CN110735060A - A Continuous Orthogonal Rolling Method for Improving Properties of Aluminum Alloys - Google Patents

Abstract

The invention discloses a continuous orthogonal rolling method for improving the properties of an aluminum alloy. The cast aluminum alloy rough blank is subjected to multiple passes of hot rolling. The two orthogonal planes of the rough blank are rotated 90° orthogonally along the rolling direction, and then they pass through the rollers again, and the rolling is repeated many times. Each orthogonal rolling process is the first time the rough blank passes through the rollers- Orthogonal rotation - the rough blank passes through the rollers again. When the orthogonally rolled sample reaches a certain thickness, the orthogonal rotation is stopped, and the roll gap is adjusted for rolling, and finally the total reduction of the as-cast alloy rough blank is 60-80%, thereby obtaining the orthogonally rolled product. . The orthogonal rolling method of the invention has simple process requirements, high preparation efficiency and low cost, makes the structure of the as-cast aluminum alloy uniform, and improves the strength, elongation and mechanical properties of the alloy.

Description

A Continuous Orthogonal Rolling Method for Improving Properties of Aluminum Alloys

technical field

The invention belongs to the technical field of metal material preparation, and relates to a continuous orthogonal rolling method for improving the properties of an aluminum alloy.

Background technique

Aluminum and its alloys play a very important role in modern industry and are widely used. As a common material in industrial production, it has many advantages in itself, such as light weight, corrosion resistance, good electrical and thermal conductivity, excellent plastic forming performance and low practical price. Therefore, there is a wide range of needs in aerospace, construction, automobile manufacturing and other fields.

Due to the existence of casting defects, as-cast metal has poor performance and often cannot meet the needs of industrial production. Therefore, many scholars have carried out research on how to improve the performance of as-cast metal. Generally, the performance of the as-cast metal can be effectively improved by post-processing, while the ordinary rolling process along the rolling direction can improve its strength, but there will be a decrease in elongation and plastic deformation capacity, etc. question. As for how to ensure the strength of metal alloys, its plastic deformation ability is also improved, which is an urgent problem to be solved at present.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a continuous orthogonal rolling method for improving the properties of aluminum alloys, and to improve the strength and elongation of cast aluminum alloys.

In order to achieve the above object, the technical scheme adopted in the present invention is: a continuous orthogonal rolling method for improving the performance of aluminum alloy, the flow chart of which is shown in Figure 1, and the rolling method is specifically carried out according to the following steps:

1) Preheat the mold in an environment with a temperature of 240-250°C for 30-40 minutes to obtain a pre-heated mold;

2) Calculate the mass ratio of pure aluminum ingot and master alloy (AlCu50) according to the formula (m ₁ ×50%)/(m ₁ +m ₂ )=5%, where m ₁ is the mass of master alloy, m ₂ is the quality of pure aluminum ingots; respectively take pure aluminum ingots and master alloys whose masses satisfy this formula, heat the pure aluminum ingots to melting, add master alloys to the molten aluminum, and let them stand for 1-2 minutes after the master alloys are melted. , fully stirred, and after slag removal, the alloy melt is obtained; the alloy melt is cast into a preheated mold, and after solidification, the riser is cut to obtain the as-cast alloy rough embryo;

Or, calculate the mass ratio of pure aluminum ingot and master alloy (AlCu50) according to the formula (m ₁ ×50%)/(m ₁ +m ₂ )=5%, where m ₁ is the mass of master alloy, m ₂ is the quality of pure aluminum ingots; respectively take pure aluminum ingots and master alloys whose masses satisfy this formula, heat the pure aluminum ingots to melting, add master alloys to the molten aluminum, and let them stand for 1-2 minutes after the master alloys are melted. , fully stirred, and after slag removal, the alloy melt was obtained; when the temperature of the alloy melt dropped to 750 °C, a refiner was added. Stir, after slag removal, cast into the preheated mold, after solidification, cut the riser to obtain the as-cast alloy rough embryo;

The refiner is Al5Ti1B refiner. After adding the refiner, the grains are refined and the casting structure is more uniform.

3) Put the as-cast alloy rough embryo into the heat treatment furnace, heat it up to 400-450 ℃, hold the temperature for 30-40 minutes, and then carry out hot rolling; The two orthogonal planes of the billet along the rolling direction are rotated 90° orthogonally, and then it is rolled through the rolls again, and then it is placed in a heat treatment furnace and kept at a temperature of 400 to 450 ° C. 6 ~ 10min, waiting for the next orthogonal rolling;

During the re-rolling process after the orthogonal rotation, the initial hot-rolled blank should be kept free from deflection.

4) Reduce the roll gap by 1-2mm, repeat step 3), and then repeat step 3) multiple times. During the repeated process, the roll gap needs to be reduced before each rolling, so that the The reduction amount is 5 to 10%; until a billet with a thickness of 6 to 8 mm is obtained;

During each rolling process in step 4), keep the hot-rolled billet from deflecting.

5) Adjust the roll gap and roll the billet, so that the total reduction of the as-cast alloy rough billet is 60-80%, and the desired orthogonal rolled product is obtained.

The preparation method of the invention has the advantages of simple process, high preparation efficiency and low cost. The orthogonal rolling method solves the problems of poor alloy performance and uneven structure, improves the strength and elongation of the alloy, and significantly improves the mechanical properties. Compared with the as-cast samples and the products without orthogonal rolling, the as-cast microstructure after orthogonal rolling is more uniform, some casting defects are eliminated, and the performance is greatly improved.

Description of drawings

FIG. 1 is a schematic flow chart of the rolling method of the present invention.

FIG. 2 is an engineering stress-strain curve diagram of the cross-rolled product prepared in Example 1, the as-cast alloy blank prepared in Example 1, and the rolled product prepared in Comparative Example 1. FIG.

3 is an engineering stress-strain curve diagram of the cross-rolled product prepared in Example 2, the as-cast alloy rough billet prepared in Example 1, and the rolled product prepared in Comparative Example 2.

Figure 4 is a microstructure diagram of the as-cast alloy rough embryo.

5 is a structure diagram of the rolled product obtained in Comparative Example 1, the cross-rolled product obtained in Example 1, and the cross-rolled product obtained in Example 2.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

Example 1

The mold was preheated in a holding furnace with a temperature of 250°C for 30 minutes to obtain a preheated mold; 1687.5g of pure aluminum ingots were placed in a melting furnace, heated to melting, and 187.5g of master alloy was added to the molten aluminum. (AlCu50), after the master alloy is melted, let it stand for 2 minutes, fully stir, remove the surface scum, cast it into the preheated mold, cut the riser, and obtain a size of 100mm × 19.6 mm × 19.6 mm (length × width × Thick) as-cast alloy rough embryo; then, the as-cast alloy rough embryo is put into the heat treatment furnace, heated to 400 ℃, and kept for 40 minutes. During the heat preservation process, the rotational speed of the rolling mill rolls was adjusted to 10 r/min. Next, the heat-preserved as-cast alloy blanks are sent to the rolls for hot rolling to form the primary hot-rolled blanks. Through roll rolling, the initial hot-rolled billet should not be deflected during the re-rolling process after orthogonal rotation; after that, the initial orthogonal rolling sample was placed in a heat treatment furnace with a temperature of 400 ° C, and the temperature was kept for 10 minutes. The roll gap is reduced by 1mm, and the reheated sample is hot-rolled. Then, it is rotated orthogonally by 90° to perform rolling. After repeated hot rolling and orthogonal rotation of 90°, rolling is performed again until a billet with a thickness of 7mm is obtained. ; At this time, stop the orthogonal rotation, adjust the roll gap, roll the billet, and finally roll it into a flat plate, so that the total reduction of the as-cast alloy rough billet reaches 80%, and the rolling is completed, and a positive Delivered as rolled product.

Comparative Example 1

The as-cast alloy rough embryo was obtained according to the method of Example 1; the as-cast alloy rough embryo was only subjected to multiple passes of hot rolling, and rolled into a flat plate, without orthogonal rotation during the hot rolling process, to obtain a total pressure Rolled products with a lower weight of 80%.

Example 2

The mold was preheated in an incubator with a temperature of 240°C for 30 minutes to obtain a preheated mold; 1705.5g of pure aluminum ingots were placed in a melting furnace, heated to melting, and 189.5g of master alloy was added to the molten aluminum , after the master alloy is melted, let it stand for 1 min, fully stir, remove the surface scum, and obtain the alloy melt; when the temperature of the alloy melt drops to 750 ℃, add 9.475g of refiner (Al5Ti1B), after fully stirring, cast Put it into the preheated mold, solidify, cut the riser, and obtain the as-cast alloy rough embryo with a specification of 100mm × 19.6 mm × 19.6 mm. Then, put the as-cast alloy rough embryo into a heat treatment furnace, heat it up to 450 ° C, and keep the temperature. 30min; during the heat preservation process, the rotational speed of the rolling mill rolls was adjusted to 10r/min. Then, the as-cast alloy rough embryo after heat preservation is sent to the roll, after the rough embryo passes through the roll for the first time, the first hot rolling billet is formed. Make it pass through the rolls again, and keep the initial hot-rolled embryos from deflecting during the re-rolling process after orthogonal rotation; then, put the initial orthogonal rolling samples into a heat treatment furnace with a temperature of 450 ° C, and keep the temperature for 6 minutes; Reduce the roll gap by 2mm, hot-roll the sample after re-insulation, then rotate it orthogonally by 90°, and roll it again. Repeat the hot rolling and orthogonal rotation by 90°, and then roll again until a thickness of 6mm is obtained. At this time, stop the orthogonal rotation, adjust the roll gap, and roll the billet, and finally the total reduction of the as-cast alloy rough billet is 70%, and the orthogonally rolled product is obtained.

Comparative Example 2

The as-cast alloy rough blank was obtained by the method of Example 2; the as-cast alloy rough blank was only subjected to multiple passes of hot rolling, and rolled into a flat plate, without orthogonal rotation during the hot rolling process, and finally the total pressing The lower weight was 70%, and a rolled product was obtained.

The engineering stress-strain curves of the cross-rolled product prepared in Example 1, the as-cast alloy rough billet prepared in Example 1, and the rolled product prepared in Comparative Example 1 are shown in FIG. 2 . It can be seen from FIG. 2 that the mechanical properties of the orthogonally rolled product prepared in Example 1 are significantly improved, indicating that the orthogonal rolling method of the present invention can effectively improve the properties of the as-cast aluminum alloy.

The engineering stress-strain curves of the cross-rolled product prepared in Example 2, the as-cast alloy rough billet prepared in Example 2, and the rolled product prepared in Comparative Example 2 are shown in FIG. 3 . Figure 3 shows that the strength and elongation of the orthogonally rolled product after adding the refiner are significantly improved compared with the as-cast product and the rolled product without orthogonal rolling, indicating that the orthogonal rolling method of the present invention can Effectively improve the properties of aluminum alloys.

Figure 4 is a microstructure diagram (Figure 4a) of the as-cast alloy blank (Example 1) without refining agent and the microstructure diagram (Figure 4b) of the as-cast alloy (Example 2) with refining agent added. It can be seen from the figure that the alloy structure with the addition of the refiner is more uniform and fine, indicating that the alloy structure is refined after the addition of the refiner, the structure becomes uniform, some casting defects are eliminated, and the performance is greatly improved.

FIG. 5 is the microstructure diagram of the rolled product prepared in Comparative Example 1 ( FIG. 5 a ), the microstructure diagram of the cross-rolled product prepared in Example 1 ( FIG. 5 b ), and the cross-rolled product prepared in Example 2 The histogram of the state product (Fig. 5c). The microstructure of Fig. 5a is taken from the plane composed of rolling direction (RD) and normal direction (ND), Fig. 5b is also taken from this plane, and Fig. 5c is taken from the plane composed of transverse direction (TD) and normal direction (ND) On the plane, through the comparison of the structures on different planes, it is found that the structure after orthogonal rolling is more uniform, indicating that the orthogonal rolling method of the present invention can make the structure more uniform.

Example 3

The mold was preheated in a holding furnace with a temperature of 245°C for 40 minutes to obtain a preheated mold; 1723.5g of pure aluminum ingots were put into the melting furnace, heated to melting, and 191.5g of master alloy was added to the molten aluminum. , after the master alloy is melted, let it stand for 1.5min, fully stir, remove the surface scum, and obtain the alloy melt; when the temperature of the alloy melt drops to 750 ℃, add 9.575g of refiner (Al5Ti1B), after fully stirring, Cast into the preheated mold, and after solidification, cut the riser to obtain the as-cast alloy rough embryo with a size of 100mm × 19.6 mm × 19.6 mm; then, put the as-cast alloy rough embryo into the heat treatment furnace and heat it up to 425 ° C , heat preservation for 35min; in the process of heat preservation, the speed of the rolling mill roll is adjusted to 10r/min. Then, the as-cast alloy rough embryo after heat preservation is sent to the roll, after the rough embryo passes through the roll for the first time, the first hot rolling billet is formed. Make it pass through the rolls again, and keep the initial hot-rolled embryo from deflecting during the re-rolling process after orthogonal rotation; then, put the initial orthogonal rolling sample into a heat treatment furnace with a temperature of 425 ℃, and keep it for 8 minutes; Reduce the roll gap by 1.5mm, hot-roll the heat-preserved sample, then rotate it orthogonally by 90°, and roll it again. At this time, stop the orthogonal rotation, adjust the roll gap, and roll the billet, so that the total reduction of the as-cast alloy rough billet is 60%, and the orthogonally rolled product is obtained.

Claims (6)

1. a continuous orthogonal rolling method for improving aluminum alloy performance, is characterized in that, this rolling method is specifically carried out according to the following steps: 1) Preheat the mold required for casting; 2) Calculate the mass ratio of pure aluminum ingot and master alloy according to the formula (m ₁ ×50%)/(m ₁ +m ₂ )=5%, where m ₁ is the mass of the master alloy, and m ₂ is pure aluminum The quality of the ingot; take the pure aluminum ingot and the master alloy whose quality meets the formula, melt the pure aluminum ingot, add the master alloy, after the master alloy is melted, let it stand, fully stir and remove the slag, and cast it into a preheated mold. Solidification to obtain as-cast alloy rough embryo; Or, calculate the mass ratio of pure aluminum ingot and master alloy according to the formula (m ₁ ×50%)/(m ₁ +m ₂ )=5%, where m ₁ is the mass of master alloy and m ₂ is pure aluminum The quality of the ingot; take the pure aluminum ingot and the master alloy whose quality meets the formula, melt the pure aluminum ingot, add the master alloy, let the master alloy melt, let it stand, fully stir and remove the slag, and obtain the alloy melt. When the temperature of the molten metal drops to 750°C, add a refiner, stir fully, cast it into a preheated mold, and solidify to obtain a rough as-cast alloy; 3) The as-cast alloy rough embryo is heated to 400-450 ℃, kept for 30-40 minutes, hot-rolled to form the primary hot-rolled embryo, and the two orthogonal planes of the primary hot-rolled embryo along the rolling direction are made 90° orthogonal After rotating, after rolling again, keep the temperature at 400-450℃ for 6-10min; 4) Reduce the roll gap by 1-2mm, repeat step 3), and then repeat step 3) multiple times. During the repeated process, the roll gap needs to be reduced before each rolling, so that the The reduction amount is 5 to 10%; until a billet with a thickness of 6 to 8 mm is obtained; 5) Stop the orthogonal rotation, adjust the roll gap, and roll the billet so that the total reduction of the as-cast alloy rough billet is 60-80%, and the orthogonal rolled product is obtained. 2 . The continuous orthogonal rolling method for improving the properties of aluminum alloys according to claim 1 , wherein in the step 1), the mold is placed in an environment with a temperature of 240-250° C. for 30-40 minutes to preheat. 3 . , the mold must be preheated. 3 . The continuous orthogonal rolling method for improving the properties of an aluminum alloy according to claim 1 , wherein, in the step 2), after the master alloy is melted, it is allowed to stand for 1-2 minutes. 4 . 4. The continuous orthogonal rolling method for improving the properties of an aluminum alloy according to claim 1, wherein in the step 2), the quality of the refiner is 0.5 of the sum of the quality of the pure aluminum ingot and the quality of the master alloy %. 5 . The continuous orthogonal rolling method for improving the properties of an aluminum alloy according to claim 1 or 4 , wherein the refiner is an Al5Ti1B refiner. 6 . 6. The continuous orthogonal rolling method for improving the properties of an aluminum alloy according to claim 1, characterized in that, in the steps 3) and 4), in the process of re-rolling after the orthogonal rotation, the billet is kept from being rolled. deflection occurs.

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