JPH1110364A - Friction welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable removal of a recessed part formed in a joint surface and non-joining part developed on the back surface from the inner part of a machining member by rejecting a projection and also, to enlarge variable tolerance range of the inserting depth of a rotary tool during joining, by arranging the projections on the front and the back surfaces of the joining part of the machining member inserting the rotary tool. SOLUTION: The projections 8a, 8b having 0.5-3 mm height are arranged on the front and the back surfaces 1b, 1a of the joining part of the machining member 1. Further, each of the projection widths 10, 12 is the same as or larger than a shoulder diameter 9 of the rotary tool 4 at the front surface 1b side of the machining member and is larger than the diameter of the rotary tool tip part 4a at the back surface 1a side. At the time of joining, a backing metal 2 having reverse trapezoidal groove 7 is used and the rotary tool tip part 4a is penetrated to the back surface 1a of the machining member along a button surface 3 of the machining member 1 and inserted to the inner part of the projection 8b at the lower part and rotated and joined by plastic-fluidizing the joining surface 3. Then, if necessary, the formed penetrating bead is cut- removed or the non-joined part is eliminated with an arc-welding, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel friction welding method, and more particularly to a method for welding a structure using an aluminum alloy, such as a ship, an automobile, an aviation, an elevator, and a pressure vessel, by a solid phase joining method of metal. It is.

[0002]

2. Description of the Related Art Japanese Patent Publication No. Hei 7-505090 discloses a friction welding method using a tool. This special table Hei 7-505090
In the friction welding method according to (1), a tool made of a material substantially harder than the work member is inserted into the welded portion of the work member, and the tool is rotated and moved, whereby welding can be continuously performed in the welding longitudinal direction. is there. A backing plate is disposed on the entire back surface of the welded portion of Japanese Patent Application Laid-Open No. Hei 7-505090 so that the shape of the welded back surface does not change due to 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 the backing plate is damaged because the tool tip comes into contact with the 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 welding method.
In the conventional method, the processing member 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 processing member 1 while being rotated, and is inserted until just before penetrating the processing member 1. At this time, the tool tip 4a and the back surface 1 of the processing member 1
The distance from a is usually 0.2 mm or less. In this state, it is moved in the welding direction and welded. In this method, the tool tip 4
a must always move above the back surface 1a of the workpiece 1 during welding. That is, in the conventional welding method, the tool tip 4a must not penetrate the back surface 1a of the processing member 1. If the tool tip 4a penetrates the processing member 1, the backing plate 2 and the tool 4 will be damaged. Further, a defect occurs on the back surface of the processed member 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. Further, welding cannot be performed in a state where the tip 4a of the tool 4 penetrates the back surface 1a of the processing member 1. Tool tip 4
a needs to be held just before reaching the back surface 1a of the processed member 1. However, when the processing member 1 is long, the thickness of the welded portion is not constant. For this reason, an unfused portion 6 is generated in a range from below the fused portion 5 to the back surface 1a of the processed member 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 processing member 1 is always 0.2 m.
m must be controlled below. It is extremely difficult to perform this control industrially.

An object of the present invention is to provide a friction welding method which can melt the entire welded portion of a processed member and has no unmelted portion.

[0009]

[Means for Solving the Problems]

(1) By forming the front and back surfaces near the welded portion of the processed member higher than other portions and forming a projection, the tool tip can be inserted below the back surface of the processed member. In addition, the recess on the surface of the welded portion can be formed above the surface of the processed member.

(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 processed member,
The contact between the processed member and the backing plate can be prevented. In addition, by providing a groove along the welding line immediately below the welded portion of the backing plate disposed on the back surface of the processed member, welding can be performed by penetrating the tool tip from the back surface of the welded portion.

By forming the surface of the processing member in a protruding shape only in the vicinity of the welded portion by means of the above (1), a dent formed in the surface of the welded portion is formed in a projection above the surface of the processed member,
Excluded from inside the processed member. Also, by forming the back surface of the processed member only in the vicinity of the welded portion in a projecting shape, the tip of the tool can be inserted below the back surface of the processed member, and the unmelted portion generated below the leading end of the tool is formed in the protrusion, Excluded from inside the processed member.

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 processed member and the tip of the tool. Further, welding can be performed without joining the processed member and the backing plate.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION

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

FIGS. 3 (a) and 3 (b) are views showing a method of welding a processed member in which both front and back surfaces in the vicinity of a welded portion are formed in a projection shape. The projections on the surface of the processed member are for preventing dents on the surface of the welded portion. 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. Further, the projection height 11 varies depending on the shoulder diameter 9, but it is preferable that the projection height 11 be substantially the same as the gap between the shoulder diameter 9 due to the inclination of the tool 4 and the surface of the processing member. 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 processed member.

The projections on the back surface of the processed member 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 processing member and is inserted to the inside of 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 processed member is less than the tip 4a of the tool, the entire projection is agitated by the plastic flow by 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 is removed 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 processing member by a grinder or the like, so that the height of the surface 8b is the same as the surface 1b of the processing member. The unmelted portion 6 on the back surface of the processed member is formed on the projection 8b. After welding, the unfused portion 6 can be removed from the processed member 1 by cutting the protrusion 8b to the processed member back surface 1a with a grinder or the like, and can be made the same height as the processed member back surface 1a.

(Embodiment 3) FIG. 5 is a view showing a welding method when a grooved backing plate is used. In this 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 processing member 1. The welding is performed by inserting the tool 4 until the tip of the tool 4 penetrates the back surface of the processing member 1.

FIG. 5B shows a processed member having a projection 8a formed on the surface of a welded portion of the processed member. In this welding method,
In the welded portion, a part of the processed member is plastically flown into a groove 7 provided in the backing plate 2. 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 sectional view showing the vicinity of a welded portion of a processed member welded by using the present invention. Processed member 1
By providing a groove directly below the welded portion, a backwash can be formed on the back surface of the welded portion. Further, since the tip 4a of the tool 4 can be welded by penetrating from the back surface 1a of the processing member 1, an unmelted portion does not occur at the position shown in FIG. That is, the unmelted portion can be excluded from the inside of the processed member 1. Also in this method, although it depends on the welding conditions,
Unmelted portions are generated below the tip 4a of the tool 4 by more than 0.2 mm. However, the unmelted portion is generated below the back surface of the processed member 1 and inside the Uranami 14.

FIG. 7 is a cross-sectional view showing a state in which an undercut 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 remove the unmelted portion by deleting the backwash 14 formed on the back surface of the processed member 1 after the welding is completed up to the back surface of the processed member 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 processed member 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 processing member 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, the FS formed according to the present invention
In some cases, an unmelted portion may be generated in the back seam portion of the welded portion 15 due to W. 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) Regarding 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 processed member 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 processed member 1 after the welding is completed can be easily removed from the backing plate.

(Embodiment 6) FIG. 10 is a sectional view showing a backing plate having a cooling structure around a groove. As shown in the figure, a cooling port 17 is provided in the periphery of the groove 7 and inside the backing plate 2 in the welding direction, and water is circulated through the cooling port 17 during welding to cool the periphery of the groove 7. Also in this method, removal of the processed member is facilitated. The purpose of the cooling port 17 can be achieved not only by water but also by compressed air.

(Embodiment 7) FIG. 11 is a view showing the relationship between the groove width and the tool tip. That is, FIG. 11A shows the positional relationship during welding when the groove width is smaller than the diameter of the tool tip, and FIG. 11B shows the positional relationship during welding when the groove width is larger than the diameter of the tool tip. In FIG. 11A, the diameter 19 of the tool tip is larger than the groove width 18. Therefore, the tool tip 4a cannot be inserted into the groove 7. The conventional tool tip 4a is formed in a spherical shape, but is further tapered so that the tool tip 4a reaches the inside of the groove 7. At this time, the groove width 18 of the backing plate is desirably about 1 to 2 mm smaller than the tool tip diameter 19.

In FIG. 11B, the groove width 18 is larger than the tool tip diameter 19. In this case, the tool tip 4a is
Can be inserted up to the inside. However, if the groove width 18 becomes larger than necessary, a defect will occur at the boundary between the backwash and the back surface of the processed member. Therefore, in this embodiment, the groove width 18 is 1 mm larger than the tool tip diameter 19 and is limited to 5 mm at the maximum.

(Embodiment 8) An example in which the present invention is applied to a railway vehicle will be described. FIG. 12 is a perspective view showing a part of a railway vehicle, and this embodiment was used for a part of a welding portion 20 of the railway vehicle structure shown in FIG.

FIG. 13 is a sectional view showing a method of implementing the present invention in a structure of a railway vehicle. Extruded die 2
1, 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. Backing plate 2 from above with vise or device
Do it by holding it down. The material has a Si content of 0.4-
It is an aluminum alloy having a main composition of 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 were a tool rotation speed of 1800 rpm and a welding speed of 600 mm / min, and were applied to a 3 m long weld.

(Embodiment 9) FIG. 14 is a cross-sectional view showing a method for 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 joining members are extruded members 24 and 25
It is. The shape members 24 and 25 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 an aluminum alloy having a Si content of 0.4 to 0.9 wt% and a Mg content of 0.4 to 0.8 wt%. 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 are as follows: the rotation speed of the tool is 1000 rpm, and the welding speed is 400 mm / m.
in and applied to welds 2 m long.

[0032]

According to the present invention, the following effects can be obtained.

(1) By forming projections on both front and back surfaces near the welded portion of the processed member, a dent on the surface of the welded portion and an unmelted portion on the backside of the welded portion are generated inside the projection, and the projection is deleted after welding. Can be removed from the inside of the processed member.

(2) By providing a groove in the backing plate and disposing this groove immediately below the welded portion of the processing member, even if the tool penetrates the back surface of the joint, it is possible to prevent the tool and the backing plate 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 expanded as compared with the conventional method.

[Brief description of the drawings]

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

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

FIG. 3 is a view showing a method of welding a processed member in which both front and back surfaces in the vicinity of a welded 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 welding method according to the present invention.

FIG. 6 is a sectional view showing a welded portion of a processed member 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 in which the back surface of the welded portion of the processed member welded by 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 diagram showing a relationship between a groove width and a pin diameter.

FIG. 12 is a perspective view showing a structure of a railway vehicle.

FIG. 13 is a cross-sectional view showing an embodiment of the present invention applied to the structure of a railway vehicle.

FIG. 14 is a cross-sectional view showing a method for 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.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Processing member, 1a ... Processing member back surface, 1b ... Processing member surface, 2 ... Backing plate, 3 ... Weld surface, 4 ... Tool, 4a ... Tool tip, 4b ... Tool tip R part, 5 ... Fused part, 6 ... Unmelted portion, 7 ... Groove, 8a, 8b ... Protrusion, 9 ... Shoulder diameter,
10, 12 ... projection width, 11, 13 ... projection height, 14 ... Uranami, 15 ... welded part by FSW, 16 ... welded part by arc welding, 17 ... cooling port, 18 ... groove width, 19 ... tool tip diameter , 20 ... weld point 21,22,23,24,25
... Extruded material.

Claims (16)

[Claims] A plastic tool for metal is inserted by inserting a rotary tool (hereinafter abbreviated as a tool) having a shoulder portion and a screw portion thinner than the shoulder portion into a welded portion of a processing member and rotating the tool while rotating the tool. A friction welding method for welding using flow, wherein both front and back surfaces near a welded portion of a processed member are formed in a protruding shape higher than other portions. 2. The friction according to claim 1, wherein the width of the projection on the surface of the processed member is equal to or greater than the shoulder diameter, and the height of the projection is within 0.5 to 3 mm. Welding method. 3. The width of the projection on the back surface of the processed member according to claim 1 is not less than the tip diameter of the tool, and the height of the projection is 0.5 to 3 mm.
A friction welding method characterized by being within mm. 4. The friction welding according to claim 1, wherein one or both of the projections on the front surface and the back surface of the welded joint structure according to claim 1 are mechanically removed after the friction welding. Method. 5. Friction welding characterized in that one or both of the projections on the front surface and the back surface of the welded joint structure according to any one of claims 1 to 3 are melt-welded by arc welding or the like after welding. Method. 6. The friction welding method according to claim 1, wherein the backing plate disposed on the back surface of the processing member has a groove provided immediately below a tool. 7. The tool according to claim 6, wherein a tip of the tool penetrates a back surface of the welded portion of the processing member, and moves inside a groove formed between the back surface of the welded portion of the processing member and the backing plate. A friction welding method characterized by welding while performing. 8. The friction welding method according to claim 6, wherein the shape of the groove of the backing plate is formed to be the same as the tip of the rotary tool. 9. A friction welding method comprising the steps of: fusing a back surface of a weld portion obtained by friction welding according to claim 7; 10. A friction welding method according to claim 7, wherein the back surface of the welded portion welded according to claim 7 or 8 is mechanically deleted. 11. The friction welding method according to claim 6, wherein the width of the groove of the backing plate is formed larger by 1 to 5 mm than the pin diameter of the tool. 12. The backing plate according to claim 6, wherein the width of the groove of the backing plate is 1 to 2 mm with respect to the pin diameter of a tool used for welding.
A friction welding method characterized by being formed small. 13. The friction welding method according to claim 6, wherein the groove has a shape in which the width of the groove decreases downward. 14. The backing plate according to claim 6, wherein:
Alternatively, a friction welding method comprising a mechanism for forcibly cooling the entire backing plate. 15. A friction welding method according to claim 6, further comprising using a backing plate having a mechanism capable of being divided rightward and leftward from the center of the groove or substantially from the center of the groove with respect to the welding progress direction. 16. A vehicle structure manufactured by the method according to claim 1.