Method for repairing defects of semi-solid casting

Abstract

The invention relates to a method for repairing defects of a semi-solid casting, which comprises the following steps of: judging a to-be-repaired site of the casting, adding an alloy melt with the temperature of 10-20 DEG C above a liquidus into an injector, applying ultrasound to the alloy melt, cooling to a semi-solid interval to form semi-solid alloy slurry with the solid fraction of 15-35%, and the temperature of the to-be-repaired site is increased to 400-500 DEG C, an opening of an injector is placed on the to-be-repaired site, sealing connection is formed, the semi-solid alloy slurry enters the to-be-repaired site through pressure, ultrasonic waves continue to be applied for 10-30 s, the pressure is maintained, then the pressure and the ultrasonic waves are removed, the injector is removed, and repairing is completed.

Description

Technical Field

[0001] The invention relates to the technical field of semi-solid alloy materials, and in particular to a method for repairing defects of semi-solid castings. Background Art

[0002] Semi-solid castings are high-performance castings obtained by casting semi-solid slurry. They have special organizational structures and good performance. It is generally believed that semi-solid castings have fewer defects than ordinary castings. However, if defects occur in semi-solid castings, their performance will be greatly affected. Ordinary castings do not have special organizational structures and can be repaired by welding or even casting glue. However, these methods will affect the organizational structure of semi-solid castings and are not suitable for the repair of semi-solid castings. Generally, high-precision repair technologies such as laser welding are required to repair semi-solid castings well. However, these methods are costly and complex. Some metals with high heat transfer coefficients, such as magnesium alloys, require ultra-high power laser sources for welding, otherwise the overall organizational structure of the casting may change or even melt during the repair process.

[0003] Therefore, it is necessary to propose a method for repairing defects in semi-solid castings. Summary of the invention

[0004] In order to solve the problem that the current semi-solid castings are difficult to repair, the purpose of the present invention is to provide a method for repairing defects of semi-solid castings.

[0005] A method for repairing defects of a semi-solid casting comprises the following steps: determining a site to be repaired of the casting, adding an alloy melt 10-20°C above the liquidus into a syringe, wherein the alloy melt is A356.2, applying ultrasound to the alloy melt and cooling it to a semi-solid range to form a semi-solid alloy slurry with a solid phase fraction of 15-35%, raising the temperature of the site to be repaired to 400-500°C, placing the opening of the syringe on the site to be repaired and forming a sealed connection, allowing the semi-solid alloy slurry to enter the site to be repaired by pressure, continuing to apply ultrasound for 10-30S and maintaining the pressure, then removing the pressure and ultrasound and removing the syringe, thereby completing the repair.

[0006] This solution uses ultrasound to prepare and fill the alloy melt in real time in the closed inner cavity of the syringe, which can avoid the introduction of bubbles and impurities during the preparation and transfer of the alloy melt. The semi-solid alloy slurry has good fluidity and can penetrate deep into the site to be repaired to complete the filling. During the injection of the semi-solid alloy slurry, ultrasound is then applied continuously, which can promote the flow of the semi-solid slurry and the discharge of gas in the site to be repaired to promote the filling of the site to be repaired. On the other hand, the ultrasound can be transmitted to the solid phase particles in the semi-solid slurry entering the site to be repaired. The solid phase particles vibrate violently under the action of ultrasound to cause friction with the site to be repaired and rapid heat transfer so that the surface temperature of the site to be repaired after preheating rises rapidly to the semi-solid temperature, and the liquid phase of the site to be repaired merges with the liquid phase of the semi-solid alloy slurry to achieve a better metallurgical bonding effect and significantly reduce the cost. The site to be repaired is preheated to 400-500°C, at which temperature, the overall organizational structure of the casting will not change significantly, and the semi-solid temperature can be quickly reached under the synergistic heating of the heat transfer of the semi-solid slurry and the ultrasound.

[0007] Further, at least one of the sites to be repaired is distributed on the plane of the casting, and the opening covers and seals the site to be repaired. If the sites to be repaired are distributed on the plane of the casting, and the opening is sufficient to cover the site to be repaired, then a sealing connection between the opening and the site to be repaired can be achieved without using a sealing fixture.

[0008] Furthermore, at least one of the sites to be repaired is distributed on a non-planar portion of the casting, and a sealing fixture is used to seal the connection between the site to be repaired and the opening. The non-planar portion refers to the edge, joint, corner, and other areas of the casting, and a sealing fixture is required to achieve a sealed connection between the opening and the site to be repaired.

[0009] Furthermore, the bottom of the ultrasonic probe is 2-5 mm away from the bottom of the syringe. Placing the ultrasonic probe close to the bottom of the syringe, that is, close to the opening, helps to transmit the ultrasonic effect to the site to be repaired, so as to reduce excessive attenuation of the ultrasonic effect during the transmission process.

[0010] Furthermore, the ultrasonic parameters are: 500-1000W, 10kHz-30kHz. If the ultrasonic power and frequency are too low, the shear force provided is too small, and it is difficult to form a uniform semi-solid slurry on the one hand, and the solid phase particle movement rate is too low to quickly heat the site to be repaired to the semi-solid temperature; if the ultrasonic power and frequency are too high, the semi-solid slurry in the syringe may splash.

[0011] Furthermore, the temperature of the site to be repaired is increased to 480-500° C. Further increasing the temperature of the site to be repaired can help the temperature of the site to be repaired reach the semi-solid temperature faster.

[0012] Furthermore, the temperature of the site to be repaired is raised to 400-500° C. by an induction heating device. The induction heating device can quickly and accurately raise the temperature of the site to be repaired.

[0013] Furthermore, the pressure is 50-80 MPa. If the pressure is too low, the semi-solid alloy slurry cannot fully fill the repaired site; if the pressure is too high, it is difficult to ensure the sealing effect.

[0014] Further, in terms of mass fraction, the composition of the A356.2 includes: silicon: 6.5-7%, nickel: 0.05-0.10%, magnesium: 0.30-0.40%, copper: 0-0.05%, iron: 0-0.12%, zinc: 0-0.05%, titanium: 0-0.2%, manganese: 0-0.05%, strontium: 0-0.001%, and the rest is aluminum. A356.2 has good fluidity in a semi-solid state, can fully fill the site to be repaired, and A356.2 has a small linear shrinkage and no thermal cracking tendency, which can further improve the repair effect.

[0015] Furthermore, after removing the syringe, the site to be repaired is subjected to CNC surface treatment. Through CNC surface treatment, the rough surface of the site to be repaired after repair can be removed to avoid affecting the appearance of the casting. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the surface of a semi-solid casting with surface defects in Example 1.

[0017] Figure 2 This is a schematic diagram of the surface of the semi-solid casting after repair in Example 1.

[0018] Figure 3 Schematic diagram of the repair method of the present application. DETAILED DESCRIPTION

[0019] For ease of understanding of the application, the application will be described more fully below. The application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the application more thorough and comprehensive.

[0020] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In the description of the present application, the meaning of "several" is at least one, such as one, two, etc., unless otherwise clearly and specifically defined.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which the present application belongs. The terms used herein in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0022] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0023] In this application, when it comes to numerical ranges, unless otherwise specified, the above numerical ranges are deemed to be continuous and include the minimum and maximum values ​​of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0024] The percentage contents involved in this application, unless otherwise specified, refer to mass percentage for solid-liquid mixing and solid-solid mixing, and refer to volume percentage for liquid-liquid mixing.

[0025] The percentage concentrations mentioned in this application, unless otherwise specified, refer to the final concentration, which refers to the percentage of the added component in the system after the addition of the component.

[0026] The temperature parameters in this application, unless otherwise specified, allow for both constant temperature treatment and treatment within a certain temperature range. The constant temperature treatment allows the temperature to fluctuate within the accuracy range of instrument control.

[0027] The "particles" mentioned in this application, or materials with a defined particle size distribution, are not necessarily spherical in shape, but may be irregular, primary particles or secondary particles. The particle size of irregular particles is the average of their maximum diameter and minimum diameter.

[0028] The steps of the repair method of this application are as follows Figure 3 As shown, the present invention will be discussed below in conjunction with specific embodiments.

[0029] A method for repairing defects in semi-solid castings: first, the surface of the casting to be repaired (the material is A356.2, the casting is an automobile part, and it is obvious that this solution can also be applied to the repair of other materials and castings, such as 6063 aluminum alloy, 7075 aluminum alloy or AZ91D magnesium alloy, etc., and the casting can also be alloy castings such as plates, pipes, engine housings, battery housings, etc.) is cleaned to remove oil stains, and then the site to be repaired of the casting is judged by visual inspection combined with an ultrasonic flaw detector, and cracks or shrinkage holes with a width of 1-10 mm, a length of 1-10 mm, and a depth of 1-5 mm are selected as the site to be repaired.

[0030] Example 1: A356.2 melt at 20°C above the liquidus line is added into a syringe, an ultrasonic probe is fixed inside the syringe, and the bottom of the ultrasonic probe is 2 mm away from the bottom of the syringe. The ultrasonic device is started to cool the melt to a semi-solid temperature to form a semi-solid alloy slurry with a solid phase fraction of 35%, wherein the components of A356.2 include: by mass fraction, silicon: 6.5%, nickel: 0.05%, magnesium: 0.30%, copper: 0.05%, iron: 0.12%, zinc: 0.05%, titanium: 0.2%, manganese: 0.05%, strontium: 0.001%, and the rest is aluminum, wherein the ultrasonic parameters are 1000W, 30kHz.

[0031] The site to be repaired is heated to 400°C by an induction heating device, and the opening of the syringe is placed at the site to be repaired to form a sealed connection (for the site to be repaired distributed on the plane of the casting, the opening can be directly used to cover and seal the site to be repaired; for the site to be repaired distributed in non-planar areas such as the edges, joints and corners of the casting, a sealing clamp can be used to achieve a sealed connection between the opening and the site to be repaired, and other embodiments and comparative examples use the same sealing connection method).

[0032] The semi-solid alloy slurry in the syringe is forced into the repaired site by pressure (50 MPa), and then the ultrasonic action is continued for 10 seconds and the pressure is maintained. The pressure and ultrasound are then removed and the syringe is removed. The repaired area is subjected to CNC surface treatment, thus completing the repair of the repaired site.

[0033] Example 2: A356.2 melt at 10°C above the liquidus line is added into a syringe, an ultrasonic probe is fixed inside the syringe, and the bottom of the ultrasonic probe is 5 mm away from the bottom of the syringe. The ultrasonic device is started to cool the melt to a semi-solid temperature to form a semi-solid alloy slurry with a solid phase fraction of 35%, wherein the components of A356.2 include: by mass fraction, silicon: 6.5%, nickel: 0.05%, magnesium: 0.30%, copper: 0.05%, iron: 0.12%, zinc: 0.05%, titanium: 0.2%, manganese: 0.05%, strontium: 0.001%, and the rest is aluminum, wherein the ultrasonic parameters are 1000W, 30kHz.

[0034] The temperature of the site to be repaired is raised to 400° C. by an induction heating device, and the opening of the syringe is placed at the site to be repaired to form a sealed connection.

[0035] The semi-solid alloy slurry in the syringe is forced into the repaired site by pressure (50 MPa), and then the ultrasonic action is continued for 10 seconds and the pressure is maintained. The pressure and ultrasound are then removed and the syringe is removed. The repaired area is subjected to CNC surface treatment, thus completing the repair of the repaired site.

[0036] Example 3: A356.2 melt at 20°C above the liquidus line is added into a syringe, an ultrasonic probe is fixed inside the syringe, and the bottom of the ultrasonic probe is 2 mm away from the bottom of the syringe. The ultrasonic device is started to cool the melt to a semi-solid temperature to form a semi-solid alloy slurry with a solid phase fraction of 35%, wherein the components of A356.2 include: by mass fraction, silicon: 6.5%, nickel: 0.05%, magnesium: 0.30%, copper: 0.05%, iron: 0.12%, zinc: 0.05%, titanium: 0.2%, manganese: 0.05%, strontium: 0.001%, and the rest is aluminum, wherein the ultrasonic parameters are 500W, 10kHz.

[0037] The temperature of the site to be repaired is raised to 400° C. by an induction heating device, and the opening of the syringe is placed at the site to be repaired to form a sealed connection.

[0038] The semi-solid alloy slurry in the syringe is forced into the repaired site by pressure (50 MPa), and then the ultrasonic action is continued for 10 seconds and the pressure is maintained. The pressure and ultrasound are then removed and the syringe is removed. The repaired area is subjected to CNC surface treatment, thus completing the repair of the repaired site.

[0039] Example 4: A356.2 melt at 20°C above the liquidus line is added into a syringe, an ultrasonic probe is fixed inside the syringe, and the bottom of the ultrasonic probe is 2 mm away from the bottom of the syringe. The ultrasonic device is started to cool the melt to a semi-solid temperature to form a semi-solid alloy slurry with a solid phase fraction of 35%, wherein the components of A356.2 include: by mass fraction, silicon: 6.5%, nickel: 0.05%, magnesium: 0.30%, copper: 0.05%, iron: 0.12%, zinc: 0.05%, titanium: 0.2%, manganese: 0.05%, strontium: 0.001%, and the rest is aluminum, wherein the ultrasonic parameters are 1000W, 30kHz.

[0040] The temperature of the site to be repaired is raised to 480° C. by an induction heating device, and the opening of the syringe is placed at the site to be repaired to form a sealed connection.

[0041] The semi-solid alloy slurry in the syringe is forced into the repaired site by pressure (50 MPa), and then the ultrasonic action is continued for 10 seconds and the pressure is maintained. The pressure and ultrasound are then removed and the syringe is removed. The repaired area is subjected to CNC surface treatment, thus completing the repair of the repaired site.

[0042] Example 5: A356.2 melt at 20°C above the liquidus line is added into a syringe, an ultrasonic probe is fixed inside the syringe, and the bottom of the ultrasonic probe is 2 mm away from the bottom of the syringe. The ultrasonic device is started to cool the melt to a semi-solid temperature to form a semi-solid alloy slurry with a solid phase fraction of 15%, wherein the components of A356.2 include: by mass fraction, silicon: 6.5%, nickel: 0.05%, magnesium: 0.30%, copper: 0.05%, iron: 0.12%, zinc: 0.05%, titanium: 0.2%, manganese: 0.05%, strontium: 0.001%, and the rest is aluminum, wherein the ultrasonic parameters are 1000W, 30kHz.

[0043] The temperature of the site to be repaired is raised to 500° C. by an induction heating device, and the opening of the syringe is placed at the site to be repaired to form a sealed connection.

[0044] The semi-solid alloy slurry in the syringe is forced into the repaired site by pressure (50 MPa), and then the ultrasonic action is continued for 10 seconds and the pressure is maintained. The pressure and ultrasound are then removed and the syringe is removed. The repaired area is subjected to CNC surface treatment, thus completing the repair of the repaired site.

[0045] Example 6: A356.2 melt at 20°C above the liquidus line is added into a syringe, an ultrasonic probe is fixed inside the syringe, and the bottom of the ultrasonic probe is 2 mm away from the bottom of the syringe. The ultrasonic device is started to cool the melt to a semi-solid temperature to form a semi-solid alloy slurry with a solid phase fraction of 35%, wherein the components of A356.2 include: by mass fraction, silicon: 7%, nickel: 0.10%, magnesium: 0.40%, copper: 0.02%, iron: 0.05%, zinc: 0.03%, titanium: 0.05%, manganese: 0.008%, strontium: 0.001%, and the rest is aluminum, wherein the ultrasonic parameters are 1000W, 30kHz.

[0046] The temperature of the site to be repaired is raised to 400° C. by an induction heating device, and the opening of the syringe is placed at the site to be repaired to form a sealed connection.

[0047] The semi-solid alloy slurry in the syringe is forced into the repaired site by pressure (50 MPa), and then the ultrasonic action is continued for 10 seconds and the pressure is maintained. The pressure and ultrasound are then removed and the syringe is removed. The repaired area is subjected to CNC surface treatment, thus completing the repair of the repaired site.

[0048] Example 7: A356.2 melt at 20°C above the liquidus line is added into a syringe, an ultrasonic probe is fixed inside the syringe, and the bottom of the ultrasonic probe is 2 mm away from the bottom of the syringe. The ultrasonic device is started to cool the melt to a semi-solid temperature to form a semi-solid alloy slurry with a solid phase fraction of 35%, wherein the components of A356.2 include: by mass fraction, silicon: 6.5%, nickel: 0.05%, magnesium: 0.30%, copper: 0.05%, iron: 0.12%, zinc: 0.05%, titanium: 0.2%, manganese: 0.05%, strontium: 0.001%, and the rest is aluminum, wherein the ultrasonic parameters are 1000W, 30kHz.

[0049] The temperature of the site to be repaired is raised to 400° C. by an induction heating device, and the opening of the syringe is placed at the site to be repaired to form a sealed connection.

[0050] The semi-solid alloy slurry in the syringe is forced into the repaired site by pressure (80 MPa), and then the ultrasonic action is continued for 30 seconds and the pressure is maintained. The pressure and ultrasound are then removed and the syringe is removed. The repaired area is subjected to CNC surface treatment, thus completing the repair of the repaired site.

[0051] Comparative Example 1: A356.2 melt at 20°C above the liquidus line is added into a syringe. An ultrasonic probe is fixed inside the syringe, and the bottom of the ultrasonic probe is 2 mm away from the bottom of the syringe. The components of A356.2 include, by mass fraction, silicon: 6.5%, nickel: 0.05%, magnesium: 0.30%, copper: 0.05%, iron: 0.12%, zinc: 0.05%, titanium: 0.2%, manganese: 0.05%, strontium: 0.001%, and the rest is aluminum.

[0052] The temperature of the site to be repaired is raised to 400° C. by an induction heating device, and the opening of the syringe is placed at the site to be repaired to form a sealed connection.

[0053] The melt in the syringe is forced into the repaired site by pressure (50 MPa) and the pressure is maintained for 10 seconds. The pressure is then removed and the syringe is removed. The repaired area is subjected to CNC surface treatment, thus completing the repair of the repaired site.

[0054] Comparative Example 2: A356.2 melt at 20°C above the liquidus line is added into a syringe, an ultrasonic probe is fixed inside the syringe, and the bottom of the ultrasonic probe is 2 mm away from the bottom of the syringe. The ultrasonic device is started to cool the melt to a semi-solid temperature to form a semi-solid alloy slurry with a solid phase fraction of 35%, wherein the components of A356.2 include: by mass fraction, silicon: 6.5%, nickel: 0.05%, magnesium: 0.30%, copper: 0.05%, iron: 0.12%, zinc: 0.05%, titanium: 0.2%, manganese: 0.05%, strontium: 0.001%, and the rest is aluminum, wherein the ultrasonic parameters are 1000W, 30kHz.

[0055] The temperature of the site to be repaired is raised to 200° C. by an induction heating device, and the opening of the syringe is placed at the site to be repaired to form a sealed connection.

[0056] The semi-solid alloy slurry in the syringe is forced into the repaired site by pressure (50 MPa), and then the ultrasonic action is continued for 10 seconds and the pressure is maintained. The pressure and ultrasound are then removed and the syringe is removed. The repaired area is subjected to CNC surface treatment, thus completing the repair of the repaired site.

[0057] Comparative Example 3: The site to be repaired was not treated.

[0058] The repaired sites were evaluated by visual inspection, and casting samples near the sites to be repaired were tested for tensile strength, as shown in Table 1.

[0059] Table 1 Test results of embodiments and comparative examples

[0060] According to the data in Table 1, the surface quality and tensile strength of Examples 1-7 are better than those of Comparative Examples 1 and 3. This is because the semi-solid alloy slurry has good fluidity and can penetrate deep into the site to be repaired to complete the filling. During the injection process of the semi-solid alloy slurry, ultrasonic action is then continued to be applied. On the one hand, the flow of the semi-solid slurry and the discharge of gas in the site to be repaired can be promoted to promote the filling of the site to be repaired. On the other hand, the ultrasonic action can be transmitted to the solid phase particles in the semi-solid slurry entering the site to be repaired. The solid phase particles vibrate violently under the action of ultrasound, and friction and rapid heat transfer occur with the site to be repaired, so that the surface temperature of the preheated site to be repaired rises rapidly to the semi-solid temperature. The liquid phase of the site to be repaired merges with the liquid phase of the semi-solid alloy slurry to achieve a better metallurgical bonding effect, and the cost is significantly reduced. The site to be repaired is preheated to 400-500°C. At this temperature, the overall organizational structure of the casting will not change significantly. The semi-solid temperature can be quickly reached under the synergistic heating effect of the heat transfer of the semi-solid slurry and the ultrasonic action. Figure 1-2 As shown, after the defects on the surface of the casting are repaired by this method, the surface of the casting has no pores or cracks and has good surface quality. Comparative Example 1 uses a liquid melt to repair the site to be repaired, and pores and cracks are easily generated during the solidification process, which affects the surface quality and tensile strength. The surface quality of Comparative Example 2 is better, but its tensile strength is poor. This is because it only preheats the site to be repaired to 200°C, and the heating effect provided by the ultrasonic effect is poor, making it difficult to quickly heat the site to be repaired to a semi-solid temperature, and the semi-solid slurry is difficult to fuse with the surface of the site to be repaired to achieve a metallurgical bonding effect.

[0061] Example 3 uses ultrasonic parameters with lower power and frequency, and its performance is still improved compared with the comparative example. Example 4 uses a better preheating temperature, and its metallurgical bonding effect is better, and the tensile performance is improved. Example 5 uses a better preheating temperature and a semi-solid alloy slurry with a lower solid phase fraction. The semi-solid alloy slurry with a lower solid phase fraction has a higher temperature and better fluidity, which can further improve the metallurgical bonding effect, so the tensile strength is the best.

[0062] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0063] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for repairing defects of semi-solid castings, characterized in that: The method comprises the following steps: determining a site to be repaired of a casting, adding an alloy melt at 10-20° C. above the liquidus line into a syringe, wherein the alloy melt is A356.2, applying ultrasound to the alloy melt and cooling it to a semi-solid range to form a semi-solid alloy slurry with a solid phase fraction of 15-35%, raising the temperature of the site to be repaired to 400-500° C., placing the opening of the syringe on the site to be repaired and forming a sealed connection, allowing the semi-solid alloy slurry to enter the site to be repaired by pressure, continuing to apply ultrasound for 10-30S and maintaining the pressure, then removing the pressure and ultrasound and removing the syringe, thereby completing the repair.

2. The repair method according to claim 1, characterized in that: At least one site to be repaired is distributed on the plane of the casting, and the opening covers and seals the site to be repaired.

3. The repair method according to claim 1, characterized in that: At least one of the sites to be repaired is distributed on a non-planar portion of the casting, and a sealing fixture is used to seal the connection between the site to be repaired and the opening.

4. The repair method according to claim 1, characterized in that: The bottom of the ultrasonic probe is 2-5 mm away from the bottom of the syringe.

5. The repair method according to claim 1, characterized in that: The ultrasonic parameters are: 500-1000W, 10kHz-30kHz.

6. The repair method according to claim 1, characterized in that: The temperature of the site to be repaired is raised to 480-500°C.

7. The repair method according to claim 1, characterized in that: The pressure is 50-80 MPa.

8. The repair method according to claim 1, characterized in that: The temperature of the site to be repaired is raised to 400-500° C. by an induction heating device.

9. The repair method according to claim 1, characterized in that: In terms of mass fraction, the composition of A356.2 includes: silicon: 6.5-7%, nickel: 0.05-0.10%, magnesium: 0.30-0.40%, copper: 0-0.05%, iron: 0-0.12%, zinc: 0-0.05%, titanium: 0-0.2%, manganese: 0-0.05%, strontium: 0-0.001%, and the rest is aluminum.

10. The repair method according to claim 1, characterized in that: After removing the syringe, the site to be repaired is subjected to CNC surface treatment.

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