation of the components is ensured to fall within the following range under the condition of including the later required added materials: si: 1.6% -2.8%; mn: 0.4% -0.9%; ti: 0.1 to 0.3 percent.

(4) Adding the rest 10-15% of aluminum ingot to melt, and removing slag.

(5) Adding preheated magnesium at 740-760 ℃, pressing into a molten pool, melting in aluminum liquid, and controlling Mg/Si to be more than or equal to 2.5; stirring after melting, and standing for 5-10 min to reduce component segregation.

(6) Adding preheated Al-Be intermediate alloy, pressing into molten pool, and melting rapidly.

(7) And (3) adopting nitrogen or argon as a carrier gas, adding a sodium-free refining agent for refining, after the refining reaction is finished, standing for 5-10 minutes, and removing dross on the surface of the aluminum liquid after dross is separated from aluminum.

(8) Adding preheated aluminum titanium carbon boron seed crystal material at the temperature of 700-750 ℃; melting, stirring, and standing for 5-15 min.

(9) Sampling and inspecting components, wherein the components are ensured to be in the following ranges in percentage by weight: mg: 4% -7%; si: 1.6% -2.8%; mn: 0.4% -0.9%; ti: 0.1% -0.3%; be: 0.002% -0.010%; aluminum titanium carbon boron seed crystal material: 0.3% -2%, Fe: less than or equal to 0.2 percent, and Mg/Si is more than or equal to 2.5.

And continuously degassing the aluminum melt for 20-30 minutes by adopting nitrogen or argon. During degassing, the boiling height of the alloy liquid is less than 15cm, and the air pressure is between 0.15 and 0.25 MPa.

(10) And after the components are qualified, casting at the temperature of 690-740 ℃ to obtain an alloy ingot. In the casting process, nitrogen or argon is adopted to carry out online degassing at the bottom of the filter box through the air brick with the aperture of 15-25 mu m.

According to the preparation method of the high-strength and high-toughness die-casting aluminum alloy material provided by the embodiment, the prepared high-strength and high-toughness die-casting aluminum alloy material has high yield strength, high tensile strength and high elongation. Has good corrosion resistance, does not generate intergranular corrosion, and does not generate stress corrosion cracks. The high-strength and high-toughness die-casting aluminum alloy material prepared by the embodiment has better heat resistance and can bear the mutation of working temperature; has good welding performance.

The high-strength and high-toughness die-casting aluminum alloy material prepared by the embodiment can be used for preparing thin-wall parts of 4mm-7mm, and is preferably used for preparing thin-wall parts of 6mm-6.5 mm. The thin-wall part can be prepared, and simultaneously, the mechanical property can be better met.

The high-strength and high-toughness die-casting aluminum alloy material prepared by the embodiment can be widely applied to die-casting structural parts needing high strength and toughness. Such as the stress parts of the die casting automobile steering wheel, the automobile body space frame joint, the rear beam, the spoked wheel and the like.

In the high-toughness die-cast aluminum alloy material provided by the embodiment, the main alloy elements are Mg, Si and Mn, and the structure of the alloy material is composed of an alpha phase and Mg₂A eutectic crystal of Si. The Mg content is high, is a main alloy element of the alloy without heat treatment, and can adjust the mechanical property of high toughness. Relatively low Mg content materials have higher elongation in a controlled range, while relatively high Mg content materials have higher strength. The content of Si determines the components of the eutectic, the higher the components of the eutectic are, the better the fluidity of the alloy is, and the better the castability and the aluminum liquid replenishment are.

The high-toughness die-casting aluminum alloy material provided by the embodiment can ensure the corrosion resistance and the alpha phase strength by controlling the Mg/Si ratio to be more than 2.5. Further preferred embodiments have a Mg/Si ratio of 2.5 to 5, preferably 2.5 to 3.

In the high-toughness die-cast aluminum alloy material provided by the embodiment, the content of Fe is limited to be less than 0.2%, so that the precipitation of coarse AlFeSi compounds is prevented, and good yield strength is obtained. Mn is added to prevent sticking to a metal mold in place of Fe, and the content of Mn must be 0.4% or more to exhibit a significant effect. Meanwhile, the higher Mn content also improves the thermal strength performance of the material, so that the material has good heat resistance and can bear the sudden change of the working temperature. The eutectic composition and the higher Mn content enable the alloy to have good welding performance and reduce the hot cracking tendency.

In the high-toughness die-casting aluminum alloy material provided by the embodiment, the aluminum titanium carbon boron seed crystal material can be a submicron aluminum titanium carbon boron seed crystal material. The submicron-grade aluminum titanium carbon boron seed crystal material can refine an alpha aluminum phase and solve the problems of uneven grain distribution and stress concentration. And the grain refining effect has long-term effect. Meanwhile, the casting defects of shrinkage porosity, snow spot and the like can be eliminated, and the mechanical property and the processability are improved. A small amount of Ti is mainly used to refine the grains.

The high-strength and high-toughness die-casting aluminum alloy material provided by the embodiment is an aluminum-magnesium die-casting aluminum alloy material, and more magnesium needs to be added. When the magnesium is completely added into the aluminum melt to be melted, the gas content in the aluminum melt is increased compared with the original gas content, and part of the magnesium reacts with oxygen in the melt to generate MgO and MgAl₂O₃. Meanwhile, the scum is sticky, and the aluminum and the scum are not well separated. The MgO oxide film is loose and not compact, and can not play a role in blocking oxygen in the air from continuing to react with magnesium in the melt in a liquid state, and can not play a role in blocking oxygen in the air from continuing to react with magnesium below the alloy surface layer even in a solidified solid state. Therefore, a trace amount of beryllium was added immediately. When the added aluminum-beryllium intermediate alloy is melted, the aluminum-beryllium intermediate alloy reacts immediately to generate BeO and BeAl₂O₃And the like, and can effectively inhibit the continuous oxidation of magnesium.

After a small amount of oxidation reaction of beryllium occurs to play a role in inhibiting magnesium from being oxidized continuously, in order to reduce further oxidation burning loss of rare noble metal beryllium in the melt, a sodium-free refining agent is added to refine the melt. The refining process acts to degas (including removing H and removing O) the aluminum melt. After the refining is finished, the gas content in the aluminum melt is already low, and the magnesium and the beryllium are alloyed and basically do not continue to be oxidized.

In the embodiment, the addition sequence of Mg, Be and the sodium-free refining agent is reasonably determined, so that the recovery rate of the prepared high-strength and high-toughness die-casting aluminum alloy material beryllium is high, and the recovery rate is up to 98%.

In the embodiment, in the preparation process of the high-strength and high-toughness die-casting aluminum alloy material, slag is not removed between the steps of adding Mg and adding Be, at the moment, a small amount of molten dross is generated, but dross and aluminum are integrated in the dross, and the dross and the aluminum cannot Be effectively separated. Therefore, the slag is not removed for the moment. Slag is not removed between the beryllium and the refining agent, and a small amount of molten scum still cannot be effectively separated from slag and aluminum and is still integrated with slag and aluminum. Therefore, the slag is not removed temporarily. And deslagging after the aluminum magnesium sodium-free refining agent is added for refining. The dross is now separated from the aluminum, and the amount of dross is less than the molten dross after the addition of magnesium and beryllium. At the moment, the slag is removed, so that the loss of metal can be effectively reduced. After deslagging, the BeO-containing oxide film on the surface is compact, so that oxygen in the air is isolated from entering the melt to oxidize magnesium, and the aluminum melt is continuously degassed in the following processes of modification, temperature control, inspection and the like, so that the effect of the aluminum melt is strengthened.

The embodiment of the invention also provides a die-casting forming method of the high-strength and high-toughness die-casting aluminum alloy material, when the alloy ingot prepared by the preparation method of the high-strength and high-toughness die-casting aluminum alloy material is subjected to remelting die-casting forming:

the die casting temperature is 690-730 ℃. The temperature of the die casting mold is 200-300 ℃, and in the mold temperature range, the elongation of the die casting part is increased and the strength is reduced along with the increase of the mold temperature.

The demoulding inclination is controlled to be more than or equal to 1.50.

The die casting shrinkage rate is 0.6-1.1%.

If the die cast is quenched within 10 seconds after hot forming, the elongation may be increased but the yield strength may be decreased.

The embodiment of the invention also provides a heat treatment method of the high-strength and high-toughness die-casting aluminum alloy material, when the prepared casting of the high-strength and high-toughness die-casting aluminum alloy material is subjected to heat treatment, the heat treatment step is as follows:

putting the casting into a heat treatment furnace, heating the casting from 20-30 ℃ to 320-380 ℃, preserving the heat, keeping the heat for 80-100 minutes, taking out the die casting, and cooling in air. The heat treatment process may result in an increase in elongation but a decrease in yield strength.

In another embodiment of the heat treatment method, the casting is put into a heat treatment furnace, the temperature is raised from 20-30 ℃ to 220-280 ℃, then heat preservation is carried out, the die casting is taken out after heat preservation lasts for 80-100 minutes, and water cooling is carried out. The heat treatment method can increase the yield strength, but the elongation rate is reduced.

The high-strength and high-toughness die-casting aluminum alloy material provided by the embodiment can be subjected to two special heat treatments, so that the strength and the elongation can be increased or reduced in a certain degree, and the requirements of various application scenes can be met.

The casting referred to in this embodiment is a casting obtained by die-casting.

The embodiment of the invention provides a high-strength and high-toughness die-casting aluminum alloy material which comprises the following components in percentage by weight in addition to aluminum: mg: 4% -7%; si: 1.6% -2.8%; mn: 0.4% -0.9%; ti: 0.1% -0.3%; be: 0.002% -0.010%; fe: less than or equal to 0.2 percent; aluminum titanium carbon boron seed crystal material: 0.3% -2%; wherein the ratio of Mg to Si satisfies the following conditions: Mg/Si is more than or equal to 2.5;

in a preferred embodiment, the sub-micron aluminum titanium carbon boron seed material contains 2-4% of seed crystals, so that the grain refining effect has long-term effect.

In a preferred embodiment, the high-strength high-toughness die-cast aluminum alloy material further comprises; cu: less than or equal to 0.2 percent; zn: less than or equal to 0.3 percent; pb: less than or equal to 0.1 percent; sn: less than or equal to 0.01 percent; cd: less than or equal to 0.01 percent.

In a preferred embodiment, the addition amount of the sodium-free refining agent in the preparation process of the high-strength and high-toughness die-casting aluminum alloy material is 0.2-0.4%.

In a preferred embodiment, the sodium-free extractThe refining agent comprises Ba. In the embodiment, the sodium-free refining agent contains Ba, and is added immediately after beryllium (Be) is added, so that the refining agent can generate a plurality of reactions in a melt and generate Ba₃Al₂O₆、BaAl₂O₄Product, Ba₃Al₂O₆、BaAl₂O₄The change values of the free energy of the products are-2943.175 KJ/mol and-1933.300 KJ/mol respectively, the negative numbers of the change values are far larger than the free energy of the oxidation products of the beryllium, and the continuous oxidation burning loss of the beryllium and the magnesium is effectively inhibited. After the refining is finished, the gas content in the aluminum melt is already low, and the magnesium and the beryllium are alloyed and basically do not continue to be oxidized. On one hand, the recovery rate of beryllium can be better improved, and on the other hand, the mechanical property of the material can be better improved.

In a preferred embodiment, the composition of the sodium-free refining agent further comprises K (potassium), Cl (chlorine), F (fluorine), Mg (magnesium). Due to the special elemental composition of such refining agents, a number of reactions will take place in the melt and a number of products will be formed, such as: ba₃Al₂O₆、BaAl₂O₄、BaF₂、K₂Cl₂、K₂F₂、MgCl₂、MgF₂、Mg₂F₄And so on. Various reaction products of the refining agent are combined with dross integrated with slag aluminum before refining, so that the wetting angle of the slag aluminum is increased, and a good slag aluminum separation effect is achieved.

In a preferred embodiment, the sodium-free refining agent is an aluminum magnesium sodium-free refining agent, and the aluminum magnesium sodium-free refining agent comprises the following components in percentage by mass: 10 to 16 percent; na: less than or equal to 3 percent; si: less than or equal to 8 percent; cl: 40-55 percent; f: 3 to 6 percent; mg: 8 to 12 percent; ba: 2 to 8 percent; ca: 1 to 3 percent. In a further preferred embodiment, the aluminum magnesium sodium-free refining agent is prepared from the following components in percentage by mass: 10 to 16 percent; na: less than or equal to 3 percent; si: less than or equal to 8 percent; cl: 40-55 percent; f: 3 to 6 percent; mg: 8 to 12 percent; ba: 2-8% and Ca: 1-3 percent of the composition. In the embodiment, various reaction products of the aluminum-magnesium sodium-free refining agent are combined with viscous scum before refining, so that the wetting angle of the aluminum slag is increased, and a good aluminum slag separation effect is achieved.

The embodiment is providedThe high-strength and high-toughness die-casting aluminum alloy material, the cast aluminum ingot and the die-casting piece die-cast after remelting also have a compact beryllium oxide protective film to prevent magnesium under the surface layer from being continuously oxidized. Has good corrosion resistance and does not generate intergranular corrosion. Meanwhile, the alloy does not contain beta-phase Mg₂Al₃The possibility of existence of stress corrosion cracks is avoided, so that the problem that the common aluminum-magnesium alloy is caused by beta-phase Mg is solved₂Al₃The crystal grains are precipitated on the grain boundary, and stress corrosion cracking is easily caused.

The embodiment of the invention also provides a high-strength and high-toughness die-casting aluminum alloy material which comprises the following components in percentage by weight: mg: 4% -7%; si: 1.6% -2.8%; mn: 0.4% -0.9%; ti: 0.1% -0.3%; be: 0.002% -0.010%; aluminum titanium carbon boron seed crystal material: 0.3% -2%; fe: less than or equal to 0.2 percent; cu: less than or equal to 0.2 percent; zn: less than or equal to 0.3 percent; pb: less than or equal to 0.1 percent; sn: less than or equal to 0.01 percent; cd: less than or equal to 0.01 percent, and the sum of other inevitable impurity elements: less than or equal to 0.2 percent; the balance of Al, wherein the ratio of Mg to Si is satisfied: Mg/Si is more than or equal to 2.5.

In order that the technical solutions of the present invention may be further understood and appreciated, several preferred embodiments are now described in detail.

The formulation ingredients, preparation methods and heat treatment methods of examples 1-5 and comparative examples 1-5 are shown in Table 1.

TABLE 1

In Table 1, the seed crystal is a submicron aluminum titanium carbon boron seed crystal material, and contains 2-4% of seed crystal.

Wherein, the preparation method 1 comprises the following steps:

(1) adding 85-90% aluminum ingot and all silicon, melting and heating to 830-860 deg.C.

(2) When the temperature is 830-860 ℃ and the silicon is melted evenly, adding the manganese additive and the titanium additive, stirring and melting, and then standing for 10-20 minutes.

(3) Sampling and inspecting components;

(4) adding the rest 10-15% of aluminum ingot to melt, and removing slag.

(5) Adding preheated magnesium at 740-760 ℃, pressing into a molten pool, melting in aluminum liquid, and controlling Mg/Si to be more than or equal to 2.5; stirring after melting, and standing for 5-10 minutes.

(6) Adding preheated Al-Be intermediate alloy, pressing into molten pool, and melting rapidly.

(7) And (3) adopting nitrogen or argon as a current-carrying gas, adding an aluminum-magnesium sodium-free refining agent for refining, after the refining reaction is finished, standing for 5-10 minutes, and removing dross on the surface of the aluminum liquid after dross is separated from aluminum. The aluminum magnesium sodium-free refining agent comprises the following components in percentage by mass: 10 to 16 percent; na: less than or equal to 3 percent; si: less than or equal to 8 percent; cl: 40-55 percent; f: 3 to 6 percent; mg: 8 to 12 percent; ba: 2-8% and Ca: 1-3 percent of the composition.

(8) Adding preheated aluminum titanium carbon boron seed crystal material at the temperature of 700-750 ℃; melting, stirring, and standing for 5-15 min.

(9) Sampling and inspecting the components, and continuously degassing the aluminum melt for 20-30 minutes by adopting nitrogen or argon. During degassing, the boiling height of the alloy liquid is less than 15cm, and the air pressure is between 0.15 and 0.25 MPa.

(10) And after the components are qualified, casting at the temperature of 690-740 ℃ to obtain an alloy ingot. In the casting process, nitrogen or argon is adopted to carry out online degassing at the bottom of the filter box through the air brick with the aperture of 15-25 mu m.

Preparation method 2

Compared with the preparation method 1, in the preparation method 2, the rest 10-15% of aluminum ingots are added to be melted, and after the step of deslagging, preheated aluminum-beryllium intermediate alloy is added firstly and pressed into a molten pool to be melted rapidly; then adding preheated magnesium when the temperature is controlled to be 740-760 ℃, pressing the magnesium into a molten pool to melt the magnesium in molten aluminum, and controlling Mg/Si to be more than or equal to 2.5; stirring after melting, and standing for 5-10 minutes. The remaining steps are the same as in preparation method 1.

Preparation method 3

Compared with the preparation method 1, in the preparation method 3, the rest 10-15% of aluminum ingots are added to be melted, after the step of deslagging, refining is carried out, nitrogen or argon is used as carrier gas, an aluminum-magnesium sodium-free refining agent is added to carry out refining, after the refining reaction is finished, the aluminum-magnesium sodium-free refining agent is placed for 5-10 minutes, and dross on the surface of the aluminum liquid is removed after dross is separated. Then adding preheated magnesium at 740-760 ℃, pressing into a molten pool, melting in aluminum liquid, and controlling Mg/Si to be more than or equal to 2.5; stirring after melting, and standing for 5-10 minutes; then adding preheated aluminum-beryllium intermediate alloy, pressing into a molten pool, and rapidly melting.

The alloy ingots of examples 1 to 5 and the alloy ingots of comparative examples 1 to 5, which were prepared by the corresponding preparation methods, were respectively die-cast according to the following die-casting molding methods to respectively obtain die-cast articles.

The die-casting molding conditions are as follows:

the die casting temperature is 690-730 ℃;

the die casting shrinkage rate is 0.6-1.1%;

the demoulding inclination is controlled to be more than or equal to 1.5 degrees during die-casting;

the temperature of the die casting mold is 200-300 ℃. In this mold temperature range, the elongation of the die cast article increases and the strength decreases as the mold temperature increases.

Wherein the die castings prepared in example 4 and example 5 were heat-treated by heat treatment method 1 and heat treatment method 2, respectively.

Heat treatment method 1

Putting the casting into a heat treatment furnace, heating the casting from 20-30 ℃ to 320-380 ℃, preserving the heat, keeping the heat for 80-100 minutes, taking out the die casting, and cooling in air.

Heat treatment method 2

In another embodiment of the heat treatment method, the die casting is put into a heat treatment furnace, the temperature is raised from 20-30 ℃ to 220-280 ℃, then heat preservation is carried out, the die casting is taken out after heat preservation lasts for 80-100 minutes, and water cooling is carried out.

Effects of the embodiment

The final materials of examples 1 to 5 and comparative examples 1 to 5 were subjected to measurements of tensile strength, yield strength, elongation, wall thickness and recovery of Be, and the specific test results are shown in table 2.

TABLE 2

As can be seen from the data in Table 2, the high-strength and high-toughness die-casting aluminum alloy materials provided by the embodiments 1 to 5 are reasonably set in formula and matched with a specific preparation method, so that the obtained aluminum alloy material has high tensile strength, yield strength and elongation after die-casting molding. Meanwhile, the method can meet the requirement of thin wall thickness forming, and also has high Be recovery rate which reaches 98 percent.

As can be seen from the data of the embodiments 1 to 3, the high-strength and high-toughness die-casting aluminum alloy material provided by the invention can realize higher tensile strength, yield strength and elongation without heat treatment. The deformation of the thin piece caused by the traditional heat treatment (such as T4, T5, T6 and T7) can be reduced, and the better performance can be realized by saving the heat treatment process.

From the data of examples 4-5, it can be seen that the high strength and toughness die-cast aluminum alloy material provided by the present invention can also improve the performance of a certain aspect of the material through a specific heat treatment manner, such as the heat treatment method 1 in example 4, although the strength of the alloy material is reduced, the elongation can be significantly improved. In example 5, the treatment using the heat treatment method 2 decreased the elongation of the material, but increased the strength of the material. The embodiment provides the high-strength and high-toughness die-casting aluminum alloy material, and the strength and the elongation of the high-strength and high-toughness die-casting aluminum alloy material can be increased or reduced with a certain emphasis by a special heat treatment mode so as to meet the requirements of various application scenes.

As can be seen from the data of comparative example 1, the use amount of the magnesium element is increased in comparative example 1, and the elongation is greatly reduced if the content of the magnesium element is higher than the range of the invention. The magnesium element is reasonably arranged, and the aluminum alloy material obtained by matching with other elements and the preparation method has better strength and elongation.

As can be seen from the data of comparative example 2, the content of silicon is reduced in comparative example 2, the use of the content of silicon is out of the scope of the present invention, and the resulting material has a significant decrease in strength. The invention has reasonable silicon element arrangement, and the aluminum alloy material obtained by matching with other elements and the preparation method has better strength and elongation.

It can be seen from the data of comparative example 3 that, although other components are within the range of the present invention, when Mg/Si <2.5 is not within the defined range, the mechanical properties of the resulting alloy material are greatly reduced. The formula of the aluminum alloy material provided by the invention requires that Mg and Si elements are required to be in a control range, and the constraint condition that Mg/Si is more than or equal to 2.5 is also required to be met simultaneously, so that the obtained aluminum alloy material has good strength and elongation.

As can Be seen from the data of comparative example 4 and comparative example 5, the recovery rate of the obtained alloy material Be is greatly reduced to only 40.28 percent by exchanging the adding sequence of Be and Mg in comparative example 4. In comparative example 5, the recovery rate of the obtained alloy material Be is greatly reduced to only 56.94% by adjusting the refining addition sequence to Be before the addition of Mg and Be. The aluminum alloy material provided by the invention has the advantages that the adding sequence of Mg, Be and the sodium-free refining agent is reasonably determined during preparation, the loss of the precious metal beryllium in the obtained aluminum alloy material is less, and the preparation cost of the alloy can Be reduced to a greater extent.

The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by the present specification, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.