JP7160090B2 - Composite welding method for metallic materials and butt welding member for metallic materials - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite welding method and a butt-welded member capable of obtaining a butt member with excellent joint strength even when gaps are formed when metal materials are butted together.

Laser beams are used in various fields in recent years because they are heat sources with high energy density. In particular, in the field of joining and welding, by combining arc welding methods such as MIG (Metal Insert Gas), MAG (Metal Active Gas), and TIG (Tungsten Insert Gas), it is possible to achieve penetration that is difficult with arc welding alone. Laser + arc hybrid welding is gaining recognition for the purpose of improving depth and increasing welding speed. In addition, a laser welding method that can obtain a welded portion equivalent to arc welding by using a filler material and laser welding instead of the arc welding can also be used as laser + hybrid welding.

Laser welding is being used as a method for welding and joining steel materials and as a means of joining various metal materials, taking advantage of its joining characteristics such as high speed, low heat input, and penetration depth. There are few examples of application to industrial products. The reason for this is that the main body of the laser welder is expensive, and that the weld bead formed by the laser alone may be dented. Welded joints such as T-joints and butt joints can also be obtained by laser welding. However, depending on the size of the gap between the welding materials, the depth of the recess formed in the weld bead may increase and the joint strength may decrease. In order to reduce the depression of the weld bead, it has been necessary to strictly control the target position of the laser beam and the butt gap between the welded materials.

The inventors of the present application considered that it would be difficult to strictly control the amount of butt gap between the materials to be welded in industrial production. The inventors of the present application, after the welding surfaces of two plate materials with different thicknesses are butted so that the surfaces adjacent to the welding surfaces are flush, the thin plate side of the flush surfaces is directed to the abutting surface. We found the usefulness of a laser welding method in which a laser beam is incident obliquely. Based on this usefulness, the inventors of the present application have found that by controlling the laser target position, incident angle, and butt spacing within appropriate ranges, it is possible to efficiently achieve excellent welding strength and finish regardless of the thickness of the plate. For the main purpose of providing a laser welding method for the obtained differential thickness materials, the inventors have developed a "laser welding method for differential thickness materials and a differential thickness welded member using the method" described in Patent Document 1.

Japanese Patent Publication "JP 2016-68092"

In the above laser welding method for materials with different thicknesses, by giving an incident angle during laser irradiation, it is possible to form a weld bead even if there is a butt gap between the materials, and excellent joint strength can be obtained by controlling the amount of gap. It has been found that a weld bead formed by However, depending on the butt gap amount, the depth of the depression may become extremely large, and there is a possibility that the depression may become a welding defect and reduce the joint strength. Therefore, in the laser welding method described above, it is desirable that the butt gap between the materials is 1 mm or less. However, in actual application to industrial products, even if the gap amount is 1 mm or less, the bonding strength may be insufficient, and when the above welding method is applied, the depth of the recess that causes insufficient bonding strength becomes large. feared the possibility.

SUMMARY OF THE INVENTION An object of the present invention is to provide a composite welding method and the like for metallic materials that can reduce the depth of a depression.

In order to solve the above problems, the method for composite welding of metal materials according to the present invention provides a method for welding two metal materials in a state in which the surfaces of the two metal materials are flush with each other, and then the other metal material is welded from the side of one metal material. forming a weld bead by obliquely irradiating a laser beam onto a target position on the end face or on an extension thereof; and welding with a welding wire or filler material from the side, wherein the depth D of the laser beam aiming position is 0 with respect to the thickness t of the metal material. .8t≤D≤1.8t.

ADVANTAGE OF THE INVENTION According to this invention, the composite welding method of the metal material etc. which can reduce the hollow depth can be provided.

It is the figure which showed the cross section after the laser-welding process trial-produced by the technique of this invention. It is the figure which showed the cross section after the laser-welding process of this invention trial-produced by a prior art. It is a figure which shows typically the laser welding process of this invention. It is the figure which showed the cross section which carried out the laser + arc welding (laser precedent) experimentally by the technique of this invention.

As a result of detailed research, the inventors of the present application found that after the joint surfaces of the materials to be welded are butted so that the surfaces adjacent to the joint surfaces are flush, from one side of the flush surfaces, the above joint surface Alternatively, in a laser welding method in which a laser beam is obliquely incident on the extension line of the joint surface, by controlling the laser target position and the incident angle within an appropriate range, laser welding with a concave shape for a certain butt gap We have found usefulness in that a bead is formed and an unmelted portion is less likely to be formed on the back surface of the welded joint. In addition, the inventors of the present invention have completed the present invention based on the fact that the interface between the laser weld bead and the arc weld bead is fused by arc welding after laser welding, so that excellent joint strength can be obtained efficiently. .

In addition, in the present invention, in a welded joint formed by welding the butt surfaces of the materials to be welded so that the surfaces of the materials to be welded are flush with each other, the flush surface (the upper surface in FIG. 4) is The "front surface of the welded joint" and the surface on which the step occurs (the lower surface in FIG. 4) may also be referred to as the "back surface of the welded joint".

The present invention will be described below with reference to the drawings.

FIG. 3 schematically shows the preceding laser welding in the hybrid welding (composite welding method) of the invention. As shown in FIG. 3, the laser target position (P) is the target position of the laser beam (3) on the end surface (1a) of the metal material (1) or the extended surface (1b) of the end surface. The angle of incidence (θ) is the angle of inclination of the irradiation direction of the laser beam (3) to the side of the metal material (2) with respect to the end face (1a) of the metal material (1) or the extended surface (1b) of the end face. is. The butt gap G is the gap between the end surface (1a) of the metal material (1) and the surface of the metal material (2) facing the end surface (1a).

Hybrid welding of the present invention includes the following steps. The surfaces of the metal material (1) (one metal material) and the metal material (2) (the other metal material) are flush with each other, and the mating surface (1a) ( A laser beam (3) is irradiated obliquely onto the surface (1b) on the end face) or its extended surface (1b) to form a weld bead. Arc welding or laser welding with a welding wire or filler metal is then performed on the weld bead with the depression formed by the laser welding. Through the above steps, a butt-welded member made of metal material according to the present invention is obtained.

The laser beam (3) is obliquely incident from the surface side of the metal material (2) made flush with the abutment end face (1a) or an extension line (1b) of the end face, and the laser beam (3) The target position (P) is on the abutment end face of the metal material (1) or an extension line of the end face, and the target position depth D from the surface of the incident side metal material (2) of the laser beam (3) is set as follows (1 ) within the formula.

0.8t≦D≦1.8t Formula (1) (where t is the thickness of the metal material (2), and both D and t are in mm.)
A more desirable range is 1.0t≤D≤1.5t.

The incident angle (θ) of the laser beam (3) is set in a direction inclined by 10° to 40° toward the metal material (2) with respect to the abutting end surface (1a) of the metal material (1) and the metal material (2). .

More preferably, the angle range for tilting the incident angle (θ) of the laser beam (3) is 15° to 30°.

By setting the butt gap (G) between the metal material (1) and the metal material (2) to t/6 or less, it is possible to suppress the melted metal from falling into the butt gap even when laser welding is performed. To obtain a welded member in which the depression on the back side of the welded part in is 5% or less of the plate thickness.

The type of laser beam (3) in the present invention is not particularly limited. For example, a carbon dioxide gas laser, a YAG laser, a fiber laser, a disk laser, or the like, which has a relatively large output, can be used. Fiber lasers or disk lasers are preferred because they can be transmitted through optical fibers and have excellent beam quality. The laser output and beam diameter may be appropriately selected according to the type and thickness of the metal material to be welded.

The subsequent welding method after the preceding laser welding may be an arc welding method such as MIG, MAG, or TIG using a welding wire or filler material, or laser welding may be performed again. Since the welding wire or filler metal to be used is diluted by mixing with the material to be welded, it is generally recommended by the manufacturer of each welding wire or filler metal to use the type that matches the material to be welded. is desirable. However, it is not desirable to have an adverse effect on the structure, such as causing phase transformation (martensite transformation, etc.) in the material to be welded by using it.

It is also desirable that the weld bead formed by post-welding be free of weld defects such as blowholes and pits. In addition, when there is plating metal for rust prevention on the surface of the material, it is desirable that there is little excess metal by welding wire etc. so that there is little plating damage and the range of repair painting is narrow for the rust prevention effect range. .

In the present invention, the type of material to be welded is not particularly limited. Low carbon steel, stainless steel, or Zn-based plating, Al-based plating, Zn-Al-based alloy plating, Al-Si-based alloy plating, Zn-Al-Mg-based alloy plating, Zn-Al-Mg-Si-based alloy on these It may be plated or the like. In addition, the present invention can be applied not only to welding between steel materials but also to hybrid welding between non-ferrous metals such as Al and between steel materials and non-ferrous metals. Furthermore, the method of cutting the material to be welded is not limited. A general cutting method such as a shear may be used. Moreover, after cutting, it may be finished by mechanical polishing.

In the present invention, the thickness of the metal materials 1 and 2 is not limited. The material is not limited to a plate material, and may be in the form of a block. If the thicknesses of the metal material 1 and the metal material 2 are different from each other, the metal material 2 having the smaller thickness may be used.

EXAMPLES The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to these Examples.

(Test material)
First, as shown in Table 1, a hot-dip Zn-6 mass % Al-3 mass % Mg coating of low carbon steel as a base sheet was prepared as a test material. There are two thicknesses, 3.2 mm and 6.0 mm. The plating weight per side is 90 g/m ² .

そして、全ての供試材を、シャー、チップソー、バンドソーにより切断し、幅５０ｍｍ、長さ１５０ｍｍのサイズに切り出した。また、一部の供試材については切断端面を機械研磨仕上げした。

Then, all test materials were cut with a shear, chip saw, and band saw, and cut into pieces having a width of 50 mm and a length of 150 mm. In addition, the cut end faces of some test materials were finished by mechanical polishing.

Two specimens having the same plate thickness were selected from the cut specimens, and the surfaces of the two specimens were butted against each other so that the surfaces thereof were flush with each other.

(Measurement of butt clearance)
Subsequently, before laser welding, the size of the maximum butt gap between the widths of 100 mm of the butt portions was measured with a gap gauge. In addition, when the gap gauge with a thickness of 0.05 mm does not fit in the butted portion, the maximum butt interval is set to 0.05 mm or less.

(preceding welding)
Then, only butt laser welding was performed on the butt portion using a fiber laser welder under the conditions of the target position depth D of the laser beam and the incident angle θ of the laser beam shown in Table 2. Table 2 also shows the size of the butt gap of the butt portion measured using a gap gauge. The laser welding conditions are as follows.

Output: 4kW,
beam spot diameter: 0.6 mm,
Defocus: 7mm,
Shielding gas: None The laser welding speed was changed according to the plate thickness as follows.

Plate thickness 6.0mm: 0.75m/min,
Plate thickness 3.2 mm: 1.2 m/min

図１は、レーザ溶接のみを行なった状態の本発明例Ｎｏ．１の供試材を光学顕微鏡で観察した溶接部の断面写真である。図２は、レーザ溶接のみを行なった状態の比較例Ｎｏ．１１の供試材を光学顕微鏡で観察した溶接部の断面写真である。

FIG. 1 shows Example No. 1 of the present invention in a state where only laser welding was performed. 1 is a cross-sectional photograph of a welded portion of test material No. 1 observed with an optical microscope. FIG. 2 shows comparative example No. 1 in a state in which only laser welding was performed. 11 is a cross-sectional photograph of a welded portion observed with an optical microscope in No. 11 test materials.

(following welding)
Subsequently, the joint in which the weld bead was formed was arc-welded as a subsequent welding under the following conditions. In addition, as an evaluation, the shape of the back side of the welded joint was observed and a tensile test was performed.

The subsequent arc welding conditions are as follows.

Welding current, voltage: 160A, 20.3V,
Shield gas, flow rate: CO ₂ , 20 L/min
Welding wire: MG-50T, φ1.2mm
The arc welding speed was the same as the preceding laser welding speed.

(Observation of the shape of the back side of the welded joint)
The shape of the back side of the welded joint after subsequent welding was evaluated. Specifically, the depth of the depression on the back surface of the welded joint was measured, and the depth was evaluated as a percentage of the plate thickness t before welding. Table 3 shows the results obtained.

発明例Ｎｏ．１～Ｎｏ．９は、本発明の範囲であるレーザ狙い位置Ｄが0.8ｔ≦Ｄ≦1.8ｔ（ｔ：板厚）を満足しており、継手裏側窪み量の溶接前板厚に対する比率（％）は５．０％以下と良好である。さらに、レーザビームの入射角(θ)が１０°～４０°で、突合せ隙間間隔(Ｇ)がｔ／６以下（ｔ：板厚）であるＮｏ．１、２，４，６，８の継手裏側窪み量は２．０％と特に優れている。

Invention Example No. 1 to No. 9 satisfies 0.8 t ≤ D ≤ 1.8 t (t: plate thickness) for the laser target position D, which is within the scope of the present invention, and the ratio (%) of the amount of depression on the back side of the joint to the plate thickness before welding is 5. 0% or less is good. Further, No. 1, in which the incident angle (θ) of the laser beam is 10° to 40° and the butt gap interval (G) is t/6 or less (t: plate thickness). 1, 2, 4, 6, and 8 have a particularly excellent joint back side recess amount of 2.0%.

On the other hand, Comparative Example No. 10 to No. In No. 17, the ratio (%) of the amount of depression on the back side of the joint to the plate thickness before welding exceeds 5.0%.

(Tensile test)
Table 3 also shows the results of the tensile test. Inventive Example No. in which subsequent welding was performed. 1 to No. In No. 9, all tensile tests resulted in base metal fracture. That is, there was no decrease in strength due to poor welding. FIG. 4 shows Example No. of the present invention. 4 is an observation of the shape of the back side of the welded joint observed with the optical microscope of No. 4.

INDUSTRIAL APPLICABILITY The present invention can be used as a method of welding metal materials 1 and 2 by melting the metal materials 1 and 2 to fill the gap even if there is a gap in the butt welding of the metal materials 1 and 2. can. This can be applied to the automobile field, the industrial equipment field, the home appliance field, the switchboard field, the housing field, and the joining of members such as road materials.

1 metal material 1 (the other metal material)
2 Metal material 2 (one metal material)
1a butt end face 1b of metal material 1 extended surface 3 of the butt end face of metal material 1 laser beam P target position D target position depth

Claims (3)

With the surfaces of the two metal materials facing each other so that they are flush with each other, a laser beam is obliquely irradiated from the side of one of the metal materials to a target position on the end face of the other metal material or on its extended surface. and forming a weld bead;
a step of performing welding with a welding wire or a filler material on the weld bead formed by the irradiation of the laser beam from the surface side of the two metal materials irradiated with the laser beam;
A composite welding method for metallic materials comprising
The depth D of the target position of the laser beam is within the range of 0.8t ≤ D ≤ 1.8t with respect to the thickness t of the one metal material,
A weld is formed by welding the two metal materials,
By setting the abutting distance between the other metal material and the one metal material to be t/6 or less, the depression of the welded portion on the side opposite to the surface side is 5% or less of the plate thickness of the metal material. A composite welding method for metal materials, characterized by: 2. The metal according to claim 1, wherein the irradiation direction of the laser beam is a direction inclined by 10° to 40° toward the one metal material with respect to the end surface or an extended surface thereof. A composite welding method for materials. 3. A butt-welded member of metallic materials, wherein the depression on the back side of the welded portion is 5% or less of the plate thickness, using the composite welding method for metallic materials according to claim 1 or 2.

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