Aluminum alloy cylinder head heat treatment method and aluminum alloy cylinder head

Abstract

The application relates to a rapid air-cooling aluminum alloy cylinder cover heat treatment method and an aluminum alloy cylinder cover, which comprises sequentially performing solid solution treatment, rapid air-cooling quenching treatment and artificial aging treatment on an aluminum alloy cylinder cover casting to obtain the aluminum alloy cylinder cover; the rapid air-cooling quenching treatment comprises: cooling the aluminum alloy cylinder cover casting through air cooling, and the cooling speed between 430 DEG C and 260 DEG C is 7+ / -2 DEG C / min. The application utilizes air-cooling quenching, designs corresponding cooling speed, has little influence on strength and elongation, and better cutting performance. T6 uses water cooling, has no speed requirement, and the actually obtained strength and elongation are much higher, leading to poor cutting performance, great influence on mass production cost and efficiency. After the technology is adopted, the heat treatment process parameters are solidified, the performance detection result of the cylinder cover verified through multiple rounds of debugging is good, the stable and reliable method effectively avoids broken chip defects, abnormal tool wear or breakage, the tool has good broken chip effect, and waste loss and machining cost are reduced.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of heat treatment, in particular to a heat treatment method for an aluminum alloy cylinder head with rapid air cooling and the aluminum alloy cylinder head. BACKGROUND

[0002] Heat treatment generally does not change the shape and overall chemical composition of a workpiece, but changes the microstructure inside the workpiece to improve the strength and intrinsic performance of the workpiece, which is generally invisible to the naked eye. The microstructure of metal materials is complex and can be controlled through heat treatment, so the composition of metal materials is also an important content of casting process research; aluminum, copper, magnesium, iron and their alloys can also change their mechanical properties and physical properties through heat treatment to obtain different use performances. In order to make metal material workpieces have the required mechanical properties, physical properties and chemical properties, in addition to reasonable selection of materials and various casting processes, heat treatment process is also very critical. Heat treatment process generally includes heating, holding and cooling three processes, sometimes only heating and cooling two processes, which are connected with each other and cannot be interrupted.

[0003] The heat treatment process of the cylinder head blank in the initial stage of domestic trial production is according to T5 heat treatment, and the aging treatment is carried out after rapid cooling. This conventional heat treatment method will lead to insufficient hardness and mechanical strength of the cylinder head, and the performance of the obtained cylinder head cannot meet the product hardness and performance requirements. In order to improve the mechanical properties and prevent cracking, a feasible process method is explored. According to the conventional heat treatment method of T6 gravity cast aluminum alloy cylinder head, that is, after solid solution treatment, water quenching is carried out and then artificial aging heat treatment is carried out. Although the strength of the cylinder head is improved through water quenching, the cooling speed of heat treatment is relatively fast, and a large number of metallographic structures similar to martensite are generated, so that the surface hardness of the cylinder head product is too high, the machinability is poor during machining, the aluminum chip shape is long, and problems such as tool breakage and aluminum chip scratch occur, which greatly affect the production efficiency and manufacturing cost. SUMMARY

[0004] The embodiment of the application provides a heat treatment method for an aluminum alloy cylinder head with rapid air cooling and the aluminum alloy cylinder head, so as to solve the problem that in the related art, after solid solution treatment, water quenching and artificial aging heat treatment are carried out, the strength performance of the cylinder head is improved, but the surface hardness is too high, the elongation is large, the machinability is poor during machining, the aluminum chip shape is long, and problems such as tool breakage and aluminum chip scratch occur, which greatly affect the production efficiency and manufacturing cost.

[0005] In a first aspect, a heat treatment method for an aluminum alloy cylinder head with rapid air cooling is provided, which includes the following steps:

[0006] The aluminum alloy cylinder head is subjected to solid solution treatment, rapid air quenching treatment and artificial aging treatment in sequence to obtain the aluminum alloy cylinder head.

[0007] The rapid air cooling quenching treatment comprises: cooling the aluminum alloy cylinder head casting by air cooling, wherein the cooling speed between 430 DEG C and 260 DEG C is 7±2 DEG C / min.

[0008] In some embodiments, the cooling of the aluminum alloy cylinder head casting comprises: cooling the aluminum alloy cylinder head casting from 490±10 DEG C to 210±10 DEG C.

[0009] In some embodiments, the solution treatment comprises: a solution temperature of 490±10 DEG C and a solution time of 6±0.5 hours.

[0010] In some embodiments, the artificial aging treatment comprises: a holding treatment, and then cooling to a set temperature, wherein the total length of the artificial aging treatment is 6±0.5 hours, the holding temperature is 210±10 DEG C, and the holding time is 3.5±0.5 hours.

[0011] In some embodiments, before the holding treatment, the artificial aging treatment further comprises: heating to the holding temperature.

[0012] In some embodiments, when heating to the holding temperature, the heating speed is 2±0.5 DEG C / min.

[0013] In some embodiments, the set temperature is 50±5 DEG C.

[0014] In some embodiments, when cooling to the set temperature, the cooling speed is 2-3 DEG C / min.

[0015] In some embodiments, the aluminum alloy cylinder head casting is cast from an aluminum alloy, and the aluminum alloy comprises at least one of A319 and A356.

[0016] In a second aspect, an aluminum alloy cylinder head is provided, which is prepared by the rapid air cooling aluminum alloy cylinder head heat treatment method as described in any of the above.

[0017] The technical scheme provided in the application has the beneficial effects of:

[0018] The embodiments of the application provide a rapid air cooling aluminum alloy cylinder head heat treatment method and an aluminum alloy cylinder head. The application utilizes air cooling quenching and designs a corresponding cooling speed, which has less influence on strength and elongation, and better cutting performance. The T6 conventional method uses water cooling without speed requirement, so that the actual obtained strength and elongation are much higher, resulting in poor cutting performance, which greatly affects the cost and efficiency of mass production.

[0019] After the technology is adopted, the heat treatment process parameters are solidified, the cylinder cover performance detection result is good after multiple rounds of debugging verification, the stable and reliable process method effectively avoids the poor chip breaking, abnormal tool wear or breakage, the tool chip breaking effect is good, and the waste loss and processing cost are reduced. The heat treatment process method is worth popularizing and applying in the casting production of aluminum alloy workpieces. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0021] Figure 1 The fast air cooling quenching temperature-time curve provided by the embodiment of the present application is provided.

[0022] Figure 2 The artificial aging treatment temperature-time curve provided by the embodiment of the present application is provided.

[0023] Figure 3 The metallographic structure diagram (DAS value) of Example 1 of the present application is provided.

[0024] Figure 4 The metallographic structure diagram (porosity) of Example 1 of the present application is provided.

[0025] Figure 5 The metallographic structure diagram (DAS value) of Comparative Example 3 of the present application is provided.

[0026] Figure 6 The metallographic structure diagram (porosity) of Comparative Example 3 of the present application is provided. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0028] The embodiment of the present application provides a fast air cooling aluminum alloy cylinder cover heat treatment method, which comprises the following steps:

[0029] The aluminum alloy cylinder cover casting is sequentially subjected to solid solution treatment, rapid air cooling quenching treatment and artificial aging treatment to obtain the aluminum alloy cylinder cover; wherein, the rapid air cooling quenching treatment comprises: cooling the aluminum alloy cylinder cover casting by air cooling, wherein, referring to Figure 1 the cooling speed between 430 DEG C and 260 DEG C is 7±2 DEG C / min.

[0030] When the cooling speed is lower than 7±2 DEG C / min, the mechanical properties and hardness of the prepared aluminum alloy cylinder cover are too low to meet the product requirements. When the cooling speed is higher than 7±2 DEG C / min, the mechanical properties and hardness of the prepared aluminum alloy cylinder cover are too high to meet the production cutting process requirements.

[0031] The application utilizes air cooling quenching and designs the corresponding cooling speed, which has less influence on the strength and elongation and better cutting property. The T6 conventional method uses water cooling without speed requirement, so the actual obtained strength and elongation are much higher, resulting in poor cutting property and great influence on mass production cost and efficiency.

[0032] After adopting the technology, the heat treatment process parameters are solidified, the performance detection results of the cylinder cover verified by multiple rounds of debugging are good, the stable and reliable process method effectively avoids the chip breaking defect and abnormal wear or breakage of the tool, the tool has good chip breaking effect, reduces the waste loss and processing cost. The heat treatment process method is worth popularizing and applying in the casting production of aluminum alloy workpieces.

[0033] The technology does not use water and oil, does not exist water and oil pollution, and air is only for cold and heat exchange, so it is more environmentally friendly and safer. The heat treatment efficiency is high, economical and practical, saves energy consumption and reduces the manufacturing cost by about 20%.

[0034] Generally, after the solid solution treatment is completed, the aluminum alloy cylinder cover casting is transferred as soon as possible for air cooling quenching, and then transferred for artificial aging treatment. At this time, the temperature decreases little or even little during the transfer process. At this time, the rapid air cooling quenching treatment mainly reduces the aluminum alloy cylinder cover casting from the solid solution temperature during the solid solution treatment to the holding temperature during the artificial aging treatment, that is, cools the aluminum alloy cylinder cover casting from 490±10 DEG C to 210±10 DEG C.

[0035] In fact, there are some uncontrollable factors in the transfer process, so the aluminum alloy cylinder cover casting is cooled by air cooling after the solid solution treatment is completed, but it is not necessarily cooled from 490±10 DEG C, and the temperature at which the cooling ends is also not necessarily 210±10 DEG C. If the temperature is lower than this temperature, the artificial aging treatment can be heated by itself.

[0036] When the rapid air cooling quenching treatment is performed, a rapid cooling device can be used, the rapid cooling device adopts a cooling channel mode, is arranged outside a heat treatment equipment, and comprises a cooling station and a conveying device, specifically, a refrigerating unit and a blower are installed on a conveying roller, a plurality of circulating fans are uniformly distributed above the roller, the conveying speed of the conveying roller is adjustable, the cooling station is provided with a temperature sensor, the blower is a variable frequency blower, and the temperature is set and adjusted through an industrial computer. The temperature sensor can monitor the temperature of the casting in real time, and the cooling speed is obtained in combination with the cooling time, so that the cooling speed is adjusted through the speed regulating device of the variable frequency blower, and the effect of the casting treatment is ensured.

[0037] The solution treatment comprises a solution temperature of 490±10℃ and a solution time of 6±0.5 hours. The solution treatment adopts the process condition, so that the material has a stable metallographic structure and has the advantages of high production efficiency.

[0038] Referring to Figure 2 As shown in the figure, the artificial aging treatment comprises heating to a holding temperature, holding treatment, and cooling to a set temperature, wherein the total length of the artificial aging treatment is 6±0.5 hours, the holding temperature is 210±10℃, and the holding time is 3.5±0.5 hours. This holding temperature and holding time can not only eliminate residual stress, but also obtain a stable treatment method and high production efficiency.

[0039] It should be noted that when the rapid air cooling quenching treatment is completed, the aluminum alloy cylinder head casting is transferred to the aging furnace for artificial aging treatment, if the temperature of the aluminum alloy cylinder head casting reaches the holding temperature, heating treatment is not required, and if the temperature of the aluminum alloy cylinder head casting is lower than the holding temperature, heating treatment is required.

[0040] In the artificial aging treatment, when heating to the holding temperature, the heating speed is 2±0.5℃ / min.

[0041] In the artificial aging treatment, the set temperature is 50±5℃.

[0042] In the artificial aging treatment, when cooling to the set temperature, the cooling speed is 2-3℃ / min.

[0043] The aluminum alloy cylinder head casting is made of aluminum alloy, and the aluminum alloy comprises at least one of A319 and A356, for example, A319 aluminum alloy, the material grade is AlSi7Cu3Mg0.35(Fe), and the main chemical element composition requirements are as follows: Si content 7.0-8.5%, Cu content 2.8-3.5%, Mg content 0.25-0.4%, and Fe content 0-0.7%.

[0044] The application further provides an aluminum alloy cylinder cover prepared by the rapid air-cooling aluminum alloy cylinder cover heat treatment method.

[0045] The application will be further described in connection with examples and comparative examples. It should be understood that the examples are only used for illustrating the application and are not used for limiting the scope of the application. Furthermore, it should be understood that after reading the content taught by the application, those skilled in the art can make various modifications or changes to the application, and these equivalent forms also fall within the scope defined by the appended claims of the application.

[0046] Example 1

[0047] A rapid air-cooling aluminum alloy cylinder cover heat treatment method, comprising the following steps:

[0048] 101: cast A319 aluminum alloy into an aluminum alloy cylinder cover casting, and vertically place the aluminum alloy cylinder cover casting with the rear end face downward in a heat treatment rack. Perform solid solution treatment on the aluminum alloy cylinder cover casting: the solid solution temperature is set to 490±10℃, and the solid solution time is 6 hours.

[0049] 102: after the solid solution treatment in the solid solution furnace, rapidly transfer to a modified annular cooling channel to perform rapid air-cooling quenching treatment. Start the air blower, and rotate the aluminum alloy cylinder cover casting to perform air-cooling quenching. During the cooling process of the aluminum alloy cylinder cover casting, use the air-cooling medium to cool the aluminum alloy cylinder cover casting at a cooling rate of 7℃ per minute, and rapidly cool the aluminum alloy cylinder cover casting from 430℃ to 260℃. After completing the rapid air-cooling quenching treatment, transfer to an aging furnace.

[0050] 103: perform artificial aging treatment on the aluminum alloy cylinder cover casting. The total length of the artificial aging treatment is 6 hours, wherein the holding temperature is 210±10℃, the holding time is 3.5 hours, and then cool to 50℃ at a cooling rate of 2℃ / min. By changing the microstructure of the material, the DAS value (dendrite arm spacing, which refers to the center distance between adjacent secondary dendrites) and the porosity (which refers to the percentage of the volume of the internal pores in the total volume of the material) are effectively controlled, so that the product performance meets the actual requirements, and the cutting process is good. Photographed by a metallographic microscope XJG-05 / XJP-300, as shown in FIG. 2, the measured value of the secondary dendrite arm spacing is 28μm, which meets the requirement of being less than 50μm, as shown in FIG. 3, and the measured value of the porosity is 0.54%, which meets the requirement of being less than 2.0%. After the heat treatment is completed, the strength and surface hardness are detected. Figure 3 Figure 4

[0051] Example 2

[0052] ​​The difference between this embodiment and embodiment 1 is that the aluminum alloy cylinder head casting is cooled by the air cooling medium at a cooling rate of 5℃ per minute. The specific process is as follows.

[0053] A rapid air cooling aluminum alloy cylinder head heat treatment method comprises the following steps:

[0054] 101: A319 aluminum alloy is cast into an aluminum alloy cylinder head casting, and the aluminum alloy cylinder head casting is vertically placed in a heat treatment rack with the rear end face downward. The aluminum alloy cylinder head casting is subjected to solid solution treatment, and the solid solution temperature is set to 490±10℃, and the solid solution time is 6 hours.

[0055] 102: After the solid solution treatment in the solid solution furnace, the aluminum alloy cylinder head casting is rapidly transferred to the modified annular cooling channel for rapid air cooling quenching treatment. The fan is turned on, and the aluminum alloy cylinder head casting is rotated for air cooling quenching. During the cooling process of the aluminum alloy cylinder head casting, the aluminum alloy cylinder head casting is rapidly cooled from 430℃ to 260℃ at a cooling rate of 5℃ per minute by using the air cooling medium. After the rapid air cooling quenching treatment is completed, the aluminum alloy cylinder head casting is transferred to the aging furnace.

[0056] 103: The aluminum alloy cylinder head casting is subjected to artificial aging treatment. The total artificial aging treatment time is 6 hours, wherein the holding temperature is 210±10℃, the holding time is 3.5 hours, and then the cooling rate is 2℃ / min to 50℃. By changing the microstructure of the material, the DAS value (dendrite arm spacing, which refers to the center distance between adjacent secondary dendrites) and the porosity (the porosity refers to the percentage of the volume of the internal pores in the total volume of the material) are effectively controlled, so that the product performance meets the actual requirements, and the cutting process is good. After the heat treatment is completed, the strength and surface hardness are detected.

[0057] Embodiment 3

[0058] The difference between this embodiment and embodiment 1 is that the aluminum alloy cylinder head casting is cooled by the air cooling medium at a cooling rate of 6℃ per minute. The specific process is as follows.

[0059] A rapid air cooling aluminum alloy cylinder head heat treatment method comprises the following steps:

[0060] 101: A319 aluminum alloy is cast into an aluminum alloy cylinder head casting, and the aluminum alloy cylinder head casting is vertically placed in a heat treatment rack with the rear end face downward. The aluminum alloy cylinder head casting is subjected to solid solution treatment, and the solid solution temperature is set to 490±10℃, and the solid solution time is 6 hours.

[0061] 102: After the solution treatment in the solution furnace, the aluminum alloy cylinder head casting is quickly transferred to the modified annular cooling channel for rapid air cooling quenching treatment. The fan is turned on, and the aluminum alloy cylinder head casting is rotated for air cooling quenching. During the cooling process of the aluminum alloy cylinder head casting, the aluminum alloy cylinder head casting is rapidly cooled from 430°C to 260°C at a cooling rate of 8°C per minute by using the air cooling medium. After the rapid air cooling quenching treatment is completed, the aluminum alloy cylinder head casting is transferred to the aging furnace.

[0062] 103: Artificial aging treatment is performed on the aluminum alloy cylinder head casting. The total duration of the artificial aging treatment is 6 hours, wherein the holding temperature is 210±10°C, the holding time is 3.5 hours, and then the cooling speed is 2°C / min to 50°C. By changing the microstructure of the material, the DAS value (dendrite arm spacing, which refers to the center distance between adjacent secondary dendrites) and the porosity (the percentage of the volume of the internal pores in the total volume of the material) are effectively controlled, so that the product performance meets the actual requirements, and the cutting process is good. After the heat treatment is completed, the strength and surface hardness are detected.

[0063] Example 4

[0064] The difference between this embodiment and Example 1 is that the aluminum alloy cylinder head casting is cooled at a cooling rate of 8°C per minute by using the air cooling medium. Specifically as follows:

[0065] A rapid air cooling heat treatment method for an aluminum alloy cylinder head, comprising the following steps:

[0066] 101: A319 aluminum alloy is cast into an aluminum alloy cylinder head casting, and the aluminum alloy cylinder head casting is vertically placed in a heat treatment rack with the rear end face downward. The aluminum alloy cylinder head casting is subjected to solution treatment: the solution temperature is set to 490±10°C, and the solution time is 6 hours.

[0067] 102: After the solution treatment in the solution furnace, the aluminum alloy cylinder head casting is quickly transferred to the modified annular cooling channel for rapid air cooling quenching treatment. The fan is turned on, and the aluminum alloy cylinder head casting is rotated for air cooling quenching. During the cooling process of the aluminum alloy cylinder head casting, the aluminum alloy cylinder head casting is rapidly cooled from 430°C to 260°C at a cooling rate of 8°C per minute by using the air cooling medium. After the rapid air cooling quenching treatment is completed, the aluminum alloy cylinder head casting is transferred to the aging furnace.

[0068] 103: The aluminum alloy cylinder head casting is subjected to artificial aging treatment. The total artificial aging treatment time is 6 hours, wherein the holding temperature is 210±10°C, the holding time is 3.5 hours, and then the cooling is performed at a cooling rate of 2°C / min to 50°C. By changing the microstructure of the material, the DAS value (dendrite arm spacing, which refers to the center distance between adjacent secondary dendrites) and the porosity (the porosity refers to the percentage of the volume of the internal pores of the material in the total volume of the material) are effectively controlled, so that the product performance meets the actual requirements, and the cutting process is good. After the heat treatment is completed, the strength and surface hardness are detected.

[0069] Example 5

[0070] The difference between this embodiment and Example 1 is that the aluminum alloy cylinder head casting is cooled at a cooling rate of 9°C per minute by using a forced air cooling medium. Specifically as follows:

[0071] A rapid air cooling aluminum alloy cylinder head heat treatment method, comprising the following steps:

[0072] 101: The A319 aluminum alloy is cast into an aluminum alloy cylinder head casting, and the aluminum alloy cylinder head casting is vertically placed in a heat treatment rack with the rear end face downward. The aluminum alloy cylinder head casting is subjected to solid solution treatment, wherein the solid solution temperature is set to 490±10°C, and the solid solution time is 6 hours.

[0073] 102: After the solid solution treatment in the solid solution furnace, the aluminum alloy cylinder head casting is quickly transferred to a modified annular cooling channel for rapid air cooling quenching treatment. The fan is turned on, and the aluminum alloy cylinder head casting is rotated for air cooling quenching. During the cooling process of the aluminum alloy cylinder head casting, the aluminum alloy cylinder head casting is rapidly cooled from 430°C to 260°C at a cooling rate of 9°C per minute by using a forced air cooling medium. After the rapid air cooling quenching treatment is completed, the aluminum alloy cylinder head casting is transferred to an aging furnace.

[0074] 103: The aluminum alloy cylinder head casting is subjected to artificial aging treatment. The total artificial aging treatment time is 6 hours, wherein the holding temperature is 210±10°C, the holding time is 3.5 hours, and then the cooling is performed at a cooling rate of 2°C / min to 50°C. By changing the microstructure of the material, the DAS value (dendrite arm spacing, which refers to the center distance between adjacent secondary dendrites) and the porosity (the porosity refers to the percentage of the volume of the internal pores of the material in the total volume of the material) are effectively controlled, so that the product performance meets the actual requirements, and the cutting process is good. After the heat treatment is completed, the strength and surface hardness are detected.

[0075] Comparative Example 1

[0076] The difference between the present comparative example and Example 1 is that the aluminum alloy cylinder head casting is cooled at a cooling rate of 3°C per minute by using the air cooling medium. The specific process is as follows.

[0077] A rapid air cooling aluminum alloy cylinder head heat treatment method comprises the following steps:

[0078] 101: A319 aluminum alloy is cast into an aluminum alloy cylinder head casting, and the aluminum alloy cylinder head casting is vertically placed in a heat treatment rack with the rear end face downward. The aluminum alloy cylinder head casting is subjected to solid solution treatment, and the solid solution temperature is set to 490±10°C, and the solid solution time is 6 hours.

[0079] 102: After the solid solution treatment in the solid solution furnace, the aluminum alloy cylinder head casting is rapidly transferred to the modified annular cooling channel for rapid air cooling quenching treatment. The fan is turned on, and the aluminum alloy cylinder head casting is rotated for air cooling quenching. During the cooling process of the aluminum alloy cylinder head casting, the aluminum alloy cylinder head casting is rapidly cooled from 430°C to 260°C at a cooling rate of 3°C per minute by using the air cooling medium. After the rapid air cooling quenching treatment is completed, the aluminum alloy cylinder head casting is transferred to the aging furnace.

[0080] 103: The aluminum alloy cylinder head casting is subjected to artificial aging treatment. The total artificial aging time is 6 hours, the holding temperature is 210±10°C, the holding time is 3.5 hours, and then the temperature is cooled to 50°C at a cooling rate of 2°C / min. After the heat treatment is completed, the strength and surface hardness are detected.

[0081] Comparative Example 2

[0082] The difference between the present comparative example and Example 1 is that the aluminum alloy cylinder head casting is cooled at a cooling rate of 10°C per minute by using the air cooling medium. The specific process is as follows.

[0083] A rapid air cooling aluminum alloy cylinder head heat treatment method comprises the following steps:

[0084] 101: A319 aluminum alloy is cast into an aluminum alloy cylinder head casting, and the aluminum alloy cylinder head casting is vertically placed in a heat treatment rack with the rear end face downward. The aluminum alloy cylinder head casting is subjected to solid solution treatment, and the solid solution temperature is set to 490±10°C, and the solid solution time is 6 hours.

[0085] 102: After the solid solution treatment in the solid solution furnace, the aluminum alloy cylinder head casting is rapidly transferred to the modified annular cooling channel for rapid air cooling quenching treatment. The fan is turned on, and the aluminum alloy cylinder head casting is rotated for air cooling quenching. During the cooling process of the aluminum alloy cylinder head casting, the aluminum alloy cylinder head casting is rapidly cooled from 430°C to 260°C at a cooling rate of 10°C per minute by using the air cooling medium. After the rapid air cooling quenching treatment is completed, the aluminum alloy cylinder head casting is transferred to the aging furnace.

[0086] 103: The aluminum alloy cylinder head casting is subjected to artificial aging treatment. The total artificial aging treatment time is 6 hours, wherein the holding temperature is 210±10°C, the holding time is 3.5 hours, and then the cooling speed is 2°C / min to 50°C. After the heat treatment is completed, the strength and surface hardness are detected.

[0087] Comparative Example 3

[0088] The comparative example is treated by using the heat treatment method of the T6 gravity casting aluminum alloy cylinder head. Referring to Figure 5 , the measured value of the secondary dendrite arm spacing is 40 μm, which meets the requirement of being less than 50 μm, but is much higher than the 28 μm of the embodiments of the present application, referring to Figure 6 , the measured value of the porosity is 1.57%, which meets the requirement of being less than 2.0%, but is much higher than the 0.54% of the embodiments of the present application.

[0089] The strength and surface hardness test results of each embodiment and comparative example are shown in Table 1 below.

[0090] Table 1

[0091]

[0092]

[0093] From the data in Table 1 above, it can be seen that the aluminum alloy cylinder heads treated in the embodiments 1-5 of the present application have moderate strength.

[0094] In combination with Comparative Example 1 and embodiments 1-5, the surface hardness of Comparative Example 1 is 88 HB, which is too low, because the cooling speed between 430°C and 260°C is 3°C / min, which is too low. The mechanical properties and hardness of the aluminum alloy cylinder head prepared thereby are too low. In contrast, the surface hardness of the embodiments 1-5 of the present application is 91-99 HB, which is appropriate, because the cooling speed between 430°C and 260°C is 5-9°C / min, which is appropriate.

[0095] In combination with Comparative Example 2 and embodiments 1-5, the surface hardness of Comparative Example 2 is 100 HB, which is too high, because the cooling speed between 430°C and 260°C is 10°C / min, which is too high. The mechanical properties and hardness of the aluminum alloy cylinder head prepared thereby are too high, and cannot meet the production cutting process requirements. In contrast, the surface hardness of the embodiments 1-5 of the present application is 91-99 HB, which is appropriate, because the cooling speed between 430°C and 260°C is 5-9°C / min, which is appropriate.

[0096] In combination with Comparative Example 3 and embodiments 1-5, the surface hardness of Comparative Example 3 is 102 HB, which is too high, because the T6 process is used, and cannot meet the production cutting process requirements.

[0097] In the description of the present application, it should be noted that the terms "upper", "lower", and the like are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise expressly specified and limited, the terms "mounting", "connecting", "connecting" should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication between two elements inside. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0098] It should be noted that in the present application, relational terms such as "first" and "second" and the like are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the sentence "including a" does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0099] The above is only a specific embodiment of the present application, which enables those skilled in the art to understand or implement the present application. Various modifications of these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features applied herein.

Claims

1. A rapid air cooling heat treatment method for an aluminum alloy cylinder head, characterized by, It comprises the following steps: The aluminum alloy cylinder head casting is sequentially subjected to solid solution treatment, rapid air cooling quenching treatment and artificial aging treatment to obtain an aluminum alloy cylinder head; The rapid air cooling quenching treatment comprises: cooling the aluminum alloy cylinder head casting by air cooling, wherein the cooling rate between 430℃ and 260℃ is 6-9℃ / min; The aluminum alloy cylinder head casting is cooled, comprising: cooling the aluminum alloy cylinder head casting from 490±10℃ to 210±10℃; The solid solution treatment comprises: a solid solution temperature of 490±10℃ and a solid solution time of 6±0.5 hours; The artificial aging treatment comprises: first, heat preservation treatment, and then cooling to a set temperature, wherein the total artificial aging treatment time is 6±0.5 hours, the heat preservation temperature is 210±10℃, the heat preservation time is 3.5±0.5 hours; the set temperature is 50±5℃; when cooling to the set temperature, the cooling rate is 2-3℃ / min; The aluminum alloy cylinder head casting is made of aluminum alloy, and the aluminum alloy is A319.

2. The rapid air-cooled heat treatment method of an aluminum alloy cylinder head according to claim 1, characterized by, Before the heat preservation treatment, the artificial aging treatment further comprises: heating to the heat preservation temperature.

3. The rapid air-cooled heat treatment method of aluminum alloy cylinder head according to claim 2, characterized by: When heating to the heat preservation temperature, the heating rate is 2±0.5℃ / min.

4. An aluminum alloy cylinder head characterized by: The aluminum alloy cylinder head is prepared by using the rapid air cooling aluminum alloy cylinder head heat treatment method according to any one of claims 1-3.

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