Metal profile online quenching device and quenching method

Abstract

The invention discloses an online quenching device and method for a metal profile. The method comprises the steps that the quenching inflection point temperature T0 of the metal profile is obtained; the metal profile is slowly cooled in an air cooling and / or fog cooling mode, and the temperature distribution of a section temperature field at the position, where slow cooling is completed, of the metal profile ranges from T0-T0 + 50 DEG C; and carrying out water quenching on the slowly cooled metal profile in a water cooling manner, so that the metal profile is cooled to the room temperature. According to the metal profile online quenching device and quenching method provided by the invention, cooling stages are reasonably divided and different cooling modes are switched through quenching inflection point temperature, and dynamic control of the cooling rate and uniformity management of a temperature field are realized through optimal combination of gradual cooling and multiple cooling modes; the mechanical performance of the profile can be guaranteed to the maximum extent, the profile has good dimensional stability, and the yield and the production efficiency can be remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of metal material processing, and in particular relates to an online quenching device and a quenching method for metal profiles. Background Art

[0002] In order to achieve the requirements of excellent mechanical properties and stable shape and size, extruded aluminum profiles usually need to be quenched online and artificially aged. Among them, online quenching quickly cools the aluminum profile through the cooling medium, causing changes in its internal structure, thereby significantly improving its strength and hardness. At the same time, after quenching, the alloying elements in the aluminum alloy will be retained in the supersaturated solid solution, preparing for subsequent aging precipitation, further improving the mechanical properties of the aluminum profile. However, if the selection of quenching medium (such as wind, water, fog, etc.) and the regulation of quenching intensity are unreasonable, the cooling speed of various parts of the profile will be inconsistent, causing residual stress inside the profile, which will cause deformation, resulting in a decrease in the mechanical properties and shape and size accuracy of the profile. In severe cases, the profile becomes scrap or defective, reducing the product qualification rate. Therefore, it is crucial to reasonably select the quenching medium and regulate the quenching process to ensure the quality of extruded profiles.

[0003] At present, commonly used online quenching methods include air cooling, water cooling, and mist cooling. Air cooling and mist cooling usually do not cause large stress in the profile, thereby reducing the deformation of the profile and maintaining the dimensional accuracy of the product. However, its cooling speed is relatively slow and cannot meet the quenching requirements of some alloys that require high cooling speed. During mist cooling, the mist will instantly vaporize when it comes into contact with the high-temperature profile, forming a water vapor layer, which hinders the direct contact between the mist and the profile surface, resulting in unstable cooling effect. Water cooling can quickly cool the profile due to its high thermal conductivity and heat capacity, so that the profile forms a supersaturated solid solution and improves the mechanical properties of the material. However, if the cooling speed of water cooling is too fast, it may cause large thermal stress in the aluminum alloy during the quenching process, especially for profiles with uneven wall thickness distribution and complex cross-sectional shapes, which will increase the deformation of the profile. In severe cases, quenching cracks will also occur, ultimately leading to a decrease in the product qualification rate.

[0004] Therefore, it is necessary to provide a new solution to the above technical problems. Summary of the invention

[0005] The object of the present invention is to provide an online quenching device and a quenching method for metal profiles, which can reduce the quenching deformation problem while ensuring the mechanical properties of the metal profiles.

[0006] To achieve the above purpose, the technical solution provided by the present invention is as follows: In a first aspect, the present invention provides an online quenching method for a metal profile, comprising: The quenching inflection point temperature T0 of the metal profile is obtained; the metal profile is slowly cooled by air cooling and / or mist cooling, so that the temperature distribution of the cross-sectional temperature field at the slow cooling position of the metal profile is between T0 and T0+50°C; the metal profile that has completed the slow cooling is water quenched by water cooling to cool it to room temperature.

[0007] In one or more embodiments, obtaining the mechanical property inflection point temperature T0 of the metal profile includes: Solution treatment is performed on multiple samples of the same grade as the metal profile; the multiple samples after solution treatment are gradient air-cooled to different target temperatures and then water-quenched to room temperature; peak aging treatment is performed on the multiple samples after water quenching, and then the mechanical properties of each sample are tested to obtain the quenching inflection point temperature T0 of the metal profile.

[0008] In one or more embodiments, the target temperatures for air cooling of the plurality of samples are arranged in a gradient, and the temperature difference between two adjacent target temperatures is 5°C to 60°C.

[0009] In one or more embodiments, the metal profile is slowly cooled by air cooling and / or mist cooling so that the temperature distribution of the cross-sectional temperature field at the slow cooling position of the metal profile is between T0 and T0+50° C., including: The air cooling and / or mist cooling process of the metal profile is simulated by simulation software to determine the quenching parameters of the metal profile; the metal profile is slowly cooled according to the quenching parameters so that the temperature distribution of the cross-sectional temperature field at the slow cooling position of the metal profile is between T0 and T0+50°C.

[0010] In one or more embodiments, the air cooling and / or mist cooling process of the metal profile is simulated by simulation software to determine the quenching parameters of the metal profile, including: Use simulation software to simulate the air cooling and / or mist cooling process of the metal profile to determine the cross-sectional temperature distribution when the lowest cross-sectional temperature at the slow cooling position of the metal profile reaches the quenching inflection point temperature T0; determine whether the cross-sectional temperature distribution is within the range of T0~T0+50℃; if the cross-sectional temperature distribution does not meet the range of T0~T0+50℃, adjust the quenching parameters according to the simulation results; re-simulate according to the adjusted quenching parameters until the cross-sectional temperature distribution at the slow cooling position of the metal profile is within the range of T0~T0+50℃.

[0011] In one or more embodiments, the water cooling method is used to quench the slowly cooled metal profile to cool it to room temperature, specifically including: The simulation software is used to simulate the online water quenching of the metal profile that has completed slow cooling. By adjusting the water quenching parameters, the temperature difference of the metal profile cross section is between 5℃ and 10℃, and the metal profile that has completed slow cooling is cooled to room temperature within 10 s.

[0012] In the second aspect, the present invention provides a quenching device for the aforementioned online quenching method for metal profiles, comprising: a slow cooling zone and a fast cooling zone arranged in sequence along the extrusion direction of the metal profile; the slow cooling zone is used to air-cool and / or mist-cool the extruded metal profile, so that the temperature distribution of the cross-sectional temperature field at the slow cooling position of the metal profile is between T0~T0+50°C; the fast cooling zone is used to water-cool the metal profile after air cooling and / or mist cooling.

[0013] In one or more embodiments, the slow cooling zone and the fast cooling zone form a cooling channel through which the metal profile can pass, and nozzles for spraying cooling medium are arranged around the cooling channel, and the angle and flow rate of the nozzles are adjustable.

[0014] In one or more embodiments, the quenching device includes a bottom bracket and a top bracket, the left and right sides of the top bracket are provided with mounting plates extending downward, and the top of the bottom bracket, the bottom of the top bracket and the mounting plate are all provided with nozzles facing the cooling channel.

[0015] In one or more embodiments, the bottom bracket is provided with a support seat for supporting the metal profile, the bottom bracket is connected to the lifting mechanism and can be lifted and lowered under the drive of the lifting mechanism, and the support seat is provided with rollers for supporting the metal profile to feed along the extrusion direction.

[0016] Compared with the prior art, the metal profile online quenching device and quenching method provided by the present invention reasonably divide the cooling stages and switch different cooling modes through the quenching inflection point temperature, and realize dynamic control of the cooling rate and uniformity management of the temperature field through the optimized combination of gradual cooling and multiple cooling methods, so that the profile can not only guarantee the mechanical properties to the greatest extent, but also have good dimensional stability, and can significantly improve the yield rate and production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] 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 prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 It is a flow chart of a method for online quenching of metal profiles in one embodiment of the present invention; Figure 2 It is a structural schematic diagram of a quenching device in one embodiment of the present invention; Figure 3a It is a front view of a quenching device in one embodiment of the present invention; Figure 3b A schematic diagram of the layout of cooling channels and nozzles of a quenching device in one embodiment of the present invention; Figure 4 Schematic diagram of the cross-sectional shape of the aluminum alloy profile in Example 1 of the present invention; Figure 5 Schematic diagram of the cross-sectional shape of the aluminum alloy profile in Example 2 of the present invention; Figure 6 The Vickers hardness test diagram of the aluminum alloy profiles in Examples 1 and 2 of the present invention at different water quenching temperatures.

[0019] Description of main reference numerals: 31-bottom bracket, 32-top bracket, 33-mounting plate, 34-nozzle, 35-cooling channel, 36-support seat, 37-lifting mechanism, 38-roller. DETAILED DESCRIPTION

[0020] 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.

[0021] The metal profile online quenching method of the present invention is proposed to solve the problems of uneven cooling rate and severe quenching deformation in the existing aluminum alloy profile quenching process. In modern industrial production, aluminum alloy profiles are widely used in aviation, transportation, construction and other fields as a lightweight and high-strength structural material. However, in order to improve the mechanical properties of the profile, the quenching process becomes an indispensable process, but the existing online quenching method has many limitations.

[0022] Specifically, the online quenching methods commonly used in the prior art, such as air cooling, mist cooling, spraying and water immersion, have their own shortcomings. The cooling rate of air cooling and mist cooling is low, and it is difficult to meet the quenching strength requirements of aluminum alloy profiles, resulting in the mechanical properties not being fully exerted. Although water immersion and spray quenching can quickly cool the profile, the temperature gradient generated by the excessively fast cooling rate is large, especially in different parts of the profile cross section due to the different wall thickness and cross-sectional dimensions, resulting in serious uneven cooling rates. For the above reasons, large internal stresses will be generated in the profile, leading to deformation, distortion, and even the appearance of microcracks, which seriously affect the dimensional accuracy and performance of the profile. Because the cooling process involves the mutual influence of multiple complex factors, it is difficult for the prior art to achieve precise control of the cooling rate, and thus it is impossible to effectively suppress deformation.

[0023] In view of the above problems, the present invention proposes an innovative online quenching method for metal profiles. The implementation idea of ​​this method can be summarized as follows: reasonably divide the cooling stages and switch different cooling modes according to the quenching inflection point temperature to achieve gradual changes and control of the cooling rate. Specifically, first obtain the inflection point temperature of the mechanical properties of the metal profile, and use air cooling in the high temperature stage to reduce the internal stress caused by the temperature gradient and reduce the risk of deformation at high temperatures. When the temperature drops to close to the inflection point temperature of the mechanical properties, switch to a faster cooling method, such as water cooling or mist cooling, to quickly reduce the profile temperature to ensure quenching strength and mechanical properties. The entire cooling process can balance the contradiction between quenching strength and dimensional accuracy by regulating the cooling rate and temperature field distribution.

[0024] The online quenching method for metal profiles provided by the present invention reasonably divides the cooling stages and switches different cooling modes through the quenching inflection point temperature, and realizes dynamic control of the cooling rate and uniformity management of the temperature field through the optimized combination of gradual cooling and multiple cooling methods, so that the profile can not only guarantee the mechanical properties to the greatest extent, but also have good dimensional stability, can significantly improve the yield rate and production efficiency, and has broad industrial application prospects.

[0025] Please refer to Figure 1 FIG. 1 is a flow chart of an online quenching method for metal profiles in an embodiment of the present invention. The online quenching method for metal profiles specifically comprises the following steps: S101: Obtaining the quenching inflection point temperature T0 of the metal profile.

[0026] It should be noted that the inflection point temperature T0 represents the critical point at which the mechanical properties of the metal profile change significantly during the cooling process. When the temperature of the metal profile is significantly higher than T0, its strength and hardness are usually low, and the material is more susceptible to plastic deformation. Therefore, in the range above T0, a slower cooling method should be adopted to reduce the risk of deformation. When the temperature drops to near T0 or below, in order to ensure the mechanical properties of the alloy, the cooling rate should be accelerated to achieve a stronger quenching effect.

[0027] In an exemplary embodiment, the quenching inflection point temperature T0 of the metal profile is obtained, specifically including: performing solution treatment on multiple samples of the same grade as the metal profile; gradient air cooling the multiple samples after the solution treatment to different target temperatures, and then water quenching to room temperature; performing peak aging treatment on the multiple samples after water quenching, and then testing the mechanical properties of each sample to obtain the quenching inflection point temperature T0 of the metal profile.

[0028] The purpose of solution treatment is to fully dissolve the alloying elements in the metal to form a uniform solid solution structure, providing a good foundation for subsequent cooling and strengthening. The sample is usually heated to a predetermined high temperature (such as 540°C) and kept at this temperature for a period of time to ensure that the internal structure of the material reaches a stable state.

[0029] After the solution treatment is completed, the samples are taken out of the heat treatment furnace and air-cooled at different cooling rates. Multiple samples are air-cooled to different target temperatures, such as 520°C, 480°C, 440°C, 400°C, 360°C, 300°C, etc. The selection of these target temperature points can be based on material properties and experimental requirements, with the aim of capturing the key points of changes in the mechanical properties of the material during the cooling process. The cooling rate of air cooling is relatively gentle, which can avoid drastic changes in internal stress of the material in the high temperature section, thereby reducing early plastic deformation. Afterwards, each sample is quickly transferred to water for water quenching, quickly reducing the temperature to room temperature. The purpose of water quenching is to form a supersaturated solid solution in preparation for aging strengthening.

[0030] After the cooling treatment is completed, the sample needs to be aged. Aging treatment is to keep the sample at a certain temperature for a long time (for example, 175℃ for 8 hours) to precipitate the alloy elements in the solid solution and form a strengthening phase. After the aging treatment, the sample is taken out and mechanical properties are tested, such as Vickers hardness test or other strength test. Through the test, the hardness and strength changes of each sample at different air cooling temperature points can be evaluated.

[0031] After analyzing these test data, the inflection point temperature T0 of the mechanical properties can be determined. It is usually manifested as a critical point where the hardness or strength changes significantly as the temperature decreases. Above T0, the performance changes little; below T0, the performance decreases significantly. This inflection point temperature T0 represents the temperature area that requires special attention during the cooling process and is the key point in determining the cooling method and rate.

[0032] By obtaining T0, the best cooling strategy can be formulated for the quenching process of metal profiles. In the temperature range above T0, a relatively slow air cooling and / or mist cooling method is used to reduce internal stress and deformation; when approaching T0, it is switched to rapid cooling (such as water cooling) to ensure the strength and hardness of the material. This can effectively balance the deformation and mechanical properties of the profile, and reduce the quenching deformation while ensuring that the mechanical properties of the profile meet the use requirements.

[0033] In an exemplary embodiment, the size of the sample is Φ9.5×H10 mm, and a jack for inserting a thermocouple is provided on the sample. The target temperature gradient of the air-cooled samples is arranged, and the temperature difference between two adjacent target temperatures is 30-60°C.

[0034] The size of the sample is Φ9.5 × H10mm, which means that the metal sample used in the experiment has a specific geometric specification, that is, the diameter of the sample is 9.5 mm and the height is 10 mm. The appropriate sample size can ensure that the thermal conductivity and cooling characteristics of the material can represent the behavior of the actual profile during the heat treatment process, and it is convenient to insert the thermocouple for accurate temperature measurement. Due to the small volume and regular shape of the sample, it can provide a controllable and stable cooling environment in the experiment, reducing the errors introduced by excessive size or complex shape. In addition, such a size setting can ensure the temperature measurement accuracy after the thermocouple is inserted, because the temperature field inside the sample is relatively uniform, which helps to accurately monitor the thermal changes of the material at different temperature stages.

[0035] During the solution treatment and air cooling experiments, multiple specimens were arranged to be air-cooled to different target temperature points to form an orderly temperature gradient. This target temperature gradient arrangement means that the temperature points to which the specimens are cooled are distributed according to a predetermined rule, and the temperature difference between two adjacent target temperatures is controlled within the range of 30~60°C. Specifically, the temperature difference of 30~60°C can clearly capture the effect of different cooling temperatures on the mechanical properties of the specimens; at the same time, this temperature difference will not be too large to miss the key temperature range information. Therefore, the purpose of adopting this gradient arrangement is to systematically observe and analyze how material properties change with temperature, so as to accurately determine the quenching inflection point temperature T0.

[0036] For example, multiple specimens with a size of Φ9.5 × H10mm are prepared, and a small hole for inserting a K-type thermocouple is drilled in the center of the specimen height. The thermocouple is used to monitor the temperature of the specimen in real time during the heat treatment process. Next, the specimens are placed in a heat treatment furnace for solution treatment, and the specimens are heated to a predetermined temperature (such as 540°C) and kept warm for a certain period of time. Subsequently, the specimens are taken out of the furnace in turn, air-cooled in front of a fan to different target temperatures, such as 520°C, 480°C, 440°C, 400°C, 360°C, and 300°C, and then quickly placed in water to cool to room temperature. After water cooling, an aging treatment is carried out at 175°C for 8 hours to stabilize the microstructure of the specimen.

[0037] Afterwards, the Vickers hardness test was performed on these samples after aging treatment, and the hardness change pattern of each sample was analyzed. By comparing the mechanical performance data at different air cooling target temperatures, the inflection point temperature T0 can be determined. When water cooling is performed below this temperature point T0, the hardness and strength of the sample increase significantly as the temperature decreases, while when water cooling is performed above this temperature point T0, the hardness and strength change tends to decrease gently. Through the above experimental analysis, the specific value of T0 can be determined.

[0038] S102: Slowly cool the metal profile by air cooling and / or mist cooling, so that the temperature distribution of the cross-sectional temperature field at the slow cooling position of the metal profile is between T0 and T0+50°C.

[0039] It is understandable that T0 represents the quenching inflection point temperature of the material, that is, the critical point where the strength and hardness of the material increase rapidly. Controlling the temperature distribution of the cross-sectional temperature field at the position where the metal profile has completed slow cooling (the position where the slow cooling has just been completed and is ready for water quenching) between T0 and T0+50°C can not only ensure that the profile will not be severely deformed in the high-temperature section due to excessively fast cooling, but also lay a uniform temperature foundation for subsequent rapid cooling, ultimately ensuring the quenching effect and the mechanical properties of the profile.

[0040] For example, you can use Figure 2 The quenching device shown in the figure quenches the metal profile. As the metal profile is extruded, the metal profile passes through the slow cooling zone and the fast cooling zone in sequence. The metal profile is slowly cooled in the slow cooling zone, so that the temperature distribution of the cross-sectional temperature field at the position where the metal profile completes the slow cooling (that is, the position where the metal profile just enters the fast cooling zone after completing the slow cooling in the slow cooling zone and passing through the slow cooling zone) is between T0 and T0+50℃.

[0041] Air cooling and / or mist cooling equipment can be arranged along the extrusion direction of the metal profile so that the air cooling and / or mist cooling medium can be evenly distributed around the metal profile. In order to accurately control the temperature field, the air cooling equipment should have the function of flow and wind direction adjustment. For example, the adjustable nozzle can adjust the intensity and angle of air cooling according to the cross-sectional shape, size and material properties of the profile to achieve more efficient temperature control. In addition, real-time temperature monitoring systems, such as thermocouple arrays or infrared temperature sensors, can be used to dynamically monitor the temperature field distribution of the cross section. Through these sensors, the system can obtain temperature data at different positions of the profile and feed it back to the control module, so as to adjust the parameters of the air cooling equipment as needed to ensure that the temperature field is evenly distributed within the target range.

[0042] In an exemplary embodiment, the metal profile is slowly cooled by air cooling and / or mist cooling, so that the temperature distribution of the cross-sectional temperature field of the metal profile at the slow cooling position is between T0 and T0+50°C, specifically including: simulating the air cooling and / or mist cooling process of the metal profile by simulation software to determine the quenching parameters of the metal profile; air cooling the metal profile according to the quenching parameters, so that the temperature distribution of the cross-sectional temperature field of the metal profile at the slow cooling position is between T0 and T0+50°C.

[0043] It should be noted that the air cooling and / or mist cooling behavior of metal profiles can be virtually simulated through heat treatment simulation software to optimize quenching parameters, such as air cooling flow rate, flow rate, nozzle angle and injection position. Through such simulation analysis, researchers can foresee the distribution of temperature fields under different cooling conditions in advance, select the optimal cooling strategy, and avoid problems caused by uneven cooling speed.

[0044] Due to the changes in the cross-sectional shape and wall thickness of metal profiles, a single air cooling and / or mist cooling strategy often makes it difficult to evenly distribute the temperature field, which may cause the thin-walled part to cool rapidly while the thick-walled part cools slowly, thus causing internal stress concentration and deformation problems. In this case, using heat treatment simulation software (such as QForm or ANSYS) for air cooling simulation can greatly improve the controllability of the cooling process. Through simulation, researchers are able to observe the temperature changes in different areas and accurately adjust the position and spray angle of the air cooling and / or mist cooling nozzles to match the air cooling and / or mist cooling effects with the cross-sectional characteristics of the profile. For example, software simulations may show that areas with thicker walls require higher wind speeds or more concentrated air cooling flows to speed up cooling, while thin-walled areas require lower wind speeds to avoid cooling too quickly.

[0045] After determining the optimal quenching parameters, they are applied to the actual cooling equipment to achieve precise control. A multi-angle adjustable nozzle system can be used to fine-tune the position and direction of the nozzle according to the parameters obtained from the simulation. Such a control strategy reduces the uncertainty in the cooling process by predetermining and optimizing the parameters, ensuring the uniformity of the temperature field, and thus providing a stable foundation for subsequent rapid cooling.

[0046] The combination of simulation and optimization can overcome the difficulty of accurately controlling temperature distribution in traditional cooling methods. Compared with setting cooling parameters based on experience alone, using simulation software for analysis can greatly improve the accuracy of the cooling process, reduce the number of tests and adjustments, and reduce production costs. Software simulation can also help identify and solve potential cooling problems, especially in the cooling process of complex cross-section profiles, where accurate control of the temperature field becomes more reliable.

[0047] Specifically, the air cooling and / or mist cooling process of the metal profile is simulated by simulation software to determine the quenching parameters of the metal profile, including: using simulation software to simulate the air cooling and / or mist cooling process of the metal profile to determine the cross-sectional temperature distribution when the lowest temperature of the cross section at the slow cooling position of the metal profile reaches the quenching inflection point temperature T0; judging whether the cross-sectional temperature distribution is within the range of T0~T0+50℃; if the cross-sectional temperature distribution does not meet the range of T0~T0+50℃, adjusting the quenching parameters according to the simulation results; re-simulating according to the adjusted quenching parameters until the cross-sectional temperature distribution at the slow cooling position of the metal profile is within the range of T0~T0+50℃.

[0048] In the specific implementation, first use heat treatment simulation software (such as QForm or ANSYS) to virtually simulate the air cooling and / or mist cooling process of metal profiles. The core of the simulation is to observe and analyze the temperature field distribution of the profile cross section, especially the overall temperature change when the lowest temperature of the cross section reaches T0 at the position where the profile completes slow cooling. When the lowest temperature of the profile reaches T0, the temperature distribution of its cross section must be maintained within the range of T0~T0+50℃ to ensure uniform cooling and avoid performance degradation or material deformation caused by too fast or too slow cooling.

[0049] In the actual simulation, the simulation software will calculate and display the temperature field distribution of the profile section according to the preset quenching parameters, such as the flow rate, wind speed, injection angle of the air cooling nozzle and the spatial position of the nozzle. If the simulation results show that the temperature of certain areas is not in the range of T0~T0+50℃, it means that the current quenching parameters cannot achieve ideal temperature control and need further adjustment. This adjustment process may include increasing or decreasing the flow rate of air cooling and / or mist cooling, changing the injection angle of the air cooling and / or mist cooling nozzle, or redistributing the position of the air cooling and / or mist cooling device. The adjusted quenching parameters are then input into the simulation software for a new round of simulation to observe the modified cooling effect. If the temperature distribution still does not meet the requirements, continue to adjust and simulate until the distribution of the temperature field of the profile section fully meets the requirements.

[0050] S103: The slowly cooled metal profile is quenched by water cooling to cool it to room temperature.

[0051] It should be noted that the purpose of step S103 is to rapidly cool the profile that has been slowly cooled to a specific temperature range by water cooling (the temperature of the water cooling medium is 5-25°C), thereby achieving a quenching effect and ensuring that the metal profile has ideal mechanical properties and dimensional stability. The rapid cooling method is used to quickly reduce the temperature of the profile, so that the internal microstructure of the material undergoes corresponding changes, such as the precipitation of alloy elements in the solid solution to form a strengthening phase, thereby significantly improving the strength and hardness of the material.

[0052] Under high temperature conditions, metal materials have low yield strength and are prone to plastic deformation due to thermal stress generated by rapid cooling. Therefore, the present invention first slowly cools down by air cooling to uniformly control the temperature field within the range of T0~T0+50℃, which helps to reduce the temperature gradient inside the material, reduce thermal stress concentration, and thus reduce the risk of deformation.

[0053] When the profile temperature approaches the quenching inflection point temperature T0, the yield strength of the material has been improved and can withstand a faster cooling rate. At this time, switching to water cooling and / or mist cooling can achieve an ideal quenching effect through rapid cooling, which can promote the transformation of the microstructure inside the material and form a strengthening phase, thereby improving the mechanical properties.

[0054] In an exemplary embodiment, the metal profile that has completed slow cooling is water quenched by water cooling to cool it to room temperature, specifically including: using simulation software to perform online water quenching simulation on the metal profile that has completed slow cooling, and adjusting the water quenching parameters so that the temperature difference of the metal profile cross section is between 5°C and 10°C, and the metal profile that has completed slow cooling is cooled to room temperature within 10 seconds.

[0055] During water quenching, the profile goes through a process of decreasing from the temperature at the completion of slow cooling to room temperature. During this process, the difference between the highest and lowest temperatures of the profile cross section does not exceed 10°C. At the same time, this process does not exceed 10 seconds. The cooling uniformity can be maintained by adjusting the water cooling nozzle to prevent the profile from excessive quenching deformation. The process of decreasing from the temperature at the completion of slow cooling to room temperature does not exceed 10 seconds. This is to cool quickly so that the alloying elements in the aluminum alloy after quenching will be retained in the supersaturated solid solution, preparing for subsequent aging precipitation and ensuring the mechanical properties of the aluminum profile.

[0056] Please refer to Figure 2 As shown, in one embodiment of the present invention, a quenching device for the above-mentioned online quenching method for metal profiles is also provided. The quenching device includes: a slow cooling zone and a fast cooling zone sequentially arranged along the extrusion direction of the metal profile; the slow cooling zone is used to air cool and / or mist cool the extruded metal profile, so that the temperature distribution of the cross-sectional temperature field at the slow cooling position of the metal profile is between T0 and T0+50°C; the fast cooling zone is used to water cool the metal profile after air cooling and / or mist cooling.

[0057] The slow cooling zone is used to air cool and / or mist cool the metal profile that has just been extruded, so that the temperature distribution of the cross-sectional temperature field at the position where the metal profile has completed slow cooling (i.e., the position where the metal profile has just entered the fast cooling zone after completing slow cooling in the slow cooling zone) is between T0 and T0+50°C. The design basis of this section is that the temperature of the metal profile is high when it is just extruded. If a drastic cooling method such as water cooling or spray cooling is used immediately, it may cause internal stress concentration or severe deformation of the material, seriously affecting the dimensional accuracy of the profile. Therefore, the slow cooling zone slowly cools down by air cooling to gradually reduce the temperature of the profile surface. The air cooling and / or mist cooling process is relatively mild, which helps to control the temperature gradient within an acceptable range, thereby reducing the internal stress of the material caused by drastic temperature differences.

[0058] The air cooling equipment may include multiple adjustable air cooling nozzles or fan arrays, which can be adjusted according to the shape of the profile section and the difference in wall thickness to achieve uniform distribution of the cooling effect. This design can not only effectively alleviate the impact of rapid cooling of high-temperature materials, but also provide a temperature basis for the subsequent cooling process, so that the profile has a more uniform temperature field when entering the next stage of cooling.

[0059] The rapid cooling zone is used to cool the metal profiles more quickly after slow cooling, such as water cooling. The rapid cooling zone is set up to further reduce the temperature of the profiles to achieve the quenching effect and lock the microstructure of the material. The water cooling method quickly removes heat through high-pressure water flow, which is suitable for scenes that require rapid and large-scale cooling. It can significantly increase the cooling rate and ensure the quenching strength of the profiles.

[0060] The slow cooling zone provides a buffer stage, gradually lowering the temperature of the profile, reducing the stress distribution inside the material, and laying the foundation for subsequent rapid cooling; while the rapid cooling zone is responsible for quickly completing the cooling process within a relatively low temperature range to ensure the quenching strength and hardness of the material. In this way, the entire cooling process achieves a gradual change from slow to fast, which not only avoids deformation caused by excessive cooling, but also meets the requirements of the metal profile for mechanical properties.

[0061] The independent control systems of the two cooling zones can be optimized and adjusted according to the different requirements of the profiles. For example, during the production process, air cooling, water cooling and mist cooling can be flexibly switched or combined according to the material characteristics and cross-sectional complexity, thereby improving the adaptability of the device, meeting the production requirements of various complex profiles, and improving the overall production efficiency and product qualification rate.

[0062] In an exemplary embodiment, the slow cooling zone and the fast cooling zone form a cooling channel 35 through which the metal profile can pass. The cooling channel 35 is surrounded by nozzles 34 for spraying cooling medium, and the angle and flow rate of the nozzles 34 are adjustable.

[0063] The cooling channel 35 formed by the slow cooling zone and the fast cooling zone ensures that the metal profile can pass smoothly and receive continuous and efficient cooling treatment. The cooling channel 35 surrounds the metal profile to form a closed or semi-closed structure. Such a design can ensure that the cooling medium flows efficiently in the channel and reduce the interference of the external environment on the cooling process, thereby achieving more stable and accurate temperature control.

[0064] Adjustable nozzles 34 are evenly distributed around the cooling channel 35. The nozzles 34 can be evenly distributed up and down and left and right along the four main directions of the channel to form a three-dimensional cooling network. This all-round arrangement ensures that the cooling medium can cover the entire cross-section of the profile, and no matter how complex the shape of the profile is or how the wall thickness changes, a uniform cooling effect can be achieved in all parts. The design of the nozzle 34 allows the angle and flow rate to be freely adjusted. By adjusting the angle of the nozzle 34, the spray direction of the cooling medium can be accurately controlled to ensure that the cooling medium can directly hit the surface of the profile or a specific area, thereby achieving efficient local cooling. At the same time, the adjustability of the flow rate of the nozzle 34 enables the system to accurately control the supply of the cooling medium according to the actual cooling needs, thereby avoiding the problem of excessive or insufficient cooling.

[0065] In an exemplary embodiment, please refer to Figure 3a and Figure 3b As shown, the quenching device includes a bottom bracket 31 and a top bracket 32. The top bracket 32 ​​is provided with a mounting plate 33 extending downward on both sides. The top of the bottom bracket 31, the bottom of the top bracket 32 ​​and the mounting plate 33 are all provided with a nozzle 34 facing the cooling channel 35.

[0066] The bottom bracket 31 is the base of the whole device, and plays a role in stabilization and bearing. It is provided with nozzles 34 on the top, which are oriented toward the cooling channel 35 so as to spray cooling medium to cool the area below the profile, ensuring that the cooling effect at the bottom of the profile is uniform and stable. The design of the bottom bracket 31 takes into account the center of gravity and stability of the device, so that the entire cooling system can remain stable under the action of high-pressure water flow or high-speed air flow, and will not be displaced or vibrated due to the impact force of the cooling medium, thereby ensuring the accuracy and stability of the cooling process. The cooling channel 35 is sequentially arranged with a slow cooling zone and a fast cooling zone along the extrusion direction of the profile.

[0067] The top bracket 32 ​​is located above the cooling channel 35, providing additional support and structural rigidity for the cooling system. The left and right sides of the top bracket 32 ​​are provided with downwardly extending mounting plates 33, which are designed to extend vertically so that the nozzles 34 can be installed at the best angle, facing the top and sides of the profile in the cooling channel 35. This arrangement ensures that the cooling medium can cover the entire cross-section of the profile, and uniform cooling can be achieved regardless of the bottom, top or side areas.

[0068] The nozzles 34 are distributed on the top of the bottom bracket 31, the bottom of the top bracket 32, and the left and right mounting plates 33, forming an all-round cooling network. This three-dimensional arrangement allows the cooling medium to act on the profile from different directions at the same time, thereby achieving a comprehensive and uniform cooling effect. Each nozzle 34 can adjust the flow rate and angle as needed to adapt to the different cross-sectional characteristics of the profile.

[0069] Specifically, a support seat 36 for supporting the metal profile is provided on the bottom bracket 31. The bottom bracket 31 is connected to a lifting mechanism 37 and can be lifted and lowered under the drive of the lifting mechanism 37. A roller 38 for supporting the metal profile to feed along the extrusion direction is provided on the support seat 36. The main function of the support seat 36 is to provide reliable support and positioning for the metal profile passing through the cooling channel 35, and ensure that the profile remains stable during the cooling process.

[0070] In order to further improve the flexibility and adaptability of the cooling system, the bottom bracket 31 is connected to a lifting mechanism 37 and can move up and down under the drive of the lifting mechanism 37. Through the lifting mechanism 37, the support base 36 can be adjusted according to the height of different metal profiles, thereby ensuring that the distance between the nozzle 34 and the profile is always in the optimal cooling range.

[0071] Embodiment 1: This embodiment provides an online quenching method for aluminum alloy extruded profiles, and the specific steps are as follows: The grade is 6D10, and the cross-sectional shape is as follows Figure 4The aluminum alloy profile 4 shown is used as an experimental material. The aluminum alloy profile 4 can be used for lightweight automotive parts, such as control arms, steering knuckles, subframes, etc.

[0072] S1: Obtain the quenching inflection point temperature T0 that affects the mechanical properties of the profile. Take 6 groups of extruded samples of this grade and keep them at 555℃ for 1 hour for solution treatment. Then the 6 groups of samples are air-cooled to 520℃, 480℃, 440℃, 400℃, 360℃, and 300℃ respectively, quickly water quenched, and then kept at 175℃ for 8 hours for aging treatment. Finally, the Vickers hardness of each group of samples is measured. Analysis shows that the Vickers hardness of the samples air-cooled to below 400℃ for quenching and aging is significantly reduced, such as Figure 6 As shown, the quenching inflection point temperature T0 that affects the mechanical properties of the profile is 400 ℃.

[0073] S2: Use simulation software to simulate the online quenching of extruded profiles in the slow cooling zone. Use air cooling and mist cooling media. By adjusting the flow intensity and distribution position of the nozzle, the temperature distribution of the profile cross section when it arrives at the exit position of the slow cooling zone is between 400 ℃ and 450 ℃.

[0074] S3: Use simulation software to simulate the online quenching of the extruded profile in the rapid cooling zone. Use water cooling medium (temperature is 20°C) and adjust the nozzle position, spray intensity and spray angle to further optimize the quenching stability and uniformity. At the same time, the profile is cooled to room temperature within 10 seconds after entering the entrance of the rapid cooling zone.

[0075] S4: using the quenching device provided by the present invention, according to the parameters used in the simulation in the above steps S2 and S3, actual extrusion trial production is carried out, and tensile performance test is carried out according to GB / T 228.1-2010.

[0076] Embodiment 2: The method is basically the same as that described in Example 1, except that the grade is 7075 and the cross-sectional shape is Figure 5 The aluminum alloy profile 5 shown in the figure was tested and the quenching inflection point temperature T0 that affects the mechanical properties of the profile was measured as shown in the attached figure. Figure 6 As shown, it is 440° C. Aluminum alloy profiles 5 are mainly used in high stress and lightweight fields, such as for manufacturing high stress parts such as aircraft fuselage frames, wing beams, and keel beams.

[0077] Comparative Example 1 The profiles with the same alloy and cross-sectional shape as those in Example 1 were used, the position of the nozzle, the spray angle and the flow intensity were kept unchanged, and online quenching was performed using full air cooling.

[0078] Comparative Example 2 The profiles with the same alloy and cross-sectional shape as those in Example 1 were used, the position of the nozzle, the spray angle and the flow intensity were kept unchanged, and online quenching was performed using a full-process water cooling method.

[0079] Comparative Example 3 The profiles with the same alloy and cross-sectional shape as those in Example 2 were used, the nozzle position, spray angle and flow intensity were kept unchanged, and online quenching was performed using full air cooling.

[0080] Comparative Example 4 The profiles with the same alloy and cross-sectional shape as those in Example 2 were used, the position of the nozzle, the spray angle and the flow intensity were kept unchanged, and online quenching was performed using a full-process water cooling method.

[0081] For each embodiment and comparative example, according to the length of the extruded profile, the deformation displacement of the profile along the cross-sectional direction was recorded every 1 m, and the absolute average deformation displacement was calculated. The obtained results are shown in Table 1.

[0082] Table 1

[0083] From the results in Table 1, it can be seen that, compared with Comparative Examples 2 and 4, the corresponding quenching deformation degree of Examples 1 and 2 is greatly improved, and the mechanical properties are slightly reduced, which meets the actual use requirements. On the other hand, although the quenching deformation degree of Examples 1 and 2 is greater than that of Comparative Examples 1 and 3, the yield strength of Comparative Examples 1 and 3, which are fully air-cooled, is significantly reduced, which does not meet the use requirements.

[0084] In summary, the online quenching device and quenching method for metal profiles provided by the present invention reasonably divide the cooling stages and switch different cooling modes through the quenching inflection point temperature, and realize dynamic control of the cooling rate and uniformity management of the temperature field through the optimized combination of gradual cooling and multiple cooling methods, so that the profile can not only guarantee the mechanical properties to the greatest extent, but also have good dimensional stability, and can significantly improve the yield rate and production efficiency.

[0085] 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.

[0086] 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 method for online quenching of metal profiles, characterized in that: include: Obtain the quenching inflection point temperature T0 of the metal profile; The metal profile is slowly cooled by air cooling and / or mist cooling, so that the temperature distribution of the cross-sectional temperature field at the slow cooling position of the metal profile is between T0 and T0+50°C; The metal profile that has been slowly cooled is quenched by water cooling to cool it to room temperature.

2. The metal profile online quenching method according to claim 1, characterized in that: Get the inflection point temperature T0 of the mechanical properties of metal profiles, including: Solution treatment is performed on multiple specimens of the same grade as the metal profile; After the solution treatment, multiple samples were gradiently air-cooled to different target temperatures, and then water-quenched to room temperature; Peak aging treatment is performed on multiple samples after water quenching, and then the mechanical properties of each sample are tested to obtain the quenching inflection point temperature T0 of the metal profile.

3. The metal profile online quenching method according to claim 2, characterized in that: The target temperatures of the air-cooled samples are arranged in a gradient manner, and the temperature difference between two adjacent target temperatures is 5°C to 60°C.

4. The metal profile online quenching method according to claim 1, characterized in that: The metal profile is slowly cooled by air cooling and / or mist cooling, so that the temperature distribution of the cross-sectional temperature field at the slow cooling position of the metal profile is between T0 and T0+50°C, including: The air cooling and / or mist cooling process of the metal profile is simulated by simulation software to determine the quenching parameters of the metal profile; The metal profile is slowly cooled according to the quenching parameters, so that the temperature distribution of the cross-sectional temperature field at the position where the metal profile completes the slow cooling is between T0 and T0+50°C.

5. The metal profile online quenching method according to claim 4, characterized in that: The air cooling and / or mist cooling process of metal profiles is simulated by simulation software to determine the quenching parameters of metal profiles, including: Use simulation software to simulate the air cooling and / or mist cooling process of the metal profile to determine the cross-sectional temperature distribution when the lowest cross-sectional temperature at the position where the metal profile completes slow cooling reaches the quenching inflection point temperature T0; Determine whether the cross-section temperature distribution is within the range of T0~T0+50℃; If the cross-section temperature distribution does not meet the range of T0~T0+50℃, adjust the quenching parameters according to the simulation results; According to the adjusted quenching parameters, the simulation is repeated until the cross-sectional temperature distribution at the position where the metal profile completes slow cooling is within the range of T0~T0+50℃.

6. The metal profile online quenching method according to claim 1, characterized in that: The method of water cooling the slowly cooled metal profile by water quenching to cool it to room temperature specifically includes: The simulation software is used to perform online water quenching simulation on the metal profile that has completed slow cooling. By adjusting the water quenching parameters, the temperature difference of the metal profile cross section is between 5°C and 10°C, and the metal profile that has completed slow cooling is cooled to room temperature within 10 seconds.

7. A quenching device for the online quenching method for metal profiles according to any one of claims 1 to 6, characterized in that: include: A slow cooling zone and a fast cooling zone are sequentially arranged along the extrusion direction of the metal profile; the slow cooling zone is used to air cool and / or mist cool the extruded metal profile so that the temperature distribution of the cross-sectional temperature field at the slow cooling position of the metal profile is between T0 and T0+50°C; the fast cooling zone is used to water cool the metal profile after air cooling and / or mist cooling.

8. The quenching device according to claim 7, characterized in that: The slow cooling zone and the fast cooling zone form a cooling channel through which the metal profile can pass. Nozzles for spraying cooling medium are arranged around the cooling channel, and the angle and flow rate of the nozzles are adjustable.

9. The quenching device according to claim 8, characterized in that: The quenching device comprises a bottom bracket and a top bracket, the left and right sides of the top bracket are provided with mounting plates extending downward, and the top of the bottom bracket, the bottom of the top bracket and the mounting plate are all provided with nozzles facing the cooling channel.

10. The quenching device according to claim 9, characterized in that: The bottom bracket is provided with a support seat for supporting the metal profile. The bottom bracket is connected to the lifting mechanism and can be lifted and lowered under the drive of the lifting mechanism. The support seat is provided with a roller for supporting the metal profile to feed along the extrusion direction.

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