CN114393293B

CN114393293B - Additive stirring head with small shaft shoulder action area and stirring needle with high specific surface area

Info

Publication number: CN114393293B
Application number: CN202210139041.3A
Authority: CN
Inventors: 付瑞东; 李艺君; 雷雨
Original assignee: Yanshan University
Current assignee: Yanshan University
Priority date: 2022-02-15
Filing date: 2022-02-15
Publication date: 2022-11-15
Anticipated expiration: 2042-02-15
Also published as: CN114393293A

Abstract

The application discloses stirring head for vibration material disk with little shaft shoulder active area and high specific surface area pin relates to metal welding technical field. Comprises a holding part, a shaft shoulder and a stirring pin which are connected in sequence, wherein the ratio of the diameter of the stirring pin to the diameter of the shaft shoulder is 0.6-0.8; the ratio of the volume of the stirring pin to the surface area is 2.5-3.5, a cylindrical first groove is formed in one end, away from the shaft shoulder, of the stirring pin along the axis direction of the stirring pin, and spiral flow guide grooves are formed in the outer circumferential surface of the stirring pin and the inner circumferential surface of the first groove. The method and the device are used for reducing the overlapping pass and can avoid the problem that the interfaces of all layers are not welded.

Description

Additive stirring head with small shaft shoulder action area and stirring needle with high specific surface area

Technical Field

The application relates to the technical field of metal welding, in particular to a stirring head for material increase, which is provided with a small shaft shoulder acting area and a stirring needle with a high specific surface area.

Background

In recent years, based on the urgent demand for light structure in the fields of aviation, ships, military equipment, rail traffic and the like, the welding of high-performance light alloys such as aluminum, magnesium and the like with large thickness (not less than 15 mm) becomes a key technology which needs to be solved. The welding of such alloys by conventional fusion welding methods is highly susceptible to metallurgical defects such as hot cracks and blowholes, and friction stir welding is considered to be the most effective method for welding such alloys.

However, although the single-sided or double-sided large-thickness friction stir welding process is adopted at home and abroad to realize the welding of the aluminum alloy with the joint thickness of 100mm, the problems of uneven tissue distribution, high joint residual stress, short service life of the stirring head and the like exist in the joint, so that the large-thickness friction stir welding technology is only limited to the experimental verification of short and straight welding seams, and no practical application report exists. In addition, current large-thickness friction stir welding equipment is mostly large-scale planer-type structure, and not only equipment investment is big, and can't realize the welding of the complicated welding seam in space.

The multilayer and multi-channel material increase friction stir welding process can well solve the problems, a principle diagram of the multilayer and multi-channel friction stir welding process is shown in figure 1, and the diameter ratio of a stirring needle to a shaft shoulder of a conventional stirring head is more than 0.25-0.4, so that the structure and the performance of a secondary overlapping area are deteriorated due to overlarge heat input of the shaft shoulder; meanwhile, the stirring pin is in a typical conical shape, so that the size of a weld nugget at a joint surface is small, the joint surface can be welded only by increasing the overlapping rate of the welding nuggets, and the welding workload is multiplied. In addition, the conventional stirring pin has a small flat end, and the joint surface is prone to weak connection or unwelded problems when welding the base metal.

In order to solve the problem of the 'hook' defect of the weld nugget edge in the lap joint, the invention patent (CN 103521912A) provides a stirring head design with an 'inverted cone' stirring pin, namely the diameter of the end part of the stirring pin is larger than that of the root part. Although the size of the bottom of the welding core is increased by the stirring pin, the overlapping coincidence rate is favorably reduced, but the problems of large shaft shoulder and small welding core area still exist. In addition, the root of the inverted cone-shaped stirring pin is too thin, so that unreasonable stress distribution of the stirring pin is caused, and the situation of broken pin at the root is easy to occur. More importantly, after the arc grooves which are processed on the outer side of the stirring pin and distributed along the axial direction are intersected with the concave arc surface at the bottom, the downward plastic metal flow of the end part of the stirring pin is weakened, the depth of the stirring pin inserted into the joint surface is increased to ensure the welding of the joint surface, and the single-layer material increase thickness is correspondingly reduced. Therefore, the stirring head device can not meet the requirements of multilayer and multi-pass friction stir welding.

Disclosure of Invention

The application provides a stirring head for vibration material disk with little shaft shoulder effect area and high specific surface area stirring needle through the specific surface area of increase stirring needle and shaft shoulder diameter ratio and stirring needle, satisfies multilayer multichannel friction stir welding needs, has both reduced the overlap joint pass, has still avoided the drawback that each layer interface department not welded.

In order to achieve the purpose, the application provides a stirring head for additive materials, which is provided with a small shaft shoulder acting area and a stirring pin with a high specific surface area, and comprises a holding part, a shaft shoulder and the stirring pin which are sequentially connected, wherein the ratio of the diameter of the stirring pin to the diameter of the shaft shoulder is 0.6-0.8.

Further, the stirring pin is of a columnar structure.

Further, the ratio of the diameter of the stirring pin to the diameter of the shaft shoulder is 0.75.

Furthermore, one end of the stirring pin, which is far away from the shaft shoulder, is provided with a cylindrical first groove along the axis direction; spiral diversion grooves are formed in the outer circumferential surface and the inner circumferential surface of the stirring pin; the ratio of the volume of the stirring pin to the surface area is 2.5-3.5.

Further, the ratio of the volume of the stirring pin to the surface area was 3.0.

Further, the spiral direction of the spiral diversion trench on the outer circumferential surface and the inner circumferential surface of the stirring pin is opposite.

Furthermore, a plurality of inclined notches are arranged at equal angular intervals along the circumferential direction at one end of the stirring pin, which is far away from the shaft shoulder.

Furthermore, a second groove is formed in one end, close to the stirring pin, of the shaft shoulder.

Further, the number of the slits is three, the inclination angle of the slits is 60 °, and adjacent slits are spaced 120 ° apart.

Compared with the prior art, the application has the following beneficial effects: the utility model provides a stirring head satisfies multilayer multichannel vibration material disk friction stir welding's needs, can effectively reduce thick plate ladder groove size, reduces the adverse effect of shaft shoulder to overlap joint coincidence region, increases each layer interface department seam width, and then reduces the overlap joint pass. The special concave design of the end part of the stirring pin can reduce the depth of the stirring pin inserted into each layer of interface, improve the material increase and avoid the problem of no welding at each layer of interface. The stirring head of the application can be used for small-sized friction stir welding equipment or a robot platform to realize the stirring friction of large-thickness aluminum and magnesium light alloy and other non-ferrous metal materials.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, it is obvious that 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 efforts.

FIG. 1 is a schematic diagram of a multi-layer, multi-pass friction stir welding process;

FIG. 2 is a three-dimensional perspective view of a stir head according to the present application;

FIG. 3 is an axial view of the stirring head of the present invention;

FIG. 4 is a cross-sectional view of a stirring head of the present invention;

FIG. 5 is a weld nugget region configuration obtained in example 4;

FIG. 6 is a weld nugget region configuration obtained in example 5;

FIG. 7 is a weld nucleus region configuration obtained in example 6.

In the figure: 1-shaft shoulder, 2-stirring needle, 3-right spiral diversion trench, 4-second groove, 5-first groove, 6-notch, 7-mother material and 8-conventional stirring head.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In the description of the present application, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the present application and simplifying the description, but do not indicate or imply that the referred device or element must have a particular orientation, be constructed in a particular orientation, and be operated, and thus should not be construed as limiting the present application.

In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; the specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.

The terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, the meaning of "a plurality" is two or more unless otherwise specified.

Referring to fig. 1, when a base material 7 is welded by a pin of a conventional pin tool 8, the structure and performance of two secondary overlapping regions are deteriorated due to excessive heat input from a shoulder; and since the conventional probe 8 has a small flat end, weak connection or non-welding problems easily occur at the joint surface when welding the base materials.

Referring to fig. 2, in this embodiment 1, there is provided an additive mixing head having a small shaft shoulder acting region and a mixing pin with a high specific surface area, the mixing head includes a holding portion, a shaft shoulder 1 and a mixing pin 2 connected in sequence from top to bottom, an axis of the shaft shoulder 1 coincides with an axis of the mixing pin 2, the mixing pin 2 is in a columnar or forward tapered structure, and a ratio of a diameter of the mixing pin 2 to a diameter of the shaft shoulder 1 is 0.6 to 0.8. The diameter ratio of the large stirring pin 2 to the shaft shoulder 1 is large, so that the size of the step of the groove can be effectively reduced, and the total welding pass is further reduced; and simultaneously, the adverse effect of the heat input of the shaft shoulder 1 on the multi-pass overlapping area is also reduced.

One end of the shaft shoulder 1 close to the stirring pin 2 is provided with a second groove 4. The stirring pin 2 is of a cylindrical structure, a cylindrical first groove 5 is formed in the bottom surface of the stirring pin 2 along the axis direction of the stirring pin, a first spiral diversion trench is formed in the outer circumferential surface of the stirring pin 2 from the bottom of the stirring pin to the shaft shoulder 1, a second spiral diversion trench is formed in the inner circumferential surface of the first groove 5 from the bottom of the stirring pin to the shaft shoulder 1, and the spiral directions of the first spiral groove and the second spiral groove are opposite. The bottom of the stirring pin 2 is provided with a plurality of inclined notches 6 at equal angular intervals in the circumferential direction. The structure enables the stirring pin 2 to have a numerical ratio of the volume to the surface area of about 2.5-3.5, and the stirring pin 2 with a large specific surface area and a hollow structure is 2.5 times of the stirring pin 2 with the same volume and the conventional solid conical shape. The specific surface area of the stirring pin 2 is increased, so that the flow and heat generation of plastic metal can be enhanced, and the problem of insufficient heat generation caused by the small shaft shoulder 1 can be solved.

This embodiment 2 provides a multilayer multi-pass friction stir welding, which includes the stir head as in embodiment 1, and the stir head is not only suitable for welding aluminum alloy and magnesium alloy materials, but also suitable for additive friction stir welding of other nonferrous metal materials.

Referring to fig. 2 to 4, the present embodiment 3 provides a stirring head for additive friction stir welding, including a holding portion, a shaft shoulder 1 and a stirring pin 2 connected in sequence from top to bottom, where an axis of the shaft shoulder 1 coincides with an axis of the stirring pin 2, and a ratio of a diameter of the stirring pin 2 to a diameter of the shaft shoulder 1 is 0.75. The bottom surface of the shaft shoulder 1 is provided with a second groove 4. The axial section of the stirring needle 2 is cylindrical, a cylindrical first groove 5 is formed in the bottom surface of the stirring needle 2 along the axis direction, a right spiral diversion trench 3 is formed in the outer circumferential surface of the stirring needle 2 from the bottom to the shaft shoulder 1, a left spiral diversion trench is formed in the inner circumferential surface of the first groove 5, three 60-degree inclined notches 6 are further processed in the bottom of the stirring needle 2, the adjacent notches 6 are separated by 120 degrees, and the numerical ratio of the volume to the surface area of the stirring needle 2 is 3.0. The structure of the stirring pin 2 can effectively enhance the plastic metal flow, reduce the depth of the stirring pin 2 penetrating through each layer of interface and improve the material increase efficiency in the thickness direction; meanwhile, the extrusion force at the joint surface can be improved, the metal flowing and mixing state at the joint surface can be improved, and the advancing resistance of the stirring needle 2 can be reduced.

The dimensions of each part of the stirring head are as follows: the shaft shoulder 1 has a diameter D, the stirring pin 2 has a diameter D, D/D =0.75, and the height h, h =0.5D. The second grooves 4 had a width of 0.02D and a depth of 0.02D. The diameter of the first groove 5 is 0.5-0.6D, and the depth is 0.12D.

Example 4 a 5mm thick 5083 aluminum alloy plate was welded using the stir head of example 3. The shaft shoulder 1 of the stirring head is set to have a diameter D =8mm, the stirring pin 2 is set to have a diameter D =6mm, α =60 °, and the stirring pin 2 is set to have a length of 3mm. The rotational speed of the stirring head was 800rpm, and the running speed was 30mm/min. The shape of the obtained nugget area is shown in fig. 5. As can be seen from FIG. 5, the cross-sectional shape of the obtained nugget area is approximately a regular rectangle, the width is slightly larger than the diameter of the probe 2, and the height is slightly longer than the length of the probe 2.

Example 5 a 5mm thick 5083 aluminum alloy plate was welded using the stir head of example 3. The diameter D =10mm of the stirring head shaft shoulder 1, the diameter D =7.5mm of the stirring pin 2, the angle α =60 °, and the length h =3.8mm of the stirring pin 2 are set. The rotational speed of the stirring head was 800rpm, and the running speed was 30mm/min. The solder pit area obtained is shown in fig. 6. As can be seen from FIG. 6, the cross-sectional shape of the obtained nugget region is approximately a regular rectangle, the width is slightly larger than the diameter of the probe 2, and the height is slightly longer than the length of the probe 2.

Example 6 a 5mm thick 5083 aluminum alloy plate was welded using the stir head of example 3. The diameter D =10mm of the pin shaft shoulder 1, the diameter D =7.5mm of the pin 2, α =60 °, and the length h =3.8mm of the pin 2 are set. The rotation speed of the stirring head is 800rpm, and the advancing speed is 60mm/min. The shape of the obtained nugget area is shown in fig. 7. As can be seen from FIG. 7, the cross-sectional shape of the nugget area obtained is approximately a regular rectangle, the width is slightly larger than the diameter of the probe 2, and the height is equivalent to the length of the probe 2.

The above is only an embodiment of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions within the technical scope of the present disclosure should be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. The additive stirring head is provided with a small shaft shoulder action area and a stirring needle with a high specific surface area, and is characterized by comprising a holding part, a shaft shoulder and the stirring needle which are sequentially connected, wherein the ratio of the diameter of the stirring needle to the diameter of the shaft shoulder is 0.6-0.8; one end of the stirring pin, which is far away from the shaft shoulder, is provided with a cylindrical first groove along the axis direction; spiral diversion trenches are arranged on the outer circumferential surface and the inner circumferential surface of the stirring needle; the ratio of the volume of the stirring pin to the surface area is 2.5-3.5; and a plurality of inclined notches are formed in one end of the stirring pin, which is far away from the shaft shoulder, at equal angular intervals along the circumferential direction.

2. The additive tool tip having a small shoulder region and a pin with a high specific surface area of claim 1 wherein the pin is of a cylindrical configuration.

3. An additive tool tip having a small shoulder region and a pin with a high surface area as in claim 1, wherein the pin diameter to shoulder diameter ratio is 0.75.

4. The additive mixing head having a small shoulder region and a high surface area pin of claim 1 wherein the pin volume to surface area ratio is 3.0.

5. The additive mixing head having a small shoulder region and a high surface area pin as claimed in claim 1, wherein the pin has an outer circumferential surface that is opposite to the spiral direction of the spiral guide grooves on the inner circumferential surface.

6. The additive tool tip having a small shoulder region and a pin with a high specific surface area of claim 1 wherein the end of the shoulder adjacent to the pin is provided with a second groove.

7. The additive tool tip having a small shoulder action zone and a pin with a high specific surface area of claim 1 wherein the number of cuts is three, the angle of inclination of the cuts is 60 °, and adjacent cuts are spaced 120 ° apart.