JP2000061635A - Welded joint structural material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain satisfactorily high joint strength even through the bending of a base stock, an ununiform cut end surface or defective joint part position setting or the like and the fluctuation of a welding condition owing to these are caused by forming the thickness of a joining part of a pair of members which are composed into a joint structural material by being welded thicker than that of a part succeeding thereto. SOLUTION: Thick wall parts 3, 4 which are thicker than parts succeeding to butting end parts are respectively formed into the butting end parts of members 1, 2. The thick wall parts 3, 4 are parts to be joined by welding, and the parts succeeding to the thick wall parts 3, 4 are provided with a thickness required as ordinary members 1, 2. In such a manner, since joining end parts of the members 1, 2 are provided with a thick shape, even though positions of the butting end parts of the members 1, 2 are vertically deviated in the case of butt welding those, a weld metal which is satisfactorily thicker than a thickness of a base metal part (stationary part) is formed between both, and satisfactorily high joint strength is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welded joint structural material having a joint portion obtained by welding a metal member such as aluminum or an aluminum alloy, and in particular, a welded joint suitable as a structural material for railway vehicles and ships. Regarding structural materials.

[0002]

2. Description of the Related Art Metal members such as steel materials and aluminum materials (aluminum or aluminum alloys) are formed into a predetermined shape by rolling, and to some extent arbitrary materials such as cast materials, forged materials and extruded materials. Some are manufactured with a shape. And these become a member through a cutting and plastic working process, and these members are joined by welding and it becomes a structure.

In this case, the members 1 and 2 are jointed by lap fillet welding shown in FIG. 9 (a), butt welding shown in FIG. 9 (b), fillet welding shown in FIG. 9 (c), etc. It is completed as a welded joint structural material by being welded and obtaining a weld metal having a shape satisfying the welded portion dimensions required for design.

[0004]

However, the conventional welded joint structural materials have the following problems.
That is, it is only necessary for the member to obtain the required welded portion dimensions at all positions, but in reality, the bending of the material, the unevenness of the cut end surface, the poor positioning of the joint portion, and the like Due to fluctuations, it is difficult to keep the size of the welded part constant, and this causes the joint strength to decrease.

For example, in the case of butt welding as shown in FIG. 10 (a), as shown in FIG. 19 (b), when the member 1 and the member 2 are displaced in the direction perpendicular to the butt direction, There is a problem that the predetermined thickness of the weld metal cannot be ensured, only strength equivalent to the thickness of the welded portion is obtained as the structural material, and the welded portion is broken.

Further, as shown in FIG. 11 (a), in the case of lap fillet welding, as shown in FIG. 11 (b), the member 1
If the member 2 is separated from the member 2, the weld metal often has a thickness (throat thickness) of only about 60 to 80% of the thickness of the member 1, and the strength of the welded joint becomes lower than that of the base metal. Therefore, in this case as well, there is a problem that the weld is broken.

The present invention has been made in view of the above problems, and even if the material is bent, the cutting end face is not uniform, the position of the joint is improperly set, or the like, and variations in welding conditions occur, An object of the present invention is to provide a welded joint structure material capable of obtaining a sufficiently high joint strength.

[0008]

A welded joint structural material according to the present invention is a welded joint structural material formed by welding a pair of members by welding, and the joints of the members are thicker than the subsequent portions. It is formed and is joined by welding the thick portion.

In this welded joint structural material, the member may be made of aluminum or an aluminum alloy, and in particular, the member is preferably an extruded shape member.

The thickness of the thick portion is preferably 1.4t to 2t, where t is the thickness of the subsequent portion. Further, the tip end surface of the thick portion is preferably inclined in the thickness direction of the member, and the inclination angle is 10 to 45 with respect to the direction perpendicular to the bottom surface of the thick portion.
It makes an angle of °. And the said member can be welded by lap fillet welding.

In the present invention, the joining end portion (thick portion)
Is thicker than the steady part (the part following it), a sufficient leg length can be obtained even in fillet welding, and even if the welding dimension is about 70% of the thickness of this end, The dimensions are the same as those of the stationary part, and the strength of the joint as a whole is as high as that of the base metal.

By providing an inclined surface at the end,
The root portion can be reliably melted in, and the joint strength will not be insufficient. Furthermore, since only the end corresponding to the joint is thickened, it is not necessary to increase the overall plate thickness,
An increase in weight is prevented.

In order to thicken only this joint end, the plate material may be machined, or only the end may be thickened in advance by forging, casting or extrusion. Since aluminum or an aluminum alloy is easily extruded, if this extrusion is used, it is easy to thicken the butt ends.

However, even in the case of steel materials, in the material whose strength is increased by heat treatment, the welding heat affected zone is softened. Therefore, the technique of thickening and welding the end portions as in the present invention is effective.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the accompanying drawings. FIG. 1 is a sectional view showing a welded joint structure material according to the first embodiment of the present invention.
This embodiment applies the present invention to butt welding.
As shown in FIG. 1, each of the members 1 and 2 has a thick-walled portion 3 or 4 formed at the abutting end portion thereof, which is thicker than the portions following it. The thick portions 3 and 4 are portions to be welded and joined, and the portions following the thick portions 3 and 4 are the normal members 1 and 2.
Has the required thickness.

As described above, since the joining ends of the members 1 and 2 have a thick shape, the positions of the abutting ends of the members 1 and 2 are displaced vertically when they are butt welded. However, a weld metal sufficiently thicker than the thickness of the base material portion (steady portion) can be formed between the both, and a sufficiently high joint strength can be obtained.

Next, an embodiment in which the present invention is applied to lap fillet welding will be described with reference to FIG. In the present embodiment, the lower surface of the joint portion of the one member 1 projects downward,
The thick portion 5 is formed, so that the joint portion is thicker than the portion following the joint portion. The other member 2
Has a constant thickness as in the past.

Also in this embodiment, a sufficiently long leg length can be obtained and high joint strength can be obtained even if the positions of the members 1 and 2 are deviated. In this case,
The thickness T of the thick portion 5 of the member 1 is preferably 1,4t to 2t, where t is the thickness of the stationary portion. This is, as shown in FIG. 3, when lap fillet welding is performed between the thick portion 5 and the joint end portion of the member 2 to form the weld metal 6, the weld line and the weld metal surface are The shortest distance x between is
Assuming that the cross-sectional shape of the weld metal 6 is an isosceles right triangle with the length of the hypotenuse T, then x = T / 2 ^0.5 .
The shortest distance of the weld metal 6 is the thickness t of the base metal (steady part).
Or, if the length is longer than that, it is estimated that the strength of the portion of the weld metal 6 becomes equal to or higher than the strength of the steady portion. Therefore,
When ^{x = T / 2 0. 5 ≧} t, T ≧ 2 0.5 × t = 1.4t
Becomes On the other hand, when T exceeds 2t, the portion of the weld metal 6 becomes excessive, resulting in an unnecessary increase in weight. Therefore,
It is preferable that 2t ≧ T ≧ 1.4t.

Next, a third embodiment of the present invention will be described with reference to FIG. In the present embodiment, the member 1 has the thick-walled portion 7 at its joint end, and when the thick-walled portion 7 and the member 2 are joined, the thick-walled portion 7 is inclined with its tip end surface inclined. It constitutes the surface 8. The inclined surface 8 is formed by the members 1 and 2
It is inclined at an angle of θ with respect to the direction perpendicular to the superimposing plane with. This inclination angle θ is 10 to 45 °.

In this way, since the tip end surface of the thick portion is inclined, when the members 1 and 2 are fillet welded, the weld metal is easily overlaid and the joint strength is further improved. The inclined surface 8 at the tip may be formed at the same time when the thick portion 7 is formed, or after the thick portion 7 is formed,
You may form this inclined surface 8 by another process.

The present invention is not limited to the above embodiment,
Various modifications are possible. For example, as shown in FIG.
The thick portion 9 of the member 1 may project in the opposite direction from the overlapping surface of the member 1 and the member 2. In addition, FIG.
As shown in FIG. 5, the thick portion 10 of the member 1 may be projected on both the overlapping surface side with the member 2 and the opposite side.

Further, as shown in FIG. 7, a part of the tip surface of the projecting portion 11 of the member 1 may be vertical and the other part may be inclined. Further, as shown in FIG. 8, the front end surface of the thick portion 12 of the member 1 may be an arc in which it is drawn so as to be entirely inclined.

Furthermore, as the welding method itself, in addition to MIG welding, various methods such as TIG welding, plasma arc welding, or laser welding can be adopted.

[0024]

EXAMPLES The results of comparing the strength of the joints of the examples of the present invention with the comparative examples will be described below.

First Embodiment This embodiment is a case where members 1 and 2 having the shapes shown in FIG. 1 are joined, and as a comparative example, FIG. 9 (b) or FIG.
Welding was performed by conventional butt welding as shown in (a).
A5083-0 material specified in JIS H 4000 was used, the thickness of the stationary portion was set to 3 mm, and the thickness of the joining end portions (thick portions 3, 4) was variously set. In addition, butt welding by MIG welding was performed using A5183WY defined by JIS Z3232 and a diameter of 1.2 mm as a welding wire.

After welding, two tensile tests were performed to measure the breaking strength of each piece, the breaking position was confirmed, and the joint efficiency was calculated as the ratio of the breaking strength to the strength of the base metal.

[0027]

[Table 1]

As shown in Table 1, in the Examples of the invention of wood, all of them are fractured by the base metal and the joint efficiency is 100%, whereas in Comparative Examples, fracture is caused by the weld metal under any welding condition. There is variation in the value of breaking strength, and the joint efficiency of the comparative example is low at 58 to 87%.

Second Embodiment This embodiment is lap fillet welding shown in FIG. In the comparative example, lap fillet welding was performed by the method shown in FIG. 9 (a) or FIG. 11 (a). Aluminum or aluminum alloy extruded profile A6063-defined in JIS H 4100
Using T6 material, the thickness of the steady part is 3 mm, and the thickness of the end part is set variously.
Using A5356WY specified by SZ3282 and a wire having a diameter of 1.2 mm, lap fillet welding was performed between the same kind of material by MIG welding.

After welding, two tensile tests were conducted for each,
The joint strength was measured, the fracture position was confirmed, and the joint efficiency was calculated as the ratio of the fracture strength and the strength of the base material.
The results are shown in Tables 2 and 3 below.

[0031]

[Table 2]

[0032]

[Table 3]

As shown in Tables 2 and 3, the heat treatment type A
In the 6063-T6 material, which is an 1-Mg-Si alloy, the heat-affected zone of the base metal softens due to welding heat, but in the examples of the present invention, the heat-affected zone almost breaks in the base metal and its joint efficiency is 5
It was 0% or more. On the other hand, in the comparative example, the weld metal fractures under any of the conditions, the joint efficiency is 49% or less, and the joint efficiency is lower than in the case of the present invention.

Third Embodiment This embodiment is shown in FIG. 4, and the comparative example is shown in FIGS. 9 (a) and 11 (a), like the second embodiment. Similar to the second embodiment, aluminum and aluminum alloy extruded profile A specified in JIS H 4100
Prepare a material with a thickness of the stationary part of 3 mm and various thicknesses of the end parts using 6063-T6 material, and use A5356WY diameter 1.2 mm specified in JIS Z 3232 as the welding wire. Overlap fillet welding was performed between the same kind of materials by welding. In this example, the test was conducted by inclining the tip surface at various angles. Further, the wire aiming position was changed by about 1 mm around the root portion, and the degree of margin for the wire deviation was investigated.

After welding, two tensile tests were conducted for each,
The joint strength was measured, the fracture position was confirmed, and the ratio with the strength of the base metal was calculated as joint efficiency. The results are shown in Tables 4 and 5 below.

[0036]

[Table 4]

[0037]

[Table 5]

As shown in Tables 4 and 5, if the tip end surface of the thick wall portion is inclined, most of the base material is broken even if the target position of the wire is slightly displaced, and the joint efficiency is high. Further, when the inclination angle θ is 10 ° to 45 °, high joint strength is obtained. Therefore, the inclination angle θ is preferably 10 ° to 45 °. Although the effect of the present invention can be obtained with other tilt angles, the taper angle is preferably within the above range in order to cope with an extreme deviation of the wire aiming position.

[0039]

As described above, according to the present invention,
Even if the material is bent, the cutting end face is not uniform, the position of the joint is improperly set, or the welding conditions fluctuate, the margin is large and the joint strength is high enough to absorb the fluctuation. Can be obtained. Therefore, the present invention makes a great contribution to the manufacture of various welded structures such as railway vehicles and ships.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a second embodiment of the present invention.

FIG. 3 is a diagram illustrating a numerical value preset condition according to a second embodiment.

FIG. 4 is a diagram showing a third embodiment of the present invention.

FIG. 5 is a diagram showing a modified example of the present invention.

FIG. 6 is a diagram showing a modified example of the present invention.

FIG. 7 is a diagram showing a modified example of the present invention.

FIG. 8 is a diagram showing a modified example of the present invention.

FIG. 9 is a diagram showing a conventional (a) lap fillet welding method, (b) butt welding method, and (c) fillet welding method.

FIG. 10 is a diagram showing a drawback of the conventional butt welding method.

FIG. 11 is a diagram showing a drawback of the conventional lap fillet welding method.

[Explanation of symbols]

1,2: member 3, 4, 5, 7, 9, 10, 11, 12: Thick part 8: Inclined surface

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B23K 33/00 B23K 33/00 Z (72) Inventor Seiji Sasabe 100-1 Kawakamichi, Miyazawa Fujisawa, Kanagawa F-term at Fuji Steel Works, Kobe Steel Works (reference) 4E001 AA03 BB01 BB07 BB08 BB11 BB12 CB01 DA05 4E081 BA08 BA18 BA47 DA06 DA12 FA15 YA10 YC10

Claims (7)

[Claims] 1. In a welded joint structural material constituted by joining a pair of members by welding, the joint portion of the members is formed thicker than the subsequent portion, and the thick portion is joined by welding. Welded joint structural material characterized by being 2. The welded joint structural material according to claim 1, wherein the member is made of aluminum or an aluminum alloy. 3. The welded joint structure material according to claim 1, wherein the member is an extruded shape member. 4. The welding according to claim 1, wherein the thickness of the thick portion is 1.4t to 2t, where t is the thickness of the portion that follows. Joint structure material. 5. The welded joint structural material according to any one of claims 1 to 4, wherein a tip surface of the thick portion is inclined in a thickness direction of the member. 6. The welded joint structural material according to claim 5, wherein the tip end surface is inclined at an angle of 10 to 45 ° with respect to a direction perpendicular to the bottom surface of the thick portion. 7. The welded joint structural material according to any one of claims 1 to 6, wherein the member is welded by lap fillet welding.