4571D high-silicon zinc-aluminum alloy continuous cast-rolling process and cast-rolling equipment

Abstract

The invention provides a continuous casting method of 4571D high-silicon zinc-aluminum alloy. The continuous casting method comprises the following steps: preparing the following components in parts by weight: 2.25-2.65% of Si, less than or equal to 0.05% of Mg, less than or equal to 0.25% of Fe, less than or equal to 0.035% of Cu, less than or equal to 1.1-1.3% of Mn, less than or equal to 1.4-1.6% of Zn, less than or equal to 0.05% of Ti, less than or equal to 0.05% of Cr, less than or equal to 0.05% of other impurities, less than 0.15% of the sum of other impurities, and the balance of Al and other inevitable impurities; and through alloy component optimization and process control, the problems that a traditional aluminum alloy is insufficient in strength, poor in wear resistance and uneven in grain structure in the casting process are solved, and meanwhile the electric conductivity and the mechanical performance are improved. The invention further provides casting equipment of the 4571D high-silicon zinc-aluminum alloy. The casting equipment comprises a batching device, a smelting furnace, a cast rolling unit and a rapid cooling device.

Description

TECHNICAL FIELD

[0001] The present application relates to a 4571D high-silicon zinc-aluminum alloy continuous casting and rolling process and a casting and rolling device. BACKGROUND

[0002] Aluminum alloys are widely used in industrial fields, especially in the automotive, aerospace, electronics and electrical industries, due to their excellent mechanical properties, corrosion resistance and recyclability. With the rapid development of new energy and new infrastructure industries, the comprehensive performance requirements of aluminum alloy materials are continuously increasing, requiring higher electrical conductivity, strength and wear resistance.

[0003] However, traditional aluminum alloy materials still have some limitations in meeting these emerging needs. For example, conventional Al-Mg-Si series aluminum alloys have good extrusion processing performance and oxidation coloring effect, but their strength is generally low, making it difficult to meet the needs of high-strength application scenarios. In addition, existing zinc-aluminum alloys have simple composition and uncontrolled microstructure, resulting in poor wear resistance, limiting their further application in wear-resistant fields. In particular, during continuous casting, traditional process control methods are difficult to accurately monitor the grain refinement direction, which can easily lead to uneven alloy organization and affect the mechanical properties of the final product. At the same time, existing casting equipment also has deficiencies in terms of batching accuracy, melt uniformity and cooling control, which restricts the industrial production of high-performance aluminum alloys.

[0004] Therefore, developing a new type of aluminum alloy material and its preparation method and special equipment to meet the multiple requirements of high electrical conductivity, high strength, excellent oxidation performance, etc. has become an important direction of current aluminum alloy material research. This requires innovation in the chemical composition, heat treatment process and processing technology of aluminum alloys to achieve overall improvement of material performance and meet the application requirements of different fields. SUMMARY

[0005] The purpose of the present application is to solve the above problems of the prior art and provide a 4571D high-silicon zinc-aluminum alloy continuous casting and rolling process and a casting and rolling device. By optimizing the alloy composition and process control, the problems of insufficient strength, poor wear resistance and uneven grain organization during the casting process of traditional aluminum alloys are solved, and the electrical conductivity and mechanical properties are improved. The purposes of the present application are achieved as follows:

[0006] In one aspect, the present application provides a 4571D high-silicon zinc-aluminum alloy, which is composed of the following components by mass percentage: Si 2.25-2.65%, Mg ≤0.05%, Fe ≤0.25%, Cu ≤0.035%, Mn ≤1.1-1.3%, Zn ≤1.4-1.6%, Ti ≤0.05%, Cr ≤0.05%, other impurities less than 0.05% individually, the sum of other impurities less than 0.15%, and the balance of Al and inevitable other impurities.

[0007] In another aspect, the present application provides a continuous casting method for manufacturing the 4571D high-silicon zinc-aluminum alloy, which comprises the following steps: step one, preparing the raw materials according to the following components by weight percentage: Si 2.25-2.65%, Mg ≤0.05%, Fe ≤0.25%, Cu ≤0.035%, Mn ≤1.1-1.3%, Zn ≤1.4-1.6%, Ti ≤0.05%, Cr ≤0.05%, other impurities less than 0.05% individually, the sum of other impurities less than 0.15%, and the balance of Al and inevitable other impurities; step two, heating the prepared raw materials in an electric arc furnace to 720°C, maintaining for 2.5 hours, stirring uniformly, and detecting the purity; step three, pouring the melt into a preheated mold at 695-720°C, monitoring the grain refinement direction in real time through an infrared thermal imager, controlling the casting and rolling temperature, and detecting the rolling force through a main sensor; step four, rapid cooling through water at a flow rate of 100-160 l / s and a temperature of 16-60°C, and detecting through a thermocouple and a data acquisition system; step five, detecting the earing rate, checking the grain structure, and ensuring the uniform distribution of the grains.

[0008] Further, a sodium-free refining agent is added during the heating process in step two.

[0009] Further, between step four and step five, a double-stage filter plate is used for filtering, and a 40+60 ppi double-stage filter plate is selected for filtering.

[0010] Further, step six is included, which is to perform ice water quenching after solid solution heat treatment of the alloy cold-rolled plate at 530-580°C for 4-6 minutes, and then artificial aging at 160-175°C for 1.8-2.5 hours, so as to obtain an Al-Mg-Si alloy with fine and uniformly distributed grains.

[0011] Further, inert gas protection is used in the electric arc furnace heating process in step two, the argon flow rate and temperature are controlled, and the oxygen content in the melt is reduced to prevent the oxidation reaction of the aluminum alloy.

[0012] Further, the water cooling process in step four uses a two-stage cooling device, the first stage uses high flow rate cooling water to rapidly reduce the alloy temperature, and the second stage uses low flow rate cooling water to maintain the balance of the alloy temperature, reducing the internal stress and deformation generated during the cooling process.

[0013] In another aspect, the application provides a casting device for manufacturing 4571D high-silicon zinc-aluminum alloy, comprising: a batching device for automatically weighing and feeding aluminum alloy raw materials according to mass percentage; a melting furnace connected with the batching device for heating the prepared aluminum alloy raw materials to form a uniform melt; a casting and rolling unit including a set of casting and rolling rolls; and a rapid cooling device arranged at a predetermined position of the casting and rolling unit for rapid cooling of the strip-shaped aluminum alloy blank.

[0014] Compared with the prior art, the application has the beneficial effects that: by precisely controlling the alloy component ratio and continuous casting process parameters, combined with real-time monitoring and multi-stage cooling technology, the grain refinement direction and organizational uniformity are effectively improved, thereby improving the strength, wear resistance and electrical conductivity of the material, and the comprehensive performance is stronger than that of traditional aluminum alloy. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a flowchart of a 4571D high-silicon zinc-aluminum alloy continuous casting and rolling method. DETAILED DESCRIPTION

[0016] In order to deepen the understanding of the application, the application will be further described below in conjunction with the embodiments and drawings, which are only used to explain the application and do not constitute a limitation on the protection scope of the application.

[0017] In the prior art, aluminum alloy materials are widely used in the fields of automobiles, aerospace, etc., but the traditional Al-Mg-Si series aluminum alloy has the problems of insufficient strength and poor wear resistance. Conventional zinc-aluminum alloy is difficult to meet the performance requirements under high load working conditions due to simple component design and inaccurate microstructure control. For example, automobile engine parts require materials to have high wear resistance and fatigue resistance, and existing materials are prone to surface wear and crack propagation during long-term use.

[0018] In order to solve the above problems, it is necessary to develop a new type of aluminum alloy to improve the performance by optimizing the proportion of alloy elements. Research shows that silicon can significantly improve the hardness and wear resistance of the alloy, but excessive addition will increase the brittleness. The synergistic effect of manganese and zinc can enhance the solid solution strengthening effect, and the content of impurity elements such as iron and copper needs to be strictly controlled to avoid corrosion at the grain boundary. By balancing the proportion of each element, the comprehensive mechanical properties can be improved on the premise of ensuring the processing performance.

[0019] Therefore, the present application proposes an aluminum alloy consisting of the following mass percentages: silicon content of 2.25-2.65%, not more than 0.05% of magnesium, not more than 0.25% of iron, not more than 0.035% of copper, manganese content of 1.1-1.3%, zinc content of 1.4-1.6%, not more than 0.05% of titanium and chromium, less than 0.05% of other single impurities, less than 0.15% of total impurities, and the balance of aluminum and unavoidable impurities.

[0020] The silicon content range of 2.25-2.65% is based on the consideration of balancing hardness and toughness, for example, when the silicon content is less than 2.25%, the wear resistance is insufficient, and when it exceeds 2.65%, the material brittleness will significantly increase. Controlling the manganese content in the range of 1.1-1.3% can effectively improve the solid solution strengthening effect, while avoiding excessive manganese elements causing lattice distortion. Limiting the zinc content in the range of 1.4-1.6% can not only improve the strength through solid solution strengthening, but also prevent the corrosion resistance from decreasing due to zinc segregation. Strictly limiting impurity elements such as iron and copper is to reduce the risk of intergranular corrosion and ensure the electrical conductivity.

[0021] Specifically, the alloy forms uniform distribution of strengthening phases in the aluminum matrix by precisely controlling the synergistic ratio of main elements such as silicon, manganese, and zinc. For example, the eutectic structure formed by silicon and aluminum can improve the surface hardness of the material, and the solid solution strengthening effect of manganese and zinc enhances the matrix strength. Strict control of impurity elements ensures the purity of the material organization, so that the alloy has excellent wear resistance and fatigue strength while maintaining good electrical conductivity.

[0022] Compared with the prior art, the manganese content of conventional Al-Mg-Si alloy is usually less than 0.8%, and the zinc content is usually controlled below 0.5%, which makes it difficult to break through 300MPa in strength index. By increasing the content of manganese and zinc and optimizing the silicon ratio, the present application improves the tensile strength by about 15% while maintaining good ductility. In addition, the control standard of impurity elements such as iron and copper in the prior art is relatively loose, and a single impurity is usually allowed to reach 0.1%, which will affect the corrosion resistance of the material. By more strictly controlling the impurities, the present application prolongs the corrosion resistance time of the alloy in the salt spray environment by more than 30%.

[0023] Through the above technical solutions, the present application effectively solves the problem that the strength and wear resistance of traditional aluminum alloy are difficult to be considered. The Vickers hardness of the alloy can reach more than 120HV while the elongation rate is maintained in a reasonable range of 8-10% on the basis of maintaining good electrical conductivity. It is particularly suitable for manufacturing mechanical parts that need to withstand high-frequency friction, such as automobile engine piston rings, which can still maintain stable friction coefficient and wear resistance under high-temperature working conditions.

[0024] Further, the heating process in step two adds sodium-free refining agent; the step four and step five also includes the use of double-stage filter plate filtering, filter when choosing 40+60 ppi double-stage filter plate; also includes step six: the alloy cold-rolled plate in 530-580 ℃ solid solution heat treatment 4-6 minutes after ice water quenching, and then in 160-175 ℃ artificial aging 1.8-2.5 hours, to obtain grain size small, uniform distribution of Al-Mg-Si alloy; the arc furnace heating process in step two uses inert gas protection, by controlling the argon flow and temperature, reduce the content of oxygen in the melt, to prevent the oxidation of aluminum alloy; the water cooling process in step four uses two-stage cooling device, the first stage uses higher flow rate of cooling water to rapidly reduce the alloy temperature, the second stage uses low flow rate cooling water to maintain the balance of alloy temperature, reduce the internal stress and deformation generated in the cooling process.

[0025] It should be noted that the arc furnace is heated to 720℃, which means that the alloy raw materials are melted at a specific temperature, which can be achieved by using an arc furnace with a temperature feedback control system. This temperature range is beneficial for promoting the full diffusion of alloy elements. The real-time monitoring of the grain refinement direction by the infrared thermal imager means that the solidification process of the melt is tracked by non-contact thermal imaging technology. This can be achieved by using a high-resolution infrared sensor to dynamically adjust the casting and rolling parameters to optimize the grain structure. The water quenching flow rate is controlled at 100-160 l / s, which means that rapid cooling is achieved by adjusting the cooling water flow rate. This can be achieved by using a variable frequency water pump and flow meter linkage control. This flow rate range can balance the cooling efficiency and material stress. Sodium-free refining agent means that the melt purification material does not contain sodium elements. This can be achieved by using a mixture of fluoroaluminate or chloride. It is added to the melt by mechanical stirring or gas injection. This substance can effectively absorb the gas and inclusions in the melt, avoiding the brittle interfacial weakening caused by residual sodium elements. The double-stage filter plate is a composite structure composed of two different pore densities of filter layers. This can be achieved by using a coarse filter layer and a fine filter layer in a stacked manner. The coarse filter layer is used to intercept large-sized inclusions, and the fine filter layer is used to remove small particles. 40+60 ppi represents the combination of the pore density of the filter plate. Specifically, a coarse filter layer with 40 pores per square inch and a fine filter layer with 60 pores per square inch are used together to achieve the step-by-step removal of different sizes of impurities in the melt. Solid solution heat treatment means that the alloy is heated to a specific temperature range to make the strengthening phase fully dissolve in the aluminum matrix. This can be achieved by using a box-type resistance furnace or a continuous heat treatment furnace. The temperature in the furnace is monitored in real time by a temperature sensor. Argon flow control means that the gas input rate is dynamically adjusted according to the pressure change in the arc furnace. This can be achieved by using a pressure sensor and a flow regulating valve in a linkage manner to maintain a slight positive pressure in the furnace. The two-stage cooling device is a cooling system that contains different flow rate control modules. This can be achieved by using parallel pipelines and independent valve adjustment to control the temperature gradient by adjusting the water flow rate in stages. The higher flow rate of the cooling water refers to the water flow rate in the range of 100-160 liters per second. This can be achieved by using a booster pump and a large-diameter nozzle to quickly remove heat from the alloy surface. The low flow rate of the cooling water refers to the water flow rate in the range of 16-60 liters per second. This can be achieved by using a throttle valve and a small-diameter nozzle to maintain the uniformity of the alloy internal temperature.

[0026] In another aspect, the present application proposes a casting equipment for manufacturing 4571D high-silicon zinc-aluminum alloy, comprising: a batching device for automatically weighing and feeding aluminum alloy raw materials according to mass percentage; a melting furnace connected with the batching device for heating the prepared aluminum alloy raw materials to form a uniform melt; a casting and rolling unit including a set of casting and rolling rolls; a rapid cooling device arranged at a predetermined position of the casting and rolling unit for rapidly cooling the strip-shaped aluminum alloy blank.

[0027] Wherein, the batching device refers to an automated equipment capable of realizing accurate proportioning of raw materials, which can be specifically realized by using a feeding mechanism with a weighing sensor and a PLC control system, the melting furnace refers to a heating device capable of converting solid raw materials into liquid alloy, which can be specifically realized by using an electric resistance or induction type heating furnace body in cooperation with a stirring mechanism, and through temperature closed-loop control, the composition of the melt is ensured to be uniform, the casting and rolling unit refers to a forming device for processing molten metal into strip-shaped blank, which can be specifically realized by using an upper and lower roller set in cooperation with a hydraulic drive system, and through adjusting the roller gap distance, the thickness of the blank is controlled, and the rapid cooling device refers to a quenching system capable of realizing rapid cooling of alloy materials, which can be specifically realized by using a multi-stage type spraying water cooling mechanism in cooperation with a temperature feedback module, and through adjusting the water flow speed and distribution mode, the cooling rate is controlled.

[0028] Specifically, after the batching device completes the proportioning of raw materials through an automated weighing system, the mixed material is delivered to the melting furnace for heating and melting, and after the melt is fully stirred, it is transferred to the casting and rolling unit for continuous rolling and forming, and in the casting and rolling process, the rapid cooling device implements controllable quenching on the just-formed strip-shaped blank, so that the alloy microstructure forms a fine grain structure in the solidification process, the melting furnace and the batching device are directly connected, which can reduce the composition deviation caused by the intermediate transfer link, and the synergistic effect of the casting and rolling roller set and the cooling device can inhibit the stress concentration in the material.

[0029] Compared with the prior art, the traditional casting equipment usually adopts manual batching and batch melting mode, which is easy to cause composition fluctuation and oxidation inclusion, the present scheme combines automatic batching and continuous casting process, which can realize accurate control of alloy composition, and the rapid cooling device can avoid organizational defects caused by uneven cooling rate through phased temperature control technology, in addition, the integrated design of the melting furnace and the casting and rolling unit reduces heat energy loss and improves production efficiency.

[0030] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present application and are not limiting, although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the purpose and scope of the present application, which should be covered in the scope of the claims of the present application.

Claims

1. A 4571D high-silicon zinc-aluminum alloy characterized in that, The alloy comprises the following ingredients by mass percentage: Si 2.25-2.65%, Mg≤0.05%, Fe≤0.25%, Cu≤0.035%, Mn≤1.1-1.3%, Zn≤1.4-1.6%, Ti≤0.05%, Cr≤0.05%, other impurities less than 0.05% individually, the sum of other impurities less than 0.15%, and the balance of Al and inevitable other impurities.

2. A continuous casting method of producing a 4571D high-silicon zinc-aluminum alloy as claimed in claim 1, characterized by, The method comprises the following steps: Step one: preparing the alloy according to the mass percentage of the following ingredients: Si 2.25-2.65%, Mg≤0.05%, Fe≤0.25%, Cu≤0.035%, Mn≤1.1-1.3%, Zn≤1.4-1.6%, Ti≤0.05%, Cr≤0.05%, other impurities less than 0.05% individually, the sum of other impurities less than 0.15%, and the balance of Al and inevitable other impurities; Step two: heating the prepared raw materials to 720℃ in an electric arc furnace, maintaining for 2.5 hours, stirring uniformly, and detecting purity; Step three: pouring the melt into a preheated casting mold at 695-720℃, monitoring the grain refinement direction in real time through an infrared thermal imager, controlling the casting and rolling temperature, and detecting the rolling force through a main sensor; Step four: rapid cooling through water at a flow rate of 100-160l / s, with the water temperature controlled at 16-60℃, and detecting through a thermocouple and a data acquisition system; Step five: detecting the earing rate, checking the grain structure, and ensuring uniform distribution of the grains.

3. The method of continuously casting a 4571D high-silicon zinc-aluminum alloy of claim 2, wherein, The heating process in step two is performed with the addition of a sodium-free refining agent.

4. The method of continuously casting a 4571D high-silicon zinc-aluminum alloy of claim 2, wherein, Between step four and step five, a double-stage filter plate is further used for filtering, and a 40+60 ppi double-stage filter plate is selected for filtering.

5. The method of continuously casting a 4571D high-silicon zinc-aluminum alloy of claim 2, wherein, Step six: after the alloy cold-rolled plate is subjected to solid solution heat treatment at 530-580℃ for 4-6 minutes, ice water quenching is performed, and then artificial aging is performed at 160-175℃ for 1.8-2.5 hours, so as to obtain an Al-Mg-Si alloy with small and uniformly distributed grain size.

6. The method of continuously casting a 4571D high-silicon zinc-aluminum alloy of claim 2, wherein, In the electric arc furnace heating process in step two, inert gas protection is adopted, the oxygen content in the melt is reduced by controlling the argon flow rate and temperature, and the oxidation reaction of the aluminum alloy is prevented.

7. The method of continuously casting a 4571D high-silicon zinc-aluminum alloy of claim 2, wherein, In the water cooling process in step four, a two-stage cooling device is used, a higher flow rate of cooling water is used in the first stage to rapidly reduce the alloy temperature, and a low flow rate of cooling water is used in the second stage to maintain the balance of the alloy temperature, so as to reduce the internal stress and deformation generated in the cooling process.

8. A casting apparatus for producing the 4571D high-silicon zinc-aluminum alloy of claim 1, characterized by, The method comprises the following steps: a melting furnace connected with the batching device, used for heating the prepared aluminum alloy raw materials to form a uniform melt; a casting and rolling unit comprising a casting and rolling roller set; a rapid cooling device arranged at a preset position of the casting and rolling unit, used for rapidly cooling the strip-shaped aluminum alloy blank.

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