Refining agent for composite grain refining and Fe-rich phase regulation, preparation method and application

Abstract

The invention discloses a composite refined grain and Fe-rich phase regulated refining agent, a preparation method and application, the composite refined grain and Fe-rich phase regulated refining agent comprises the following elements in percentage by weight: 4.85-5.2% of Ti, 0.5-0.8% of B, 6-8% of Sr, 4.5-5.5% of Mo, less than or equal to 0.2% of Fe, less than or equal to 0.15% of Si and the balance of Al and inevitable impurities, each impurity is less than or equal to 0.05%, and the sum of the impurities is less than or equal to 0.15%. The refiner is used for grain refinement and Fe-rich phase regulation and control of the high-Fe-content aluminum alloy, and the Fe-rich phase regulation and control of the regenerated aluminum alloy can achieve the effect that long needle-shaped beta-Fe is converted into Chinese character-shaped alpha-Fe, or the alpha-Fe is converted into small-size Chinese character-shaped or skeleton-shaped from complex fishbone-shaped, flower-shaped and long-strip-shaped; the strength of the refined aluminum alloy is improved by at least 15% compared with the strength of the aluminum alloy obtained through a traditional refining agent.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum alloy refiners, and in particular relates to a refiner for composite grain refinement and Fe-rich phase regulation, a preparation method and application thereof. Background Art

[0002] Aluminum alloy has good weldability, formability, corrosion resistance and medium strength. It is widely used in rail transportation, new energy vehicles, ships and other fields. It has extremely high recycling value. Compared with electrolytic aluminum, the energy consumption of recycled aluminum is only about 5% of that of electrolytic aluminum, which has significant advantages in reducing carbon footprint.

[0003] However, recycling aluminum alloys will inevitably introduce high levels of impurity elements, especially high levels of Fe, Si and other elements, forming coarse Alx(Fe,Mn), Al(Fe,Mn)Si and other particles in the aluminum alloy, and presenting complex morphologies such as long needles, fish bones and flowers. Traditional grain refiners cannot regulate the size and morphology of the iron-rich phase in the recycled aluminum alloy. These coarse second phases are extremely difficult to fully crush or dissolve during the production process of aluminum alloys, and are retained in the final aluminum alloy products, seriously reducing the performance of the alloy. In addition, due to the high content of impurity elements such as Fe, Si, Mn, Cr, and V in recycled aluminum alloys, refiner poisoning is easily caused when using traditional refiners, resulting in a weakened grain refinement effect.

[0004] Grain refinement and regulation of Fe-rich phase morphology are the most effective methods to improve the performance of recycled aluminum alloys. Currently, the most widely used refiners are Al-Ti-B, Al-Ti-C, Al-10Sr, etc. Adding Al-Ti-B and Al-Ti-C to the aluminum alloy melt, the TiAl3, TiB2 and other particles therein can have a good grain refinement effect. Sr-containing refiners such as Al-10Sr are mainly used in cast aluminum alloys, and Al-Ti-B-Re and Al-Ti-C-Re refiners have been developed successively. Although rare earth elements such as La, Ce, Sc, and Er have a positive effect on the regulation of iron-rich phases, it is difficult to achieve industrial-scale application due to their high prices.

[0005] Patent CN118291791A discloses a modifier and a method for modifying the iron-rich phase in a recycled aluminum alloy. The modifier is mainly composed of Sc2O3 and chloride. The high surface activity of free Sc is utilized to adsorb on the surface of the primary iron-rich phase, thereby inhibiting the diffusion of Fe atoms and the growth of the iron-rich phase. At the same time, the generated nanoscale A12O3 is a good nucleation particle for the iron-rich phase, providing a large number of nucleation sites for the nucleation of the iron-rich phase.

[0006] Patent CN117144201A discloses an aluminum alloy refiner Al-Er-Zr-Ti with both grain refinement and microalloying effects, wherein the mass percentage of Er is 1-6%, the mass percentage of Ti is 0.1-1%, the mass percentage of Zr is 0.1-5%, and the balance is Al. The refiner prepared by this method has excellent refinement effect for pure aluminum or aluminum alloy, obvious refinement anti-fading property, and significant microalloying effect of the refined sample.

[0007] Patent CN118308630A discloses an Al-Ti-Nb-BC refiner for alloy casting, its preparation method and application. When the refiner of the invention refines aluminum silicon alloy, due to the addition of Nb element, it is not easy to form NbSi compounds with Si element, but promotes the formation of NbC, TiC, NbB2 and TiB2 nucleation particles, which effectively refines the grains of the alloy while preventing the grains that have already been formed from growing again, thereby ensuring the microscopic stability of the grain size.

[0008] In summary, although there are many types of refiners at present, there is no refiner specifically for recycled aluminum alloys with high Fe content that can simultaneously achieve grain refinement and Fe-rich phase morphology control and has low cost and is suitable for industrial application.

[0009] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0010] The purpose of the present invention is to provide a refiner, preparation method and application for composite grain refinement and Fe-rich phase regulation. The refiner of the present invention can simultaneously achieve grain refinement and regulation of Fe-rich phase morphology, and the recycled aluminum alloy has higher strength after refinement.

[0011] In order to achieve the above object, a technical solution provided by a specific embodiment of the present invention is as follows:

[0012] A refiner for composite grain refinement and Fe-rich phase regulation, wherein the element composition comprises, by weight percentage, Ti 4.85-5.2%, B 0.5-0.8%, Sr 6-8%, Mo 4.5-5.5%, Fe≤0.2%, Si≤0.15%, a single impurity ≤0.05%, a total impurity ≤0.15%, and the rest is Al and unavoidable impurities, wherein a single impurity ≤0.05%, a total impurity ≤0.15%.

[0013] In one or more embodiments of the present invention, the refiner contains TiAl3 particles, SrAl4 particles, Al 12Mo particles, TiB2 particles, MoB2 particles and Al2B particles.

[0014] In one or more embodiments of the present invention, the refiner comprises SrAl4 particles, Al 12 The average size of Mo particles and TiAl3 particles is ≤14μm, the average size of TiB2 particles, MoB2 particles, and Al2B particles is ≤1.4μm, and the content of particles with a size less than 2μm is ≥95%.

[0015] Another specific embodiment of the present invention provides a technical solution as follows:

[0016] A method for preparing a composite grain refiner and a Fe-rich phase control refiner comprises the following steps:

[0017] Step 1, using original aluminum ingot, Al-Ti master alloy, Al-B master alloy, Al-Mo master alloy, Al-Sr master alloy as raw materials, preparing with refiner element composition, wherein the refiner element composition includes, by weight percentage: Ti 4.85-5.2%, B 0.5-0.8%, Sr 6-8%, Mo 4.5-5.5%, Fe≤0.2%, Si≤0.15%, single impurity≤0.05%, total impurity≤0.15%, the rest is Al and unavoidable impurities, and single impurity≤0.05%, total impurity≤0.15%;

[0018] Step 2, heating the original aluminum ingot to 750-850° C. in a smelting furnace to melt, then adding Al-B master alloy, Al-Ti master alloy and Al-Mo master alloy, stirring and melting;

[0019] Step 3, cooling the smelting furnace to 730-760°C, refining with inert gas, standing and slagging;

[0020] Step 4, lowering the temperature of the smelting furnace to 720-740° C., adding Al-Sr master alloy, stirring and melting, refining with inert gas, standing and slagging;

[0021] Step 5, casting the melt to obtain an aluminum alloy cast rod;

[0022] Step 6: Heat the aluminum alloy cast rod to 420-480° C. and extrude it to obtain a refiner for composite grain refinement and Fe-rich phase regulation.

[0023] In one or more embodiments of the present invention, in step 3, high-purity argon is used for refining for 30 to 50 minutes, the H content in the melt after refining is ≤0.15ml / 100gAl, and the melt is allowed to stand for 5 to 10 minutes after refining; and / or,

[0024] In step 4, high-purity argon is used for refining for 10 to 30 minutes, and the H content in the melt after refining is ≤0.15ml / 100gAl. After refining, the melt is allowed to stand for 2 to 10 minutes.

[0025] Another specific embodiment of the present invention provides a technical solution as follows:

[0026] A composite grain refinement and Fe-rich phase control refiner is used for composite grain refinement and Fe-rich phase control of aluminum alloy with high Fe content, and the refiner is the composite grain refinement and Fe-rich phase control refiner or is prepared by the preparation method of the composite grain refinement and Fe-rich phase control refiner;

[0027] The aluminum alloy is 1XXX aluminum alloy, 3XXX aluminum alloy or 5XXX aluminum alloy.

[0028] In one or more embodiments of the present invention, when the aluminum alloy is 1XXX aluminum alloy, the impurity element Fe is ≤2% by mass, and the total content of other impurities is ≤1.5% by mass; and / or,

[0029] When the aluminum alloy is a 3XXX aluminum alloy, it contains, by mass percentage, 0.05-2% Mn, 0-2% Mg, ≤0.5% Zn, ≤0.5% Ti, ≤1.5% impurity element Fe, and the total content of other impurity elements is ≤1%, and the rest is Al; and / or,

[0030] When the aluminum alloy is a 5XXX aluminum alloy, it contains, by mass percentage, Mg 1-5.5%, Mn 0.05-1.5%, Cr 0-0.5%, Cu 0-0.8%, Zn 0-1.0%, Ti≤0.5%, the impurity element Fe content ≤0.8%, the total content of other impurity elements ≤0.5%, and the rest is Al.

[0031] In one or more embodiments of the present invention, the amount of the refiner added is 0.02-0.15wt% of the aluminum alloy melt.

[0032] In one or more embodiments of the present invention, the specific method of using the refiner is:

[0033] Recycled aluminum alloy is used as raw material, mixed with a small amount of original aluminum, heated to 750-850℃ in a smelting furnace to melt, and a melt is obtained;

[0034] The melt is subjected to composition adjustment, refining, slagging and standing, and the melt temperature is controlled at 720-740°C, and the H content in the melt is ≤0.15ml / 100gAl;

[0035] The refiner is added into the melt to be refined by adopting an online refinement method;

[0036] The melt is cast into ingots to obtain a secondary aluminum alloy.

[0037] In one or more embodiments of the present invention, the Fe-rich phase in the aluminum alloy is adjusted to transform the long needle-shaped β-Fe into Chinese character-shaped α-Fe, or promote the transformation of the α-Fe morphology from a complex fishbone shape or flower shape to a small Chinese character or bone shape.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] 1. The introduction of Mo element can introduce Al into the refiner 12 Mo particles can increase the number density of heterogeneous nucleation particles; secondly, Mo element is enriched around TiB2 particles, inhibiting the agglomeration and growth of TiB2 particles, improving the number density and distribution uniformity of TiB2 particles, and reducing the size of TiB2 particles. Mo element can also inhibit the nucleation and growth of Al3Ti particles, effectively reducing the number and size of Al3Ti particles. 12 The Mo particles are transformed into Al2B particles and MoB2 particles, which increases the number of heterogeneous nucleation cores and makes the Al2B particles more stable, thus solving the poisoning effect of impurity elements in the recycled aluminum alloy on the refiner.

[0040] 2. The introduction of Sr element can replace Ti element to form (Ti, Sr) Al3 particles, inhibit the growth of TiAl3 particles, and increase the number density of (Ti, Sr) Al3 or TiAl3 particles; Sr element can play a role similar to Mo element and enrich around TiB2 particles, inhibit the agglomeration and growth of TiB2 particles, improve the number density and distribution uniformity of TiB2 particles, and reduce the size of TiB2 particles. Sr element forms massive Al4Sr phase in the alloy. Due to the presence of TiB2, MoB2, and Al2B grain refining particles, the size of Al4Sr phase is significantly reduced, and the absorption rate in the subsequent use process is improved; Sr in the refiner will preferentially combine with Si element in the recycled aluminum alloy, avoiding Si poisoning of the refiner and improving the refinement effect of the refiner.

[0041] 3. The porosity in the casting structure caused by the introduction of Sr element is reduced. The traditional process adds Sr in the form of pure Sr or Al10Sr, Al20Sr master alloy, but the chemical property of Sr element is active, and it is easy to react with moisture in the air under high temperature conditions, resulting in an increase in the H element content in the aluminum alloy melt. In the subsequent casting process, the H element forms H2, which causes a large number of pores in the alloy casting structure. In addition, the large consumption of Sr element in this process reduces the actual recovery rate of Sr element and increases production costs. In the present invention, Sr element exists in the form of small-sized Al4Sr, and the size is fully refined, which is conducive to the rapid and uniform dispersion of Sr element in the melt, reduces the burning loss and hydrogen absorption behavior of Sr element, improves the actual recovery rate and reduces the porosity in the alloy casting structure.

[0042] 4. Due to the introduction of Mo and Sr elements, small-sized and evenly distributed TiAl3, SrAl4, Al 12 Mo, TiB2, MoB2, Al2B grain refining particles improve the refining effect of the refiner. 12 Mo and SrAl4 particles, due to their refined size, accelerate the rapid dissolution rate in the recycled aluminum alloy, releasing Mo and Sr atoms. Mo and Sr atoms are enriched around the Fe-rich phase to form composition supercooling, which inhibits the coarsening of the Fe-rich phase and its growth along a specific crystallographic direction. Therefore, it can refine the size and morphology of the Fe-rich phase and improve the strength and plasticity of the recycled aluminum alloy.

[0043] In summary, the refiner of the present invention can simultaneously achieve the functions of grain refinement of recycled aluminum alloy and morphology regulation of Fe-rich phase, and the grain refinement effect is better than that of the traditional Al-5Ti-B refiner. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0045] Figure 1 is a SEM photograph of the Al-Ti-B-Sr-Mo refiner in Example 1;

[0046] Figure 2 The Al3Ti / Al4Sr / Al of the Al-Ti-B-Sr-Mo refiner in Example 1 12 Mo particle size distribution diagram;

[0047] Figure 3 is the TiB2 particle size distribution diagram of the Al-Ti-B-Sr-Mo refiner in Example 1;

[0048] Figure 4 This is a polarized photo of the as-cast structure of the regenerated 5XXX aluminum alloy refined by the Al-Ti-B-Sr-Mo refiner in Example 1;

[0049] Figure 5 The Fe-rich phase morphology of the regenerated 5XXX aluminum alloy refined by the Al-Ti-B-Sr-Mo refiner in Example 1;

[0050] Figure 6 This is a polarized photo of the cast structure of the regenerated 3XXX aluminum alloy refined by the Al-Ti-B-Sr-Mo refiner in Example 2;

[0051] Figure 7 The Fe-rich phase morphology of the regenerated 3XXX aluminum alloy refined by the Al-Ti-B-Sr-Mo refiner in Example 2;

[0052] Figure 8 This is a polarized photograph of the cast structure of the regenerated 1XXX aluminum alloy refined by the Al-Ti-B-Sr-Mo refiner in Example 3;

[0053] Fig. 9 The Fe-rich phase morphology of the regenerated 1XXX aluminum alloy refined by the Al-Ti-B-Sr-Mo refiner in Example 3;

[0054] Fig.10 This is a polarized photo of the as-cast structure of the regenerated 5XXX aluminum alloy refined by the conventional Al-5Ti-1B refiner in Comparative Example 1;

[0055] Fig.11 The Fe-rich phase morphology of the regenerated 5XXX aluminum alloy refined by the conventional Al-5Ti-1B refiner in Comparative Example 1;

[0056] Fig.12 This is a polarized photo of the as-cast structure of the recycled 5XXX aluminum alloy produced by comparative example 2 using traditional Al-5Ti-1B refinement, Al5Mo and Al10Sr master alloys;

[0057] Fig.13 The Fe-rich phase morphology of the recycled 5XXX aluminum alloy produced by comparative example 2 using conventional Al-5Ti-1B refinement, Al5Mo and Al10Sr master alloys;

[0058] Fig.14 This is a polarized photo of the as-cast structure of the regenerated 3XXX aluminum alloy refined by using Al-Ti-B-Mo refiner in Comparative Example 3;

[0059] Fig.15 The Fe-rich phase morphology of the regenerated 3XXX aluminum alloy refined by using Al-Ti-B-Mo refiner in Comparative Example 3;

[0060] Fig.16 This is a polarized photo of the as-cast structure of the regenerated 1XXX aluminum alloy refined by using Al-Ti-B-Sr refiner in Comparative Example 4;

[0061] Fig.17 This is the Fe-rich phase morphology of the regenerated 1XXX aluminum alloy refined by Al-Ti-B-Sr refiner in comparative example 4. DETAILED DESCRIPTION

[0062] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0063] After decades of development, Al-5Ti-1B is the most widely used grain refiner in the industry. TiB2 and Al3Ti, as heterogeneous nucleation particles, undergo peritectic reaction during solidification and have obvious grain refining effect. However, conventional Al3Ti particles and TiB2 particles are large in size and mostly exist in agglomerates, with low number density and uneven distribution, which seriously affects the grain refining effect. In addition, complex impurity elements such as Fe, Si, Mn, Cr, and V in recycled aluminum silicon alloys can cause the refiner to decay, i.e., refinement poisoning. In addition, conventional refiners can only refine grains, but have no effect on refining and improving the morphology of the Fe-rich phase of recycled aluminum alloys with high Fe content.

[0064] The invention prepares a refiner in the manner of Ti 4.85-5.2wt%, B 0.5-0.8wt%, Sr 6-8wt%, Mo 4.5-5.5wt%, Fe≤0.2wt%, Si≤0.15wt%, a single impurity≤0.05wt%, a total impurity≤0.15wt%, and the rest is Al. The obtained refiner contains TiAl3, SrAl4, Al 12 Mo, TiB2, MoB2, Al2B grain refinement particles, and SrAl4, Al 12The average size of Mo and TiAl3 is ≤14μm, the average size of TiB2, MoB2, and Al2B particles is ≤1.4μm, and the content of particles smaller than 2μm is >95%. The grain refinement particles are small in size, high in number density, and evenly distributed, which can significantly improve the grain refinement effect. At the same time, they have a significant refinement and morphology control effect on the Fe-rich phase in the recycled aluminum alloy, solving the problems of high cost, easy poisoning, and unstable refinement effect when the existing refiners such as Al-5Ti-1B grain refiner are used to refine recycled aluminum alloys. At the same time, they have the functions of refining the Fe-rich phase and morphology control, and improve the strength of the recycled aluminum alloy.

[0065] The present invention is further described in detail below in conjunction with specific embodiments.

[0066] Example 1

[0067] The original aluminum ingot, Al-Ti master alloy, Al-B master alloy, Al-Mo master alloy and Al-Sr master alloy are prepared according to the following element compositions in weight percentage: Ti 4.9%, B 0.6%, Sr 6.5%, Mo 4.8%, Fe≤0.2%, Si≤0.15%, single impurity≤0.05%, total impurities≤0.15%, and the rest is Al.

[0068] First, heat the original aluminum ingot to 780℃ in a smelting furnace to melt it, then add Al-B master alloy, Al-Ti master alloy and Al-Mo master alloy, stir for 30 minutes, so that the master alloy is fully dissolved and evenly distributed. Then cool down to 740℃, use high-purity argon to refine for 30 minutes, then let it stand for 5 minutes, the H content in the melt after refining is ≤0.15ml / 100gAl, then scrape off the surface scum to obtain a pure aluminum alloy melt. Then cool down to 730℃, add Al-Sr master alloy, stir the melt for 20 minutes, so that the Al-Sr master alloy is fully dissolved and evenly distributed in the melt, use high-purity argon to refine for 15 minutes, control the H content in the melt to ≤0.15ml / 100gAl, let it stand for 5 minutes after refining, and scrape off the surface scum. Cast the melt into a cylindrical copper mold to obtain a diameter Al-Ti-B-Sr-Mo aluminum alloy casting rod, The Al-Ti-B-Sr-Mo aluminum alloy cast rod is heated to 450℃ and extruded at an extrusion speed of 3.5mm / s to obtain a refiner with a diameter of 9mm. The microstructure of the refiner is as follows Figure 1 shown.

[0069] Depend on Figure 1 The SEM photo of the medium refiner shows that in addition to the conventional TiAl3 particles and TiB2 particles, there are also Al 12The introduction of Mo particles and SrAl4 particles further increases the number density of TiAl3 particles and TiB2 particles in the refiner and makes them evenly distributed. Figure 2 and Figure 3 shown.

[0070] The refinement effect was verified by taking the common 5754 alloy as an example. The recycled aluminum alloy was used as the raw material, and a small amount of raw aluminum was added. The aluminum alloy melt was heated to 800°C in a smelting furnace for melting to obtain an aluminum alloy melt with an Fe content of 0.52wt%. The aluminum alloy melt was analyzed for composition, and the alloy composition was adjusted to 5754 alloy (except for Fe and Mn elements), and a high Fe content 5754 aluminum alloy melt with the following composition was obtained: Fe 0.52wt%, Si 0.2wt%, Mg 3.2wt%, Mn 0.85wt%, Cr0.1wt%, Zn 0.1wt%, and the rest was Al and unavoidable impurities.

[0071] After the above-mentioned high-Fe content 5754 aluminum alloy melt is refined, slag-stripped, and allowed to stand, the melt temperature is controlled at 720°C, and the H content in the melt is ≤0.15ml / 100gAl. The refiner is added to the melt by online refinement, and the amount of the refiner added is 0.1wt%. Then the melt is cast into an ingot, and the average grain size of the ingot structure is measured and the Fe-rich phase morphology is observed. Figure 4 , Figure 5 As shown in Table 1. After the casting, the ingot was kept at 480°C x 6h, and then the Vickers hardness was tested, as shown in Table 1.

[0072] Example 2

[0073] The original aluminum ingot, Al-Ti master alloy, Al-B master alloy, Al-Mo master alloy and Al-Sr master alloy are prepared according to the following element compositions in weight percentage: Ti 5.0%, B 0.7%, Sr 7%, Mo 5.0%, Fe≤0.2%, Si≤0.15%, single impurity≤0.05%, total impurities≤0.15%, and the rest is Al.

[0074] First, heat the original aluminum ingot to 800℃ in a smelting furnace to melt it, then add Al-B master alloy, Al-Ti master alloy and Al-Mo master alloy, stir for 45 minutes, so that the master alloy is fully dissolved and evenly distributed. Then cool to 740℃, use high-purity argon to refine for 45 minutes, then let it stand for 10 minutes, the H content in the melt after refining is ≤0.15ml / 100gAl, then scrape off the surface scum to obtain a pure aluminum alloy melt. Then cool to 735℃, add Al-Sr master alloy, stir the melt for 25 minutes, so that the Al-Sr master alloy is fully dissolved and evenly distributed in the melt, use high-purity argon to refine for 15 minutes, control the H content in the melt to ≤0.15ml / 100gAl, let it stand for 10 minutes after refining, and scrape off the surface scum. Cast the melt into a cylindrical copper mold to obtain a diameter Al-Ti-B-Sr-Mo aluminum alloy casting rod, The Al-Ti-B-Sr-Mo aluminum alloy cast rod was heated to 450°C and extruded at an extrusion speed of 4.0 mm / s to obtain a refiner with a diameter of 9 mm.

[0075] The refinement effect was verified by taking the common 3104 alloy as an example. The recycled aluminum alloy was used as the raw material, and a small amount of raw aluminum was added. The aluminum alloy melt was heated to 850°C in a smelting furnace for melting to obtain an aluminum alloy melt with an Fe content of 0.6wt%. The aluminum alloy melt was analyzed for composition, and the alloy composition was adjusted to 3104 alloy (except for Fe and Mn elements), and a high Fe content 3104 aluminum alloy melt with the following composition was obtained: Fe 0.6wt%, Si 0.2wt%, Mg 1.2wt%, Mn 1.0wt%, Cr 0.1wt%, Zn 0.1wt%, and the rest was Al and unavoidable impurities.

[0076] After the high Fe content 3104 aluminum alloy melt is refined, slag-stripped and allowed to stand, the melt temperature is controlled at 740°C, and the H content in the melt is ≤0.15ml / 100gAl. The refiner is added to the melt by online refinement, and the amount of the refiner added is 0.1wt%. The melt is then cast into an ingot, and the average grain size of the ingot structure is measured and the Fe-rich phase morphology is observed. Figure 6 , Figure 7 As shown in Table 1. After the casting, the ingot was kept at 480°C x 6h, and then the Vickers hardness was tested, as shown in Table 1.

[0077] Example 3

[0078] The original aluminum ingot, Al-Ti master alloy, Al-B master alloy, Al-Mo master alloy and Al-Sr master alloy are prepared according to the following element compositions in weight percentage: Ti 5.0%, B 0.8%, Sr 8%, Mo 5.0%, Fe≤0.2%, Si≤0.15%, single impurity≤0.05%, total impurities≤0.15%, and the rest is Al.

[0079] First, heat the original aluminum ingot to 800℃ in a smelting furnace to melt it, then add Al-B master alloy, Al-Ti master alloy and Al-Mo master alloy, stir for 45 minutes, so that the master alloy is fully dissolved and evenly distributed. Then cool to 740℃, use high-purity argon to refine for 45 minutes, then let it stand for 10 minutes, the H content in the melt after refining is ≤0.15ml / 100gAl, then scrape off the surface scum to obtain a pure aluminum alloy melt. Then cool to 735℃, add Al-Sr master alloy, stir the melt for 25 minutes, so that the Al-Sr master alloy is fully dissolved and evenly distributed in the melt, use high-purity argon to refine for 15 minutes, control the H content in the melt to ≤0.15ml / 100gAl, let it stand for 10 minutes after refining, and scrape off the surface scum. Cast the melt into a cylindrical copper mold to obtain a diameter Al-Ti-B-Sr-Mo aluminum alloy casting rod, The Al-Ti-B-Sr-Mo aluminum alloy cast rod was heated to 450°C and extruded at an extrusion speed of 4.0 mm / s to obtain a refiner with a diameter of 9 mm.

[0080] The refinement effect was verified by taking the common 1050 alloy as an example. Recycled aluminum alloy was used as raw material, and a small amount of original aluminum was added. It was heated to 800°C in a smelting furnace for melting to obtain an aluminum alloy melt with an Fe content of 0.8wt%. The aluminum alloy melt was analyzed for composition, and the alloy composition was adjusted to 1050 alloy (except for Fe and Mn elements), and a high Fe content 1050 aluminum alloy melt with the following composition was obtained: Fe 0.8wt%, Si 0.3wt%, Mg 0.05wt%, Mn 0.05wt%, Cu0.05wt%, V 0.05wt%, and the remaining impurities were individually ≤0.03%, and the rest were Al.

[0081] After the high Fe content 3104 aluminum alloy melt is refined, slag-stripped and allowed to stand, the melt temperature is controlled at 740°C, and the H content in the melt is ≤0.15ml / 100gAl. The refiner is added to the melt by online refinement, and the amount of the refiner added is 0.1wt%. The melt is then cast into an ingot, and the average grain size of the ingot structure is measured and the Fe-rich phase morphology is observed. Figure 8 , Fig. 9As shown in Table 1. After the casting, the ingot was kept at 480°C x 6h, and then the Vickers hardness was tested, as shown in Table 1.

[0082] Comparative Example 1

[0083] This comparative example uses a conventional Al-5Ti-B refiner purchased from the market, and the amount of the refiner added is 0.1wt% of the melt, and then the refinement effect is verified by taking the common 5754 alloy as an example. Recycled aluminum alloy is used as raw material, and a small amount of raw aluminum is added, and heated to 750°C in a smelting furnace for melting to obtain an aluminum alloy melt with an Fe element content of 0.52wt%. The aluminum alloy melt is analyzed for composition, and the alloy composition is adjusted to 5754 alloy (except for Fe and Mn elements), and a high Fe content 5754 aluminum alloy melt with the following composition is obtained: Fe 0.52wt%, Si 0.2wt%, Mg 3.2wt%, Mn0.85wt%, Cr 0.1wt%, Zn 0.1wt%, and the rest is Al and unavoidable impurities.

[0084] After the above-mentioned high-Fe content 5754 aluminum alloy melt is refined, slag-stripped, and allowed to stand, the melt temperature is controlled at 720°C, and the H content in the melt is ≤0.15ml / 100gAl. The refiner is added to the melt by online refinement, and the amount of the refiner added is 0.1wt%. Then the melt is cast into an ingot, and the average grain size of the ingot structure is measured and the Fe-rich phase morphology is observed. Fig.10 , Fig.11 As shown in Table 1. After the casting, the ingot was kept at 480°C x 6h, and then the Vickers hardness was tested, as shown in Table 1.

[0085] Comparative Example 2

[0086] This comparative example uses conventional Al-5Ti-B refiner, Al-5Mo master alloy and Al-10Sr master alloy purchased on the market, and then takes the common 5754 alloy as an example to verify the refinement effect. Recycled aluminum alloy is used as raw material, combined with a small amount of raw aluminum, heated to 800°C in a smelting furnace for melting, and an aluminum alloy melt with an Fe element content of 0.52wt% is obtained. The aluminum alloy melt is analyzed for composition, and the alloy composition is adjusted to 5754 alloy (except Fe and Mn elements), and a high Fe content 5754 aluminum alloy melt with the following composition is obtained: Fe 0.52wt%, Si 0.2wt%, Mg 3.2wt%, Mn 0.85wt%, Cr0.1wt%, Zn 0.1wt%, and the rest is Al and unavoidable impurities.

[0087] After the high Fe content 5754 aluminum alloy melt is refined, slag-stripped and allowed to stand, the melt temperature is controlled at 720°C, and the H content in the melt is ≤0.15ml / 100gAl. Al-5Mo master alloy and Al-10Sr master alloy are added, and the addition amount of Al-5Mo master alloy and Al-10Sr master alloy is 0.1wt%. The refiner is added to the melt by online refinement, and the addition amount of the refiner is 0.1wt%. Then the melt is cast into an ingot, and the average grain size of the ingot structure is measured and the Fe-rich phase morphology is observed, such as Fig.12 , Fig.13 As shown in Table 1. After the casting, the ingot was kept at 480°C x 6h, and then the Vickers hardness was tested, as shown in Table 1.

[0088] according to Fig.12 , Fig.13 As can be seen from Table 1, although the combined addition of Al-5Ti-B refiner, Al-5Mo master alloy and Al-10Sr master alloy also plays a role in refining grains and regulating the morphology of Fe-rich phase to a certain extent, its grain refinement obviously does not achieve the grain refinement effect in the embodiment of the present invention, and the alloy refined in this way has a large number of pore defects in the ingot structure, which will inevitably have an adverse effect on the strength and plasticity of the alloy.

[0089] Comparative Example 3

[0090] The original aluminum ingot, Al-Ti master alloy, Al-B master alloy and Al-Mo master alloy are prepared according to the following element compositions in weight percentage: Ti 4.9%, B 0.6%, Mo 4.8%, Fe≤0.2%, Si≤0.15%, single impurity≤0.05%, total impurity≤0.15%, and the rest is Al.

[0091] First, heat the original aluminum ingot to 780℃ in a smelting furnace to melt it, then add Al-B master alloy, Al-Ti master alloy and Al-Mo master alloy, stir for 30 minutes, so that the master alloy is fully dissolved and evenly distributed. Then cool it to 740℃, use high-purity argon gas to refine for 45 minutes, and then let it stand for 10 minutes. After refining, the H content in the melt is ≤0.15ml / 100gAl, and then scrape off the surface scum to obtain a pure aluminum alloy melt. Cast the melt into a cylindrical copper mold to obtain a diameter Al-Ti-B-Mo aluminum alloy casting rod, The Al-Ti-B-Mo aluminum alloy cast rod is heated to 450°C and extruded at an extrusion speed of 3.5 mm / s to obtain a refiner with a diameter of 9 mm.

[0092] The refinement effect was verified by taking the common 3104 alloy as an example. The recycled aluminum alloy was used as the raw material, and a small amount of raw aluminum was added. The aluminum alloy melt was heated to 850°C in a smelting furnace for melting to obtain an aluminum alloy melt with an Fe content of 0.6wt%. The aluminum alloy melt was analyzed for composition, and the alloy composition was adjusted to 3104 alloy (except for Fe and Mn elements), and a high Fe content 3104 aluminum alloy melt with the following composition was obtained: Fe 0.6wt%, Si 0.2wt%, Mg 1.2wt%, Mn 1.0wt%, Cr 0.1wt%, Zn 0.1wt%, and the rest was Al and unavoidable impurities.

[0093] After the high Fe content 3104 aluminum alloy melt is refined, slag-stripped and allowed to stand, the melt temperature is controlled at 740°C, and the H content in the melt is ≤0.15ml / 100gAl. The refiner is added to the melt by online refinement, and the amount of the refiner added is 0.1wt%. The melt is then cast into an ingot, and the average grain size of the ingot structure is measured and the Fe-rich phase morphology is observed. Fig.14 , Fig.15 As shown in Table 1. After the casting, the ingot was kept at 480°C x 6h, and then the Vickers hardness was tested, as shown in Table 1.

[0094] Comparative Example 4

[0095] The original aluminum ingot, Al-Ti master alloy, Al-B master alloy and Al-Sr master alloy are prepared according to the following element compositions in weight percentage: Ti 4.9%, B 0.6%, Sr 6.5%, Fe≤0.2%, Si≤0.15%, single impurity≤0.05%, total impurity≤0.15%, and the rest is Al.

[0096] First, heat the original aluminum ingot to 780℃ in a smelting furnace to melt it, then add Al-B master alloy and Al-Ti master alloy, stir for 30 minutes, so that the master alloy is fully dissolved and evenly distributed. Then cool it to 740℃, use high-purity argon to refine for 30 minutes, then let it stand for 5 minutes, the H content in the melt after refining is ≤0.15ml / 100gAl, then scrape off the surface scum to obtain a pure aluminum alloy melt. Then cool it to 730℃, add Al-Sr master alloy, stir the melt for 20 minutes, so that the Al-Sr master alloy is fully dissolved and evenly distributed in the melt, use high-purity argon to refine for 15 minutes, control the H content in the melt to ≤0.15ml / 100gAl, let it stand for 5 minutes after refining, and scrape off the surface scum. Cast the melt into a cylindrical copper mold to obtain a diameter Al-Ti-B-Sr aluminum alloy casting rod, The Al-Ti-B-Sr aluminum alloy cast rod is heated to 450℃ and extruded at a speed of 3.5mm / s to obtain a refiner with a diameter of 9mm. The microstructure of the refiner is as follows Figure 1 shown.

[0097] The refinement effect was verified by taking the common 1050 alloy as an example. Recycled aluminum alloy was used as raw material, and a small amount of original aluminum was added. It was heated to 800°C in a smelting furnace for melting to obtain an aluminum alloy melt with an Fe content of 0.8wt%. The aluminum alloy melt was analyzed for composition, and the alloy composition was adjusted to 1050 alloy (except for Fe and Mn elements), and a high Fe content 1050 aluminum alloy melt with the following composition was obtained: Fe 0.8wt%, Si 0.3wt%, Mg 0.05wt%, Mn 0.05wt%, Cu0.05wt%, V 0.05wt%, and the remaining impurities were individually ≤0.03%, and the rest were Al.

[0098] After the high Fe content 1050 aluminum alloy melt is refined, slag-stripped and allowed to stand, the melt temperature is controlled at 720°C, and the H content in the melt is ≤0.15ml / 100gAl. The refiner is added to the melt by online refinement, and the amount of the refiner added is 0.1wt%. The melt is then cast into an ingot, and the average grain size of the ingot structure is measured and the Fe-rich phase morphology is observed. Fig.16 , Fig.17 As shown in Table 1. After the casting, the ingot was kept at 480°C x 6h, and then the Vickers hardness was tested, as shown in Table 1.

[0099] Table 1 Average grain size, Fe-rich phase morphology and Vickers hardness of ingot

[0100]

[0101] The refiner in Comparative Example 3 is an Al-Ti-B-Mo refiner, and the refiner in Comparative Example 4 is an Al-Ti-B-Sr refiner. According to the grain refining and Fe-rich phase control effects of the refiners in Comparative Examples 3 and 4, compared with Examples 1-3, the grain refining effects and Fe-rich phase control effects of the refiners in Comparative Examples 3 and 4 are weaker and cannot reach the levels of Examples 1-3.

[0102] Combining comparative examples 1-3 and comparative examples 1-4, it can be seen that the average grain size of the aluminum alloy refined by the refiner of the present invention is small, and the grain refining effect is better than the traditional Al-5Ti-B or Al-5Ti-B and Al10Sr, Al5Mo master alloy composite addition method, and the grain refining effect can be improved by more than 20%. In addition, the refiner of the present invention can transform the complex large-sized fishbone and flower-shaped α-Fe into Chinese character-shaped or bone-shaped α-Fe, and the microhardness and alloy strength of the ingot after homogenization are improved, which is significantly improved compared with the comparative example.

[0103] In summary, the refiner in the present invention has significant grain refining and Fe-rich phase regulation effects on high Fe content 1XXX, 3XXX and 5XXX recycled aluminum alloys. The grain refining effect is improved by more than 20% compared with the traditional refiner, and the iron-rich phase morphology can be transformed from complex fishbone, flower-shaped, and long strip-shaped to Chinese character-shaped or bone-shaped α-Fe. After refinement, the alloy has higher strength and plasticity, low cost, no rare earth elements need to be added, and is suitable for industrial production.

[0104] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0105] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A composite grain refinement and Fe-rich phase control refiner, characterized in that: Its element composition includes, by weight percentage: Ti 4.85-5.2%, B 0.5-0.8%, Sr 6-8%, Mo 4.5-5.5%, Fe≤0.2%, Si≤0.15%, and the rest is Al and inevitable impurities, with a single impurity ≤0.05% and a total impurity ≤0.15%.

2. The composite grain refinement and Fe-rich phase control refiner according to claim 1, characterized in that: The refiner contains TiAl3 particles, SrAl4 particles, Al 12 Mo particles, TiB2 particles, MoB2 particles and Al2B particles.

3. The composite grain refinement and Fe-rich phase control refiner according to claim 2, characterized in that: In the refiner, SrAl4 particles, Al 12 The average size of Mo particles and TiAl3 particles is ≤14μm, the average size of TiB2 particles, MoB2 particles, and Al2B particles is ≤1.4μm, and the content of particles with a size less than 2μm is ≥95%.

4. A method for preparing a composite grain refiner and a Fe-rich phase control refiner, characterized in that: The steps include: Step 1, using original aluminum ingot, Al-Ti master alloy, Al-B master alloy, Al-Mo master alloy, Al-Sr master alloy as raw materials, preparing with refiner element composition, wherein the refiner element composition includes, by weight percentage: Ti 4.85-5.2%, B 0.5-0.8%, Sr 6-8%, Mo 4.5-5.5%, Fe≤0.2%, Si≤0.15%, single impurity≤0.05%, total impurity≤0.15%, and the rest is Al; Step 2, heating the original aluminum ingot to 750-850° C. in a smelting furnace to melt, then adding Al-B master alloy, Al-Ti master alloy and Al-Mo master alloy, stirring and melting; Step 3, cooling the smelting furnace to 730-760°C, refining with inert gas, standing and slagging; Step 4, lowering the temperature of the smelting furnace to 720-740° C., adding Al-Sr master alloy, stirring and melting, refining with inert gas, standing and slagging; Step 5, casting the melt to obtain an aluminum alloy cast rod; Step 6: Heat the aluminum alloy cast rod to 420-480° C. and extrude it to obtain a refiner for composite grain refinement and Fe-rich phase regulation.

5. The method for preparing a composite grain refiner and Fe-rich phase control refiner according to claim 4, characterized in that: In step 3, high-purity argon is used for refining for 30 to 50 minutes, the H content in the melt after refining is ≤0.15ml / 100gAl, and the melt is allowed to stand for 5 to 10 minutes after refining; and / or, In step 4, high-purity argon is used for refining for 10 to 30 minutes, and the H content in the melt after refining is ≤0.15ml / 100gAl. After refining, the melt is allowed to stand for 2 to 10 minutes.

6. A composite grain refinement and Fe-rich phase control refiner for composite grain refinement and Fe-rich phase control of high Fe content aluminum alloy, the refiner being the composite grain refinement and Fe-rich phase control refiner according to any one of claims 1 to 3 or prepared by the preparation method of the composite grain refinement and Fe-rich phase control refiner according to any one of claims 4 to 5; The aluminum alloy is 1XXX aluminum alloy, 3XXX aluminum alloy or 5XXX aluminum alloy.

7. The use of the composite grain refinement and Fe-rich phase control refiner according to claim 6, characterized in that: When the aluminum alloy is 1XXX aluminum alloy, the impurity element Fe is ≤2% by mass, and the total content of other impurities is ≤1.5% by mass; and / or, When the aluminum alloy is a 3XXX aluminum alloy, it contains, by mass percentage, 0.05-2% Mn, 0-2% Mg, ≤0.5% Zn, ≤0.5% Ti, ≤1.5% impurity element Fe, and the total content of other impurity elements is ≤1%, and the rest is Al; and / or, When the aluminum alloy is a 5XXX aluminum alloy, it contains, by mass percentage, Mg 1-5.5%, Mn 0.05-1.5%, Cr 0-0.5%, Cu 0-0.8%, Zn 0-1.0%, Ti≤0.5%, the impurity element Fe content ≤0.8%, the total content of other impurity elements ≤0.5%, and the rest is Al.

8. The use of the composite grain refinement and Fe-rich phase control refiner according to claim 6, characterized in that: The addition amount of the refiner is 0.02-0.15wt% of the aluminum alloy melt.

9. The use of the composite grain refinement and Fe-rich phase control refiner according to claim 6, characterized in that: The specific method of using the refiner is: Recycled aluminum alloy is used as raw material, mixed with a small amount of original aluminum, heated to 750-850℃ in a smelting furnace to melt, and a melt is obtained; The melt is subjected to composition adjustment, refining, slagging and standing, and the melt temperature is controlled at 720-740°C, and the H content in the melt is ≤0.15ml / 100gAl; The refiner is added into the melt to be refined by adopting an online refinement method; The melt is cast into ingots to obtain a secondary aluminum alloy.

10. The use of the composite grain refinement and Fe-rich phase control refiner according to claim 6, characterized in that: The Fe-rich phase in the aluminum alloy is adjusted to transform the long needle-shaped β-Fe into Chinese character-shaped α-Fe, or to promote the morphology of α-Fe from complex fishbone, flower, and long strip shapes to small Chinese character or bone shapes.

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