Online heat treatment method for continuous cast rolling of aluminum alloy

Abstract

The invention relates to an online heat treatment method for continuous cast rolling of an aluminum alloy. An on-line heat treatment method for continuous cast rolling of aluminum alloy comprises the steps that after a cast-rolled aluminum cast-rolled plate passes through a hydraulic shear, the cast-rolled aluminum cast-rolled plate is forcibly cooled to be below 200 DEG C, and then a cast-rolled coil is produced through a deflector roller, a wrapper pressing roller and a coiling machine in an upper coiling mode. According to the on-line heat treatment method for continuous cast rolling of the aluminum alloy, the tensile strength is improved, and meanwhile the ductility is not affected.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum alloys, and in particular relates to an online heat treatment method for continuous casting and rolling of aluminum alloys. Background Art

[0002] Continuous casting and rolling of aluminum alloys is a production process in which liquid aluminum is continuously input between the roll gaps of two relatively rotating and water-cooled rolls, and aluminum alloy sheet and coil billets are continuously rolled out through cooling, casting, and continuous rolling. Since cooling, casting, and rolling are completed in one process, continuous casting and rolling of aluminum alloys usually produces 1XXX, 3XXX, and 8XXX series aluminum alloys. With technological advances and market competition, downstream users need to continuously improve the performance requirements of aluminum cast and rolled sheet products, thereby improving the mechanical properties of subsequent processed products - tensile strength and elongation.

[0003] The existing technology mainly adopts the method of adjusting alloy elements, adding strengthening phases in the process of aluminum alloy batching, forming new solid solution phases to improve tensile strength. However, due to the increase of solid solution compounds, the elongation will be reduced.

[0004] In the prior art, rare earth and other additives are used to refine the grains of aluminum alloys to make the internal structure denser, thereby improving product performance. However, in actual production practice, it is difficult to significantly increase the tensile strength while also increasing the elongation, and the elongation may even decrease.

[0005] Therefore, a new method is currently needed, which can improve the tensile strength while at least not affecting the elongation, and is easy to implement. Based on this, the present invention proposes a new method for online heat treatment of aluminum alloy continuous casting and rolling, which improves the tensile strength while not affecting the elongation. Summary of the invention

[0006] The object of the present invention is to provide an online heat treatment method for continuous casting and rolling of aluminum alloy, which can improve the tensile strength without affecting the elongation.

[0007] In order to achieve the above purpose, the technical solution adopted is:

[0008] An online heat treatment method for continuous casting and rolling of aluminum alloys comprises: the aluminum cast-rolled plate after cast-rolling is subjected to hydraulic shearing, forced cooling to below 200°C, and then the cast-rolled coil is produced by an upper coiling method through a deflection roller, a coiling-assisting pressure roller and a coiler.

[0009] Furthermore, the temperature of the cast aluminum plate is 400-420°C.

[0010] Furthermore, the strong cooling uses compressed air with a temperature below 10°C.

[0011] Furthermore, the strong cooling is at least 60 seconds.

[0012] Furthermore, the coiling-assisting pressing roller ensures that the aluminum coil is tightly wound.

[0013] Furthermore, the rolling assistance pressure roller is a hollow water-cooled structure.

[0014] Furthermore, the auxiliary winding pressure roller is located 30-50 mm behind the cutting point of the winding shaft.

[0015] Furthermore, the pressure of the auxiliary winding pressure roller is 0.3-0.5 MPa.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The technical solution of the present invention proposes for the first time an online heat treatment process in the continuous production of aluminum casting and rolling, and improves the tensile strength of the product by forced cooling with cold air. After the aluminum casting and rolling plate that has undergone the online heat treatment process is processed and produced in the post-process, the mechanical properties of the aluminum plate and strip product - the tensile strength is increased by more than 10MPa, and the elongation remains unchanged, achieving the effect of improving the tensile strength without affecting the elongation.

[0018] 2. The technical solution of the present invention is to install an air cooling device in the transition zone between the hydraulic shear and the deflection roller of the existing casting and rolling mill, and to add a coiling-assisting pressing roller to the coiler. The investment cost is low and it is easy to start and shut down. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a diagram of the original aluminum alloy continuous casting and rolling mill;

[0020] Figure 2 This is the diagram of the aluminum alloy continuous casting and rolling mill after adding online heat treatment;

[0021] In the attached drawings, 1 is a degassing box; 2 is a filter box, 3 is a casting nozzle, 4 is a casting roller, 5 is an exit guide roller, 6 is a hydraulic shear, 7 is a deflection roller; 8 is a coiler, 9 is high-temperature aluminum liquid, 10 is an aluminum cast-rolled slab, 11 is an air-cooling heat treatment device, and 12 is a coiling-assisting pressing roller. DETAILED DESCRIPTION

[0022] In order to further explain the online heat treatment method of aluminum alloy continuous casting and rolling of the present invention and achieve the expected purpose of the invention, the following is a detailed description of the online heat treatment method of aluminum alloy continuous casting and rolling proposed by the present invention, its specific implementation method, structure, characteristics and efficacy in combination with the preferred embodiment. In the following description, different "one embodiment" or "embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0023] The following is a detailed description of an online heat treatment method for continuous casting of aluminum alloy according to the present invention in conjunction with specific embodiments:

[0024] The invention discloses an online heat treatment method for continuous casting of aluminum alloy, which uses compressed cold air below 10°C to forcefully cool the high-temperature aluminum cast-rolled plate online for more than 60 seconds, so that the high-temperature aluminum cast-rolled plate is rapidly cooled from 400-420°C to below 200°C, and the mechanical properties of the aluminum plate and strip, namely, the tensile strength is increased by more than 10MPa, and the elongation remains unchanged. The technical scheme of the invention is:

[0025] An online heat treatment method for continuous casting and rolling of aluminum alloys comprises: the aluminum cast-rolled plate after cast-rolling is subjected to hydraulic shearing, forced cooling to below 200°C, and then the cast-rolled coil is produced by an upper coiling method through a deflection roller, a coiling-assisting pressure roller and a coiler.

[0026] Preferably, the temperature of the cast aluminum plate is 400-420°C.

[0027] Preferably, the forced cooling uses compressed air with a temperature below 10°C.

[0028] Preferably, the strong cooling lasts for at least 60 seconds.

[0029] In the above technical solution, in the continuous casting and rolling production of aluminum alloy, the cast-rolled plate is subjected to online heat treatment, and the casting structure is rapidly solidified to a cold state by a low-temperature air cooling method, thereby achieving the requirements for improving performance.

[0030] Preferably, the upper winding is adopted and an auxiliary winding pressure roller is added.

[0031] In the above technical solution, due to the increase in tensile strength of aluminum cast rolled plate after strong cooling, gaps appear between layers of aluminum cast rolled strip during coiling, resulting in other quality defects. The present invention adopts an upper coiling method and designs and adds a coiling-assisting pressing roller above the coiling mandrel to solve the quality defect of loose layers of aluminum cast rolled plate during coiling.

[0032] Preferably, the winding-assisting pressure roller is a hollow water-cooled structure.

[0033] In the above technical solution, the auxiliary coiling pressure roller needs to be hollow-core water-cooled to ensure that the auxiliary coiling pressure roller does not adhere to the aluminum coil.

[0034] Preferably, the auxiliary winding pressure roller is located 30-50 mm behind the cutting point of the winding shaft.

[0035] Preferably, the pressure of the auxiliary winding pressure roller is 0.3-0.5 MPa.

[0036] Example 1.

[0037] Before improvement: Figure 1 The figure is a diagram of the original aluminum alloy continuous casting and rolling mill. After the high-temperature aluminum liquid is degassed and filtered through the degassing box 1 and the filter box 2, the high-temperature aluminum casting and rolling plate is obtained through the casting nozzle 3 and the casting and rolling roller 4. After the high-temperature aluminum casting and rolling plate passes through the outlet guide roller 5, it passes through the hydraulic shear 6 to obtain the aluminum casting and rolling slab 10. The aluminum casting and rolling slab 10 then passes through the deflection guide roller 7 and the coiler 8 to produce the casting and rolling coil.

[0038] Combination Figure 1 In the actual production of the original aluminum alloy continuous casting and rolling process, the temperature of the aluminum alloy cast-rolled plate at the exit of the casting roll is usually 450-480℃, and the temperature when it reaches the coiler to start coiling is usually 350-380℃.

[0039] After improvement: The present invention is designed between the hydraulic shear 6 of the casting and rolling mill and the deflection roller 7 (such as Figure 2 As shown), the temperature of the cast-rolled plate in operation in this area is about 400-420°C. A forced air cooling heat treatment device 11 is installed, and an industrial refrigerator is used to obtain compressed air with a temperature below 10°C. The low-temperature compressed air is then used to force cool the high-temperature aluminum cast-rolled plate for more than 60 seconds, so that the high-temperature aluminum cast-rolled plate is quickly cooled to below 200°C, and then the cast-rolled coil is produced through coiling.

[0040] In addition, an auxiliary coiling pressing roller 12 is designed to be added above the coiling mandrel of the coiler 8. Therefore, the coiling of the aluminum cast rolled plate after forced cooling needs to adopt the upper coiling method, and the auxiliary coiling pressing roller is added to ensure that the aluminum coil is tightly wound. The auxiliary coiling pressing roller should be hollow water-cooled to ensure that the auxiliary coiling pressing roller does not adhere to the aluminum coil. The pressing position of the auxiliary coiling pressing roller changes with the diameter of the aluminum coil and is maintained at 30-50mm behind the entry point of the aluminum coil at the coiling shaft to press the aluminum coil, and the pressure is 0.3-0.5MPa.

[0041] Example 2.

[0042] The method of Example 1 is adopted, but the difference lies in the strong cooling temperature and the temperature of the aluminum cast rolled plate after cooling. A control group CK is set: no strong cooling treatment.

[0043] Aluminum alloy grade 1100, specification 6.7×1340×C aluminum cast and rolled coil, will be forced air-cooled cast and rolled coil, and then subjected to subsequent cold rolling and foil rolling to measure tensile strength and elongation. See Table 1 for details.

[0044] Table 1

[0045]

[0046]

[0047] It can be seen from Table 1 that after adopting the technical solution of the present invention, the tensile strength is increased by more than 10 MPa and the elongation remains unchanged, meeting the requirements for improving performance.

[0048] Example 3.

[0049] The method of Example 1 is adopted, and the temperature is cooled to 190°C under the strong cooling temperature condition of 5°C. The difference lies in the coiling method. The different coiling methods are:

[0050] Method 1: Use Figure 1 The system performs conventional curling through the deflector roller 7 and the coiler 8.

[0051] Method 2: Based on method 1, increase the winding tension by 5%.

[0052] Method 3: Based on method 1, increase the winding tension by 10%.

[0053] Method 4: Based on method 1, increase the winding tension by 20%.

[0054] Method 5: Based on method 1, an auxiliary winding pressure roller is designed and added below the winding mandrel of the winding machine 8.

[0055] Method 6: Combination Figure 2 On the basis of method 1, an auxiliary coiling pressing roller is designed above the coiling mandrel of the coiler 8. The auxiliary coiling pressing roller is a common steel roller, and the pressing position of the auxiliary coiling pressing roller changes with the diameter of the aluminum coil and is kept at 30-50mm behind the cutting point of the aluminum coil at the coiling shaft to press the aluminum coil, and the pressure is 0.8-1.0MPa.

[0056] Method 7: Combination Figure 2 On the basis of method 1, an auxiliary coiling pressing roller is designed above the coiling mandrel of the coiler 8. The auxiliary coiling pressing roller is a hollow water-cooled steel roller, and the pressing position of the auxiliary coiling pressing roller changes with the diameter of the aluminum coil and is maintained at 30-50mm behind the cutting point of the aluminum coil at the coiling shaft to press the aluminum coil, and the pressure is adjusted to 0.5-0.7MPa.

[0057] Method 8: Combination Figure 2 On the basis of method 1, an auxiliary coiling pressing roller is designed above the coiling mandrel of the coiler 8. The auxiliary coiling pressing roller is a hollow water-cooled steel roller, and the pressing position of the auxiliary coiling pressing roller changes with the diameter of the aluminum coil and is kept at 30-50mm behind the cutting point of the aluminum coil at the coiling shaft to press the aluminum coil. The pressure is adjusted to 0.3-0.5MPa, the temperature of the auxiliary coiling pressing roller will not rise, and the pressing pressure is moderate, which solves the problem of steel roller sticking to and crushing the aluminum plate.

[0058] Aluminum cast-rolled coils with an aluminum alloy grade of 1100 and a specification of 6.7×1340×C will be subjected to subsequent cold rolling and foil rolling through forced air cooling to determine product quality. See Table 2 for details.

[0059] Table 2

[0060]

[0061] Combined with Table 2, it can be seen that there are problems in the coiling process after strong cooling. Specifically:

[0062] Since the tensile strength of the aluminum cast rolled sheet increases after strong cooling, gaps appear between the layers of the aluminum cast rolled strip during coiling, which is usually called a loose layer quality defect. The subsequent rolling and rolling of the aluminum sheet and strip will cause scratches and other quality problems on the surface. Based on this, it can be seen that the setting of the strong cooling process of the present invention leads to gaps between the coiling layers, which easily leads to scratches and other quality problems during the subsequent rolling process.

[0063] Then, the applicant conducted a test to increase the coiling tension and found that the original coiling tension needs to be increased by 20% to be able to wind tightly. However, a new problem arises: the increased coiling tension is likely to break the aluminum cast strip from the seam of the casting roll (casting roll 4), making it impossible to operate normally and continuously. Therefore, increasing the coiling tension cannot solve the technical problems caused by the above-mentioned strong cooling process.

[0064] Therefore, the applicant observed and analyzed the situation on site and found that the lower coiling method could not realize the addition of the coiling-assisting pressure roller. Then the upper coiling method was adopted, and the coiling-assisting pressure roller was designed and added above the coiling mandrel to solve the quality defect of the loose layer of the aluminum cast rolled plate. Therefore, the present invention adopts the strong cooling process + the improved upper coiling method, which improves the mechanical properties of the product without affecting the subsequent process.

[0065] The above is only a preferred embodiment of the embodiment of the present invention, and does not impose any form of limitation on the embodiment of the present invention. Any simple modification, equivalent changes and modifications made to the above embodiment based on the technical essence of the embodiment of the present invention are still within the scope of the technical solution of the embodiment of the present invention.

Claims

1. An online heat treatment method for continuous casting and rolling of aluminum alloy, characterized in that: The online heat treatment method is as follows: the cast aluminum plate is hydraulically sheared and then forced cooled to below 200°C, and then the cast coil is produced by an upper coiling method through a deflection roller, a coiling pressing roller and a coiler.

2. The line heat treatment method according to claim 1, characterized in that: The temperature of the cast aluminum plate is 400-420°C.

3. The line heat treatment method according to claim 1, characterized in that: The strong cooling uses compressed air with a temperature below 10°C.

4. The line heat treatment method according to claim 1, characterized in that: The strong cooling lasts for at least 60 seconds.

5. The line heat treatment method according to claim 1, characterized in that: The auxiliary coiling pressing roller ensures that the aluminum coil is tightly wound.

6. The line heat treatment method according to claim 1, characterized in that: The rolling assistance pressing roller is a hollow water-cooling structure.

7. The line heat treatment method according to claim 1, characterized in that: The auxiliary winding pressure roller is located 30-50 mm behind the cutting point of the winding shaft.

8. The line heat treatment method according to claim 1, characterized in that: The pressure of the auxiliary winding pressure roller is 0.3-0.5MPa.

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