A friction stir welding tool

Abstract

The utility model discloses a kind of friction stir welding heads, including shaft shoulder, stirring needle and handle portion with ladder structure, shaft shoulder is connected to the bottom end of handle portion, shaft shoulder is used to transfer equipment axial pressure to compact welding product, one end of stirring needle is connected to the bottom end surface middle of shaft shoulder, the outer surface of stirring needle is equipped with continuous spiral protrusion, the height of spiral protrusion gradually decreases from the end close to shaft shoulder to the end far from shaft shoulder;Plastic metal is pushed to shaft shoulder direction by rotating stirring needle.The utility model can orderly push plastic metal by the continuous spiral protrusion of stirring needle, cooperate the axial compaction effect of shaft shoulder, can reduce the defect such as blowhole, loose in weld, improve weld density and connection strength, to improve weld quality.The progressive design of the height of spiral protrusion can optimize metal flow path in welding process, reduce local wear and stress concentration of welding head, to effectively prolong single continuous welding life.

Description

Technical Field

[0001] This utility model relates to, but is not limited to, the field of friction stir welding technology, and in particular to a friction stir welding head. Background Technology

[0002] Friction stir welding (FSW), as a highly efficient and high-quality solid-state joining technology, has been widely used in aerospace, rail transportation, and automotive manufacturing. Its core component is the friction stir welding head (hereinafter referred to as the "stirring head"). During the welding process, the stirring head directly contacts the workpiece and must withstand high temperatures, high pressures, and intense friction. Its performance directly determines the welding quality, efficiency, and production economy. Currently, commercially available stirring heads on the market are limited by material properties, structural design, and processing technology, resulting in a generally short service life. Under normal operating conditions, the lifespan of a single continuous welding operation is approximately 800 meters. This lifespan level is insufficient to meet the demands of large-scale mass production. Utility Model Content

[0003] The following is an overview of the subject matter described in detail herein. This overview is not intended to limit the scope of the claims. This invention aims to at least solve one of the technical problems existing in the prior art. To this end, embodiments of this invention provide a friction stir welding head that can effectively extend the welding head's life and improve weld quality.

[0004] This utility model provides a friction stir welding head, including a shoulder, a stirring pin, and a shank with a stepped structure. The shoulder is connected to the bottom end of the shank and is used to transmit axial pressure of the equipment to compact the weld. One end of the stirring pin is connected to the middle of the bottom end face of the shoulder. The outer surface of the stirring pin is provided with continuous spiral protrusions, and the height of the spiral protrusions gradually decreases from the end near the shoulder to the end away from the shoulder. By rotating the stirring pin, ductile metal is pushed towards the shoulder.

[0005] According to some embodiments of the present invention, the stepped structure of the handle includes a first cylindrical segment and a second cylindrical segment, the first cylindrical segment and the second cylindrical segment having different diameters; the first cylindrical segment and the second cylindrical segment are connected by a transition slope, the transition slope being inclined outward along the radial direction of the second cylindrical segment.

[0006] According to some embodiments of the present invention, the stepped structure of the handle further includes a third cylindrical segment, which is connected to the second cylindrical segment by a transition straight surface, which expands outward along the radial direction of the third cylindrical segment.

[0007] According to some embodiments of the present invention, the bottom end face of the shoulder is provided with at least three guide grooves evenly distributed in the circumferential direction; the guide grooves extend from the edge of the shoulder to the outer circumferential surface of the stirring needle, and are used to guide the plastic metal to converge towards the center of the weld.

[0008] According to some embodiments of the present invention, the surface of the stirring needle is covered with a protective coating.

[0009] According to some embodiments of the present invention, the surface of the protective coating is provided with a nanoscale textured surface, which is used to reduce the adhesion between the stirring needle and the plastic metal.

[0010] According to some embodiments of the present invention, the outer peripheral surface of the shoulder is provided with an annular groove; the annular groove is located below the connection position between the shoulder and the handle, and is used to accommodate the plastic metal overflowing during the welding process.

[0011] According to some embodiments of the present invention, the top end of the handle is provided with a positioning hole; the positioning hole is provided through the central axis of the handle and is used to connect with the drive shaft of the welding equipment.

[0012] The embodiments of this utility model have at least the following beneficial effects: (1) The continuous spiral protrusions of the stirring pin can push the plastic metal in an orderly manner. Combined with the axial compaction effect of the shaft shoulder, it can reduce defects such as porosity and looseness inside the weld, improve the density and connection strength of the weld, and thus improve the quality of the weld. (2) The progressive design of the spiral protrusion can optimize the metal flow path during welding, reduce local wear and stress concentration of the welding head, and effectively extend the life of a single continuous welding compared with commercial welding heads on the market (life of about 800 meters).

[0013] Other features and advantages of this invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of this invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0014] The accompanying drawings are provided to further understand the technical solution of this utility model and constitute a part of the specification. They are used together with the embodiments of this utility model to explain the technical solution of this utility model, and do not constitute a limitation on the technical solution of this utility model.

[0015] Figure 1 This is a top view of the structure of a friction stir welding head provided in one embodiment of the present invention; Figure 2 This is a side view of the structure of a friction stir welding head provided in one embodiment of the present invention; Figure 3 This is an overall structural diagram of a friction stir welding head provided in one embodiment of the present invention; Reference numerals: shoulder 110; stirring needle 120; handle 130; first cylindrical section 210; second cylindrical section 220; transition slope 230; third cylindrical section 240; transition straight surface 250. Detailed Implementation

[0016] The embodiments of this utility model are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0017] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0018] In the description of this utility model, the use of "first" and "second" is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features or the order of the technical features.

[0019] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0020] The embodiments of this utility model will be further described below with reference to the accompanying drawings.

[0021] See Figure 1 , Figure 1This is a top view of the structure of a friction stir welding head according to an embodiment of the present invention. The friction stir welding head includes a shoulder 110, a stirring pin 120, and a shank 130 with a stepped structure. The entire head can be made of high-temperature resistant, heat-fatigue-resistant nickel-based high-temperature alloy steel, with enhanced toughness through a gradient structure design. Specifically: the shoulder 110 is connected to the bottom end of the shank 130 and is used to transmit axial pressure to compact the weld. One end of the stirring pin 120 is connected to the middle of the bottom end face of the shoulder 110. The outer surface of the stirring pin 120 has continuous spiral protrusions (spiral structure, pitch can be set to 0.75mm), and the height of the spiral protrusions gradually decreases from the end near the shoulder 110 to the end away from the shoulder 110. During operation, the stirring head rotates counterclockwise, and the friction generates heat to melt the aluminum material. The rotating stirring pin 120 pushes the ductile metal towards the shoulder 110, while the shoulder 110 and the spiral structure accumulate and compact downwards, thereby forming a dense weld layer. After the design is matched with the process parameters, the lifespan of the friction stir welding head can reach more than 2,500 meters, far exceeding the lifespan of about 800 meters for commercial products on the market.

[0022] In one feasible embodiment, such as Figure 2 As shown, the stepped structure of the shank 130 includes a first cylindrical section 210 and a second cylindrical section 220, wherein the diameter of the first cylindrical section 210 is larger than that of the second cylindrical section 220. The first cylindrical section 210 and the second cylindrical section 220 are connected by a transition slope 230, which is radially outward along the second cylindrical section 220. This stepped design increases the overall structural strength, while the tool shaft spacing of the shank 130 is controlled at Φ6mm±0.1mm to ensure the coaxiality of the stirring head and the equipment, avoiding wobble that could affect the weld quality.

[0023] In one feasible embodiment, the stepped structure of the handle 130 further includes a third cylindrical segment 240, which is connected to the second cylindrical segment 220 by a transition straight surface 250 that expands radially outward along the third cylindrical segment 240. This structure further optimizes force transmission and, in conjunction with the gradient structure design, effectively enhances the toughness of the handle 130, making it less prone to deformation or breakage during welding operations.

[0024] In one feasible embodiment, the bottom end face of the shoulder 110 is provided with at least three circumferentially evenly distributed guide grooves; the guide grooves extend from the edge of the shoulder 110 to the outer peripheral surface of the stirring pin 120, and are used to guide the ductile metal to converge towards the center of the weld. Combined with the function of the shoulder 110 in transmitting the axial pressure of the equipment, the welded product can be compacted and tightened more efficiently, improving the weld density.

[0025] In one feasible embodiment, the surface of the stirring pin 120 is covered with a protective coating, specifically a TiAlN coating, which can improve the wear resistance of the stirring pin 120.

[0026] In one feasible embodiment, the surface of the protective coating is provided with a nanoscale textured surface, which is used to reduce the adhesion between the stirring pin 120 and the plastic metal, further reducing wear and extending the service life of the stirring pin 120.

[0027] In one feasible embodiment, the outer peripheral surface of the shoulder 110 is provided with an annular groove; the annular groove is located below the connection position between the shoulder 110 and the handle 130, and is used to accommodate the plastic metal overflowing during the welding process, so as to avoid metal accumulation affecting the welding quality, and also to reduce unnecessary friction between the shoulder 110 and the workpiece.

[0028] In one feasible embodiment, a positioning hole is provided at the top of the handle 130; the positioning hole is arranged through the central axis of the handle 130 for docking with the drive shaft of the welding equipment. This design ensures the precise installation of the stirring head on the equipment and provides a structural basis for achieving preset process parameters, such as a rotation speed of 1800 rpm, a feed rate of 300 mm / min, and a Z-axis feed of 0.4 ± 0.1 mm, thus ensuring the stability and consistency of the welding process.

[0029] The above is a detailed description of the preferred embodiments of the present utility model. However, the present utility model is not limited to the above embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present utility model. All such equivalent modifications or substitutions are included within the scope defined by the claims of the present utility model.

Claims

1. A friction stir welding head, characterized in that, It includes a shoulder, a stirring pin, and a shank with a stepped structure. The shoulder is connected to the bottom end of the shank and is used to transmit axial pressure of the equipment to compact the welded part. One end of the stirring pin is connected to the middle of the bottom end face of the shoulder. The outer surface of the stirring pin is provided with continuous spiral protrusions, and the height of the spiral protrusions gradually decreases from the end near the shoulder to the end away from the shoulder. By rotating the stirring pin, plastic metal is pushed towards the shoulder.

2. The friction stir welding head according to claim 1, characterized in that, The stepped structure of the handle includes a first cylindrical segment and a second cylindrical segment, the first cylindrical segment and the second cylindrical segment having different diameters; the first cylindrical segment and the second cylindrical segment are connected by a transition slope, the transition slope being radially outward along the second cylindrical segment.

3. The friction stir welding head according to claim 2, characterized in that, The stepped structure of the handle also includes a third cylindrical segment, which is connected to the second cylindrical segment by a transition straight surface that expands outward along the radial direction of the third cylindrical segment.

4. The friction stir welding head according to claim 1, characterized in that, The bottom end face of the shoulder is provided with at least three guide grooves evenly distributed in the circumferential direction; the guide grooves extend from the edge of the shoulder to the outer circumferential surface of the stirring needle, and are used to guide the plastic metal to converge towards the center of the weld.

5. The friction stir welding head according to claim 1, characterized in that, The surface of the stirring needle is covered with a protective coating.

6. The friction stir welding head according to claim 5, characterized in that, The protective coating has a nanoscale textured surface, which is used to reduce the adhesion between the stirring needle and the plastic metal.

7. The friction stir welding head according to claim 1, characterized in that, The outer circumferential surface of the shoulder is provided with an annular groove; the annular groove is located below the connection position between the shoulder and the handle, and is used to accommodate the plastic metal that overflows during the welding process.

8. The friction stir welding head according to claim 1, characterized in that, The top of the handle is provided with a positioning hole; the positioning hole is provided through the central axis of the handle and is used to connect with the drive shaft of the welding equipment.

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