JPS58167076A - One-side welding method by stepped backing strip - Google Patents

Abstract

PURPOSE:To prevent welding defect and the dislocation between base materials in the stage of one-side welding using a backing strip, by forming a stepped part on the contact surface of the backing strip so as to provide a clearance between the low surface part and the surface of the base material on the stepped part side and performing pointing welding. CONSTITUTION:The contact surface side of a backing strip 30 is constituted of a thick-walled part 31 and a thin-walled part 32, and the section of the strip 30 is made into roughly an L shape. A difference (d) in level between the surface of the part 31 and the surface of the part 32 is determined by taking the distance at which the strip 30 is moved by pointing welding into consideration. The surface of the part 31 of the strip 30 is brought into contact with the rear of a base material 1; in this case, an angle part 33 is placed in the position deviated from the bottom end of the material 1. If a clearance (d) is beforehand provided between the surface of the part 32 and the bottom surface of a base material 2, the movement of the strip 30 by the shrinkage stress of a weld zone 4 on solidification of said zone and consequent upward movement of the rear of the material 2 are prevented by the clearance (d).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a single-sided welding method using a stepped backing metal.

Figure 1 is a sectional view showing an example of a backing metal welding method. In the normal backing metal welding method, a backing metal 3
Both welding points (1) in 4.5 are welded from the back side. Unless the backing metal can be placed on the back side of the base metal and welded, as shown in Figure 2, the backing metal 3 must be welded from the front side of the base metal l. It was constant.

However, with this welding method, there is no room for the gas at the corner of the contact area between the base metal 1 and the backing metal 3 to escape, so the area surrounded by the base metal 1, the welded part 4, and the backing metal 3 is Blowhole 5
It has the disadvantage of causing welding defects such as.

Another problem is that when backing metal welding is performed using the method shown in Figure 2, the backing metal 3 is exposed to stress as it solidifies or cools, as shown in Figure 3. There was a drawback in that it moved (rotated) and pushed up the back surface of the base material 2 with its tip, causing a misalignment such as a step difference Δt between the two base materials 1.2.

The purpose of the present invention is to overcome the drawbacks of the conventional single-sided welding method, to prevent welding defects such as blowholes from occurring in the welded part, and to prevent welding defects such as blowholes from occurring in the welded part, and also to prevent the welding from occurring between the base metals by attaching the tip (2) of the backing metal. An object of the present invention is to provide an improved single-sided welding method that does not cause misalignment.

In order to achieve this purpose, the present invention provides a step on the contact surface of the backing metal, and when the backing metal is attached later, a gap is provided between the part and the base material, and this backing metal is attached first. This is characterized in that the position of the base material to be retrofitted is not moved during welding.

More specifically, a step is provided in the backing metal to form an L-shaped cross section, and the short side of the stepped backing metal is applied parallel to one of the base metals to be welded. This method is characterized by welding to fix the gold and then welding one side of the base metal together.

The present invention will be described in detail below based on the drawings.

FIG. 4 shows an embodiment of the present invention, in which the contact surface side of the backing metal 30 is configured with a thick part 31 and a thin part 32. When manufacturing this backing metal 30, it is preferable (3) to cut one surface of a flat plate to form a stepped portion. When the step portion is formed by cutting a flat plate in this manner, the cross section of the backing metal 30 becomes VL-shaped.

The difference d between the surface of the thick part 3I and the surface of the N part 32 becomes a step, and this step d is formed by pre-welding to the backing metal 30.
This is determined by taking into consideration the distance over which the rotation (movement) is performed.

The surface of the thick portion 31 of the backing metal 30 prepared as described above is brought into contact with the back surface of the base material 1, but in this case, the corner portion 33 is placed at a position away from the lower end of the base material 1.

Selecting the position of the backing money 30 as described above is the fourth step.
As shown in the figure, when the welded part 4 is formed, a gap 35 is formed between it and the corner part 33, and even if gas or air generated during welding is accommodated in this gap 35, it will not affect the welded part 5. This is to avoid giving.

Further, as shown in FIG. 4, it is necessary to provide a gap d between the surface of the thin portion 320 and the lower surface of the base material 2. By providing the gap d in this way (4), when the welded part 4 solidifies, the backing metal 30 moves as shown by the arrow in FIG. 5 due to the shrinkage stress. Since this is provided, it is possible to prevent the upper surface of the thin portion 32 from pushing up the back surface of the base material 2.

As explained above, the present invention forms a stepped part on the contact surface of the backing metal, the protruding part of this stepped part is used as the front attachment part, the lower surface part and the rear attachment part, and the protruding part is used as the front attachment part. Pre-welding is performed with the corner portion and the end of the base material being shifted, and a gap being provided between the portion having the low surface and the surface of the base material on the side of the rear attachment portion. It is something to do.

By carrying out single-sided welding using a backing metal as described above, it is possible to eliminate the conventional problems such as the occurrence of blowholes in the welded portion and misalignment of base materials.

Therefore, according to the present invention, welding defects do not occur in the welded portion, and it is possible to prevent misalignment of base materials.

(5)

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of single-sided welding using a conventional backing metal, and Figure 2 is FI! J and FIG. 3 are explanatory diagrams of a conventional single-sided welding method in which welding is performed from the front side. FIG. 4 and FIG. 5 are explanatory diagrams of a single-sided welding method using a backing metal according to the present invention. 12...Base metal, 3...Backing metal, 4...Welded part, 5...Blowhole, 30...Backing metal, 31...Thick wall part, 32...Thin wall part, 3
3...Corner, 35...Gap. Agent Patent Attorney Makoto Ogawa − Patent Attorney Kensho Noguchi Patent Attorney Kazuhiko Saishita (6) Procedural Amendment (Director of the Patent Office 1982) Patent Application No. 49440 2, Title of invention: Single-sided welding method using stepped backing metal 3, Person making amendments/Relationship with 11 cases Patent applicant 4, Agent fl/Place: 105 Nishi, Minato-ku, Tokyo Shinbashi 3'l'L
Ja number 3 Pelican Building 367-

Claims (1)

[Claims] A backing metal is placed on the back side of the base metal. In this method of welding by fixing the position of the welding point on the base metal, a step is provided on the contact surface of the backing metal so that the protruding side of the backing metal is Welding to one base metal, a gap is formed between the surface on the side where the step is provided and a base metal other than the base metal, and the backing metal moves as the welding progresses. 1. A single-sided welding method using a stepped backing metal, characterized in that the back surface of another base material is supported at the end of the stepped portion when the step is performed.