CN113201703B - Aluminum alloy ingot casting homogenizing annealing stepped cooling process - Google Patents

Abstract

The invention relates to a homogenizing annealing stepped cooling process for an aluminum alloy ingot, which relates to the field of aluminum alloy casting and comprises the following steps: (S1) heating the cast aluminum alloy ingot from room temperature to 560 ℃ for 6 hours, and preserving heat for 10 hours; (S2) cooling the aluminum alloy ingot after heat preservation for 10 hours in the step (S1) to 440-460 ℃ at a cooling speed of 190-200 ℃/h by adopting a cooling process; (S3) cooling the aluminum alloy ingot obtained in the step (S2) to 150-160 ℃ at a cooling speed of 240-260 ℃/h by adopting a cooling process; (S4) cooling the aluminum alloy ingot obtained in the step (S3) to room temperature at a cooling speed of 110-120 ℃/h by adopting a cooling process. The aluminum alloy ingot casting homogenizing annealing stepped cooling process has low extrusion resistance and thin coarse crystal layer when being extruded into an aluminum profile.

Description

Alloy Ingot Homogenizing Annealing Step Cooling Process

technical field

The invention relates to an aluminum alloy manufacturing process, in particular to an aluminum alloy ingot homogenization annealing step cooling process, which belongs to the field of aluminum alloy casting.

Background technique

As an important part of heat treatment, the ingot homogenization cooling process directly affects the structure and properties of the ingot. Due to the heritability of the ingot structure, it will have a great impact on the structure and properties of the extruded profile, which mainly affects the size, quantity and distribution of the precipitates.

When the cooling rate of the ingot is slow, coarse and needle-like precipitates will precipitate in the ingot structure, so that the ingot will form a band-like structure during subsequent processing, which increases the extrusion deformation resistance, which is not conducive to the extrusion process. conduct. During quenching, the coarse precipitates are difficult to dissolve completely, which reduces the strength after quenching and artificial aging, and seriously reduces the surface quality of the product.

When the cooling rate of the ingot is too fast, fine and dispersed precipitates will be precipitated in the ingot structure, which is beneficial to improve the yield strength of the product and improve the surface quality. However, the cooling rate is too fast, which will produce a quenching effect.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is: in order to overcome the deficiencies in the prior art and grasp a reasonable cooling rate of the ingot, the present invention provides an aluminum alloy ingot homogenization annealing step cooling process.

The technical solution of the present invention to solve the above technical problems is as follows: a step cooling process for homogenization annealing of an aluminum alloy ingot, wherein the aluminum alloy is a 6XXX series ingot, comprising the following steps:

(S1) the aluminum alloy ingot formed by melting and casting is raised from room temperature to 560°C at a heating rate of 80-100°C, and kept for at least 10 hours;

(S2) using a cooling process, the aluminum alloy ingot after heat preservation in step (S1) is cooled to 440-460°C at a cooling rate of 190-200°C/h;

(S3) using a cooling process, the aluminum alloy ingot obtained in the step (S2) is cooled to 150-160°C at a cooling rate of 240-260°C/h;

(S4) Using a cooling process, the aluminum alloy ingot obtained in step (S3) is cooled to room temperature at a cooling rate of 110-120° C./h.

Further, in step ( S2 ), after the aluminum alloy ingot is cooled to 440-460° C., it directly enters the next stage of cooling without heat preservation.

Further, in step (S3), after the aluminum alloy ingot is cooled to 150-160° C., it directly enters the next stage of cooling without heat preservation.

Further, the cooling process adopted in steps (S2) to (S4) is air cooling, water cooling or water mist cooling.

Further, the cooling process adopted in step (S2) is air cooling.

Further, the cooling process adopted in the step (S3) is air cooling and water mist cooling, wherein the water pressure of the water mist cooling is 0.01-0.02Mpa.

Further, the cooling process adopted in the step (S4) is air cooling and water cooling, wherein the water pressure of the water cooling is 0.05-0.10Mpa.

Beneficial effects: The step cooling process for homogenizing annealing of aluminum alloy ingots according to the present invention divides the cooling into three stages, namely, a high temperature section (555-570° C.) to a medium temperature section (440-460° C.), a medium temperature section ( 440-460℃) to low temperature section (150-160℃), low temperature section (150-160℃) to room temperature section, the dendrite structure in the metallographic phase of the ingot is basically eliminated, and the intragranular structure is more uniform; A comparative test was carried out for the production process of the present invention, wherein the experimental group adopted the cooling process of the present invention, and the comparison group adopted the existing cooling process. When extruded into aluminum profiles, the extrusion resistance is low and the extruded product speed is high, thereby improving the production efficiency; at the same time, the thickness of the coarse crystal layer of the extruded product is reduced, and the product quality is improved.

Description of drawings

Fig. 1 is the metallographic structure of test example ingot of the present invention;

Fig. 2 is the metallographic structure of comparative example ingot of the present invention;

Fig. 3 is the coarse-grained layer after extrusion of the test example of the present invention;

FIG. 4 is the coarse-grained layer after extrusion of the comparative example of the present invention.

Detailed ways

The principles and features of the present invention are described below, and the examples are only used to explain the present invention, but not to limit the scope of the present invention.

An aluminum alloy ingot homogenization annealing step cooling process, the specific aluminum alloy is an ingot of 6A02 and a diameter of 302mm, the aluminum alloy ingot is heated from room temperature to 560 DEG C after 6 hours of heating, and the temperature is kept for 10 Hour. Then adopt air-cooled cooling method to cool to 440-460°C at a cooling rate of 190-200°C/h; after the cooling temperature is qualified, change the cooling rate to 240-260°C/h and continue cooling until it reaches 150-160°C. The cooling methods in this step are air cooling and water mist cooling, wherein the water pressure of water mist cooling is 0.01-0.02Mpa; after the cooling temperature is qualified, the cooling rate is changed to 110-120℃/h and continues to cool to room temperature. In this step The cooling method is air cooling and water cooling, and the water pressure of water cooling is 0.05-0.10Mpa.

After the ingot is homogenized, annealed and cooled, its metallographic structure is checked, and the results are shown in Figure 1.

In order to verify the properties and characteristics of the aluminum ingots adopting the cooling process described in this scheme during and after extrusion into aluminum alloy profiles, three extrusion tests were carried out as test examples, namely F21, F22 and F23. , as shown in Table 1. Subsequently, the thickness of the coarse-grained layer of the extruded aluminum profile was measured, and the thickness of the coarse-grained layer was in the range of 112-117 um, as shown in FIG. 3 .

Table 1 Test Example Extrusion Test

Comparative ratio

Using the existing aluminum alloy ingot annealing and cooling process, the aluminum alloy under the same conditions is cooled to room temperature. Specifically, after air-cooling for 70min, the water pressure is adjusted to 0.1-0.15Mpa and water is added for air-cooling for 60min.

After the ingot is homogenized, annealed and cooled, its metallographic structure is checked, and the results are shown in Figure 2.

Similarly, three extrusion tests were performed on the aluminum ingots using the cooling process described in the comparative example, respectively F11, F12 and F13, as shown in Table 2. Subsequently, the thickness of the coarse-grained layer of the extruded aluminum profile was measured, and the thickness of the coarse-grained layer was in the range of 253-273 um, as shown in FIG. 4 .

Table 2 Comparative extrusion test

From the comparison between Table 1 and Table 2, it can be seen that in the process of extrusion molding of aluminum alloy profiles, the breakthrough pressure and intermediate pressure in the test example are both lower than those in the comparative example, that is, the extrusion resistance in the test example is lower. At the same time squeezing faster.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection of the present invention. within the range.

Claims (5)

1. an aluminum alloy ingot homogenization annealing step cooling process, the aluminum alloy is a 6XXX series ingot, is characterized in that, comprises the following steps: (S1) the aluminum alloy ingot formed by melting and casting is raised from room temperature to 560°C at a heating rate of 80-100°C, and kept for at least 10 hours; (S2) using a cooling process, the aluminum alloy ingot after heat preservation in step (S1) is cooled to 440-460°C at a cooling rate of 190-200°C/h, and after the aluminum alloy ingot is cooled to 440-460°C, No need to keep warm, go directly to the next stage of cooling; (S3) Using a cooling process, the aluminum alloy ingot obtained in step (S2) is cooled to 150-160°C at a cooling rate of 240-260°C/h, and after the aluminum alloy ingot is cooled to 150-160°C, no heat preservation is required , directly into the next stage of cooling; (S4) Using a cooling process, the aluminum alloy ingot obtained in step (S3) is cooled to room temperature at a cooling rate of 110-120° C./h. 2. The aluminum alloy ingot homogenization annealing step cooling process according to claim 1, wherein the cooling process adopted in the steps (S2) to (S4) is air cooling, water cooling or water mist cooling. 3. The aluminum alloy ingot homogenization annealing step cooling process according to claim 2, characterized in that: the cooling process adopted in the step (S2) is air cooling. 4. aluminum alloy ingot homogenization annealing step cooling process according to claim 2, is characterized in that: the cooling process adopted in step (S3) is air cooling and water mist cooling, and wherein the water pressure of water mist cooling is 0.01 -0.02MPa. 5. The aluminum alloy ingot homogenization annealing step cooling process according to claim 2, wherein the cooling process adopted in the step (S4) is air cooling and water cooling, wherein the water pressure of the water cooling is 0.05-0.10MPa.

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