JP2000273564A - Aluminum or aluminum alloy material for laser cutting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate cutting by laser light and to reduce the deposited weight of dross in the cut face cut by laser light by allowing the material to have a base material composed of aluminum or an aluminum alloy and an oxidized film of a film thickness in a specified range formed on this base material. SOLUTION: The oxidized film is the one formed on the surface of a base material and having 2 to 150 μm film thickness. The base material is preferably composed of an extruded shape material for a welding structural material and is desirably incorporated with 0.5 to 5.5 wt.% Mg and 0.1 to 0.6 wt.% Mn. The base material having 2 mm sheet thickness is used, the film thickness of the oxidized film is controlled, thereafter, cutting by laser light is executed under the prescribed conditions, the cut edge faces are butted each other, and butt welding is executed by MIG welding. As to the depositing condition of dross, the deposition height of dross is measured at the three places in the cut face, the average value is defined as the deposited weight of dross, and the one of <=0.5 mm is past. As to the result of testing for oxidized films of 2 to 150 μm, all is past.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum or aluminum alloy material for laser cutting used for a welded structural material, and more particularly to a cutting method using a laser beam and the amount of dross adhered when cutting with a laser beam. The present invention relates to an aluminum or aluminum alloy material for laser cutting, which does not require removal of dross after cutting with a laser beam and which does not require much.

[0002]

2. Description of the Related Art Aluminum or aluminum alloy materials (hereinafter, aluminum or aluminum alloy materials are collectively referred to as aluminum materials) are lighter in weight and more excellent in corrosion resistance than steel materials. Used as a member.

[0003] This aluminum material is often assembled as a structure through processes such as cutting, plastic working, welding and the like, similar to steel materials.

Conventionally, machining and cutting have been used for cutting or separating aluminum materials. In machining, it is necessary to remove the lubricating oil for cutting the aluminum material. If the subsequent process includes a welding process, a cleaning process is required to prevent the occurrence of welding defects.

[0005] Recently, cutting has been performed using high-density energy of laser light. FIG. 1 is a sectional view showing a cutting method using a laser beam. Since cutting by laser light is easy to automate and can perform three-dimensional processing and the like, it is used for cutting metal materials.

As shown in FIG. 1, a laser beam 103 is applied to a cut portion of a member 100 made of aluminum, and at the same time, a cutting gas 104 is blown to the cut portion to cut the member. At this time, the dross 102 adheres to the cut surface 101 on the side opposite to the side irradiated with the laser beam 103. Then, when the cut surface 101 is welded after cutting by the laser beam 103, if the dross 102 is welded to the weld surface, particularly the end surface of the cut surface 101, welding failure occurs. Therefore, the dross 102 needs to be removed. Further, since the dross 102 attached to the inside of the cut surface 101 is mainly composed of aluminum oxide, there is a problem that it is difficult to remove the dross 102 and it is costly to remove it. For this reason, it is desired to prevent the dross 102 from being generated.

Therefore, a laser beam for cutting the workpiece and a laser beam for removing dross generated near the back surface of the cut surface of the workpiece at the time of the cutting are divided and irradiated to separate the laser beam. At the same time, a cutting method using a laser beam for removing dross has been proposed (Japanese Patent No. 2798223).

[0008]

However, a cutting method using a laser beam (Japanese Patent No. 2798223) has been proposed, but at present, no proposal has been made regarding the device of the aluminum material itself.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and is easy to cut by a laser beam.
An object of the present invention is to provide an aluminum or aluminum alloy material for laser cutting in which the amount of dross adhered to a cut surface cut by laser light is small.

[0010]

An aluminum or aluminum alloy material for laser cutting according to the present invention has a base made of aluminum or an aluminum alloy and a film formed on a surface of the base having a thickness of 2 to 150 μm. And an oxide film of

In this case, the base material is preferably an extruded shape for a welded structural material.

Further, the base material contains 0.5 to 5.5 Mg.
It is preferable that 0.01% to 0.6% by weight of Mn and Mn are contained.

[0013] Further, the base material is used for an application to be melt-welded after laser cutting.

In the present invention, the thickness of the oxide film formed on the surface of the base material made of aluminum or aluminum alloy is set to 2 to 150 μm, so that dross is generated on the cut surface even when cut by laser light. Can be reduced.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an aluminum or aluminum alloy material for laser cutting according to an embodiment of the present invention will be described in detail.

The inventors of the present application have conducted intensive studies on the cutting properties of aluminum or aluminum alloy materials by laser light. As a result, by controlling the thickness of the oxide film formed on the aluminum material surface to an appropriate thickness, the laser light Found that it is possible to reduce the amount of dross formed on the back side at the time of cutting, and to perform welding as it is without a step of removing dross, and to obtain sufficient welding strength. Was.

The reason for limiting the numerical value of the aluminum or aluminum alloy material for laser cutting according to the present invention will be described below.

Thickness of oxide film: 2 to 150 μm Since aluminum or aluminum alloy material easily reflects laser light, if the thickness of the oxide film is less than 2 μm, the reflection of laser light increases and cutting is difficult. Is not practical because it requires a very large output. On the other hand, if the thickness of the oxide film exceeds 150 μm, dross adheres to the back surface of the cut surface during cutting. This dross cannot be peeled off easily. For this reason, the cutting performance is inferior. Therefore, the thickness of the oxide film is set to 2 to 150 μm.

The method of adjusting the thickness of the oxide film is not particularly limited, such as a chemical method or a mechanical method. For example, an alkali cleaning such as sodium phosphate or an acid cleaning such as nitric acid is performed. Thus, the thickness of the oxide film can be adjusted. In the case of extruded profiles, the thickness of the oxide film can be adjusted by adjusting the cooling atmosphere in the extrusion step. The thickness of the oxide film was measured using ES
It is measured by CA (X-ray photoelectron spectroscopy analyzer).

Mg: 0.5 to 5.5% by weight Mg is an element necessary for maintaining the strength of the aluminum alloy material and also contributes to the absorption of laser light. Mg
Is less than 0.5% by weight, this effect cannot be obtained. Therefore, the lower limit of the Mg content is set to 0.5% by weight. On the other hand, if the content of Mg exceeds 5.5% by weight, the corrosion resistance deteriorates, so the upper limit of the content of Mg is 5.5.
% By weight. Therefore, the content of Mg is 0.5 to 5.
Preferably it is 5% by weight.

Mn: 0.01 to 0.6% by weight Mn is effective in improving stress corrosion cracking resistance. If the Mn content is less than 0.01% by weight, sufficient strength cannot be obtained. On the other hand, when the content of Mn exceeds 0.6% by weight, the effect is saturated. Therefore, the content of Mn is 0.01
The content is preferably set to about 0.6% by weight.

In order to improve the strength, Cu can be added up to 0.5% by weight.

The laser device used for cutting by laser light includes a carbon dioxide gas laser and a YAG laser, but is not particularly limited thereto, and other lasers can be used. Further, the laser output is preferably 1000 W or more. However, if the aluminum material can be rapidly heated by narrowing the laser beam by the optical system to increase the output density, it is possible to cut even if the laser output is lower than 1000 W. Further, a plurality of laser beams may be used, or a heat source other than the laser beam may be used in combination.

The cutting gas supplied together with the laser beam is preferably an inert gas containing nitrogen or argon as a main component.
In particular, the present invention is not limited to this, and any inert gas can be appropriately selected.

[0025]

EXAMPLES Hereinafter, examples of aluminum or aluminum alloy materials for laser cutting that fall within the scope of the present invention will be described.
The characteristics will be specifically described in comparison with a comparative example.

Example 1 As a substrate, an A5182-0 material specified in JIS H 4000 having a plate thickness of 2 mm was used, and as shown in Table 1, the thickness of the oxide film was adjusted. Cutting was performed by laser light under the cutting conditions shown in FIG. Then, the cut end faces are abutted to each other, and A53 specified in JIS Z 3232 is used.
Butt welding was performed by MIG welding using a 56WY wire. The welded base material was subjected to a joint tensile test, and the fracture position and the fracture strength were investigated. Note that the thickness of the oxide film was measured by an ESCA (X-ray photoelectron spectroscopy analyzer).

The dross adhesion state was measured by measuring the dross adhesion height at three points in the cutting direction of the cut surface by the laser beam, and the average value was defined as the dross adhesion amount. In the evaluation, those having a dross adhesion amount of 0.5 mm or less were accepted.

The evaluation of the breaking strength was the average value of the joint strengths of the three joint tensile tests. Table 1 shows the results.

[0029]

[Table 1]

[0030]

[Table 2]

As shown in Table 1 above, in Examples Nos. 1 to 8 which fall within the scope of the present invention, dross hardly occurs even when cut by laser light, and the cut surface after cutting by laser light remains as it is. In the case of butt welding, the fracture position was the base metal and good joint strength was obtained.

On the other hand, Comparative Example No.
In Nos. 26 and 28, good results could not be obtained in cutting by laser light. Further, when the cut surfaces were directly butt-welded, the fracture position was the weld metal portion, and good joint strength could not be obtained.

In Comparative Example No. 26, since the thickness of the oxide film was 1 μm, which was less than the range of the present invention, the amount of reflection of laser light on the surface of the aluminum alloy base material was increased, and sufficient output density was obtained. However, under the conditions of the present example, cutting could not be performed by laser light.

In Comparative Example No. 27, the thickness of the oxide film was 171 μm.
m, which exceeds the range of the present invention, the amount of dross adhered to the cut surface increases, and if the cut surface is welded as it is, the dross-adhered portion is insufficiently welded, and the joint strength is poor and compared with the example. And less than half.

In Comparative Example No. 28, the thickness of the oxide film was 202 μm.
m, which exceeds the range of the present invention, the amount of dross adhered to the cut surface increases, and if the cut surface is welded as it is, the dross-adhered portion is insufficiently welded, and the joint strength is poor and compared with the example. Was 1/3 or less.

Second Embodiment Next, a second embodiment will be described. A6063 specified in JIS H4100 with a plate thickness of 2 mm as a base material
After adjusting the thickness of the oxide film as shown in Table 3 using -T6 material, cutting by laser light was performed under cutting conditions shown in Table 4. After that, the cut end faces are butted together and JI
Butt welding was performed by MIG welding using A5356WY wire specified in SZ3232. The welded base material was subjected to a joint tensile test, and the fracture position and the fracture strength were investigated. The thickness of the oxide film was measured using ESCA (X
Line photoelectron spectroscopy).

The dross adhesion state was determined by measuring the dross adhesion height at three points in the cutting direction of the cut surface by the laser beam, and the average value was taken as the dross adhesion amount. In the evaluation, those having a dross adhesion amount of 0.5 mm or less were accepted.

The evaluation of the breaking strength was the average value of the joint strengths in the three joint tensile tests. Table 3 shows the results.

[0039]

[Table 3]

[0040]

[Table 4]

As shown in Table 3 above, in Examples Nos. 9 to 16 which fall within the scope of the present invention, almost no dross is generated even when cut by laser light.
When the cut surfaces were directly butt-welded, the fracture position was the base metal and good joint strength was obtained. In addition. In this embodiment, the absolute value of the joint strength is lower than that in the first embodiment, which is considered to be because the vicinity of the welded portion of the base metal was softened by welding heat.

On the other hand, Comparative Example No.
Nos. 29 to 31 could not obtain good results in cutting by laser light. Further, when the cut surfaces were directly butt-welded, the fracture position was the weld metal portion, and good joint strength could not be obtained.

In Comparative Example No. 29, since the thickness of the oxide film was 1 μm, which was less than the range of the present invention, the amount of laser light reflected on the surface of the aluminum alloy base material was increased, and sufficient output density was obtained. However, under the conditions of the present example, cutting could not be performed by laser light.

In Comparative Example No. 30, the thickness of the oxide film was 165 μm.
m, which exceeds the range of the present invention, the dross adhesion amount on the cut surface increases, and if the cut surface is welded as it is, the dross-adhered portion is insufficiently welded, the joint strength deteriorates, and Compared to less than half.

In Comparative Example No. 31, the thickness of the oxide film was 210 μm.
m, which exceeds the range of the present invention, so that the amount of dross adhered to the cut surface is large. Was 1/3 or less.

Third Embodiment The base material had the composition shown in Table 5 below and had a thickness of 2 mm.
After adjusting the film thickness of the oxide film using the aluminum alloy material of No. 1, the laser light was cut under cutting conditions shown in Table 6. After that, the cut end faces are abutted against each other and JIS Z
Butt welding was performed by MIG welding using A5356 WY wire specified in 3232. Note that the thickness of the oxide film was measured by an ESCA (X-ray photoelectron spectroscopy analyzer).

The dross attachment state was determined by measuring the dross attachment height at three points in the cutting direction of the cut surface by the laser beam, and the average value was used as the dross attachment amount. Evaluation of the cut portion was performed in the same manner as in the first example, and those having a dross adhesion amount of 0.5 mm or less were evaluated as acceptable.

The welded base material was subjected to a joint tensile test, and the ratio between the strength of the joint and the strength of the base material before welding was measured. When the ratio (joint efficiency) between the joint strength and the substrate strength (joint efficiency) was 90% or more, the evaluation was 、, and when the ratio was 80 to less than 90%, the evaluation was ○. Table 5 shows the results.

[0049]

[Table 5]

[0050]

[Table 6]

As shown in Table 5, in Examples Nos. 17 to 25, dross hardly occurs even when cut by laser light by specifying the contents of Mn and Mg in aluminum or an aluminum alloy material. In the case where the cut surfaces cut by the laser beam were butt-welded as they were, a high joint efficiency could be obtained, and an excellent overall evaluation could be obtained. In particular, in Examples Nos. 17 to 21 satisfying claim 3 of the present invention, the quality of the cut portion and the joint efficiency were excellent, and a more excellent overall evaluation could be obtained.

[0052]

As described in detail above, in the present invention,
By adjusting the thickness of the oxide film formed on the surface of the base material made of aluminum or aluminum alloy, it is easy to cut with laser light, and the amount of dross adhered to the cut surface after cutting with laser light is small. Alternatively, an aluminum alloy material can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a cutting method using a laser beam.

[Explanation of symbols]

 100; member 101; cut surface 102; dross 103; laser beam 104; cutting gas

Claims (4)

[Claims] An aluminum or aluminum for laser cutting, comprising: a substrate made of aluminum or an aluminum alloy; and an oxide film having a thickness of 2 to 150 μm formed on the surface of the substrate. Alloy material. 2. The aluminum or aluminum alloy material for laser cutting according to claim 1, wherein the base material is an extruded shape for a welded structural material. 3. The laser according to claim 1, wherein the base material contains 0.5 to 5.5% by weight of Mg and 0.01 to 0.6% by weight of Mn. Aluminum or aluminum alloy material for cutting. 4. The aluminum or aluminum alloy material for laser cutting according to claim 1, wherein the base material is used for a purpose of fusion welding after laser cutting.