Pullback static shaft shoulder friction stir welding device and welding method

Abstract

The invention provides a pumpback static shaft shoulder friction stir welding device. A static shaft shoulder fixing mechanism, a movable shaft shoulder fixing mechanism and a stirring needle transmission mechanism are sequentially arranged from outside to inside in a sleeving mode and are all of a conical structure; the large round end of the static shaft shoulder fixing mechanism is connected with the static end face of the friction stir welding main shaft, and the small round end is connected with the static shaft shoulder body. The large round end of the movable shaft shoulder transmission mechanism is connected with the rotating end face of the friction stir welding main shaft, the small round end of the movable shaft shoulder transmission mechanism is connected with the first end of the movable shaft shoulder body, and the second end of the movable shaft shoulder body is sleeved with the static shaft shoulder body. The large round end of the stirring needle transmission mechanism is connected with the welding main shaft withdrawing shaft, and the stirring needle body is arranged between the small round end and the movable shaft shoulder; the end of the stirring needle body sequentially penetrates through the movable shaft shoulder body and the static shaft shoulder body and is exposed out of the static shaft shoulder body. The welding precision and the welding quality of products with small thicknesses are improved, the production efficiency of the products is improved, and the labor intensity of workers is reduced.

Description

Technical Field

[0001] The invention belongs to the field of friction stir welding, and in particular relates to a friction stir welding device and a welding method for a withdrawable stationary shoulder. Background Art

[0002] With the approval of major national projects such as space station construction and manned lunar landing, launch vehicles have put forward higher requirements for their reliability. The tank bottom is an important component of the launch vehicle tank. Therefore, the design has carried out tank series structural optimization work to reduce its own weight and improve the quality of welds. At present, the thickness of the tank structure has been greatly reduced, and the thinnest position of the welding area has been reduced to about 3mm;

[0003] In order to improve the quality of welds and product precision, the current mainstream welding process is friction stir welding. The friction stir welding process is mainly divided into two technologies: dynamic shoulder friction stir welding and static shoulder friction stir welding. The dynamic shoulder friction stir welding technology is the conventional friction stir welding. During the welding process, the shoulder rotates with the stirring needle. Due to the large friction area between the shoulder and the weld surface, the heat input of the weld is high during the welding process, which ultimately leads to high residual stress in the weld and severe deformation characteristics of the product. In contrast, the heat input during static shoulder friction stir welding is low, so the degree of weld deformation is small after welding is completed. However, the current static shoulder friction stir welding technology cannot achieve retraction welding, so it is impossible to achieve keyhole defect welding in the welding and manufacturing process of the launch vehicle tank;

[0004] From the perspective of high-quality friction stir welding of thin-walled structural welds, the existing technology has the following main disadvantages:

[0005] (1) Conventional friction stir welding technology: ① During the welding process, a large amount of friction heat is generated between the shoulder and the workpiece, resulting in a large heat input and vertical gradient of the weld temperature, which ultimately leads to extremely poor forming accuracy of the product after welding. ② In order to ensure the quality of the weld, the shoulder of the stirring head needs to be pressed into the surface of the workpiece to form a closed cavity during the welding process. Affected by the characteristics of the shoulder of the conventional stirring head, the weld will be thinned to a certain extent, which will affect the strength of the weld to a certain extent. ③ After conventional friction stir welding is completed, if there are welding defects in the weld, post-welding repair is required. Post-welding repair with a conventional stirring head will further deteriorate the product accuracy. ④ After welding, the friction stir weld has serious flash, and the operator needs to spend a lot of energy to grind the weld.

[0006] (2) Traditional static shoulder friction stir welding technology: During the welding process, the stirring head can only rotate horizontally and cannot be retracted radially. Therefore, it is impossible to achieve defect-free welding of the circumferential seam. Therefore, it does not meet the production needs of closed circumferential seam welding in the actual production process of the project. Summary of the invention

[0007] In view of this, the present invention aims to propose a retractable static shoulder friction stir welding device and welding method, so as to improve the welding accuracy and welding quality of products with smaller thickness, improve product production efficiency and reduce manual labor intensity.

[0008] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0009] A retractable static shoulder friction stir welding device, a static shoulder fixing mechanism, a dynamic shoulder transmission mechanism, a static shoulder body, a dynamic shoulder body, a stirring needle body and a stirring needle transmission mechanism;

[0010] The static shoulder fixing mechanism, the dynamic shoulder fixing mechanism, and the stirring needle transmission mechanism are sequentially sleeved from outside to inside, and are all conical structures;

[0011] The large round end of the static shoulder fixing mechanism is connected to the static end face of the friction stir welding spindle, and the small round end is connected to the static shoulder body;

[0012] The large round end of the moving shoulder transmission mechanism is connected to the rotating end face of the stir friction welding main shaft, and the small round end is connected to the first end of the moving shoulder body, and the second end of the moving shoulder body is sleeved into the static shoulder body;

[0013] The large round end of the stirring needle transmission mechanism is connected to the welding spindle retraction shaft, and the stirring needle body is arranged between the small round end and the dynamic shoulder; and the end of the stirring needle body passes through the dynamic shoulder body and the static shoulder body in sequence, and is exposed outside the static shoulder body.

[0014] Furthermore, the static shoulder body is fixed to the static shoulder fixing mechanism, and the static shoulder fixing mechanism and the friction stir welding spindle maintain a static state and transmit this state to the static shoulder body.

[0015] Furthermore, the dynamic shoulder body is fixed to the dynamic shoulder fixing mechanism, and the dynamic shoulder fixing mechanism rotates together with the rotating end face of the stir friction welding spindle and transmits this state to the dynamic shoulder.

[0016] Furthermore, the stirring needle body is fixedly connected to the stirring needle transmission mechanism, and the stirring needle transmission mechanism rotates or extends or retracts with the retraction shaft of the stir friction welding main shaft, and transmits the movement posture of the retraction shaft to the stirring needle body to achieve non-destructive welding of the static shoulder stir friction weld.

[0017] Furthermore, the movable shoulder body is provided with a No. 1 step structure, which forms a limit between the movable shoulder fixing mechanism.

[0018] Furthermore, the stirring needle body is provided with a second step mechanism, which forms a limit between the stirring needle transmission mechanism.

[0019] A welding method of a retractable static shoulder friction stir welding device, comprising a conventional static shoulder friction stir welding process and a retractable static shoulder friction stir welding process;

[0020] In the conventional static shoulder friction stir welding process, the stirring needle transmission mechanism and the stirring needle body only rotate horizontally, and no movement occurs in the length direction of the withdrawal axis;

[0021] During the friction stir welding process of withdrawing the static shoulder: in addition to horizontal rotation, the stirring needle body and the stirring needle transmission mechanism also have relative movement in the length direction of the withdrawal shaft to shorten the stirring needle length during welding and ultimately achieve defect-free welding of the weld.

[0022] Furthermore, during the welding process, the spindle inclination angle is -5 to 5°, the welding speed is 20 to 1000 mm / min, and the spindle speed is 100 to 3000 rpm.

[0023] Compared with the prior art, the retractable static shoulder friction stir welding device and welding method described in the present invention have the following advantages:

[0024] (1) The present invention provides a friction stir welding device and a welding method for a retractable static shoulder. During the welding process, the peripheral static shoulder structure does not rotate and remains stationary. Therefore, the heat input to the weld is small, the plasticizing stirring zone is small, and the residual stress of the weld is low after welding. The welding accuracy of the product can be greatly improved.

[0025] (2) The present invention provides a friction stir welding device and method for a retractable static shoulder. To ensure the welding quality, the heat input of the weld during the welding process must meet the plasticization conditions of the material in the stirring zone. Therefore, the present invention uniquely designs and develops an inner ring dynamic shoulder. During the welding process, the dynamic shoulder rotates to provide the heat source required during the welding process.

[0026] (3) The present invention provides a friction stir welding device and a welding method with a retractable static shoulder. During the welding process, the outer static shoulder remains stationary and is basically flush with the surface of the workpiece. Therefore, after the welding is completed, the weld will not be significantly thinned, thereby improving the welding quality of the weld.

[0027] (4) The present invention provides a retractable static shoulder friction stir welding device and a welding method. The heat input during the static shoulder friction stir welding process is low. Even if there are welding defects in the product, the product accuracy can still be effectively guaranteed after repair welding.

[0028] (5) The present invention provides a friction stir welding device and a welding method with a retractable static shoulder. During the welding process, the peripheral static shoulder plays a smoothing role and can extrude the plasticized material in the stirring zone. Therefore, the weld surface is smooth and has no burrs, which can avoid the weld grinding work after welding is completed, greatly reducing labor intensity and improving welding efficiency.

[0029] (6) The present invention provides a retractable static shoulder friction stir welding device and a welding method. During the welding process, the motion state is transmitted through the outer static shoulder fixing mechanism, the inner ring dynamic shoulder transmission mechanism, and the stirring needle traditional mechanism. Through the relative movement of the outer static shoulder, the inner ring dynamic shoulder and the stirring needle, high-quality welding without keyhole defects can be achieved in all welds. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0031] Figure 1 A cross-sectional view of a friction stir welding device with a retractable stationary shoulder according to an embodiment of the present invention;

[0032] Figure 2 A cross-sectional view of a stationary shoulder fixing mechanism according to an embodiment of the present invention;

[0033] Figure 3 A cross-sectional view of a dynamic shoulder transmission mechanism according to an embodiment of the present invention;

[0034] Figure 4 A cross-sectional view of a stirring needle transmission mechanism according to an embodiment of the present invention;

[0035] Figure 5 A cross-sectional view of a movable shoulder body according to an embodiment of the present invention;

[0036] Figure 6 A cross-sectional view of a static shoulder body according to an embodiment of the present invention;

[0037] Figure 7 This is a cross-sectional view of the stirring needle body described in an embodiment of the present invention.

[0038] Description of reference numerals:

[0039] 1. Static shoulder fixing mechanism; 2. Dynamic shoulder transmission mechanism; 3. Static shoulder body; 4. Dynamic shoulder body; 5. Stirring needle body; 6. Stirring needle transmission mechanism. DETAILED DESCRIPTION

[0040] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0041] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0042] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0043] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0044] A retractable static shoulder friction stir welding device, comprising a static shoulder fixing mechanism 1, a dynamic shoulder transmission mechanism 2, a static shoulder body 3, a dynamic shoulder body 4, a stirring needle body 5 and a stirring needle transmission mechanism 6;

[0045] The static shoulder fixing mechanism 1, the dynamic shoulder fixing mechanism, and the stirring needle transmission mechanism 6 are sequentially sleeved from outside to inside, and are all conical structures;

[0046] The large round end of the static shoulder fixing mechanism 1 is connected to the static end face of the friction stir welding spindle, and the small round end is connected to the static shoulder body 3;

[0047] The large round end of the moving shoulder transmission mechanism 2 is connected to the rotating end face of the stir friction welding main shaft, and the small round end is connected to the first end of the moving shoulder body 4, and the second end of the moving shoulder body 4 is sleeved into the static shoulder body 3;

[0048] The large round end of the stirring needle transmission mechanism 6 is connected to the welding spindle retraction shaft, and the stirring needle body 5 is arranged between the small round end and the dynamic shoulder; and the end of the stirring needle body 5 passes through the dynamic shoulder body 4 and the static shoulder body 3 in turn, and is exposed outside the static shoulder body 3.

[0049] The stirring needle transmission mechanism 6, the dynamic shoulder transmission mechanism 2 and the static shoulder fixing mechanism 1 are matched and adapted to the end surface structure of the welding spindle and are determined by the characteristics of the welding spindle.

[0050] Preferably, the static shoulder body 3 is fixed to the static shoulder fixing mechanism 1 , and the static shoulder fixing mechanism 1 and the friction stir welding spindle maintain a static state and transmit this state to the static shoulder body 3 .

[0051] Preferably, the movable shoulder body 4 is fixed to a movable shoulder fixing mechanism, and the movable shoulder fixing mechanism rotates together with the rotating end face of the friction stir welding spindle, and transmits this state to the movable shoulder body 4;

[0052] The movable shoulder body 4 does not rotate during the welding process and remains stationary, and mainly plays the role of wrapping, leveling and discharging the plasticized material in the stirring zone.

[0053] Preferably, the stirring needle body 5 is fixedly connected to the stirring needle transmission mechanism 6, and the stirring needle transmission mechanism 6 rotates or extends or retracts following the retraction shaft of the friction stir welding main shaft, and transmits the movement posture of the retraction shaft to the stirring needle body 5, so as to realize non-destructive welding of the static shoulder friction stir weld;

[0054] It mainly generates heat by friction with the material in the stirring zone during welding and adjusts the material flow in the welding zone.

[0055] Preferably, the movable shoulder body 4 is provided with a No. 1 step structure to form a limit between it and the movable shoulder fixing mechanism.

[0056] Preferably, the stirring needle body 5 is provided with a second step mechanism to form a limit between it and the stirring needle transmission mechanism 6 .

[0057] A welding method of a retractable static shoulder friction stir welding device, comprising a conventional static shoulder friction stir welding process and a retractable static shoulder friction stir welding process;

[0058] In the conventional static shoulder friction stir welding process, the stirring needle transmission mechanism 6 and the stirring needle body 5 only rotate horizontally, and no movement occurs in the length direction of the withdrawal axis;

[0059] During the friction stir welding process of withdrawing the static shoulder, the stirring needle body 5 and the stirring needle transmission mechanism 6 not only rotate horizontally, but also move relative to each other in the length direction of the withdrawal shaft to shorten the stirring needle length during welding and finally achieve defect-free welding of the weld.

[0060] Preferably, during the welding process, the spindle inclination angle is -5 to 5°, the welding speed is 20 to 1000 mm / min, and the spindle speed is 100 to 3000 rpm.

[0061] The invention innovatively designs a three-body structure with a retractable static shoulder friction stir welding device, which solves the problems of severe deformation and poor welding accuracy of thin-walled structural parts in launch vehicles after welding, and provides a new solution for high-quality and high-precision friction stir welding of launch vehicles and other friction stir welding products.

[0062] The present invention breaks through the defect-free forming technical scheme of static shoulder friction stir weld by developing a three-body structure retractable static shoulder friction stir welding device and assembly welding scheme. In addition, by using the present invention, the product welding quality can be greatly improved, the labor intensity can be reduced, and the welding efficiency can be improved.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A friction stir welding device with a retractable stationary shoulder, characterized in that: Static shoulder fixing mechanism, dynamic shoulder transmission mechanism, static shoulder body, dynamic shoulder body, stirring needle body and stirring needle transmission mechanism; The static shoulder fixing mechanism, the dynamic shoulder fixing mechanism, and the stirring needle transmission mechanism are sequentially sleeved from outside to inside, and are all conical structures; The large round end of the static shoulder fixing mechanism is connected to the static end face of the friction stir welding spindle, and the small round end is connected to the static shoulder body; The large round end of the moving shoulder transmission mechanism is connected to the rotating end face of the stir friction welding main shaft, and the small round end is connected to the first end of the moving shoulder body, and the second end of the moving shoulder body is sleeved into the static shoulder body; The large round end of the stirring needle transmission mechanism is connected to the welding spindle retraction shaft, and the stirring needle body is arranged between the small round end and the dynamic shoulder; and the end of the stirring needle body passes through the dynamic shoulder body and the static shoulder body in sequence, and is exposed outside the static shoulder body.

2. The friction stir welding device with a retractable stationary shoulder according to claim 1, characterized in that: The static shoulder body is fixed to the static shoulder fixing mechanism, and the static shoulder fixing mechanism and the friction stir welding spindle maintain a static state and transmit the state to the static shoulder body.

3. The friction stir welding device with a retractable stationary shoulder according to claim 1, characterized in that: The movable shoulder body is fixed to the movable shoulder fixing mechanism, and the movable shoulder fixing mechanism rotates together with the rotating end face of the stir friction welding main shaft and transmits this state to the movable shoulder.

4. The friction stir welding device with a retractable stationary shoulder according to claim 1, characterized in that: The stirring needle body is fixedly connected to the stirring needle transmission mechanism. The stirring needle transmission mechanism rotates or extends or retracts following the retraction shaft of the stir friction welding main shaft, and transmits the movement posture of the retraction shaft to the stirring needle body to achieve non-destructive welding of the static shoulder stir friction weld.

5. The friction stir welding device with a retractable stationary shoulder according to claim 1, characterized in that: The movable shaft shoulder body is provided with a No. 1 step structure, which forms a limit between the movable shaft shoulder fixing mechanism.

6. The friction stir welding device with a retractable stationary shoulder according to claim 1, characterized in that: The stirring needle body is provided with a second step mechanism, which forms a limit between the stirring needle transmission mechanism.

7. A welding method according to any one of claims 1 to 6, characterized in that: It includes conventional static shoulder friction stir welding process and retracted static shoulder friction stir welding process; In the conventional static shoulder friction stir welding process, the stirring needle transmission mechanism and the stirring needle body only rotate horizontally, and no movement occurs in the length direction of the withdrawal axis; During the friction stir welding process of withdrawing the static shoulder: in addition to horizontal rotation, the stirring needle body and the stirring needle transmission mechanism also have relative movement in the length direction of the withdrawal shaft to shorten the stirring needle length during welding and ultimately achieve defect-free welding of the weld.

8. The welding method of the friction stir welding device with a retractable stationary shoulder according to claim 7 is characterized in that: During the welding process, the spindle inclination angle is -5 to 5°, the welding speed is 20 to 1000 mm / min, and the spindle speed is 100 to 3000 rpm.

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