JPH11104867A - Method for laser beam-welding of aluminum or aluminum alloy member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To weld two aluminum alloy members at a high speed and to prevent the occurrence of defective welding by arranging a filler metal in a thin plate side of the butting parts of end surfaces to each other in the two aluminum alloy members having different thicknesses and welding by irradiating this filler metal with a laser beam. SOLUTION: The end surfaces of two aluminum alloy members of a thick plate 3 and a thin plate 4 are butted to each other and a filler metal 2 is arranged in the butting part on the aluminum alloy member 4 at the thin plate side. At the time of irradiating this filler metal 2 with a laser beam 1, the filler metal 2 is melted, a melt-starting part of the filler metal 2 is formed just after starting the irradiation of the laser beam 1 and the welding is progressed. By this method, a welded metal part without generating deflective welding, is formed. That is, at the time of welding, in the case of making the thin plate side member 4 an aiming position while irradiating the filler metal 2 with the laser beam 1, the filler metal is added while keeping the welding condition at a low heat inputting side in the thin plate side and the formation of a molten metal can be accelerated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for laser welding aluminum or aluminum alloy members capable of welding aluminum or aluminum alloy members having different thicknesses at high speed and suppressing welding defects.

[0002]

2. Description of the Related Art In recent years, lighter structures have been adopted in transport vehicles such as automobiles, railway vehicles, ships, etc. due to the demand for improved fuel efficiency and higher speed. In recent years, members made of aluminum or an aluminum alloy (hereinafter, collectively referred to as an aluminum alloy member) have been used instead of steel because these materials are lightweight.

On the other hand, laser welding can perform high-speed processing with the power of light energy density using a condensed beam having a small diameter. Becomes possible. For this reason,
This laser welding method has been intensively studied as a method for welding aluminum alloy members, and is being put to practical use.

As a processing method using laser welding, there is known a technique of performing plastic working on a member obtained by butt-welding members having different thicknesses in advance (for example, see Japanese Patent Application Laid-Open No.
155064).

In these welding methods, a sufficient molten metal is formed by setting a thick plate side as a target position of a laser beam to join welds.

[0006]

However, when the irradiation position is on the thick plate side, the heat input does not melt unless the heat input amount is larger than when the irradiation position is on the thin plate side. Also, even if the position of the lamp is aimed at the thick plate side, if the precision of the groove is not high, the amount of molten metal changes and the formation of the molten portion is disturbed, so that it takes time and effort to perform processing to increase the groove accuracy. .

On the other hand, when the thin plate side is set as the target position, the amount of heat input is reduced, but the amount of molten metal formed is reduced, and the formation of excess metal at the joint is hindered, and the joint strength is reduced.

The present invention has been made in view of such a problem, and can weld two aluminum alloy members having different thicknesses at a high speed and can prevent the occurrence of welding defects. An object of the present invention is to provide a laser welding method for aluminum or an aluminum alloy member.

[0009]

According to a laser welding method for an aluminum or aluminum alloy member according to the present invention, two aluminum alloy members having different thicknesses are joined to each other and end faces thereof are joined to each other. It is characterized in that a filler is arranged, and the filler is irradiated with a laser beam and welded.

[0010] In another laser welding method for aluminum or aluminum alloy members according to the present invention, the thickness differs.
The end faces of the two aluminum alloy members are butted together, and a filler material is arranged at the butted portion. When irradiating the filler material with a laser beam and welding, the laser beam irradiation position should be on the thin plate side. It is characterized by.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described.
This will be specifically described with reference to the accompanying drawings. As shown in FIG. 1, in the embodiment of the present invention, end faces of two aluminum alloy members 3 (thick plate) and aluminum alloy member 4 (thin plate) having different wall thicknesses are abutted to each other to form a filler material 2. It is arranged at the butting portion on the aluminum alloy member 4 on the thin plate side. When the filler material 2 is irradiated with the laser beam 1,
As shown in FIG. 2, the filler material 2 is melted, and a melting start portion 5 of the filler material is formed immediately after the start of laser beam irradiation, and welding proceeds. Reference numeral 6 indicates the original position of the filler before melting. As described above, when the filler material 2 is arranged on the thin plate side and the laser beam is irradiated on the filler material and welded, as shown in FIG. 3, a weld metal portion 7 having no welding defect is formed after welding. . That is, in welding, when the thin plate side member 4 is set to the target position while irradiating the filler metal 2 with the laser beam 1, the welding material is added while maintaining the welding conditions on the low heat input side of the thin plate. To promote the formation of molten metal.

On the other hand, as shown in FIG. 4, when the filler material 2 is disposed on the aluminum alloy member 3 on the thick plate side and irradiated with the laser beam 1, as shown in FIG. The starting portion 5 remains on the side of the thick plate, and the molten metal tends to be excessive, so that the molten metal cannot be held and the molten metal spreads on the thin plate side member 4. As a result, the formation of a stable fusion zone is impaired, and the shape of the keyhole formed in the fusion zone is disturbed by the high power density. As shown in FIG. The occurrence of is remarkable.

On the other hand, as in the present invention, when the irradiation position of the laser beam is set to the thin plate side, not only an appropriate amount of molten metal is formed but also the molten metal is applied to the end wall on the thick plate side. Very stable adhesion due to tension. For this reason, since a molten portion is formed without the molten metal being scattered, the occurrence of welding defects due to the disorder of the keyhole shape disappears.

The welding conditions for laser welding applied to welding of aluminum alloy materials are not particularly limited. For example, in selecting the laser itself, in order to melt aluminum, an output of about 2 kW or more for a carbon dioxide laser and about 0.8 kW or more for a YAG laser is desirable. Welding conditions such as laser output and welding speed may be selected according to the type of laser used, the thickness and shape of the workpiece, and the like.

When the filler material is added, the insertion direction does not necessarily have to be parallel to the welding line direction, and there is no particular limitation on the insertion direction as long as a focused laser beam is applied to the filler material.

Further, the flow rate of the shielding gas is not particularly defined because it varies depending on the welding conditions.

[0017]

EXAMPLES Examples of the present invention will be described below in comparison with comparative examples. Wiping material is JIS A5052P-0
The plate thickness is 1 mm and 2 mm, and the filler material is A53
It was 56 WY, the diameter was 1.2 mm, the type of shielding gas was Ar gas, and the flow rate was 15 liters per minute. As the welding conditions, the conditions shown in Table 1 below were employed according to the laser irradiation position of the filler material.

The occurrence of porosity was determined by counting the number of generators having a diameter of 0.4 mm or more by a radiation transmission test. The tensile test was conducted according to JIS Z 220
Using a No. 15 test piece, the efficiency was shown as a value obtained by dividing the joint strength by the base metal strength on the basis of the base metal strength on the thin plate side. Table 1 below shows the welding conditions, and Table 2 below shows the welding results.

As a result, as shown in Table 1 below, in the case of Examples 1 and 2 in which the filler material was irradiated with laser light, and the laser light-irradiated portion of the filler material was arranged on the thin plate side and welded. As shown in Table 2 below, under the conditions of high-speed welding, there was no welding defect (porosity), the joint efficiency was 100%, and a welded joint that broke with the base material could be obtained. On the other hand, in the case of Comparative Examples 1 to 3, since the laser beam irradiated portion is on the side of the thick plate or the groove portion, porosity occurs, the joint efficiency is not 100%, and the weld metal portion is broken. Occurred.

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

As described in detail above, according to the present invention, despite the high speed welding, welding defects are prevented during laser welding and the joint efficiency such that the joint is broken on the base metal side is high. A weld can be obtained, a stable weld of an aluminum alloy member can be obtained, and a high-quality structure can be manufactured.

Thus, by applying laser welding to a structure using an aluminum alloy member, it is possible to improve the mechanical performance such as the strength and ductility of the whole structure, and it is possible to widen its application range. The present invention makes a great contribution in making use of the advantage of weight reduction by the aluminum alloy member over a wide range.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a state before welding in a laser welding method according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram showing the behavior of the molten material of the filler immediately after the start of laser beam irradiation in the laser welding method according to the embodiment of the present invention.

FIG. 3 is a conceptual diagram showing a welding cross-sectional shape after welding in a laser welding method according to an embodiment of the present invention.

FIG. 4 is a conceptual diagram showing a state before welding in a laser welding method according to a comparative example.

FIG. 5 is a conceptual diagram showing a behavior of a molten portion of a filler material immediately after the start of laser beam irradiation in a laser welding method according to a comparative example.

FIG. 6 is a conceptual diagram showing a weld cross-sectional shape after welding in a laser welding method according to a comparative example.

[Explanation of symbols]

 1: laser beam 2: filler material (cross section) 3: test material (thick plate) 4: test material (thin plate) 5: melting start part of filler material 6: original filler material position 7: weld metal Part 8: Porosity

Claims (2)

[Claims] 1. An end face of two aluminum alloy members having different wall thicknesses is abutted to each other, a filler material is arranged on the thin plate side at the abutting portion, and the filler material is irradiated with a laser beam and welded. A method for laser welding aluminum or aluminum alloy members, characterized in that: 2. An end face of two aluminum alloy members having different thicknesses is abutted to each other, a filler material is arranged at the abutting portion, and a laser beam is applied to the filler material for welding. A laser welding method for an aluminum or aluminum alloy member, wherein the irradiation position of the laser beam is on the thin plate side.