3-series high-iron-manganese-aluminum alloy, cast rolling method thereof and heat exchange fin

Abstract

The invention provides a 3-series high-iron-manganese-aluminum alloy and a cast rolling method and a heat exchange fin thereof, the cast rolling method comprises the following steps: (1) after alloy ingredients are smelted, an obtained alloy melt enters a front box for heat preservation, and the alloy contains at least 0.4 wt% of Fe and at least 1.2 wt% of Mn; (2) the alloy melt subjected to heat preservation in the front box is fed into a casting nozzle, a flow dividing cushion block is arranged in the casting nozzle, and the surface roughness parameter Ra of the flow dividing cushion block is smaller than or equal to 4.5 micrometers; and (3) the alloy melt flowing out of the casting nozzle is conveyed to a roller to be cast and rolled, cast-rolled blanks are obtained after the alloy melt is sequentially cooled and rolled through the roller, and the problem that thick aluminum-manganese or aluminum-manganese-iron compounds appear in the cast-rolling process of the 3-series high-iron-manganese-aluminum alloy can be solved.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy casting and rolling technology, and in particular to a 3-series high-iron manganese aluminum alloy, its casting and rolling method, and heat exchange fins. Background Technology

[0002] In 3-series aluminum alloys, manganese (Mn) is the sole main alloying element. Mn and Al can form the MnAl6 phase, and the strength of the alloy increases with increasing Mn content. However, high Mn content easily leads to the formation of large amounts of brittle MnAl6 compounds. Furthermore, Fe can dissolve in MnAl6 to form (FeMn)Al6 compounds, and the addition of large amounts of Fe and Mn can also easily lead to the formation of large amounts of coarse, lamellar (FeMn)Al6 compounds. Reducing the content of Fe and Mn elements typically requires ensuring that the Fe content is within the range of 0.4%-0.7% and the Mn content is within the range of 1.0%-1.6%, but the Fe+Mn content must not exceed 1.85% to reduce the formation of a large number of coarse compounds during the casting and rolling process. This can effectively refine the grains after annealing the plate. Otherwise, a large number of coarse, lamellar (FeMn)Al6 compounds will be formed. The presence of these coarse compounds will lead to appearance problems of the finished product. In particular, the presence of coarse compounds ≥80μm will cause the presence of large surface pores. When center segregation occurs, there are too many coarse compounds greater than 20μm on the segregation band. This segregation band will also lead to the appearance problem of the finished product with obvious surface pores.

[0003] However, when the Fe content is greater than 0.7%, the material's electrical conductivity can be improved by 4% IACS compared to when the Fe content is 0.4%. Since electrical conductivity is directly proportional to the material's heat exchange rate, this means that a material with higher heat exchange capacity has been obtained. When the Mn content is greater than 1.2%, it can be used to produce high-strength alloy fins with tensile strength of over 190 MPa.

[0004] When casting a 3-series high-iron-manganese alloy, although fins with high heat exchange capacity and high strength can be obtained, a large number of coarse aluminum-manganese or aluminum-manganese-iron compounds will inevitably be formed. The presence of these coarse compounds will lead to fin stamping cracks and shorten the service life of the radiator. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a 3-series high-iron manganese-aluminum alloy, its casting and rolling method, and heat exchange fins, which can reduce the problem of coarse aluminum-manganese or aluminum-manganese-iron compounds appearing during the casting and rolling process of the 3-series high-iron manganese-aluminum alloy.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a casting and rolling method for a 3-series high-iron manganese-aluminum alloy, the casting and rolling method comprising the following steps:

[0008] (1) After the alloy ingredients are smelted, the resulting alloy melt enters the front box for heat preservation. The alloy contains at least 0.4 wt% Fe and at least 1.2 wt% Mn.

[0009] (2) The alloy melt after being insulated in the front box is fed into the casting nozzle. A flow divider block is provided in the casting nozzle. The surface roughness parameter Ra of the flow divider block is ≤4.5μm.

[0010] (3) The alloy melt flowing out of the casting nozzle is transported to the rolls for casting and rolling, and then cooled and rolled in sequence to obtain the cast billet.

[0011] In conventional casting and rolling processes for producing 3-series aluminum alloy sheets, the melt temperature is typically between 685-710℃. Extensive casting and rolling practices have shown that lower temperatures result in finer grains in the cast strip and allow for higher casting speeds, improving productivity. Higher temperatures, however, lead to surface defects such as hot spots and coarse grains. The inventors discovered that Fe and Mn elements in the system readily form coarse intermetallic compounds (compounds with a size of 80 μm or larger) over a relatively long period at rough nucleation sites and lower temperatures. Typically, those skilled in the art believe that such coarse intermetallic compounds originate from the casting and rolling process and are therefore unavoidable. Experimental analysis revealed that the reason for the formation of such coarse intermetallic compounds in conventional casting and rolling processes is that the melt remains in a region suitable for intermetallic compound growth within the casting nozzle for an extended period during the aluminum melt distribution and conveying section, rather than originating from the casting and rolling process itself.

[0012] There are two main reasons for the formation of large, coarse intermetallic compounds in the aluminum melt diversion and conveying section: First, diversion blocks need to be set in the casting nozzle to divert the aluminum melt and achieve uniform filling. However, the blocks are prone to carbonization and detachment in this area, which in turn makes it easy for intermetallic compounds to form nucleation sites. Second, there is aluminum melt swirling in this area, causing the melt to remain for a long time. The temperature of the melt drops locally here, and this temperature environment is suitable for the growth of intermetallic compounds.

[0013] Due to the flow diversion requirements of the casting nozzle mold design, it is unavoidable to install flow diversion blocks in the casting nozzle mold of the casting and rolling mill. Therefore, it is inevitable that an aluminum melt swirling zone will form around this area. The temperature of the aluminum melt in this swirling zone will decrease due to the relatively long residence time. The inventors discovered that coarse compounds mainly form in this area. Therefore, by adjusting the process to minimize the nucleation of metal compounds in this section, reducing excessively low temperatures, and minimizing excessively long residence times, the formation of coarse compounds can be effectively reduced or even avoided.

[0014] The material of the shim in this invention is a flow divider shim with a low surface friction coefficient at high temperature (720℃). Existing conventional flow divider shims are made of aluminum silicate, which is prone to edge carbonization in the high temperature aluminum liquid immersion environment, resulting in increased roughness of the carbonized area, aluminum dross on the shim, and the formation of metal compound nucleation points. When a flow divider shim with a low surface friction coefficient is used, this problem is effectively improved.

[0015] Specifically, the Fe content in the alloy is at least 0.4 wt%, for example, it can be 0.4 wt%, 0.42 wt%, 0.43 wt%, 0.44 wt%, 0.45 wt%, 0.48 wt%, 0.5 wt%, 0.52 wt%, 0.55 wt%, 0.58 wt%, 0.6 wt%, 0.62 wt%, 0.65 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, or 1.0 wt%, etc.

[0016] Mn is at least 1.2 wt%, and can be, for example, 1.2 wt%, 1.25 wt%, 1.3 wt%, 1.35 wt%, 1.4 wt%, 1.45 wt%, 1.5 wt%, 1.55 wt%, 1.6 wt%, 1.65 wt%, or 1.7 wt%, etc.

[0017] The surface roughness parameter Ra of the flow divider block is ≤4.5μm, for example, it can be 4.5μm, 4.4μm, 4.35μm, 4.3μm, 4.25μm, 4.2μm, 4.15μm, 4.1μm, 4.0μm, 3.9μm, 3.85μm, 3.8μm, 3.75μm or 3.7μm, etc.

[0018] Preferably, the temperature of the front box insulation in step (1) is 715 to 720°C, for example, it can be 715°C, 715.6°C, 716.2°C, 716.7°C, 717.3°C, 717.8°C, 718.4°C, 718.9°C, 719.5°C or 720°C.

[0019] Currently, the melt temperature is generally controlled at 700-710℃. The melt temperature is relatively low in this range, which causes the melt to be distributed in the low temperature region when it enters the diversion pad area, providing time for the metal compound to grow. To increase the melt temperature, the melt temperature at the outlet of step (1) is controlled at 715-720℃. If the temperature is too high, such as 730℃, it will lead to production risks and make production impossible.

[0020] Preferably, in step (2), the flow rate of the alloy melt when the fluid in the casting nozzle enters the flow divider block is above 2.8 m / min, for example, it can be 2.8 m / min, 2.9 m / min, 3 m / min, 3.1 m / min or 3.2 m / min, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0021] When the fluid enters the distribution pad, the melt flow rate is increased to above 2.8 m / min to reduce the residence time in the aluminum swirling zone. The relatively low melt flow rate results in a longer time for the melt in the low-temperature zone within the distribution pad area, providing more time for the metal compounds to grow.

[0022] Preferably, the shunt pad in step (2) is made of aluminum silicate with a boron nitride coating on its surface.

[0023] When a flow divider with a low surface friction coefficient of aluminum silicate coated with boron nitride is selected, the edge carbonization problem is improved and the number of metal compound nucleation sites is reduced.

[0024] Preferably, the water temperature for casting and rolling in step (3) is controlled to be ≤20℃, for example, it can be 15℃, 16℃, 17℃, 18℃, 19℃ or 20℃, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0025] Preferably, the distance between the leading edge of the casting nozzle and the rolling center line of the two rolls in the casting and rolling process is defined as the casting and rolling zone, and the length of the casting and rolling zone is ≤61mm, for example, it can be 55mm, 55.7mm, 56.4mm, 57mm, 57.7mm, 58.4mm, 59mm, 59.7mm, 60.4mm or 61mm, etc.

[0026] This invention effectively avoids the formation of coarse compounds by improving the temperature of the front box, the flow rate of the alloy melt, and the material of the diversion pad. However, the temperature of the alloy melt at the outlet in step (2) is relatively high, which makes it easy to aggravate the billet center segregation problem in step (3) when using conventional ambient water cooling water (ambient water temperature about 25-35℃). When center segregation occurs, the presence of the eutectic region easily triggers the formation of coarse compounds, but the size of the coarse compounds produced by the casting nozzle is smaller, generally 20-60μm. Under conventional processes, the temperature of the melt entering the casting and rolling zone is relatively low, so the center segregation problem under the existing process is not significant. However, after the process of the aluminum melt diversion and conveying section is adjusted, it is found that the center segregation problem in the casting and rolling zone is aggravated under the existing casting and rolling process, which affects the material performance to a certain extent. The inventors set the cooling water temperature of the rolls to ≤20℃ and the casting and rolling zone length to ≤61mm in step (3), which can effectively solve the appearance problem and improve the billet center segregation problem.

[0027] Preferably, the alloy ingredients consist of 0.4 wt% ≤ Fe ≤ 1.0 wt% and 1.2 wt% ≤ Mn ≤ 1.7 wt% by mass percentage.

[0028] Mn content greater than 1.2% can be used to produce high-strength alloys with tensile strengths above 190 MPa. If a 3-series high-iron manganese-aluminum alloy is to be cast and rolled, although fins with high heat exchange capacity and high strength can be obtained, the existing casting and rolling methods will inevitably form a large number of coarse aluminum-manganese or aluminum-manganese-iron compounds. The presence of these coarse compounds will lead to fin stamping cracks and shorten the service life of the radiator. The casting and rolling method provided by this invention can improve the problem of coarse compounds in high-iron manganese-aluminum alloys.

[0029] Preferably, the alloy composition comprises 0.7 wt% ≤ Fe ≤ 1.0 wt% by mass.

[0030] When the Fe content is greater than 0.7%, the electrical conductivity of the material will be increased by 4% IACS compared to when the Fe content is 0.4%. Since the electrical conductivity is proportional to the heat exchange rate of the material, it means that a material with higher heat exchange capacity is obtained. Furthermore, the casting and rolling method provided by this invention improves the problem of coarse compounds.

[0031] Secondly, the present invention provides a 3-series high-iron manganese-aluminum alloy, wherein the 3-series high-iron manganese-aluminum alloy is prepared by the casting and rolling method of the 3-series high-iron manganese-aluminum alloy described in the first aspect.

[0032] Thirdly, the present invention provides a heat exchange fin, wherein the heat exchange fin is made of the 3-series high-iron manganese aluminum alloy described in the second aspect.

[0033] Compared with the prior art, the present invention has at least the following beneficial effects:

[0034] The casting and rolling method for 3-series high-iron manganese-aluminum alloys provided by this invention can avoid the problem of coarse aluminum-manganese or aluminum-manganese-iron compounds appearing during the casting and rolling process of 3-series high-iron manganese-aluminum alloys. The number of coarse compounds with a diameter greater than or equal to 80 μm in the obtained 3-series high-iron manganese-aluminum alloy is less than 5 per 100 mm. 2 Within this range, the number of compounds with a size of 20-80 μm is 37 per 100 mm. 2 Within a certain range, the electrical conductivity is above 48.3 IACS%, and the tensile strength is above 200 MPa. Attached Figure Description

[0035] Figure 1 This is an appearance diagram of the 3-series high-iron manganese-aluminum alloy provided in Embodiment 2 of the present invention.

[0036] Figure 2 This is an appearance diagram of the 3-series high-iron manganese-aluminum alloy provided in Comparative Example 1 of the present invention. Detailed Implementation

[0037] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0038] As a specific embodiment of the present invention, a casting and rolling method for a 3-series high-iron manganese-aluminum alloy is provided, the casting and rolling method comprising the following steps:

[0039] (1) The alloy batches are smelted at 760-780℃, and after degassing and slag removal, the resulting alloy melt enters the front box for heat preservation, and the temperature of the front box is controlled at 715-720℃.

[0040] (2) The alloy melt after being insulated in the front box is fed into the casting nozzle. A flow divider block is provided in the casting nozzle to ensure that the melt is filled evenly and to prevent the aluminum liquid on both sides from failing to converge and causing perforation on the plate surface. The material of the flow divider block is aluminum silicate sprayed with boron nitride, and its surface roughness Ra≤4.5μm. The flow rate of the alloy melt before the flow divider block in the casting nozzle is controlled to be above 2.8m / min.

[0041] (3) The alloy melt flowing out from the casting nozzle is transported to the rolls for casting and rolling. The water temperature of the casting and rolling is controlled below 20℃. The distance between the front edge of the casting nozzle and the rolling center line of the two rolls is called the casting and rolling zone. The length of the casting and rolling zone is ≤61mm. After being cooled and rolled by the rolls, the casting and rolling billet is obtained.

[0042] The 3-series high-iron manganese-aluminum alloy of this invention, by mass percentage, comprises the following alloying elements: 0.8wt%≤Si≤1.2wt%, 0.4wt%≤Fe≤1.0wt%, 1.2wt%≤Mn≤1.7wt%, 0.5wt%≤Zn≤1.7wt%, preferably 0.7wt%≤Fe≤1.0wt%.

[0043] Example 1

[0044] This embodiment provides a casting and rolling method for 3-series high-iron manganese-aluminum alloys, the casting and rolling method comprising the following steps:

[0045] (1) The alloy ingredients (in terms of mass percentage, the alloy element composition includes Si: 1wt%, Fe: 0.8wt%, Mn: 1.5wt%, Zn: 1.2wt%) are smelted at 770℃, and after degassing and slag removal, the resulting alloy melt enters the front box for heat preservation, and the temperature of the front box is controlled at 718℃.

[0046] (2) The alloy melt after being insulated in the front box is fed into the casting nozzle. A flow divider block is provided in the casting nozzle to ensure that the melt is filled evenly and to prevent the aluminum liquid on both sides from failing to converge and causing perforation on the plate surface. The material of the flow divider block is aluminum silicate sprayed with boron nitride, and its surface roughness Ra is 3.18μm. The flow rate of the alloy melt before the flow divider block in the casting nozzle is controlled to be 3m / min.

[0047] (3) The alloy melt flowing out from the casting nozzle is transported to the rolls for casting and rolling. The water temperature of the casting and rolling is controlled at 18°C. The distance between the front edge of the casting nozzle and the rolling center line of the two rolls is called the casting and rolling zone. The length of the casting and rolling zone is 60 mm. After passing through the rolls for cooling and rolling, the casting and rolling billet is obtained.

[0048] Example 2

[0049] This embodiment provides a casting and rolling method for 3-series high-iron manganese-aluminum alloys, the casting and rolling method comprising the following steps:

[0050] (1) The alloy ingredients (in terms of mass percentage, the alloy element composition includes Si: 1.2wt%, Fe: 0.7wt%, Mn: 1.2wt%, Zn: 1.7wt%) are smelted at 760℃, and after degassing and slag removal, the resulting alloy melt enters the front box for heat preservation, and the temperature of the front box is controlled at 715℃.

[0051] (2) The alloy melt after being insulated in the front box is fed into the casting nozzle. A flow divider block is provided in the casting nozzle to ensure that the melt is filled evenly and to prevent the aluminum liquid on both sides from failing to converge and causing perforation on the plate surface. The material of the flow divider block is aluminum silicate sprayed with boron nitride, and its surface roughness Ra is 4.5μm. The flow rate of the alloy melt before the flow divider block in the casting nozzle is controlled to be 2.8m / min.

[0052] (3) The alloy melt flowing out from the casting nozzle is transported to the rolls for casting and rolling. The water temperature of the casting and rolling is controlled at 19°C. The distance between the front edge of the casting nozzle and the rolling center line of the two rolls in the casting and rolling process is called the casting and rolling zone. The length of the casting and rolling zone is 58 mm. After passing through the rolls for cooling and rolling, the casting and rolling billet is obtained.

[0053] Example 3

[0054] This embodiment provides a casting and rolling method for 3-series high-iron manganese-aluminum alloys, the casting and rolling method comprising the following steps:

[0055] (1) The alloy ingredients (in terms of mass percentage, the alloy element composition includes Si: 0.8wt%, Fe: 1wt%, Mn: 1.7wt%, Zn: 0.5wt%) are smelted at 780℃, and after degassing and slag removal, the resulting alloy melt enters the front box for heat preservation, and the temperature of the front box is controlled at 720℃.

[0056] (2) The alloy melt after being insulated in the front box is fed into the casting nozzle. A flow divider block is provided in the casting nozzle to ensure that the melt is filled evenly and to prevent the aluminum liquid on both sides from failing to converge and causing perforation on the plate surface. The material of the flow divider block is aluminum silicate sprayed with boron nitride, and its surface roughness Ra is 4.14μm. The flow rate of the alloy melt before the flow divider block in the casting nozzle is controlled to be 3.2m / min.

[0057] (3) The alloy melt flowing out from the casting nozzle is transported to the rolls for casting and rolling. The water temperature of the casting and rolling is controlled at 20°C. The distance between the front edge of the casting nozzle and the rolling center line of the two rolls is called the casting and rolling zone. The length of the casting and rolling zone is 61 mm. After passing through the rolls for cooling and rolling, the casting and rolling billet is obtained.

[0058] Example 4

[0059] This embodiment provides a casting and rolling method for a 3-series high-iron manganese-aluminum alloy. Except for the Fe mass percentage in the alloy feedstock being 0.4%, the casting and rolling method is the same as in Embodiment 2, and will not be repeated here.

[0060] Example 5

[0061] This embodiment provides a casting and rolling method for 3-series high-iron manganese-aluminum alloy. Except for controlling the temperature of the front box to 710°C, the casting and rolling method is the same as that in Embodiment 1, and will not be described again here.

[0062] Example 6

[0063] This embodiment provides a casting and rolling method for a 3-series high-iron manganese-aluminum alloy. Except for controlling the flow rate of the alloy melt before the flow divider block in the casting nozzle to be 2.5 m / min, the casting and rolling method is the same as in Embodiment 1, and will not be repeated here.

[0064] Example 7

[0065] This embodiment provides a casting and rolling method for 3-series high-iron manganese-aluminum alloy. Except for the casting and rolling water temperature control being 25°C, the casting and rolling method is the same as in Embodiment 1, and will not be repeated here.

[0066] Example 8

[0067] This embodiment provides a casting and rolling method for 3-series high-iron manganese-aluminum alloy. Except for the length of the casting and rolling zone being 65mm, the casting and rolling method is the same as that in Embodiment 1, and will not be described again here.

[0068] Comparative Example 1

[0069] This comparative example provides a casting and rolling method for a 3-series high-speed iron manganese aluminum alloy. Except for the material of the diversion pad, which is aluminum silicate without boron nitride coating and has a surface roughness Ra of 7.82 μm, the casting and rolling method is the same as in Example 2, and will not be described again here.

[0070] Comparative Example 2

[0071] This comparative example provides a casting and rolling method for a 3-series high-speed iron manganese aluminum alloy. Except for the material of the diversion pad, which is aluminum silicate without boron nitride coating and has a surface roughness Ra of 7.82 μm, the casting and rolling method is the same as in Example 4, and will not be repeated here.

[0072] Comparative Example 3

[0073] This comparative example provides a casting and rolling method for a 3-series high-iron manganese-aluminum alloy. The casting and rolling method is the same as in Example 1, except that the mass percentage of Fe in the alloy feed is 0.2%, and will not be described again here.

[0074] Comparative Example 4

[0075] This comparative example provides a casting and rolling method for a 3-series high-iron manganese-aluminum alloy. The casting and rolling method is the same as in Example 1, except that the mass percentage of Mn in the alloy feed is 1%, and will not be described again here.

[0076] Test method:

[0077] 1. Surface roughness parameter Ra: Surface roughness is measured according to GB / T1031-2009 standard.

[0078] 2. Average flow velocity in the inlet area of ​​the distribution block: The fluid flows in through the flow channel, is separated into multiple streams by the distribution block, and then converges again before flowing out from the flow channel outlet. The flow velocity of the fluid at the flow channel outlet can be obtained by reading and calculating the amount of material generated per unit time from the casting and rolling mill equipment. Then, the flow velocity of the fluid entering the distribution block area is calculated using the outlet flow velocity.

[0079] Outlet flow rate = Amount of material generated per unit time in casting and rolling * 2.7 / Area of ​​fluid flowing to the outlet;

[0080] The flow velocity in the diversion pad area = the area of ​​the fluid flowing to the outlet * the flow velocity at the outlet of the flow channel / the fluid area at the inlet of the pad = the amount of material generated per unit time of casting and rolling * 2.7 / the fluid area at the inlet of the pad; where 2.7 is the ratio of the density of solid aluminum alloy to the density of liquid aluminum alloy.

[0081] 3. Size and number of coarse compounds: According to GB / T3246.1-2024 Inspection Methods for the Microstructure of Wrought Aluminum and Aluminum Alloy Products Part 1: Microstructural Inspection Methods; using a metallurgical microscope at 50x magnification (Axio Imager A2m Zeiss metallurgical microscope), 10 fields of view were randomly selected, and the number of coarse compounds ≥80μm / 100mm was counted. 2 The size of a coarse compound refers to the length of the longest side of the coarse compound within the field of view.

[0082] 4. Center Segregation Test: According to GB / T3246.1-2024, Inspection Methods for the Microstructure of Wrought Aluminum and Aluminum Alloy Products, Part 1: Microstructural Inspection Methods; using a metallurgical microscope at 50x magnification (Axio Imager A2m Zeiss metallurgical microscope), 10 fields of view covering the center segregation zone were randomly selected. The size and number density of coarse compounds in the center segregation zone were counted. The center segregation did not contain coarse compounds ≥80μm, and coarse compounds smaller than 20μm had little impact on the appearance. Therefore, the number of coarse compounds between 20-80μm and excluding those ≥80μm was counted per 100mm. 2 The size of coarse compounds refers to the longest side dimension of the coarse compound within the measurement field of view. Center segregation refers to the center layer segregation specified in the standard.

[0083] 5. Tensile strength Rm: The tensile strength of the sample was determined by the standard method of GB / T228.1-2010 "Tension properties at room temperature - Part 1: Test methods" using a Zwick universal testing machine.

[0084] 6. Alloy conductivity: The conductivity of the sample was measured using the standard method of GB / T12966-2022 "Eddy current test method for conductivity of aluminum and aluminum alloys" and a Sigma conductivity meter.

[0085] The test results of the above embodiments and comparative examples are shown in Table 1.

[0086] Table 1

[0087]

[0088]

[0089] The following points can be observed from Table 1:

[0090] (1) As can be seen from Examples 1 to 3, the casting and rolling method for the 3-series high-iron manganese-aluminum alloy provided by the present invention can reduce center segregation and reduce the number of coarse compounds greater than or equal to 80 μm to 0 / 100 mm, while maintaining an electrical conductivity of over 50% and a tensile strength of over 200 MPa. 2 .

[0091] (2) The effect of the roughness of the diversion pad on the aluminum alloy of high-speed rail 3 series

[0092] Comparing Examples 2, 4, and Comparative Examples 1-2, it can be seen that when the roughness of the flow divider block is too large, the fluid containing the high-iron-manganese alloy material is prone to metal compound nucleation during its flow through the flow divider block, resulting in the formation of coarse compounds. The appearance images of the 3-series high-iron-manganese aluminum alloys obtained in Example 2 and Comparative Example 1 are shown below. Figure 1 and Figure 2 As shown, from Figure 1 and Figure 2 It can be seen that the 3-series high-iron manganese aluminum alloy obtained in Example 2 has a smooth appearance without pores, while the 3-series high-iron manganese aluminum alloy obtained in Comparative Example 1 has pores on its surface. This is because coarse compounds were generated in Comparative Example 1.

[0093] In Example 2, compared to Comparative Example 1, the roughness of the flow divider in Comparative Example 1 was higher when the iron content was 0.7%, resulting in more center segregation. However, when the iron content was 0.4%, the flow divider in Comparative Example 2 was the same as that in Comparative Example 1, but it produced less center segregation. This indicates that fluids with high iron content are more likely to produce center segregation when flowing through a flow divider with high roughness.

[0094] (3) The effect of iron on conductivity

[0095] Comparing Example 1 and Comparative Example 3, it can be seen that the addition of iron in Comparative Example 3 is reduced, and its electrical conductivity is significantly lower than that in Example 1, resulting in a decrease in heat exchange performance. This indicates that in order to obtain an aluminum alloy with high electrical conductivity, it is necessary to add an appropriate amount of iron.

[0096] (4) Effect of manganese on tensile strength

[0097] Comparing Example 1 and Comparative Example 4, it can be seen that the addition of manganese in Comparative Example 4 is reduced, and its tensile strength is significantly lower than that in Example 1. This indicates that in order to obtain an aluminum alloy with high tensile strength, it is necessary to add an appropriate amount of manganese.

[0098] (5) The effect of melt residence in the flow divider block area

[0099] 5.1 Effect of front chamber temperature on coarse compounds

[0100] Comparing Example 1 and Example 5, it can be seen that the temperature of the front chamber in Example 5 is relatively low, which causes the melt to be distributed in a low-temperature region when entering the flow divider block area, providing time for the metal compounds to grow. This results in the formation of a large number of coarse, lamellar (FeMn)Al6 compounds, which will significantly reduce the mechanical and processing properties of the alloy.

[0101] 5.2 Influence of the flow rate of the alloy melt before the flow divider block

[0102] Comparing Examples 1 and 6, it can be seen that the flow rate of the alloy melt before the flow divider block in Example 6 is relatively low, which results in the melt being distributed in a low-temperature region when entering the flow divider block area. This provides time for the metal compounds to grow, leading to the formation of a large number of coarse, lamellar (FeMn)Al6 compounds, which significantly reduces the mechanical and processing properties of the alloy.

[0103] (6) The Influence of Casting and Rolling

[0104] Comparing Examples 1 and 7-8, it can be seen that the casting temperature in Example 7 is too high and the length of the casting zone in Example 8 is too long, both of which lead to center segregation of the billet. Center segregation can also form coarse compounds, and the length of the casting zone has a greater impact on center segregation.

[0105] The present invention has been illustrated with the above embodiments to illustrate its detailed features, but the present invention is not limited to the above detailed features, that is, it does not mean that the present invention must rely on the above detailed features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the selected technical features, additions of auxiliary technical features, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A casting and rolling method for a 3-series high-iron manganese-aluminum alloy, characterized in that, The casting and rolling method includes the following steps: (1) After the alloy ingredients are smelted, the resulting alloy melt enters the front box for heat preservation. The alloy contains at least 0.4 wt% Fe and at least 1.2 wt% Mn. (2) The alloy melt after being insulated in the front box is fed into the casting nozzle. A flow divider block is provided in the casting nozzle. The surface roughness parameter Ra of the flow divider block is ≤4.5μm. (3) The alloy melt flowing out of the casting nozzle is transported to the rolls for casting and rolling, and then cooled and rolled in sequence to obtain the cast billet.

2. The casting and rolling method according to claim 1, characterized in that, The temperature of the front box insulation in step (1) is 715-720℃.

3. The casting and rolling method according to claim 1 or 2, characterized in that, In step (2), the flow rate of the alloy melt when the fluid in the casting nozzle enters the flow divider block is controlled to be above 2.8 m / min.

4. The casting and rolling method according to any one of claims 1 to 3, characterized in that, The shunt pad in step (2) is made of aluminum silicate with a boron nitride coating on its surface.

5. The casting and rolling method according to any one of claims 1 to 4, characterized in that, In step (3), the water temperature for casting and rolling is controlled to be ≤20℃; And / or, the distance between the leading edge of the casting nozzle and the rolling center line of the two rolls in the casting and rolling process is defined as the casting and rolling zone, and the length of the casting and rolling zone is ≤61mm.

6. The casting and rolling method according to any one of claims 1 to 5, characterized in that, The alloy composition, by mass percentage, comprises 0.4 wt% ≤ Fe ≤ 1.0 wt% and 1.2 wt% ≤ Mn ≤ 1.7 wt%.

7. The casting and rolling method according to any one of claims 1 to 6, characterized in that, The alloy composition comprises 0.7 wt% ≤ Fe ≤ 1.0 wt% by mass.

8. A 3-series high-iron manganese-aluminum alloy, characterized in that, The 3-series high-iron manganese-aluminum alloy is prepared by the casting and rolling method of the 3-series high-iron manganese-aluminum alloy according to any one of claims 1 to 7.

9. A heat exchange fin, characterized in that, The heat exchange fins are made of the 3-series high-iron manganese aluminum alloy as described in claim 8.

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