Method for detecting friction stir welding performance of aluminum alloy casting

Abstract

The invention discloses a method for detecting the friction stir welding performance of an aluminum alloy casting, and the aluminum alloy casting is a dissimilar material aluminum alloy casting. Comprising the following steps that according to a method for meeting the deviation requirement of the stirring friction welding seam of the dissimilar material aluminum alloy casting and the center position of a molten pool, water detection testing is conducted after the effective minimum welding depth required by machining milling depth is obtained, and if no bubbling exists in water detection, it is indicated that the welding depth is larger than or equal to the required effective welding depth; the machining end face of the deep-milled casting is corroded with strong acid with the concentration being 10%, so that a molten pool and a parent body are distinguished, and the friction stir welding area is black after corrosion; the casting is installed on the friction stir welding machine table, dotting is conducted through the welding head feeding track, and if dotting can fall to the position near the center line of a molten pool, it is judged that the casting is qualified; performing X-ray flaw detection on the internal quality after welding; and the air tightness performance after welding is confirmed through air tightness detection. The welding performance of friction stir welding of the aluminum alloy casting is effectively monitored.

Description

Technical Field

[0001] The invention mainly relates to the field of die-cast aluminum alloy stir friction welding technology, and in particular to a method for detecting the stir friction welding performance of aluminum alloy castings. Background Art

[0002] With the rapid development of new energy vehicles in recent years, friction stir welding has been widely used as a new type of connection technology in the field of new energy vehicles, especially in die-cast aluminum alloy motor housings and battery tray castings. However, there is currently a lack of effective testing methods for welding performance during the friction stir welding production process of die-cast aluminum alloy castings. Summary of the invention

[0003] The purpose of the present invention is to solve the above problems and provide a method for detecting the performance of friction stir welding of aluminum alloy castings.

[0004] The purpose of the present invention is achieved through the following technical solutions: A method for detecting the friction stir welding performance of an aluminum alloy casting, wherein the aluminum alloy casting is a heterogeneous aluminum alloy casting, comprises the following steps: A. Methods for satisfying the requirements of the offset between the friction stir weld and the center of the molten pool of dissimilar aluminum alloy castings: a1. After the machining milling depth reaches the effective minimum welding depth required, a water test is conducted. If there is no bubbling during the water test, it means that the welding depth is ≥ the required effective welding depth; a2. Then use 10% strong acid to corrode the machined end surface of the casting after deep milling. Due to the changes in microstructure and chemical composition during welding, there is a color difference between the boundary of the welding molten pool and the matrix after strong alkali corrosion, so the molten pool and the matrix can be distinguished. After corrosion, the friction stir welding area will appear black; a3. Put the casting back on the friction stir welding machine and use the welding head to make points along the cutting path. If the points can fall near the center line of the molten pool, it is considered qualified. B. Internal quality after welding is inspected by X-ray; C. Confirm the airtightness after welding through airtightness test.

[0005] A further improvement of the present invention is that when the aluminum alloy casting is made of the same material, step A is: vertically cutting the weld section and then performing metallographic grinding, and finally using a microscope to measure the effective welding depth and the offset between the weld and the center of the molten pool and observe the internal quality of the weld.

[0006] A further improvement of the present invention is that in step a2, the strong acid is HCl or HNO3.

[0007] A further improvement of the present invention is that in step C, the airtightness detection is a water detection, a gas detection or a helium detection.

[0008] Compared with the prior art, the present invention has the following advantages: The invention realizes effective monitoring of the welding performance of the friction stir welding of the aluminum alloy casting. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a cross-sectional view of the molten pool of the same aluminum alloy material during friction stir welding; Figure 2 It is a cross-sectional view of the molten pool of friction stir welding of dissimilar aluminum alloy materials. DETAILED DESCRIPTION

[0010] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The elements and features described in one embodiment of the present invention may be combined with the elements and features shown in one or more other embodiments. It should be noted that for the purpose of clarity, the representation and description of components and processes that are not related to the present invention and are known to those of ordinary skill in the art are omitted in the description. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present invention.

[0011] The present invention is further described below in conjunction with the accompanying drawings: A method for detecting the performance of friction stir welding of an aluminum alloy casting. When the aluminum alloy casting is an aluminum alloy casting of the same material, the detection steps are as follows: vertically cutting the weld section and then performing metallographic grinding, finally using a microscope to measure the effective welding depth and the offset between the weld and the center of the molten pool and observe the internal quality of the weld; using X-ray flaw detection to detect the internal quality after welding; and confirming the airtight performance after welding through airtight testing.

[0012] The friction stir welding welding performance detection method of aluminum alloy castings of the same material has its limitations in verifying the friction stir welding performance of aluminum alloy castings of different materials. The boundary of the molten pool of the friction stir welding of aluminum alloy castings of different materials is not clear, and it is impossible to confirm the effective depth and the offset between the weld and the center of the molten pool by vertically cutting the welding section; therefore, when the aluminum alloy casting is a dissimilar aluminum alloy casting, the following detection steps are included: A. Methods for satisfying the requirements of the offset between the friction stir weld and the center of the molten pool of dissimilar aluminum alloy castings: a1. After the machining milling depth reaches the effective minimum welding depth required, a water test is conducted. If there is no bubbling during the water test, it means that the welding depth is ≥ the required effective welding depth; a2. Then use 10% strong acid to corrode the machined end surface of the casting after deep milling. Due to the changes in microstructure and chemical composition during welding, there is a color difference between the boundary of the welding molten pool and the matrix after strong alkali corrosion, so the molten pool and the matrix can be distinguished. After corrosion, the friction stir welding area will appear black; a3. Put the casting back on the friction stir welding machine and use the welding head to make points along the cutting path. If the points can fall near the center line of the molten pool, it is considered qualified. B. Internal quality after welding is inspected by X-ray; C. Confirm the airtightness after welding through airtightness test.

[0013] Among them, the strong acid is HCl or HNO3; the airtightness test is water test, gas test or helium test.

[0014] The present invention fills the loophole of lacking an effective detection method for welding performance in the production process of friction stir welding of die-cast aluminum alloy castings. By applying the technology of the present invention, effective monitoring of the welding performance of friction stir welding of aluminum alloy castings can be achieved. The present invention can simply and clearly detect whether the friction stir welding can meet its effective welding depth; it can also quickly and effectively determine the offset between the friction stir weld and the center of the molten pool; it can also quickly and effectively determine the welding density through X-ray flaw detection and airtightness detection.

[0015] Finally, it should be noted that although the present invention and its advantages have been described in detail above, it should be understood that various changes, substitutions and transformations can be made without exceeding the spirit and scope of the present invention as defined by the appended claims. Moreover, the scope of the present invention is not limited to the specific embodiments of the processes, devices, means, methods and steps described in the specification. It will be readily understood by those skilled in the art from the disclosure of the present invention that existing and future processes, devices, means, methods or steps that perform substantially the same functions as the corresponding embodiments described herein or obtain substantially the same results as the corresponding embodiments described herein can be used according to the present invention. Therefore, the appended claims are intended to include such processes, devices, means, methods or steps within their scope.

Claims

1. A method for detecting the performance of friction stir welding of aluminum alloy castings, characterized in that: The aluminum alloy casting is a heterogeneous aluminum alloy casting, comprising the following steps: A. Methods for satisfying the requirements of the offset between the friction stir weld and the center of the molten pool of dissimilar aluminum alloy castings: a1. After the machining milling depth reaches the effective minimum welding depth required, a water test is conducted. If there is no bubbling during the water test, it means that the welding depth is ≥ the required effective welding depth; a2. Then use 10% strong acid to corrode the machined end surface of the casting after deep milling. Due to the changes in microstructure and chemical composition during welding, there is a color difference between the boundary of the welding molten pool and the matrix after strong alkali corrosion, so the molten pool and the matrix can be distinguished. After corrosion, the friction stir welding area will appear black; a3. Put the casting back on the friction stir welding machine and use the welding head to make points along the cutting path. If the points can fall near the center line of the molten pool, it is considered qualified. B. Internal quality after welding through X-ray inspection; C. Confirm the airtightness after welding through airtightness test.

2. The method for detecting the performance of friction stir welding of aluminum alloy castings according to claim 1, characterized in that: When the aluminum alloy casting is made of the same material, step A is: vertically cut the weld section and then perform metallographic grinding, and finally use a microscope to measure the effective welding depth and the offset between the weld and the center of the molten pool and observe the internal quality of the weld.

3. A method for detecting the performance of friction stir welding of aluminum alloy castings according to claim 1 or 2, characterized in that: In step a2, the strong acid is HCl or HNO3.

4. A method for detecting the performance of friction stir welding of aluminum alloy castings according to claim 1 or 2, characterized in that: In step C, the airtightness test is a water test, a gas test or a helium test.

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