A method for manufacturing a high-strength bendable aluminum alloy rail

Abstract

The application discloses a preparation method of a high-strength bendable aluminum alloy guide rail and belongs to the field of aluminum alloy material preparation. After optimization of components and process parameters, the grain size of the cast bar reaches level 1, effectively reducing the generation of impurity elements, and the grain grows in the extrusion process due to energy accumulation, and enough energy is generated in the extrusion process to make the structure completely recrystallize, the grain structure presents equiaxed grain structure with a size of 150 mu m, and the generation of cracks is reduced, and the elongation of the product is improved. In addition, by adding a refining agent with a specific proportion and component, active hydrogen in high-temperature aluminum liquid can be quickly melted and dispersed, impurities can be effectively and clearly carried to the surface of the aluminum alloy liquid under the action of buoyancy, and the refining agent is beneficial to slagging and further improves the quality of the prepared aluminum alloy guide rail.

Description

Technical Field

[0001] The present invention relates to the field of aluminum alloy preparation, and in particular to a method for preparing a high-strength bendable aluminum alloy guide rail. Background Art

[0002] Aluminum has advantages such as low density, high strength, and good formability, so its application areas are constantly increasing. Due to the diversity of usage scenarios, there are different requirements for the cross-section and shape of aluminum. For example, guide rail products are also widely used in rail transportation, industrial and construction hoisting, and industrial equipment. Aluminum alloy guide rails are a common guide rail. Currently, most of the research on aluminum alloy guide rails focuses on product structure and welding methods. For example, the Chinese patent number CN201410849136.X discloses an aluminum alloy guide rail and its welding method. The patent number CN202110671150.5 discloses an aluminum alloy guide rail, but the bending performance is poor.

[0003] Existing technology allows for the design of different cross-sections based on different application requirements, employing a forward extrusion method to produce the desired product. However, the guide rail profiles obtained through extrusion in the prior art are generally linear, limiting their applicability. During use, some guide rails that require corners must be bent and then spliced ​​together. Since aluminum alloys exhibit a higher strength after aging, their elongation decreases simultaneously. Bending after aging can easily lead to breakage, which also affects production efficiency. Summary of the Invention

[0004] Based on this, in order to solve the problems of low strength, decreased elongation and low production efficiency of aluminum alloy guide rails in the prior art, the present invention provides a method for preparing high-strength bendable aluminum alloy guide rails. The specific technical solution is as follows:

[0005] A method for preparing a high-strength, bendable aluminum alloy guide rail, the method comprising the following steps:

[0006] The raw materials of the aluminum alloy guide rail are prepared and put into a smelting furnace for smelting to obtain alloy liquid;

[0007] Adding a refining agent to the alloy liquid and evenly blowing it to the bottom of the furnace under an argon atmosphere, with a single refining time of not less than 20 minutes, removing hydrogen online to make the hydrogen content in the furnace ≤0.25mL / 100gAl, then performing double-stage filtration, and then casting to obtain cast rods;

[0008] The cast rod is homogenized, extruded, and then cooled in water to below 50° C. within 1 minute;

[0009] After cooling, aging treatment and bending treatment are carried out to obtain aluminum alloy guide rails;

[0010] The temperature of the extrusion-treated rod is controlled at 490°C to 510°C, the outlet temperature is controlled at 530°C to 550°C, the extrusion ratio is 40 to 50, the extrusion speed is 8 mm / s to 10 mm / s, and the extrusion treatment controls the cast rod to have an equiaxed crystalline structure with a size of ≤150 μm, and the coarse grain layer is controlled within 0.2 mm.

[0011] Furthermore, the raw material includes the following chemical composition: Si: 0.60% to 0.65%, Mg: 0.48% to 0.53%, Fe: ≤0.15%, Ti: ≤0.02%, the impurity content is ≤0.03% individually, and the balance is Al.

[0012] Furthermore, the refining agent is prepared from sodium chloride, potassium oxalate and manganese phosphide in a mass ratio of (1-3): (1-5): (1-2).

[0013] Furthermore, the addition amount of the refining agent accounts for 0.25% to 0.75% of the mass of the aluminum alloy liquid.

[0014] Furthermore, the online dehydrogenation adopts a dual-rotor degassing box, and the hydrogen content at the end of the disk is ≤0.18mL / 100gAl.

[0015] Furthermore, the double-stage filtration adopts double-stage filtration, the first-stage filtration uses a 40p foam ceramic filter plate, and the second-stage filtration uses a 60p foam ceramic filter plate.

[0016] Furthermore, the casting temperature is 700° C. to 720° C., and the casting speed is 180 mm / min to 250 mm / min.

[0017] Furthermore, the temperature of the homogenization treatment is 550° C. to 570° C., and the time is 6 h to 9 h.

[0018] Furthermore, the aging treatment is a two-stage aging heat treatment, wherein the temperature of the first-stage aging treatment is 120°C to 150°C, and the time is 1h to 3h, and the temperature of the second-stage aging treatment is 180°C to 220°C, and the time is 10h to 12h.

[0019] Furthermore, the hardness of the aluminum alloy guide rail reaches 16HW, the tensile strength is ≥300MPa, the yield strength is ≥280MPa, and the elongation is ≥12%.

[0020] After optimization of the components and process parameters in the above scheme, the grain size of the cast bar reaches level 1, effectively reducing the generation of impurity elements. In the extrusion process, the energy is accumulated to make the grains grow, and enough energy is generated in the extrusion process to make the structure completely recrystallize, and the grain structure presents equiaxed grain structure with a size of 150 μm, and reduces the second phase precipitation and growth, and produces crack sources, and improves the elongation of the product. In addition, by adding a specific proportion and component of the refining agent, the active hydrogen in the high-temperature aluminum liquid can be quickly melted and dispersed, and the active hydrogen in the high-temperature aluminum liquid can be effectively removed, and the impurities are carried to the surface of the aluminum alloy liquid under the action of buoyancy, which is beneficial to the slagging, and further improves the quality of the prepared aluminum alloy guide rail. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The product after bending of Example 1 is shown schematically;

[0022] Figure 2 The internal structure of the aluminum alloy guide rail prepared in Example 1 after extrusion treatment is shown schematically. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the present application clearer and more apparent, the present application will be further described in detail below in combination with its embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the protection scope of the present application.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0025] The preparation method of the strong and bendable aluminum alloy guide rail in an embodiment of the present application comprises the following steps:

[0026] The raw materials of the aluminum alloy guide rail are dosed and put into a melting furnace for melting to obtain an alloy liquid;

[0027] A refining agent is added to the alloy liquid and uniformly blown to the bottom of the furnace under an argon atmosphere, the single refining time is not less than 20 min, the hydrogen content in the furnace is ≤0.25 mL / 100 g Al after online hydrogen removal, then double-stage filtration is carried out, and a cast bar is obtained after casting;

[0028] The cast bar is homogenized, and after extrusion treatment, water cooling is carried out and the temperature is cooled to below 50℃ within 1 min;

[0029] After cooling, aging treatment and bending treatment are carried out to obtain aluminum alloy guide rails;

[0030] The temperature of the extrusion-treated rod is controlled at 490°C to 510°C, the outlet temperature is controlled at 530°C to 550°C, the extrusion ratio is 40 to 50, the extrusion speed is 8 mm / s to 10 mm / s, and the extrusion treatment controls the cast rod to have an equiaxed crystalline structure with a size of ≤150 μm, and the coarse grain layer is controlled within 0.2 mm.

[0031] In one embodiment, the raw material includes the following chemical composition: Si: 0.60% to 0.65%, Mg: 0.48% to 0.53%, Fe: ≤0.15%, Ti: ≤0.02%, the impurity content is ≤0.03% individually, and the balance is Al.

[0032] In one embodiment, the refining agent is prepared from sodium chloride, potassium oxalate and manganese phosphide in a mass ratio of (1-3): (1-5): (1-2).

[0033] In one embodiment, the preparation method of the refining agent is: sodium chloride, potassium oxalate and manganese phosphide are mixed, ball-milled for 10 to 20 minutes, and then treated at 800°C to 1000°C for 1 to 2 hours. After cooling, the mixture is crushed and ball-milled to obtain the refining agent.

[0034] In one embodiment, the amount of the refining agent added is 0.25% to 0.75% of the mass of the aluminum alloy liquid.

[0035] In one embodiment, the online dehydrogenation uses a dual-rotor degassing box, and the hydrogen content at the end of the disk is ≤0.18mL / 100gAl.

[0036] In one embodiment, the double-stage filtration adopts double-stage filtration, the first-stage filtration uses a 40p foam ceramic filter plate, and the second-stage filtration uses a 60p foam ceramic filter plate.

[0037] In one embodiment, the casting temperature is 700° C. to 720° C., and the casting speed is 180 mm / min to 250 mm / min.

[0038] In one embodiment, the homogenization treatment is carried out at a temperature of 550° C. to 570° C. and for a time of 6 hours to 9 hours.

[0039] In one embodiment, the aging treatment is a two-stage aging heat treatment, wherein the temperature of the first-stage aging treatment is 120°C to 150°C and the time is 1h to 3h, and the temperature of the second-stage aging treatment is 180°C to 220°C and the time is 10h to 12h.

[0040] In one embodiment, the aluminum alloy guide rail has a hardness of 16 HW, a tensile strength of ≥300 MPa, a yield strength of ≥280 MPa, and an elongation of ≥12%.

[0041] Through optimization of the composition and process parameters in the above scheme, the grain size of the cast rods reaches Level 1, effectively reducing the generation of impurity elements. During the extrusion process, energy concentration causes grain growth, and sufficient energy is generated during the extrusion process to achieve complete recrystallization. The grain structure exhibits an equiaxed grain structure of 150μm, reducing the precipitation and growth of second phases that can cause cracks, while also improving the product's elongation. Furthermore, by adding a refining agent with a specific proportion and composition, it enables rapid melting and dispersion, effectively removing active hydrogen from the hot aluminum liquid. Buoyancy carries impurities to the surface of the aluminum alloy liquid, facilitating slag removal and further improving the quality of the aluminum alloy guide rails.

[0042] The embodiments of the present invention will be described in detail below with reference to specific examples.

[0043] Example 1:

[0044] A method for preparing a high-strength bendable aluminum alloy guide rail comprises the following steps:

[0045] The raw materials of the aluminum alloy guide rail are prepared according to the following chemical composition: Si: 0.60%, Mg: 0.53%, Fe: 0.12%, Ti: 0.01%, the impurity content is ≤ 0.03% for each, and the balance is Al, and are put into a melting furnace for melting to obtain a molten alloy;

[0046] Sodium chloride, potassium oxalate, and manganese phosphide are mixed in a mass ratio of 1:5:1, ball-milled for 10 minutes, and then treated at 800° C. for 1 hour. After cooling, crushing, and ball-milling, a refining agent is obtained. Then, the refining agent, accounting for 0.55% of the mass of the aluminum alloy liquid, is added to the alloy liquid and evenly blown to the bottom of the furnace under an argon atmosphere. The single refining time is not less than 20 minutes.

[0047] Online hydrogen removal uses a dual-rotor degassing box, followed by two-stage filtration, with the first-stage filtration using a 40p foam ceramic filter plate and the second-stage filtration using a 60p foam ceramic filter plate;

[0048] Casting was performed at a temperature of 710° C. and a casting speed of 200 mm / min to obtain a cast rod;

[0049] The cast rod is homogenized at a temperature of 550° C. for 8 hours, extruded, and the rod temperature during the extrusion process is controlled at 490° C., the outlet temperature is controlled at 530° C., the extrusion ratio is 40, the extrusion speed is 8 mm / s, and the extrusion process controls the cast rod to have an equiaxed crystalline structure with a size of ≤150 μm, the coarse grain layer is controlled within 0.2 mm, and water cooled to below 50° C. within 1 minute;

[0050] A double-stage aging heat treatment is performed, wherein the temperature of the first-stage aging treatment is 120°C and the time is 1 hour, and the temperature of the second-stage aging treatment is 200°C and the time is 10 hours. Bending treatment is performed to obtain an aluminum alloy guide rail.

[0051] Example 2:

[0052] A method for preparing a high-strength bendable aluminum alloy guide rail comprises the following steps:

[0053] The raw materials of the aluminum alloy guide rail are prepared according to the following chemical composition: Si: 0.62%, Mg: 0.50%, Fe: 0.10%, Ti: 0.01%, the impurity content of each is ≤ 0.03%, and the balance is Al, and are put into a melting furnace for melting to obtain a molten alloy;

[0054] Sodium chloride, potassium oxalate, and manganese phosphide are mixed in a mass ratio of 3:3:1, ball-milled for 15 minutes, and then treated at 900° C. for 1 hour. After cooling, crushing, and ball-milling, a refining agent is obtained. Then, the refining agent, accounting for 0.60% of the mass of the aluminum alloy liquid, is added to the alloy liquid and evenly blown to the bottom of the furnace under an argon atmosphere. The single refining time is not less than 20 minutes.

[0055] Online hydrogen removal uses a dual-rotor degassing box, followed by two-stage filtration, with the first-stage filtration using a 40p foam ceramic filter plate and the second-stage filtration using a 60p foam ceramic filter plate;

[0056] Casting was performed at a temperature of 720° C. and a casting speed of 220 mm / min to obtain a cast rod;

[0057] The cast rod is homogenized at a temperature of 570° C. for 7 hours, extruded, and the rod temperature during the extrusion process is controlled at 500° C., the outlet temperature is controlled at 550° C., the extrusion ratio is 40, the extrusion speed is 8 mm / s, and the extrusion process controls the cast rod to have an equiaxed crystalline structure with a size of ≤150 μm, the coarse grain layer is controlled within 0.2 mm, and water cooled to below 50° C. within 1 minute;

[0058] A double-stage aging heat treatment is performed, wherein the temperature of the first-stage aging treatment is 120°C and the time is 1 hour, and the temperature of the second-stage aging treatment is 220°C and the time is 10 hours. Bending treatment is performed to obtain an aluminum alloy guide rail.

[0059] Example 3:

[0060] A method for preparing a high-strength bendable aluminum alloy guide rail comprises the following steps:

[0061] The raw materials of the aluminum alloy guide rail are prepared according to the following chemical composition: Si: 0.65%, Mg: 0.48%, Fe: 0.11%, Ti: 0.01%, the impurity content of each is ≤ 0.03%, and the balance is Al, and are put into a melting furnace for melting to obtain a molten alloy;

[0062] Sodium chloride, potassium oxalate, and manganese phosphide are mixed in a mass ratio of 2:3:2, ball-milled for 20 minutes, and then treated at 1000° C. for 2 hours. After cooling, crushing, and ball-milling, a refining agent is obtained. Then, the refining agent, accounting for 0.72% of the mass of the aluminum alloy liquid, is added to the alloy liquid and evenly blown to the bottom of the furnace under an argon atmosphere. The single refining time is not less than 20 minutes.

[0063] Online hydrogen removal uses a dual-rotor degassing box, followed by two-stage filtration, with the first-stage filtration using a 40p foam ceramic filter plate and the second-stage filtration using a 60p foam ceramic filter plate;

[0064] Casting is performed at a temperature of 720° C. and a casting speed of 200 mm / min to obtain a cast rod;

[0065] The cast rod is homogenized at a temperature of 570° C. for 6 hours, and is extruded to control the rod temperature at 500° C., the outlet temperature at 550° C., the extrusion ratio at 40, the extrusion speed at 8 mm / s, and the cast rod is controlled to have an equiaxed crystalline structure with a size of ≤150 μm, the coarse grain layer is controlled within 0.2 mm, and is water-cooled and cooled to below 50° C. within 1 minute;

[0066] A double-stage aging heat treatment is performed, wherein the temperature of the first-stage aging treatment is 125°C and the time is 1.5h, and the temperature of the second-stage aging treatment is 200°C and the time is 10h. Bending treatment is performed to obtain an aluminum alloy guide rail.

[0067] Comparative Example 1:

[0068] The difference between Comparative Example 1 and Example 3 is that the chemical composition of the raw materials in Comparative Example 1 is as follows: Si: 0.79%, Mg: 0.1%, Fe: 0.3%, Ti: 0.8%, the impurity content is ≤ 0.03%, and the balance is Al. All other aspects are the same as in Example 3.

[0069] Comparative Example 2:

[0070] The difference between Comparative Example 2 and Example 3 is that in Comparative Example 2, a single component of sodium chloride is used as the refining agent, and the rest is the same as in Example 3.

[0071] Comparative Example 3:

[0072] The difference between Comparative Example 3 and Example 3 is that in Comparative Example 3, a single component of potassium oxalate is used as the refining agent, and the rest is the same as Example 3.

[0073] Comparative Example 4:

[0074] The difference between Comparative Example 4 and Example 3 is that in Comparative Example 4, only manganese phosphide is used as the refining agent, and the rest is the same as in Example 3.

[0075] Comparative Example 5:

[0076] The difference between Comparative Example 5 and Example 3 is that the mass ratio of sodium chloride, potassium oxalate and manganese phosphide in Comparative Example 5 is 1:1:5, and the others are the same as Example 3.

[0077] Comparative Example 6:

[0078] The difference between Comparative Example 6 and Example 3 is that the extrusion treatment temperature in Comparative Example 6 is controlled to be 420° C., the outlet temperature is controlled to be 500° C., the extrusion ratio is 35, and the rest is the same as Example 3.

[0079] Comparative Example 7:

[0080] The difference between Comparative Example 7 and Example 3 is that the aging treatment temperature in Comparative Example 7 is 250° C. and the aging treatment time is 8 h. The other aspects are the same as those in Example 3.

[0081] Performance tests were performed on Examples 1 to 3 and Comparative Examples 1 to 7. With reference to GB / T 32186-2015, the purity of the refined aluminum alloy liquid is shown in Table 1 below.

[0082] Table 1: Purity of aluminum alloy liquid after refining

[0083]

[0084] As can be seen from the data in Table 1, after refining, the present application obtains a very pure aluminum alloy liquid that meets the test standards. Mixing sodium chloride, potassium oxalate, and manganese phosphide in a certain mass ratio can achieve a more significant purification effect, helping to improve the quality of the aluminum alloy liquid.

[0085] The aluminum alloy guide rail samples prepared in Examples 1 to 3 and the aluminum alloy guide rail comparison samples prepared in Comparative Examples 1 to 7 were subjected to performance tests, and the results are shown in Table 2 below.

[0086]

[0087]

[0088] From the data analysis in Table 2, it can be seen that after aging treatment, the aluminum alloy guide rail prepared in this application has a hardness of over 16HW, a tensile strength of ≥300MPa, a yield strength of ≥280MPa, and an elongation of ≥12%, demonstrating excellent mechanical strength overall.

[0089] in addition, Figure 1 This is a schematic diagram of the product after bending in Example 1. Figure 1 It can be seen that the aluminum alloy guide rail obtained in this application has excellent bending effect and can be used without excessive processing, has higher production effect, and has a low scrap rate. Figure 2 This is a schematic diagram of the internal structure of the aluminum alloy guide rail prepared in Example 1 of the present invention after extrusion treatment, which presents an equiaxed crystalline structure with the coarse grain layer controlled within 0.2 mm. The aluminum alloy guide rails obtained in Examples 2 and 3 are the same as those in Example 1 and will not be repeated here.

[0090] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0091] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for preparing a high-strength, bendable aluminum alloy guide rail, characterized in that: The preparation method comprises the following steps: The raw materials of the aluminum alloy guide rail are prepared and put into a smelting furnace for smelting to obtain a molten alloy; wherein the raw materials include the following chemical composition: Si: 0.60% to 0.65%, Mg: 0.48% to 0.53%, Fe: ≤0.15%, Ti: ≤0.02%, impurity content of each element ≤0.03%, and the balance is Al; A refining agent is added to the alloy liquid and evenly blown to the bottom of the furnace under an argon atmosphere, with a single refining time of not less than 20 minutes, and hydrogen is removed online so that the hydrogen content in the furnace is ≤0.25mL / 100gAl, followed by double-stage filtration and casting to obtain a cast rod; wherein the refining agent is prepared from sodium chloride, potassium oxalate and manganese phosphide in a mass ratio of (1-3): (1-5): (1-2); The cast rod is homogenized, extruded, and then cooled in water to below 50° C. within 1 minute; After cooling, aging treatment and bending treatment are carried out to obtain aluminum alloy guide rails; The extrusion treatment rod temperature is controlled at 490°C to 510°C, the outlet temperature is controlled at 530°C to 550°C, the extrusion ratio is 40 to 50, the extrusion speed is 8 mm / s to 10 mm / s, and the extrusion treatment controls the cast rod to have an equiaxed crystalline structure with a size of ≤150 μm, and the coarse grain layer is controlled within 0.2 mm; The aging treatment is a two-stage aging heat treatment, wherein the temperature of the first-stage aging treatment is 120° C. to 150° C. and the time is 1 hour to 3 hours, and the temperature of the second-stage aging treatment is 180° C. to 220° C. and the time is 10 hours to 12 hours.

2. The preparation method according to claim 1, characterized in that The addition amount of the refining agent accounts for 0.25% to 0.75% of the mass of the aluminum alloy liquid.

3. The preparation method according to claim 1, characterized in that The online dehydrogenation adopts a double-rotor degassing box, and the hydrogen content at the end of the disk is ≤0.18mL / 100gAl.

4. The preparation method according to claim 1, characterized in that The double-stage filtration adopts double-stage filtration, the first-stage filtration uses a 40p foam ceramic filter plate, and the second-stage filtration uses a 60p foam ceramic filter plate.

5. The preparation method according to claim 1, characterized in that The casting temperature is 700° C. to 720° C., and the casting speed is 180 mm / min to 250 mm / min.

6. The preparation method according to claim 1, characterized in that The temperature of the homogenization treatment is 550° C. to 570° C., and the time is 6 h to 9 h.

7. The preparation method according to claim 6, characterized in that The hardness of the aluminum alloy guide rail reaches 16HW, the tensile strength ≥300MPa, the yield strength ≥280MPa, and the elongation ≥12%.

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