Die-casting heat-treatment-free alloy material and preparation method thereof

Abstract

The invention provides a die-casting heat-treatment-free alloy material and a preparation method thereof.The alloy material comprises Si, Mn, Ti, Mo, Sr, Zr, Al and inevitable impurities, and the preparation process comprises the steps that raw materials are extracted, and a first alloy melt is prepared; adding a first part of Mo, a first part of Zr and Ti to prepare a second alloy melt; adding a second part of Zr and a second part of Mo to prepare a third alloy melt; performing refining; and casting and molding. According to the technical scheme, compared with the prior art, the tensile strength, the yield strength and the elongation of the alloy material are improved, the performance is stable under the conditions of heat treatment, aging and the like, and the quality of the alloy material is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of composite materials, and in particular to a die-casting heat-treatment-free alloy material and a preparation method thereof. Background Art

[0002] Aluminum alloys have been widely used in aerospace, machinery manufacturing, shipbuilding, electronic communications, and especially new energy vehicles due to their low density, high specific strength, good plasticity, excellent mechanical properties, low thermal expansion coefficient, good corrosion resistance, electrical conductivity, easy processing, and recyclability. For example, they are used in the casings of smart phones, laptops, and other electronic products, the heat dissipation backplanes and lampshades of LED lights, the heat dissipation substrates, filters and cabinet casings of wireless communication base stations, the heating plates of rice cookers and induction cookers, the power battery casings, control power supply chassis, drive motor casings, subframes and chassis of new energy vehicles, and other complex structural parts.

[0003] Integrated die-casting for automobiles has become an important way to achieve lightweight automobiles. Integrated die-casting technology is to redesign multiple independent parts that need to be assembled in the original design, and use super-large die-casting machines to die-cast them at one time to directly obtain complete parts and realize the design functions of parts. Based on this technology, the number of parts required for production is greatly reduced, while the die-casting, welding, and gluing links are significantly reduced, which significantly improves manufacturing efficiency, reduces labor intensity, and shortens the manufacturing time of the whole vehicle. In order to meet the high elongation performance of die-casting parts, heat treatment is usually required. However, as the size of integrated castings becomes larger and larger, the thickness of parts varies greatly. Heat treatment is likely to cause dimensional deformation of castings and bubbles on the surface of castings, which leads to an increase in the scrap rate of castings and increases production costs. Therefore, die-casting high thermal conductivity aluminum alloy materials that do not require heat treatment came into being. Summary of the invention

[0004] The purpose of the present invention is to provide a novel heat treatment-free alloy material and a preparation method thereof.

[0005] One of the purposes of the present invention is to provide a die-casting alloy material free of heat treatment, the technical solution adopted by the present invention is: A die-casting heat-treatment-free alloy material, characterized in that, based on the overall weight of the alloy material, it contains the following components in weight percentage: Si 7.7-8.6%; Mn 0.40-0.60%; Mg 0.15-0.3%; Cu 0-0.05%; Fe 0.15-0.25%; Ti 0.06-0.15%; Mo 0.015-0.035%; Sr 0.015-0.028%; Zr 0.1-0.30%; the remainder being Al and unavoidable impurities.

[0006] Another object of the present invention is to provide a preparation scheme for a die-casting alloy material free of heat treatment, the technical scheme adopted is: A method for preparing a die-casting heat-treatment-free alloy material, characterized by comprising the following steps: S1, after adding Al to a blast furnace for smelting, Si, Mn, Mg, and Fe components are added to obtain a first alloy melt; S2, adding the first portion of Mo, the first portion of Zr and Ti, Sr to the first alloy solution to obtain a second alloy solution; S3, adding the second portion of Zr and the second portion of Mo and Sr into the second alloy melt, and heating to 740-760°C and maintaining for 30 minutes to obtain a third alloy melt, S4, adding a refining agent to the third alloy melt by nitrogen or argon powder spraying for refining, and then standing for 20-30 minutes; S5, pouring the refined and static third alloy melt into a molding mold, casting and molding, and performing mold opening processing after molding to obtain an alloy material.

[0007] In the present technical solution, the total content of Zr and Ti is 0.16-0.45%.

[0008] In the present technical solution, the total Sr content is 0.015-0.028%.

[0009] In the technical solution, the ratio of the first portion of Zr to the second portion of Zr is 1:1.

[0010] In the technical solution, the ratio of the first portion of Mo to the second portion of Mo is 1:1.

[0011] In the technical solution, the ratio of the first portion of Sr to the second portion of Sr is 1:1.

[0012] In the present technical solution, in step S4, the refining includes: using a rotary blowing device to introduce nitrogen or argon containing a mixture of 30-60% NaCl, 20-30% KCl and 10-25% Na3AlF6 refining agent powders into the third alloy melt; wherein the pressure of the nitrogen or argon is 0.5-0.8MPa, the flow rate is 25-30L / min, the degassing speed is 550-580r / min, the degassing time is 20-45min, and the temperature is 730-740℃.

[0013] The beneficial effects produced by the present invention are as follows: Compared with the prior art, the technical solution provided by the present invention changes the composition ratio of the alloy and has a unique preparation method and process in terms of the preparation method, thereby improving the tensile strength, yield strength and elongation of the alloy material, and the above-mentioned properties are relatively stable under conditions of heat treatment, aging, etc., thereby ensuring the quality of the alloy material. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The figure is a flow chart of the method of the present invention.

[0015] Figure 2 The figure shows the change of tensile strength of the alloy material of the present invention before and after heat treatment.

[0016] Figure 3 The figure shows the change of yield strength of the alloy material of the present invention before and after heat treatment.

[0017] Figure 4 The figure shows the change of elongation of the alloy material of the present invention before and after heat treatment.

[0018] Figure 5 The figure shows the change of the natural aging sensitivity mechanical properties of the alloy material of the present invention.

[0019] Figure 6 The figure shows the change of natural aging sensitivity yield strength of the alloy material of the present invention.

[0020] Figure 7 The figure shows the change of natural aging sensitivity elongation of the alloy material of the present invention.

[0021] Figure 8 The figure shows the change of mechanical properties of the alloy material of the present invention due to its wall thickness sensitivity.

[0022] Fig. 9 The graph shows the change in yield strength of the alloy material of the present invention due to wall thickness sensitivity.

[0023] Fig.10 The figure shows the change of wall thickness sensitive elongation of the alloy material of the present invention. DETAILED DESCRIPTION

[0024] In order to facilitate the understanding of those skilled in the art, the present invention is further described below in conjunction with the embodiments and drawings, and the contents mentioned in the embodiments are not intended to limit the present invention. The present invention is described in detail below in conjunction with the drawings.

[0025] See also Figure 1 , which is a method for preparing a heat treatment-free alloy material provided by the present invention.

[0026] In this embodiment, a die-casting heat-treatment-free alloy material is provided, which includes Si, Mn, Mg, Ti, Mo, Sr, Zr, Al and inevitable impurity components based on the overall weight of the alloy material, wherein the weight proportions of the above components are: Si 8.3%; Mn 0.40%; Mg 0.23%; Ti 0.18%; Mo 0.025%; Sr 0.022%; Zr 0.10%; and the balance is Al and inevitable impurities.

[0027] The preparation process includes the following steps: In step S1, the above components are weighed based on the overall weight of the alloy material, Al is put into a blast furnace for melting, and Si, Mn, Fe, Mg, and Cu components are added into the Al melt after the Al melt is in a molten state, thereby obtaining a first alloy melt; In step S2, components of 0.0075% Mo, 0.05% Zr, 0.013% Sr, and 0.06% Ti are added to the second alloy melt, thereby preparing the second alloy melt.

[0028] In this step, by adding Mo, the Fe-rich phase can be improved, the heat resistance of the alloy can be improved, and it is beneficial to demolding. At the same time, Zr and Ti are added to form ZrAl3 and TiAl3 respectively, which play a role in refining the grains; Zr and Mo are beneficial to improving the mechanical properties of the alloy.

[0029] In step S3, a second portion of Mo, a second portion of Sr, and a second portion of Zr are added to the second alloy melt, wherein the proportion of Mo added in this step is 0.0095%, the proportion of Sr is 0.013%, and the proportion of Zr is 0.07%.

[0030] In this step, Mo is added to form AlSiMnMo quaternary phase and AlSiTiZrMo quinary phase; Zr is added to form AlSiTiMnZr and AlSiTiZrMo quinary phases, which have a dispersion strengthening effect on the alloy as a whole and a supplementary strengthening effect on Mn. At the same time, in this step, the second portion of Mo and the second portion of Zr are added to the second alloy melt, and the temperature is raised to 760°C and kept warm for 30 minutes, thereby obtaining a third alloy melt.

[0031] In step S4, a refining agent is added to the third alloy melt by nitrogen or argon powder spraying for refining, and then the mixture is allowed to stand for 20 minutes. In this step, the third alloy melt is refined. During this process, nitrogen or argon containing a mixture of refining agent powders of 60% NaCl, 20% KCl and 25% Na3AlF6 is introduced into the third alloy melt by a rotary blowing device; wherein the nitrogen or argon has a pressure of 0.5 MPa, a flow rate of 25 L / min, a degassing speed of 550 r / min, a degassing time of 20 minutes, and a temperature of 730°C.

[0032] In step S5, the refined third alloy melt is poured into a molding die for casting and then mold opening is performed to obtain an alloy material.

[0033] In this embodiment, a die-casting heat-treatment-free alloy material is provided, which includes Si, Mn, Mg, Ti, Mo, Sr, Zr, Al and inevitable impurity components based on the overall weight of the alloy material, wherein the weight proportions of the above components are: Si 8.4%; Mn 0.50%; Mg 0.21%; Fe 0.18%; Cu 0.02%; Ti 0.09%; Mo 0.025%; Sr0.020%; Zr 0.20%; the balance is Al and inevitable impurities.

[0034] The preparation process includes the following steps: In step S1, the above components are weighed based on the overall weight of the alloy material, Al is put into a blast furnace for melting, and Si, Mn, Fe, Mg, and Cu components are added into the Al melt after the Al melt is in a molten state, thereby obtaining a first alloy melt; In step S2, components of 0.0125% Mo, 0.021% Sr, 0.10% Zr, and 0.06% Ti are added to the second alloy melt, thereby preparing the second alloy melt.

[0035] In this step, by adding Mo, the Fe-rich phase can be improved, the heat resistance of the alloy can be improved, and it is beneficial to demolding. At the same time, Zr and Ti are added to form ZrAl3 and TiAl3 respectively, which play a role in refining the grains; Zr, Sr and Mo are beneficial to improving the mechanical properties of the alloy, especially the elongation.

[0036] In step S3, a second portion of Mo, a second portion of Sr, and a second portion of Zr are added to the second alloy melt, wherein the proportion of Mo added in this step is 0.0125%, the proportion of Sr is 0.0115%, and the proportion of Zr is 0.10%.

[0037] In this step, Mo is added to form AlSiMnMo quaternary phase and AlSiTiZrMo quinary phase; Zr is added to form AlSiTiMnZr and AlSiTiZrMo quinary phases, which have a dispersion strengthening effect on the alloy as a whole and a supplementary strengthening effect on Mn. At the same time, in this step, the second portion of Mo, the second portion of Sr and the second portion of Zr are added to the second alloy melt, and the temperature is raised to 760°C and kept warm for 30 minutes, thereby obtaining a third alloy melt.

[0038] In step S4, a refining agent is added to the third alloy melt by nitrogen or argon powder spraying for refining, and then the mixture is allowed to stand for 30 minutes. In this step, the third alloy melt is refined. During this process, nitrogen or argon containing a mixture of refining agent powders of 30% NaCl, 30% KCl and 10% Na3AlF6 is introduced into the third alloy melt by a rotary blowing device; wherein the nitrogen or argon has a pressure of 0.8 MPa, a flow rate of 30 L / min, a degassing speed of 580 r / min, a degassing time of 25 minutes, and a temperature of 740°C.

[0039] In step S5, the refined third alloy melt is poured into a molding die for casting and then mold opening is performed after molding to obtain an alloy material.

[0040] In this embodiment, a die-casting heat-treatment-free alloy material is provided, which includes Si, Mn, Mg, Ti, Mo, Sr, Zr, Al and inevitable impurity components based on the overall weight of the alloy material, wherein the weight proportions of the above components are: Si 8.0%; Mn 0.4%; Mg 0.19%; Fe 0.22%; Cu 0.04%; Ti 0.15%; Mo 0.035%; Sr 0.028%; Zr 0.30%; the balance is Al and inevitable impurities.

[0041] The preparation process includes the following steps: In step S1, the above components are weighed based on the overall weight of the alloy material, Al is put into a blast furnace for melting, and Si, Mn, Fe, Mg, and Cu components are added into the Al melt after the Al melt is in a molten state, thereby obtaining a first alloy melt; In step S2, components of Mo 0.0175%, Sr 0.014%, Zr 0.15%, and Ti 0.15% are added to the second alloy melt, thereby preparing the second alloy melt.

[0042] In this step, by adding Mo, the Fe-rich phase can be improved, the heat resistance of the alloy can be improved, and it is beneficial to demolding. At the same time, Zr and Ti are added to form ZrAl3 and TiAl3 respectively, which play a role in refining the grains; Zr and Mo are beneficial to improving the mechanical properties of the alloy.

[0043] In step S3, a second portion of Mo and a second portion of Zr are added to the second alloy melt, wherein the proportion of Mo added in this step is 0.0175%, the proportion of Sr is 0.009%, and the proportion of Zr is 0.15%.

[0044] In this step, Mo is added to form AlSiMnMo quaternary phase and AlSiTiZrMo quinary phase; Zr is added to form AlSiTiMnZr and AlSiTiZrMo quinary phases, which have a dispersion strengthening effect on the alloy as a whole and a supplementary strengthening effect on Mn. At the same time, in this step, the second portion of Mo and the second portion of Zr are added to the second alloy melt, and the temperature is raised to 755°C and kept warm for 30 minutes, thereby obtaining a third alloy melt.

[0045] In step S4, a refining agent is added to the third alloy melt by nitrogen or argon powder spraying for refining, and then the mixture is allowed to stand for 20 minutes. In this step, the third alloy melt is refined. During this process, nitrogen or argon containing a mixture of 50% NaCl, 28% KCl and 25% Na3AlF6 refining agent powders is introduced into the third alloy melt by rotary blowing equipment; wherein the nitrogen or argon pressure is 0.7MPa, the flow rate is 28L / min, the degassing speed is 570r / min, the degassing time is 30min, and the temperature is 735°C.

[0046] In step S5, the refined third alloy melt is poured into a molding die for casting and then mold opening is performed after molding to obtain an alloy material.

[0047] After testing, among the above three embodiments, embodiment 2 is the embodiment with the best performance. Figure 2-10 As shown, the test results of the alloy material of Example 2 are as follows. After testing, the performance of the alloy material is relatively stable before and after heat treatment, with basically no change; before and after natural aging, the performance of the alloy material is basically unchanged; through the wall thickness sensitivity test, the yield strength and tensile strength decrease with the increase of wall thickness.

[0048] The heat treatment-free alloy and preparation scheme provided by the present invention can produce an alloy material with relatively excellent processing performance, which has stable tensile strength, yield strength and elongation and can be used in the fields of automobiles and the like.

[0049] The above are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Although the present invention is disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with the profession can make some changes or modifications to equivalent embodiments of equivalent changes by using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technology of the present invention, which do not depart from the content of the technical solution of the present invention, are within the scope of the technical solution of the present invention.

Claims

1. A die-casting heat-treatment-free alloy material, characterized in that: Based on the overall weight of the alloy material, the alloy material contains the following components in weight percentage: Si 7.7-8.6%; Mn 0.40-0.60%; Mg 0.15-0.3%; Cu 0-0.05%; Fe 0.15-0.25%; Ti 0.06-0.15%; Mo 0.015-0.035%; Sr 0.015-0.028%; Zr 0.1-0.30%; the balance is Al and unavoidable impurities.

2. The die-casting heat-treatment-free alloy material according to claim 1, characterized in that: The weight percentages of the components are: Si 7.9%, Mn 0.50%, Ti 0.09%, Mg 0.2%, Cu 0.02%, Fe 0.2%, Mo 0.025%, Sr 0.020%, Zr 0.20%, and the balance is Al and unavoidable impurities.

3. A method for preparing a die-casting heat-treatment-free alloy material, characterized in that: The following steps are involved: S1, after adding Al to a blast furnace for smelting, adding Si, Mn, Mg, and Fe components to obtain a first alloy melt; S2, adding the first portion of Mo, the first portion of Zr and Ti, Sr to the first alloy solution to obtain a second alloy solution; S3, adding the second portion of Zr and the second portion of Mo and Sr into the second alloy melt, and heating to 740-760°C and maintaining for 30 minutes to obtain a third alloy melt, S4, adding a refining agent to the third alloy melt by nitrogen or argon powder spraying for refining, and then standing for 20-30 minutes; S5, pouring the refined and static third alloy melt into a molding mold, casting and molding, and performing mold opening processing after molding to obtain an alloy material.

4. The method for preparing a die-casting heat-treatment-free alloy material according to claim 3, characterized in that: In step S2, the total content of Zr and Ti in the first portion is 0.16-0.45%.

5. The method for preparing a die-casting heat-treatment-free alloy material according to claim 3, characterized in that: The total Sr content is 0.015-0.028%.

6. The method for preparing a die-casting heat-treatment-free alloy material according to claim 3, characterized in that: The ratio of the first portion of Zr to the second portion of Zr is 1:

1.

7. The method for preparing a die-casting heat-treatment-free alloy material according to claim 3, characterized in that: The ratio of the first portion of Mo to the second portion of Mo is 1:

1.

8. The method for preparing a die-casting heat-treatment-free alloy material according to claim 3, characterized in that: The ratio of the first portion of Sr to the second portion of Sr is 1:

1.

9. The method for preparing a die-casting heat-treatment-free alloy material according to claim 3, characterized in that: In step S4, the refining includes: using a rotary blowing device to introduce nitrogen or argon containing a mixture of 30-60% NaCl, 20-30% KCl and 10-25% Na3AlF6 refining agent powders into the third alloy melt; wherein the pressure of the nitrogen or argon is 0.5-0.8MPa, the flow rate is 25-30L / min, the degassing speed is 550-580r / min, the degassing time is 20-45min, and the temperature is 730-740°C.

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