JP3317192B2 - Friction welding method and vehicle structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to relates to a novel friction welding method <br/>及beauty car both structure, in particular by solid phase bonding method of a metal,
Ships and automobiles, aviation, elevators, it relates to a friction welding method及beauty car both assembly of the structure using an aluminum alloy such as a pressure vessel.

[0002]

2. Description of the Related Art Japanese Patent Publication No. Hei 7-505090 discloses a friction welding method using a rotary tool. Table 5-7
In the friction welding method according to No. 05090, a tool made of a material substantially harder than the workpiece is inserted into the weld of the workpiece, and the tool is moved while rotating.
Continuous welding is possible in the welding longitudinal direction. Tokiohei 5
A backing plate is arranged on the entire back surface of the welded portion of No. 05090 so that the shape of the back surface of the welded portion is not changed by plastic flow. That is, the shape of the back surface of the welded portion is the same after welding. Further, since the tool is moved while rotating, the surface of the weld is mechanically cut by the tool, and a dent is generated on the surface of the weld.

[0003]

When the friction welding method is applied to an actual industrial product, there are the following problems. (1) Since the tool is moved while rotating, the surface of the weld is mechanically cut by the tool, and a dent is generated on the surface of the weld.

(2) In a welded portion of a processed member, penetration into the depth direction can be obtained only about 0.2 mm from the tip of a tool inserted into the welded portion. For this reason, an unmelted portion (penetration defect) occurs on the back surface of the welded portion. In order to perform welding to the back of the weld without generating unfused parts on the back of the weld, the distance between the tip of the tool inserted into the weld and the back of the processed member or backing plate is always controlled to 0.2 mm or less. There is a need to. However, it is particularly difficult to control the distance from the tip of the tool inserted into the welding portion to 0.2 mm or less, especially when welding a long object.

(3) When welding is performed with the tool tip penetrating the welded part, the tool or backing plate is damaged because the tool tip comes into contact with a backing plate arranged on the back surface of the welded part. Defects also occur on the back of the weld. Further, the processed member and the backing plate may be joined.

FIG. 1 is a view showing a conventional friction welding method. In the conventional method, the workpiece 1 is arranged on the backing plate 2 as shown in the figure. The tool 4 is inserted into the joining line 3 of the workpiece 1 while being rotated, and is inserted until immediately before the workpiece 1 is penetrated. At this time, the distance between the tool tip 4a and the back surface 1a of the workpiece 1 is generally 0.2 mm or less.
In this state, it is moved in the welding direction and welded. In this method, the tool tip 4a always keeps the back surface 1a of the workpiece 1 during welding.
I have to move above. That is, in the conventional welding method, the tool tip 4a is attached to the back surface 1a of the workpiece 1.
Must not penetrate. The tool tip 4a is the workpiece 1
, The backing plate 2 and the tool 4 will be damaged. In addition, a defect occurs on the back surface of the workpiece 1.

FIG. 2 is a view showing a cross section of a welded portion after welding. With the conventional method, the surface of the weld is dented. Also, welding cannot be performed in a state where the tip 4a of the tool 4 penetrates the back surface 1a of the workpiece 1. It is necessary to hold the tool tip 4a immediately before reaching the back surface 1a of the workpiece 1. However, when the workpiece 1 is long, the thickness of the welded portion is not constant. For this reason, the unfused portion 6 is generated in a range from below the fused portion 5 to the back surface 1a of the workpiece 1. Although it depends on the welding conditions, the penetration can be obtained only about 0.2 mm from the tip 4a of the tool 4. Therefore, in order to prevent the generation of the unmelted portion 6, the distance between the tip 4a of the tool 4 and the back surface 1a of the workpiece 1 must always be controlled to 0.2 mm or less. It is extremely difficult to perform this control industrially.

An object of the present invention is to provide a friction welding method <br/>及beauty car both structure that can be bonded without unbonded portion across the weld workpiece.

[0009]

Means for Solving the Problems (1) By forming the back surface or the front and back surfaces near the welded portion of the workpiece to be higher than the surface of the non-welded portion in a protruding shape, the tip of the tool is formed on the workpiece. It can be inserted below the back surface other than the welded portion. In addition, the recess on the surface of the welded portion can be formed above the surface of the workpiece other than the joint. Said
The protrusion provided on the side opposite to the insertion of the rotating tool is
Is reduced in the height direction.
It will be good. Also, provided on the insertion surface side of the rotating tool
The projecting part reduces the width in the height direction.
You.

(2) By providing a groove along the welding line immediately below the welded portion of the backing plate arranged on the back surface of the workpiece, contact between the workpiece and the backing plate can be prevented. Further, by providing a groove along the weld line directly under the weld backing plate arranged on the rear surface of the workpiece, collision on the back welds
Welding can be performed while forming the raised portion . The groove has a small width in the depth direction and has a square shape, so that the workability after joining is good.

By forming the surface of the workpiece to be protruded only in the vicinity of the welded portion by means of the above (1), the depression formed in the surface of the welded portion is formed in the projection above the surface of the workpiece, and It is excluded from inside the member. Further, by forming the back surface of the workpiece only in the vicinity of the welded portion in a protruding shape, the tool tip can be inserted below the back surface other than the welded portion of the workpiece, and the unmelted portion generated below the tool tip. Is formed on the protrusion and is removed from the inside of the workpiece.

By means of the above (2), 500 to 2000 kgf is locally applied to the tool insertion direction during the welding process.
Large load is applied. For this reason, the metal that has plastically flowed during welding is pushed into the groove provided on the back surface of the welded portion. As a result, a backwash having the same shape as the groove is formed on the back surface of the welded portion.

By the above means, welding can be performed by penetrating the tool tip from the back surface of the welded portion. Thereby, the unmelted portion generated on the back surface of the welded portion can be eliminated.
Further, even when the tip of the tool penetrates, welding can be performed without damaging the workpiece and the tip of the tool. Further, welding can be performed without joining the workpiece and the backing plate. The shape of the groove of the backing plate is formed in the same shape as the tip shape of the rotary tool, and the width of the groove of the backing plate is 1 to the pin diameter of the tool.
-5 mm larger, 1-2 mm smaller than the pin diameter of the tool used for welding, and the shape of the groove is such that the groove width decreases downward, It is preferable that the backing plate is provided with a mechanism that can be divided right and left from the center of the groove or substantially from the center of the groove with respect to the welding progress direction.

In the present invention, the following effects can be obtained. (1) By forming protrusions on the front and back surfaces near the welded portion of the workpiece, dents on the surface of the welded portion and unmelted portions on the backside of the welded portion are generated inside the protrusions. It can be removed from inside the processed member.

(2) By providing a groove in the backing plate and disposing the groove immediately below the welded portion of the processing member, even if the tool penetrates the back surface of the joint, the tool and the backing plate are prevented from being damaged. it can.

(3) Since welding can always be performed by penetrating the tool, the entire welded portion of the processed member can be melted. Furthermore, by removing the undercut formed by welding, it is possible to eliminate the unmelted portion generated on the back surface of the welded portion.

(4) Since welding can be performed by penetrating the tool, the allowable value of the insertion depth of the tool during welding is increased as compared with the conventional method.

[0018]

(Embodiment 1) An embodiment in which the present invention is applied to butt welding of an aluminum alloy will be specifically described with reference to the drawings.

FIGS. 3 (a) and 3 (b) are views showing a method of welding a workpiece in which both front and rear surfaces in the vicinity of a welded portion are formed in a projection shape. The projections on the surface of the workpiece are for preventing dents on the surface of the weld. According to experience from experiments, when the projection width 10 is smaller than the shoulder diameter 9 of the tool 4 used for the main welding, defects are easily generated on the surface of the welded portion. If the protrusion width 10 is the same as the shoulder diameter 9 or is larger than the shoulder diameter, a defect-free welded portion is obtained. Therefore, in this embodiment, the protrusion width 10 is equal to the shoulder diameter 9 or is equal to or larger than the shoulder diameter 9. Also, the projection height 11
Although it depends on the shoulder diameter 9, it is desirable that the height be approximately the same as the gap between the shoulder diameter 9 due to the inclination of the tool 4 and the surface of the workpiece. At present, there is no problem if it is 0.5 to 3 mm. When inserting the tool, the tool 4 is inserted so that the shoulder does not reach the surface of the workpiece. Protrusion
The width of each of 8a and 8b is reduced in the height direction.
Therefore, it is easy to separate from the backing plate 2 after joining.

The projections on the back surface of the workpiece are for removing unmelted portions on the back surface of the welded portion. Therefore, the tip of the tool penetrates the back surface of the workpiece and is inserted into the projection. Fig. 3
As shown in (a), the projection width 12 needs to be larger than the tool tip 4a of the tool 4 used for welding. The projection height 13 varies depending on the size of the tool tip 4a of the tool 4 to be used, but is set to 0.5 to 3 mm because the tool 4 is inserted until the entire tool tip R portion 4b reaches the inside of the projection.

As shown in FIG. 3B, when the width of the projection on the back surface of the workpiece is equal to or less than the tip 4a of the tool, the entire projection is agitated by the plastic flow of the tool 4 during welding, and a good weld cannot be obtained.

Embodiment 2 FIG. 4 is a view showing a state in which a projection near a welded portion has been deleted after welding. The depression on the surface of the welding portion generated by the present welding method is formed on the projection 8a according to the first embodiment. After welding, the projection 8a is cut to the surface 1b of the workpiece by a grinder or the like so that the height of the surface 8b is the same as the surface 1b of the workpiece. The unmelted portion 6 on the back surface of the workpiece is formed on the projection 8b. After welding, the unfused portion 6 is cut to the back surface 1a of the workpiece by using a grinder, etc.
, And can be at the same height as the workpiece back surface 1a. The width of each of the projections 8a and 8b is in the height direction.
It is getting smaller.

Embodiment 3 FIG. 5 is a view showing a welding method when a grooved backing plate is used. In the present welding method, as shown in FIGS. 5A and 5B, the groove 7 provided in the backing plate 2 is disposed immediately below the welding surface 3 of the workpiece 1. The welding is performed by inserting the tool 4 until the tip of the tool 4 penetrates the back surface of the workpiece 1. The width of the groove 7 provided in the backing plate 2 is the direction of its depth.
Worked part after joining
The material 1 can be easily detached from the backing plate 2.
You.

FIG. 5B shows a workpiece in which a projection 8a is formed on the surface of a welded portion of the workpiece. In this welding method, a part of the workpiece is plastically flown into the groove 7 provided in the backing plate 2 at the welded portion. During welding, since the member is pushed downward by the pressing force of the tool 4 and plastically flows on the surface of the welded portion, when the metal is filled in the groove, the metal decreases on the surface of the welded portion. Therefore, the surface after welding becomes concave. By forming the projection 8 on the surface of the welded portion in advance, the metal filled in the groove can be supplemented by the projection 8a.

FIG. 6 is a cross-sectional view showing the vicinity of a welded portion of a workpiece to be welded using the present invention. By providing a groove immediately below the welded portion of the workpiece 1, it is possible to form a backwash on the back surface of the welded portion. Also, the tip 4a of the tool 4
Can be welded by penetrating from the back surface 1a of the workpiece 1 so that no unmelted portion is generated at the position shown in FIG. That is, the unmelted portion can be excluded from the inside of the workpiece 1. In this method as well, although it depends on the welding conditions, an unmelted portion occurs below the tip 4a of the tool 4 by 0.2 mm or more. However, the unmelted portion is generated below the back surface of the workpiece 1 and inside the Uranami 14. Backing
The width of the groove 7 provided in the plate 2 is small in the depth direction,
It has a square shape and backs the workpiece 1 after joining
The detachment from the plate 2 can be easily performed.

FIG. 7 is a cross-sectional view showing a state in which a backwash formed according to the present invention is mechanically removed by a grinder, cutting, or the like. In the present invention, as described above, unmelted portions are generated inside the backwash 14. Therefore, it is possible to completely eliminate the unmelted portion by deleting the back lip 14 formed on the back surface of the workpiece 1 after the welding is completed, up to the back surface of the workpiece 1 as shown in FIG.

(Embodiment 4) FIG. 8 is a cross-sectional view showing a state where the back surface of the joint portion of the workpieces joined by the friction welding method shown in Embodiment 1 is again welded by a fusion welding method such as arc or laser. FIG. In the present invention, since the tool 4 can be penetrated from the workpiece 1, the occurrence of an unmelted portion due to insufficient penetration can be eliminated from the conventional position. However, there is little expectation that the present invention will greatly improve the insufficient penetration. Therefore, an unmelted portion may be generated in the reverse seam portion of the welded portion 15 by the FSW formed according to the present invention. Therefore, the back side waves formed by the present invention are again welded using a heat source such as an arc or a laser, and an unmelted portion is eliminated by forming a welded portion 16 by arc welding. In this embodiment, since the welding portion is protruded, the melting range is extremely small, so that it is possible to melt with low heat input, and the deformation after welding can be reduced as compared with other welding methods. In addition, welding can be performed without using a filler wire.

(Embodiment 5) With respect to the backing plate which is a feature of the present invention, in this embodiment, welding was performed using several objects having the following shapes or structures.

FIG. 9 is a cross-sectional view showing the periphery of the groove of the backing plate used in the main welding. As shown in FIGS. 9A and 9B, the width of the groove 7 decreases toward the bottom. This is to facilitate the work of removing the workpiece from the backing plate after welding. FIG. 9C shows a backing plate having a structure that can be divided right and left from the center of the groove 7. By using this structure, the back seam 14 formed on the workpiece 1 after welding can be easily removed from the backing plate.

(Embodiment 6) FIG. 10 is a sectional view showing a backing plate provided with a cooling structure around a groove. As shown in the figure, cooling holes 17 are provided around the groove 7 and inside the backing plate 2 in the welding direction,
During welding, water was circulated through the cooling port 17 to cool around the groove 7. This method also facilitates removal of the workpiece. In addition, besides water,
The purpose can also be achieved with compressed air. Provided on backing plate 2
The width of the groove 7 becomes smaller in the depth direction,
Of the workpiece 1 from the backing plate 2 can be easily performed.
Can be.

[0031]

[0032]

(Embodiment 7 ) An example in which the present invention is applied to a railway vehicle will be described. Figure 1
1 is a diagram showing a part of a railway vehicle in a perspective view, the present example was used in a portion of the welding portion 20 of the railway car body structure illustrated in FIG. 11.

FIG. 12 is a sectional view showing a method of carrying out the present invention in the structure of a railway vehicle. The members to be joined are the extruded members 21, 22, 23. The shape members 21, 22 and 23 are arranged on the backing plate 2 and restrained so that the groove 7 is located immediately below the welding line. The shape is restrained by pressing the backing plate 2 from above with a vice or device. The material is Si content 0.4
It is an aluminum alloy having a main composition of about 0.9 wt% and a Mg content of 0.4 to 0.8 wt%. After the welding was completed, an undercut formed on the back surface of the welded portion was cut by a grinder. The welding conditions in this embodiment are as follows: the rotational speed of the tool is 1800 rpm,
The welding speed was 600 mm / min, and the welding speed was 600 m / min. Projection 8 provided on the insertion surface side of rotary tool 4
“a” decreases the width in the height direction.

( Eighth Embodiment) FIG. 13 is a cross-sectional view showing a method of implementing the present invention in a railway vehicle body having projections formed on both front and rear surfaces in the vicinity of a welded portion. The members to be joined are the extruded members 24 and 25. Shape material 24, 25
Is placed on the backing plate 2 and is restrained so that the groove 7 is located immediately below the welding line. The width of the protrusion 8a provided on the insertion surface side of the rotary tool 4 is reduced in the height direction. The shape is restrained by pressing the backing plate 2 from above with a vice or device. The material has a Si content of 0.4 to 0.9.
It is an aluminum alloy having a main composition of 0.4% to 0.8% by weight of Mg. After the welding was completed, the protrusions on the front and back surfaces near the welded portion were removed by a grinder. The welding conditions in this embodiment were a tool rotation speed of 1000 rpm and a welding speed of 400 mm / min, and were applied to a welded portion having a length of 2 m.

[0036]

According to the present invention, it can be obtained friction welding method及beauty car both structure that can be bonded without unbonded portion across the weld workpiece.

[Brief description of the drawings]

FIG. 1 is a view showing a conventional friction welding method.

FIG. 2 is a view showing a cross section of a welded portion after welding.

FIG. 3 is a view showing a friction welding method for a workpiece to be processed in which both front and back surfaces in the vicinity of a welding portion are formed in a projection shape.

FIG. 4 is a view showing a state in which projections on both front and back surfaces have been deleted after welding.

FIG. 5 is a view showing a friction welding method according to the present invention.

FIG. 6 is a sectional view showing a welded portion of the workpiece to be welded according to the present invention.

FIG. 7 is a cross-sectional view showing a state in which a backwash formed according to the present invention is removed.

FIG. 8 is a cross-sectional view showing a state where the back surface of the welded portion of the workpiece to be welded according to the present invention is again welded by a fusion welding method such as arc or laser.

FIG. 9 is a cross-sectional view showing a groove peripheral portion of a backing plate used in the main welding.

FIG. 10 is a cross-sectional view of a backing plate having a cooling structure around a groove.

FIG. 11 is a perspective view showing a structure of a railway vehicle.

FIG. 12 is a cross-sectional view showing an embodiment of the present invention applied to a railway vehicle structure.

FIG. 13 is a cross-sectional view showing a method for implementing the present invention in a railway vehicle structure in which projections are formed on both front and back surfaces in the vicinity of a welded portion.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-10-225780 (JP, A) JP-A-10-216964 (JP, A) JP-A-10-263852 (JP, A) JP-A-10- 52769 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B23K 20/12

Claims (7)

(57) [Claims] 1. A friction welding method for joining a workpiece by a rotary tool having a shoulder portion and a thread portion thinner than the shoulder portion, wherein a projection is formed on a surface of the joint portion of the workpiece which is opposite to the insertion side of the rotary tool. A friction welding method, wherein a portion is formed, and a width of the projection is reduced in a height direction. 2. A friction welding method in which a workpiece is joined by a rotary tool having a shoulder portion and a screw portion thinner than the shoulder portion, wherein projections are formed on both front and back surfaces of the joint portion of the workpiece. A friction welding method, wherein the width of the projection on the side opposite to the rotary tool insertion side is reduced in the height direction. 3. A friction welding method in which a workpiece is joined by a rotary tool having a shoulder portion and a screw portion thinner than the shoulder portion, wherein a projection is provided on the workpiece-joining portion on the insertion surface side of the rotary tool. Wherein the width of the projection is reduced in the height direction, and the joining is performed while forming the projection of the workpiece on the side opposite to the insertion side of the rotary tool. . 4. The method according to claim 1, wherein after the friction welding, at least one of the front and back surfaces of the projection or the projection formed by the friction welding is mechanically deleted or by arc welding. A friction welding method characterized by melting. 5. After performing frictional joining of a workpiece by a rotary tool having a shoulder portion and a thread portion thinner than the shoulder portion, one side or both sides of the joining portion of the workpiece are formed by other than the friction joining. A friction welding method characterized by performing fusion welding by means. 6. A friction welding method in which a workpiece is joined by a rotary tool having a shoulder and a threaded portion thinner than the shoulder, the friction welding method corresponding to an insertion portion of the rotary tool on the back surface of the joint of the workpiece. A friction welding method, comprising: arranging a backing plate provided with a groove in a portion thereof, and forcibly cooling the periphery of the groove of the backing plate or the entire backing plate while forcibly cooling the backing plate. 7. A vehicle structure manufactured by the friction welding method according to claim 1.