JPH04274888A - Jointing method of sheet - Google Patents

Abstract

PURPOSE:To obtain a good joint part without separating beams in electron beam welding of metallic sheets having high surface tension. CONSTITUTION:The butt parts of the sheets 1, 2 consisting of an Ni-Ti alloy or Ni-Cr-Fe alloy are worked to a shape to allow butting at 30 to 45 deg. angle theta(the upper limit is 60 deg. in the case of an Ni-Cr-Ti alloy) and thereafter, these parts are subjected to electron beam welding at the time of subjecting the above-mentioned sheets to the electron beam welding(EBW). The butt parts are preferably partially fixed by resistance welding prior to the electron beam welding. This method is suitable for production of cylindrical pipes and the production of a composite material formed by laminating another metal into the cylindrical pipe is possible.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a method of welding thin plates.
More specifically, the present invention relates to a method of electron beam welding a thin plate made of a metal with high surface tension.

0002

[Prior Art] Conventionally, arc welding, TIG welding, plasma welding, laser welding, and electron beam welding have been used for butt welding of thin plates, but the basic idea is I type (Shear cutting, etc.). At this time, it is important to keep the plates as close as possible to each other, so the I-shaped surfaces are machined with a laser, etc. to make the butt surfaces as close as possible. Efforts have been made to bring it closer.

[0003] Furthermore, in order to make the butt portion as close as possible to a flat plate situation, the present inventors have taken measures such as making the cross-sectional shape viewed from the axial direction elliptical when welding cylindrical pipes. Despite such treatment, there have been cases where the bead of the welded portion separates due to surface tension during welding, making it impossible to form the bead or causing the bead surface to become depressed.

0004

[Problems to be Solved by the Invention] Particularly, as metals with high surface tension such as Nitinol and Inconel (trade name) are made thinner, if the butt condition of the I-shaped surfaces shown in Fig. 1 is poor, molten pools may occur. is pulled by both base materials due to surface tension and separates, resulting in a situation where bonding is impossible. for example,
When manufacturing a cylindrical pipe from a thin plate by electron beam welding, it is important to make the jig that presses the groove surface closer as shown in Figure 1, or to make the welding surface as flat as possible (as shown in Figure 2). The cross-sectional shape viewed from the axial direction is elliptical). However, even with such careful attention, the molten pool sometimes separates during electron beam welding, making it impossible to join.

[0005] Therefore, the groove surface was improved to an I-shape instead of a V-shape as shown in Fig. 3, but even in such a case, the molten metal could not be easily absorbed, probably due to microscopic gaps in the plate. Due to the strong surface tension, a situation occurred where the beads separated and could not be bonded.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method that eliminates the above-mentioned drawbacks of the prior art regarding electron beam welding of thin plates made of metals with high surface tension, and that allows a good joint to be obtained without bead separation. That is.

[0007]

[Means for Solving the Problems] As mentioned above, it has been found that during electron beam welding, the separation of beads due to surface tension may not be solved by the above-mentioned method. Although it can be set with zero gap, there is a gap between the plates as the welding progresses due to thermal deformation during welding, probably because there is no gap in reality, or because the surface tension of the molten metal is strong. Although it is unclear which of the factors is the cause of the bead separation, it is thought that the phenomenon of bead separation occurred as a result.

[0008] That is, it has been found that as the welding progresses due to thermal deformation during welding, gaps may be formed between the plates, and this can be partially resolved by strengthening the restraining force that holds the plates. However, even after eliminating the gap as much as possible and strengthening the restraining force that holds the plate in place, the phenomenon of bead separation could not be resolved, perhaps due to the strong surface tension of the molten metal.

[0009] Therefore, the inventors of the present invention determined the butt shape as shown in FIG.
As shown in Figure 5, the edge of the thin plate is shaped to have an angle θ, and then the abutting part is partially joined with a resistance spot to fix the abutting part, and then fixed with a jig as shown in Figure 5. When electron beam welding was performed, good results were obtained, and the present invention was made here.

That is, in the present invention, when electron beam welding a thin plate made of a Ni-Ti alloy, the butt portion is
It is characterized in that after processing into a shape that allows abutting at an angle of 0° to 45°, the abutting portion is welded with an electron beam.

[0011] Another aspect of the present invention is that when electron beam welding a thin plate made of a Ni-Cr-Fe alloy, after processing the abutting portion into a shape that allows the butt to be abutted at an angle of 30° to 60°, It is characterized by electron beam welding of the butt portions.

The present invention will be explained in more detail below.

[0013] In short, the present invention provides a Ni-Ti alloy,
When electron beam welding thin plates made of metals with high surface tension during welding, such as Ni-Cr-Fe alloys, the shape of the butt part is made with an appropriate angle depending on the material. The butt portions are welded using an electron beam.

[0014] As the Ni-Ti alloy, Ni: 48~
Ti: 48-52% as a main component, and Nitinol (trade name) is a typical composition. In addition, as a Ni-Cr-Fe alloy,
Ni: 72.0% or more, Cr: 14-17%, Fe: 6
It is an alloy containing ~10% as a main component, and Inconel (trade name) is a typical composition. Of course,
Elements other than the main components may include Fe, Cu, Nb, Al, etc. in the case of Ni-Ti alloys, and C, Mn, Si, Ti, Al, etc. in the case of Ni-Cr-Fe alloys. .

[0015] The thin plate referred to in the present invention usually has a thickness of 1.
The diameter is 0 mm or less.

The abutting portion is processed by laser processing or the like into a shape having an angle θ as shown in FIG. Ni-Ti
In the case of alloys, if the end angle θ exceeds 45°, the welding result will be poor, so it is necessary to keep it at 45° or less. Also, Ni
In the case of -Cr-Fe alloys, if the end angle θ exceeds 60°, the welding result will be poor, so it is necessary to keep it below 60°. However, in the case of any alloy system, it is difficult to process to a small angle such as 15°, so the lower limit is 3.
Set it to 0°.

The reason why a good joint can be obtained by forming the abutting part at a predetermined angle depending on the material is not necessarily clear, but it is thought to be due to the following reason. In other words, the molten metal at the joint is pulled between the base metal on the right side and the base metal on the left side, but at this time, it is presumed that by setting an angle to the butt part, it becomes easier for the molten metal to integrate. . In other words, since the abutment part has an angular shape, the metals of the right and left plates, which are melted at the same time as they are pulled against the base metal, fit together more easily than if there were no angles, so it is thought that it is easier to integrate them. .

Prior to electron beam welding, it is preferable to join and fix the abutted portions at a plurality of locations by resistance spot welding. This is because, as mentioned above, the right and left plates are fixed by resistance spot welding, and the molten metal is already blended at the same time as it melts during welding.
It is believed that even better welding results can be obtained.

Note that the conditions for electron beam welding are not particularly limited. Although it is particularly suitable for welding cylindrical pipes, it goes without saying that joints of other shapes, such as welding flat plates together, are also possible.

Next, examples of the present invention will be shown.

[0021]

[Example 1] Width 20m with 0.3mm and 0.5mm thickness
Using a thin plate made of Nitinol (a shape memory alloy of nickel and titanium, trade name),

[Table 1] As shown in Table 1, the end angle θ (Fig. 4) of the plate is changed from 90° to 15°.
Processing is performed within the range of °, and about this butt part

Cylindrical pipes were manufactured by electron beam welding under the welding conditions shown in Table 2. Note that the abutting portions were fixed in advance using a jig having the shape shown in FIGS. 5 and 6, and a plurality of locations in the board width direction were fixed by resistance spot welding (see FIG. 4). This jig consists of an upper part and a lower part to sandwich the pipe-shaped test material, and the upper part has an opening large enough to allow resistance spot welding and electron beam welding. A backing was also used.

As a result, as shown in Table 1, the end angle θ
Good welding results were obtained when the angle was 45° or less.

[0023]

[Example 2] Width 600 with thickness of 0.5mm and 1.0mm
The procedure was the same as in Example 1 except that Inconel 600 (trade name) of mm was used (however, the welding conditions were

[Table 4] Electron beam welding was performed under the following conditions. the result,

As shown in Table 3, good welding results were obtained when the end angle θ was 60° or less.

[0024]

[Effects of the Invention] As detailed above, according to the present invention,
Since the abutting portion is angled, thin metal plates with strong surface tension can be joined, which is highly effective. In particular, since it is possible to weld cylindrical pipes, the cost is much lower than manufacturing by boring from bar stock. Suitable for manufacturing composite materials where other metals are layered inside a cylindrical pipe.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating the shape and welding procedure of a conventional butt part, and (b) shows a case where a jig 3 is brought closer than in (a).

FIG. 2 is a diagram illustrating a case where a cylindrical pipe is manufactured by welding according to a conventional method, and the cross-sectional shape is made elliptical, and the welded part is made into a state similar to a flat plate.

FIG. 3 is a cross-sectional view showing the shape of a conventional abutment part, (a)
is for V type, and (b) is for I type.

FIG. 4 is a perspective view illustrating a cross section, EBW, and resistance spot welding procedure of a butt portion having an angle θ in the present invention.

FIG. 5 is a sectional view showing a jig for fixing the abutting portion used in the example.

FIG. 6 is a plan view showing a jig for fixing the abutting portion used in the example.

FIG. 7 is a plan view of the backing used in the example.

FIG. 8 is a cross-sectional view of the backing used in the example.

[Explanation of symbols]

1 Base material (thin plate) 2 Base material (thin plate) 3 Jig 4 Jig for cylindrical pipe welding 5 Backing EBW　Electron beam welding t Plate thickness

Claims (3)

[Claims] [Claim 1] When electron beam welding a thin plate made of a Ni-Ti alloy, the abutting portions are processed into a shape that can be butted at an angle of 30° to 45°, and then the abutting portions are electron beam welded. A method for joining thin plates characterized by: [Claim 2] When electron beam welding a thin plate made of a Ni-Cr-Fe alloy, the butt portion is set at an angle of 30° to 60°.
1. A method for joining thin plates, the method comprising processing thin plates into shapes that can be butted together at an angle of .degree., and then electron beam welding the abutted portions. 3. The method according to claim 1, wherein the abutting portion is partially fixed by resistance welding prior to electron beam welding.