Highly-corrosion-resistant die-casting aluminum alloy and preparation method therefor, and housing-type die-cast component

Abstract

The present application provides a highly-corrosion-resistant die-casting aluminum alloy and a preparation method therefor, and a housing-type die-cast component. The highly-corrosion-resistant die-casting aluminum alloy comprises the following components in percentage by mass: 8-9 wt% of Si, 0.2-1 wt% of Mg, 0.1-1 wt% of Fe, 0.005-0.05 wt% of Sr, 0.2-1 wt% of Mn, 0.05-0.2 wt% of Ti, 0.05-0.15 wt% of Cr, 0-0.05 wt% of Cu, 0-0.05 wt% of Zn, and the balance of Al and inevitable impurities, wherein the sum of the percentages by mass of the inevitable impurities does not exceed 0.5 wt%. By regulating the content of silicon in the die-casting aluminum alloy, the formability of the aluminum alloy is ensured; by regulating the contents of Cu, Zn, Cr, and Sr elements within the ranges of the present application and appropriately controlling the contents of Si, Mg, Fe, Sr, Mn, Ti, Cr, Cu, Zn, and Al elements, the corrosion resistance of the die-casting aluminum alloy is improved.

Description

High corrosion-resistant die-casting aluminum alloy, preparation method thereof and shell type die-casting part

[0001] The present application claims priority to the Chinese patent application No. 202411154301.X filed on August 21, 2024 to the Chinese Patent Office and entitled "High corrosion-resistant die-casting aluminum alloy, preparation method thereof and application", the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of aluminum alloy materials, in particular to a high corrosion-resistant die-casting aluminum alloy, a preparation method thereof and a shell type die-casting part. BACKGROUND

[0003] Aluminum alloy has low density, high strength, good plasticity, excellent electrical conductivity, thermal conductivity and corrosion resistance, and is widely used in industry. The die-casting process is the most widely used forming process for aluminum alloy. In recent years, the application of aluminum alloy is more and more, the requirement for product performance is also higher and higher, the competition is also more and more fierce, and the cost pressure is also more and more great. At present, the existing commonly used die-casting aluminum ADC12 has poor corrosion resistance. SUMMARY

[0004] The purpose of the present application is to provide a high corrosion-resistant die-casting aluminum alloy, a preparation method thereof and a shell type die-casting part, so as to improve the corrosion resistance of the die-casting aluminum alloy.

[0005] The first aspect of the present application provides a high corrosion-resistant die-casting aluminum alloy, which comprises the following components by mass percentage: 8wt%-9wt% of Si, 0.2wt%-1wt% of Mg, 0.1wt%-1wt% of Fe, 0.005wt%-0.05wt% of Sr, 0.2wt%-1wt% of Mn, 0.05wt%-0.2wt% of Ti, 0.05wt%-0.15wt% of Cr, 0wt%-0.05wt% of Cu, 0wt%-0.05wt% of Zn, the rest being Al and unavoidable impurities, and the mass percentage of the unavoidable impurities is not more than 0.5wt%.

[0006] In an embodiment of the present application, the mass percentage of Fe, Mn and Cr in the high corrosion-resistant die-casting aluminum alloy satisfies: Fe:(Mn+Cr)=(0.6-0.8):1.

[0007] In an embodiment of the present application, the phases inside the microstructure of the high-corrosion-resistant die-casting aluminum alloy include eutectic α-Al phase, eutectic Al-Si phase and dispersed phase, and the dispersed phase includes at least one of Al8Fe2Si phase, Al8Mg3FeSi6 phase, Al(Fe, Mn)Si phase, Al(Fe, Cr)Si phase, Al6Mn phase or Al3Fe phase.

[0008] In an embodiment of the present application, the high-corrosion-resistant die-casting aluminum alloy is prepared by the following method: 1) putting high-purity Al raw material into a heating furnace, heating to 670-690 ℃, melting and keeping for 14-16 min; 2) heating to 750-770 ℃, adding Si and Al-Fe alloy raw material; 3) cooling to 720-740 ℃, adding Al-Cr, Al-Mn and Al-Ti alloy raw material; 4) cooling to 710-730 ℃, adding pure Mg, Al-Sr metal material raw material; 5) after melting all the above raw materials, casting to obtain the high-corrosion-resistant die-casting aluminum alloy.

[0009] The second aspect of the present application provides a shell type die-casting part comprising the high-corrosion-resistant die-casting aluminum alloy of the first aspect of the present application.

[0010] In an embodiment of the present application, the high-corrosion-resistant die-casting aluminum alloy is subjected to die-casting forming to make a shell type die-casting part.

[0011] In an embodiment of the present application, the shell type die-casting part comprises a first surface and a second surface, and the second surface reaches the C5-M corrosive level in the international standard ISO12944-6 under the condition that the first surface is sealed.

[0012] In an embodiment of the present application, the step of die-casting forming comprises: a) melting the high-corrosion-resistant die-casting aluminum alloy at 690-710 ℃ to obtain a molten alloy; b) using a die-casting method of first low-speed and then high-speed injection to inject the molten alloy into a die-casting mold, the temperature of the die-casting mold is 180-220 ℃, the low-speed injection speed is 0.2-0.4 m / s, the low-speed injection time is 1.3-1.7 s; the high-speed injection speed is 4-5 m / s, the high-speed injection time is 0.2-0.4 s, and then the mold is left, solidified, demolded and passivated to obtain the shell type die-casting part.

[0013] In an embodiment of the present application, the thickness of the shell type die-casting part is 1-4 mm.

[0014] The present application has the following beneficial effects:

[0015] The application provides a high corrosion-resistant die-casting aluminum alloy, which comprises the following components in mass percentage: 8wt%-9wt% of Si, 0.2wt%-1wt% of Mg, 0.1wt%-1wt% of Fe, 0.005wt%-0.05wt% of Sr, 0.2wt%-1wt% of Mn, 0.05wt%-0.2wt% of Ti, 0.05wt%-0.15wt% of Cr, 0wt%-0.05wt% of Cu, 0wt%-0.05wt% of Zn, the rest being Al and inevitable impurities, and the mass percentage of the inevitable impurities is not more than 0.5wt%. The content of Si in the die-casting aluminum alloy is regulated to ensure the forming performance of the aluminum alloy, the contents of Cu, Zn, Cr and Sr are regulated within the range of the application, and the contents of Si, Mg, Fe, Mn, Ti and Al are reasonably controlled, so that the corrosion resistance of the die-casting aluminum alloy is improved.

[0016] Of course, implementing any of the products or methods of the application does not necessarily require achieving all the advantages described above at the same time. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and other embodiments can also be obtained by those skilled in the art based on these drawings.

[0018] FIG. 1 is a metallographic structure diagram of the die-casting aluminum alloy provided in the embodiment 1-1 of the application. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the application will be described clearly and completely in combination with the drawings in the embodiments of the application. Obviously, the described embodiments are only some of the embodiments of the application, but not all the embodiments. All other embodiments obtained by those skilled in the art based on the application belong to the protection scope of the application.

[0020] The first aspect of the present application provides a high corrosion resistant die-casting aluminum alloy, which comprises the following components in mass percentage: 8wt%-9wt% of Si, 0.2wt%-1wt% of Mg, 0.1wt%-1wt% of Fe, 0.005wt%-0.05wt% of Sr, 0.2wt%-1wt% of Mn, 0.05wt%-0.2wt% of Ti, 0.05wt%-0.15wt% of Cr, 0wt%-0.05wt% of Cu, 0wt%-0.05wt% of Zn, the rest being Al and inevitable impurities, the mass percentage of the inevitable impurities being not more than 0.5wt%. For example, the mass percentage of Si can be 8wt%, 8.2wt%, 8.4wt%, 8.6wt%, 8.8wt%, 9wt% or a range formed by any two of them; the mass percentage of Mg can be 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1wt% or a range formed by any two of them; the mass percentage of Fe can be 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1wt% or a range formed by any two of them; the mass percentage of Sr can be 0.005wt%, 0.01wt%, 0.02wt%, 0.03wt%, 0.04wt%, 0.05wt% or a range formed by any two of them; the mass percentage of Mn can be 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1wt% or a range formed by any two of them; the mass percentage of Ti can be 0.05wt%, 0.08wt%, 0.1wt%, 0.12wt%, 0.15wt%, 0.18wt%, 0.2wt% or a range formed by any two of them; the mass percentage of Cr can be 0.05wt%, 0.06wt%, 0.07wt%, 0.08wt%, 0.09wt%, 0.1wt%, 0.11wt%, 0.12wt%, 0.13wt%, 0.14wt%, 0.15wt% or a range formed by any two of them; the mass percentage of Cu can be 0wt%, 0.01wt%, 0.02wt%, 0.03wt%, 0.04wt%, 0.05wt% or a range formed by any two of them; the mass percentage of Zn can be 0wt%, 0.01wt%, 0.02wt%, 0.03wt%, 0.04wt%, 0.05wt% or a range formed by any two of them.Since the increase of impurity elements will reduce the performance of the material, the total content of inevitable impurity elements is controlled to be not more than 0.5wt% in the present application; the content of silicon in the die-casting aluminum alloy is adjusted to ensure the forming performance of the aluminum alloy, the content of Cu, Zn, Cr and Sr is adjusted within the range of the present application, and the content of Si, Mg, Fe, Mn, Ti and Al is reasonably controlled to improve the corrosion resistance of the die-casting aluminum alloy.

[0021] In an embodiment of the present application, the mass percentage content of Fe, Mn and Cr in the high corrosion-resistant die-casting aluminum alloy satisfies: Fe:(Mn+Cr)=(0.6-0.8):1. For example, Fe:(Mn+Cr) can be 0.6:1, 0.65:1, 0.7:1, 0.75:1, 0.8:1 or a range composed of any two of the above values. By adjusting Fe:(Mn+Cr) within the above range, the relative balance of the die-casting performance and corrosion resistance of the alloy is ensured.

[0022] In an embodiment of the present application, the phase inside the microstructure of the high corrosion-resistant die-casting aluminum alloy includes eutectic α-Al phase, eutectic Al-Si phase and dispersed phase, the dispersed phase includes at least one of Al8Fe2Si phase, Al8Mg3FeSi6 phase, Al(Fe,Mn)Si phase, Al(Fe,Cr)Si phase, Al6Mn phase or Al3Fe phase. The phase refers to the aggregation state of uniform substances with the same physical and chemical properties and the same composition. The dispersed phase refers to fine and dispersed solid phase. The die-casting aluminum alloy satisfying the above characteristics has the effect of high corrosion resistance compared with commonly used materials.

[0023] In some embodiments, the Al8Fe2Si phase, Al8Mg3FeSi6 phase, Al(Fe,Mn)Si phase and Al(Fe,Cr)Si phase are included in the precipitated phase of the high corrosion-resistant die-casting aluminum alloy.

[0024] In some embodiments, as shown in Figure 1, the precipitated phase includes precipitated phase distributed in a bone-like shape and block shape.

[0025] In some embodiments, the high corrosion resistant die casting aluminum alloy has a tensile strength of 300 MPa to 350 MPa, a yield strength of 150 MPa to 200 MPa, and an elongation of 8% to 10%. For example, the tensile strength can be 300 MPa, 310 MPa, 320 MPa, 330 MPa, 340 MPa, 350 MPa, or a range defined by any two of these values; the yield strength can be 150 MPa, 160 MPa, 170 MPa, 180 MPa, 190 MPa, 200 MPa, or a range defined by any two of these values; and the elongation can be 8%, 8.2%, 8.4%, 8.6%, 8.8%, 9%, 9.2%, 9.4%, 9.6%, 9.8%, 10%, or a range defined by any two of these values. The tensile strength refers to the maximum stress value that the test sample can withstand before breaking, the yield strength refers to the stress value at which the test sample has 0.2% non-proportional elongation, and the elongation refers to the percentage of the total deformation AL of the gauge length section after the test sample is broken.

[0026] In one embodiment of the present application, the high corrosion resistant die casting aluminum alloy is prepared by the following method: 1) placing high-purity Al raw material into a heating furnace, heating to 670-690°C, melting and holding for 14-16 min; 2) heating to 750-770°C, adding Si and Al-Fe alloy raw material; 3) cooling to 720-740°C, adding Al-Cr, Al-Mn, and Al-Ti alloy raw material; 4) cooling to 710-730°C, adding pure Mg, Al-Sr metal material raw material; 5) after melting all the above raw materials, casting to obtain the high corrosion resistant die casting aluminum alloy.

[0027] The high-purity Al raw material is placed into a heating furnace, heated to 670-690°C, and melted and held for 14-16 min. For example, the heating temperature can be 670°C, 672°C, 674°C, 676°C, 678°C, 680°C, 682°C, 684°C, 686°C, 688°C, 690°C, or a range defined by any two of these values; and the melting and holding time can be 14 min, 14.5 min, 15 min, 15.5 min, 16 min, or a range defined by any two of these values.

[0028] The temperature is heated to 750-770°C, and Si and Al-Fe alloy raw material is added. For example, the heating temperature can be 750°C, 752°C, 754°C, 756°C, 758°C, 760°C, 762°C, 764°C, 766°C, 768°C, 770°C, or a range defined by any two of these values.

[0029] cooling to 720-740℃, adding Al-Cr, Al-Mn and Al-Ti alloy raw materials. For example, the cooling temperature can be 720℃, 722℃, 724℃, 726℃, 728℃, 730℃, 732℃, 734℃, 736℃, 738℃, 740℃, or a range formed by any two of them.

[0030] cooling to 710-730℃, adding pure Mg, Al-Sr metal material raw materials. For example, the cooling temperature can be 710℃, 712℃, 714℃, 716℃, 718℃, 720℃, 722℃, 724℃, 726℃, 728℃, 730℃, or a range formed by any two of them.

[0031] In some embodiments, the content of Fe in the Al-Fe alloy is 19-21%, the content of Cr in the Al-Cr alloy is 9.5-10.5%, the content of Mn in the Al-Mn alloy is 9.5-10.5%, the content of Ti in the Al-Ti alloy is 9.5-10.5%, and the content of Sr in the Al-Sr metal material is 9.5-10.5%. For example, the content of Fe in the Al-Fe alloy can be 19%, 19.5%, 20%, 20.5%, 21%, or a range formed by any two of them; the content of Cr in the Al-Cr alloy can be 9.5%, 9.8%, 10.2%, 10.5%, or a range formed by any two of them; the content of Mn in the Al-Mn alloy can be 9.5%, 9.8%, 10.2%, 10.5%, or a range formed by any two of them; the content of Ti in the Al-Ti alloy can be 9.5%, 9.8%, 10.2%, 10.5%, or a range formed by any two of them; the content of Sr in the Al-Sr metal material can be 9.5%, 9.8%, 10.2%, 10.5%, or a range formed by any two of them.

[0032] In some embodiments, the high-purity Al raw material, Si and Al-Fe alloy raw material, Al-Cr alloy raw material, Al-Mn alloy raw material, Al-Ti alloy raw material, pure Mg raw material, and Al-Sr metal material raw material in the present application are all commercially available conventional substances, and the source thereof is not particularly limited in the present application as long as the purpose of the present application can be achieved. For example, the high-purity Al raw material can be a high-purity aluminum ingot, the Si raw material can be selected from at least one of industrial silicon or instant silicon, and the pure Mg raw material can be a magnesium block.

[0033] In the present application, the Cu element is derived from impurity elements in high-purity aluminum, and the Zn element is derived from impurity elements in high-purity aluminum.

[0034] In some embodiments, the rate of temperature increase or decrease is not particularly limited in the present application, as long as the purpose of the present application can be achieved.

[0035] The second aspect of the present application provides a shell type die casting part comprising the high corrosion-resistant die casting aluminum alloy of the first aspect of the present application.

[0036] In an embodiment of the present application, the high corrosion-resistant die casting aluminum alloy is subjected to die casting to form a shell type die casting part.

[0037] In an embodiment of the present application, the shell type die casting part comprises a first surface and a second surface, and the second surface reaches the C5-M corrosive level in the international standard ISO 12944-6 under the condition that the first surface is sealed.

[0038] In some embodiments, the second surface is the surface of the shell type die casting part that is directly exposed to the external atmosphere after assembly, and the first surface is the surface opposite to the second surface.

[0039] In some embodiments, the manner of sealing the first surface is not particularly limited in the present application, as long as the purpose of the present application can be achieved.

[0040] In some embodiments, the neutral salt spray test method is tested according to the international standard ISO 9227 neutral salt spray test method, including but not limited to the following steps: (1) configuring a salt solution: dissolving (5±1) parts of salt in 95 parts of distilled water or deionized water, and the pH value of the solution is within 6.5-7.2; (2) air supply of the salt solution through a spraying device, temperature is (35±2)℃, air relative humidity ≥85%. After the shell type die casting part is exposed in the above area for at least 720h, the shell type die casting part has no white rust, and the coating obtained by passivation powdering has no blistering, peeling, cracking.

[0041] In some embodiments, the condensation test test method is tested according to the international standard ISO 6270-1 condensation test test method, and after the shell type die casting part is exposed in the above area for at least 240h, the shell type die casting part has no white rust, and the coating obtained by passivation powdering has no blistering, peeling, cracking.

[0042] In some embodiments, the detection equipment used in the test method is not particularly limited in the present application, as long as the purpose of the present application can be achieved. For example, it can be observed by visual observation; it can also be observed by magnifying glass.

[0043] In some embodiments, the device and material used in the neutral salt spray test method and the condensation test test method are not particularly limited in the present application, as long as the purpose of the present application can be achieved.

[0044] In an embodiment of the present application, the step of die casting comprises: a) melting the high-corrosion-resistance die casting aluminum alloy at 690-710°C to obtain a molten alloy; b) injecting the molten alloy into a die casting mold by using a pressure injection mode of first low speed and then high speed, the temperature of the die casting mold being 180-220°C, the low speed being 0.2-0.4 m / s, the low speed time being 1.3-1.7 s; the high speed being 4-5 m / s, the high speed time being 0.2-0.4 s, and then leaving the mold, solidifying, demolding, and passivating and powder spraying to obtain a shell type die casting part. By adjusting the process parameters of die casting within the above ranges, the yield of die casting can be improved.

[0045] The high-corrosion-resistance die casting aluminum alloy is melted at 690-710°C to obtain a molten alloy. For example, the melting temperature of the die casting aluminum alloy can be 690°C, 692°C, 694°C, 696°C, 698°C, 700°C, 702°C, 704°C, 706°C, 708°C, 710°C, or a range defined by any two of the above values.

[0046] The molten alloy is injected into a die casting mold by using a pressure injection mode of first low speed and then high speed, the temperature of the die casting mold being 180-220°C, the low speed being 0.2-0.4 m / s, the low speed time being 1.3-1.7 s; the high speed being 4-5 m / s, the high speed time being 0.2-0.4 s, and then leaving the mold, solidifying, demolding, and passivating and powder spraying to obtain a shell type die casting part. For example, the temperature of the die casting mold can be 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, 220°C, or a range defined by any two of the above values; the low speed can be 0.2 m / s, 0.22 m / s, 0.24 m / s, 0.26 m / s, 0.28 m / s, 0.3 m / s, 0.32 m / s, 0.34 m / s, 0.36 m / s, 0.38 m / s, 0.4 m / s, or a range defined by any two of the above values; the low speed time can be 1.3 s, 1.35 s, 1.4 s, 1.45 s, 1.5 s, 1.55 s, 1.6 s, 1.65 s, 1.7 s, or a range defined by any two of the above values; the high speed can be 4 m / s, 4.2 m / s, 4.4 m / s, 4.6 m / s, 4.8 m / s, 5 m / s, or a range defined by any two of the above values; and the high speed time can be 0.2 s, 0.25 s, 0.3 s, 0.35 s, 0.4 s, or a range defined by any two of the above values.

[0047] In some embodiments, the dwell time of the molten alloy in the die casting mold is 4s to 5s, for example, the dwell time can be 4s, 4.2s, 4.4s, 4.6s, 4.8s, 5s, or a range between any two of them.

[0048] In some embodiments, the solidification time of the die casting can be accelerated by connecting the die casting machine back wall part to a high pressure point cooling device.

[0049] In some embodiments, the process flow of the dwell, solidification, demolding, and passivation powder spraying is not particularly limited as long as the purpose of the present application can be achieved.

[0050] In some embodiments, the material for powder spraying in the present application is a conventional material available on the market, and the source thereof is not particularly limited as long as the purpose of the present application can be achieved. For example, the material for powder spraying can be ordinary polyester powder.

[0051] In some embodiments, the thickness of the powder sprayed is 70μm to 100μm. For example, the thickness of the powder sprayed can be 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, 100μm, or a range between any two of them.

[0052] In an embodiment of the present application, the thickness of the shell type die casting part is 1mm to 4mm. For example, the thickness of the shell type die casting part can be 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, or a range between any two of them. By controlling the thickness of the shell type die casting part within the above range, good mechanical properties can be achieved while having a high die casting yield.

[0053] Examples

[0054] Hereinafter, examples and comparative examples are given to more specifically describe the embodiments of the present application. Various tests and evaluations were performed according to the following methods. In addition, unless otherwise specified, "parts" and "%" are based on mass.

[0055] Test methods and equipment:

[0056] Phase testing within the microstructure:

[0057] The die casting aluminum alloy samples in the examples and comparative examples were measured by optical (metallographic) microscopy.

[0058] Using a metallographic microscope for observation, the types of phases (such as primary phase, eutectic phase, dispersed phase, etc.) can be determined by observing the phase morphology, distribution, and other microstructure characteristics, and the determination method is referred to Chapter 10 of the second volume of "Metal Material Metallographic Atlas" (Mechanical Industry Press, first edition in July 2006).

[0059] The C5-M corrosive level test in international standard ISO 12944-6 includes the following:

[0060] Neutral salt spray test:

[0061] The specific test is carried out according to international standard ISO 9227 using a salt spray test chamber.

[0062] Condensation test:

[0063] The specific test is carried out according to international standard ISO 6270-1 using a condensation water test chamber.

[0064] Example 1-1

[0065] <Preparation of high corrosion-resistant die-casting aluminum alloy>

[0066] Before feeding, the furnace is thoroughly cleaned, and the ash is removed. The high-purity aluminum raw materials are weighed and fed into the heating furnace according to the expected alloy composition of Example 1-1 in Table 1 (the rest is Al and unavoidable impurities), heated to 680℃, completely melted and kept for 15 min;

[0067] The temperature is raised to 760℃, and Si and Al-Fe alloy (Al-Fe 20%) are added;

[0068] The temperature is lowered to 730℃, and Al-Cr alloy (Al-Cr 10%), Al-Mn alloy (Al-Mn 10%), and Al-Ti alloy (Al-Ti 10%) are added;

[0069] The temperature is lowered to 720℃, and pure Mg, Al-Sr metal material (Al-Sr 10%) are added;

[0070] After all the above raw materials are melted, they are poured at 720℃ to obtain a high corrosion-resistant die-casting aluminum alloy.

[0071] <Die-casting>

[0072] The high-corrosion-resistance die-casting aluminum alloy obtained in the above step is melted again at 700℃ to obtain a molten alloy; the molten alloy is pre-filled in a barrel by a punch of a die-casting machine, and then is injected into a die-casting mold, the temperature of the die-casting mold is controlled at 200℃, the filling mode of the injection is low speed first and then high speed, the low speed of the injection is 0.3m / s, the low speed time is 1.5s; the high speed of the injection is 4.5m / s, the high speed time is 0.3s, the filling of 1kg of the molten alloy in the die-casting mold cavity is completed within 150ms, the mold is left in the die-casting mold for 4.5s; at the same time, a high-pressure point cooling device is connected to the rear wall part of the die-casting machine to accelerate the solidification time of the product; demolding, conveying through a track, then passivation, and then powder spraying on the second surface by a hot spray gun, the powder spraying thickness is 80μm, to obtain a shell type die-casting part.

[0073] In the high-corrosion-resistance die-casting aluminum alloy, the mass percentage of Si is 8.5wt%, the mass percentage of Mg is 0.6wt%, the mass percentage of Fe is 0.5wt%, the mass percentage of Sr is 0.03wt%, the mass percentage of Mn is 0.6wt%, the mass percentage of Ti is 0.12wt%, the mass percentage of Cr is 0.08wt%, the mass percentage of Cu is 0.025wt%, the mass percentage of Zn is 0.025wt%, and the rest is Al and inevitable impurities. Specifically, as shown in Table 1.

[0074] Examples 1-2 to 1-10

[0075] Except that the relevant parameters are adjusted according to Table 1, the rest is Al and inevitable impurities, and the rest is the same as Example 1-1.

[0076] Comparative Examples 1 to 4

[0077] Except that the relevant parameters are adjusted according to Table 1, the rest is Al and inevitable impurities, and the rest is the same as Example 1-1.

[0078] The preparation parameters and performance parameters of each example and comparative example are shown in Table 1.

[0079] Table 1

[0080] The mass percentage of elements of the die-casting aluminum alloy affects the corrosion resistance of the die-casting aluminum alloy, and the effects of the mass percentages of the elements of the die-casting aluminum alloy on the corrosion resistance of the die-casting aluminum alloy are verified by Examples 1-1 to

[0081] It can be seen from the examples 1-10 and the comparative examples 1-4 that when the die-casting aluminum alloy comprises the elements of Si, Mg, Fe, Sr, Mn, Ti, Cr, Cu, Zn, Al, and the mass percentage of the above elements is within the protection scope of the present application, the prepared die-casting aluminum alloy can reach the C5-M corrosion resistance level test in the international standard ISO12944-6, which shows that the die-casting aluminum alloy prepared by the examples has better corrosion resistance.

[0082] It should be noted that the relational terms herein such as first and second and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any such actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0083] Each of the embodiments in the specification is described in a relevant manner, and the same and similar parts between the embodiments can be referred to each other, and each embodiment mainly explains the difference from other embodiments.

[0084] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A high corrosion resistance die-casting aluminum alloy, comprising the following components in mass percentage: 8-9 wt% of Si, 0.2-1 wt% of Mg, 0.1-1 wt% of Fe, 0.005-0.05 wt% of Sr, 0.2-1 wt% of Mn, 0.05-0.2 wt% of Ti, 0.05-0.15 wt% of Cr, 0-0.05 wt% of Cu, 0-0.05 wt% of Zn, the rest being Al and inevitable impurities, the mass percentage of the inevitable impurities being not more than 0.5 wt%.

2. The high corrosion resistant die cast aluminum alloy of claim 1, wherein, The mass percentage of Fe, Mn and Cr in the high corrosion resistance die-casting aluminum alloy satisfies: Fe:(Mn+Cr)=(0.6-0.8):

1.

3. The high corrosion resistant die cast aluminum alloy of claim 1, wherein, The phase inside the microstructure of the high corrosion resistance die-casting aluminum alloy comprises eutectic α-Al phase, eutectic Al-Si phase and dispersed phase, the dispersed phase comprising at least one of Al8Fe2Si phase, Al8Mg3FeSi6 phase, Al(Fe,Mn)Si phase, Al(Fe,Cr)Si phase, Al6Mn phase or Al3Fe phase.

4. The high corrosion-resistant die cast aluminum alloy of any one of claims 1 to 3, wherein, The high corrosion resistance die-casting aluminum alloy is prepared by the following method: 1) putting high-purity Al raw material into a heating furnace, heating to 670-690℃, melting and keeping for 14-16 min; 2) heating to 750-770℃, adding Si and Al-Fe alloy raw material; 3) cooling to 720-740℃, adding Al-Cr, Al-Mn and Al-Ti alloy raw material; 4) cooling to 710-730℃, adding pure Mg, Al-Sr metal material raw material; 5) after melting all the above raw materials, casting to obtain the high corrosion resistance die-casting aluminum alloy. 5.A shell type die-casting part comprising the high corrosion resistance die-casting aluminum alloy according to any one of claims 1-4.

6. The housing class die cast part of claim 5, wherein, The high corrosion resistance die-casting aluminum alloy is subjected to die-casting forming to make the shell type die-casting part.

7. The housing class die cast part of claim 5, wherein, The shell type die-casting part comprises a first surface and a second surface, the second surface reaching C5-M corrosive level in international standard ISO12944-6 under the condition that the first surface is sealed.

8. The housing class die cast part of claim 6, wherein, The step of die-casting forming comprises: a) melting the high corrosion resistance die-casting aluminum alloy at 690-710℃ to obtain molten alloy; b) using the injection mode of low-speed first and high-speed later to inject the molten alloy into a die-casting mold, the temperature of the die-casting mold being 180-220℃, the low-speed being 0.2-0.4 m / s, the low-speed time being 1.3-1.7 s; the high-speed being 4-5 m / s, the high-speed time being 0.2-0.4 s, and then leaving the mold, solidifying, demolding and passivating powder spraying to obtain the shell type die-casting part.

9. The housing class die cast part of claim 5, wherein, The thickness of the shell type die-casting part is 1-4 mm.

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