JPH028831B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves reducing the thickness of a continuous lap welded joint by rolling, thereby reducing the plate thickness of the welded joint (preferably, the plate thickness is approximately equal to that of the base material other than the welded part). (reduced to the same level).

When the ends of two metal strips are overlapped and the overlap is continuously welded by stitch welding or seam welding, the thickness of the welded joint is:
It becomes thicker than the base metal plate thickness other than the welded part.

Therefore, after welding, the welded joint is generally rolled to crush it to a certain thickness, but in reality, the welded joint is flat and has the same thickness as the original plate. It was difficult to obtain.

That is, conventionally, the joint portion cannot be crushed to a sufficient degree by mere rolling force. Therefore, if a considerable force is used to crush the welded joint, excessive pressure is required on the reduction roll, causing defects such as the welded joint being distorted in a wavy manner and, in some cases, causing breakage.

The present invention is intended to solve the above-mentioned drawbacks, and its gist is to form a welded joint in which welding nuggets are continuously stacked and welded, and the first stage has an arcuate outer pressure surface. A pair of upper and lower reduction rolls are used to crush the metal protrusions, and then in the second stage, the metal protrusions pushed out on both sides of the welded joint are crushed by a pair of upper and lower reduction rolls that have a flat outer peripheral pressure surface. The purpose is to reduce the plate thickness to a certain level.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a schematic diagram of a seam welding machine for carrying out the method of the invention. FIGS. 2 and 3 show cross-sections of overlapped metal strips before welding.

FIG. 4 shows a cross section of the welded joint.

FIGS. 5 and 6 are enlarged views of essential parts of a reduction roll device for carrying out the method of the present invention.

In the figure, reference numerals 1 and 2 indicate metal strips, which in FIG. 1 are conveyed in a direction perpendicular to the plane of the paper in a front/back relationship. 3,4
is a clamping device that aligns and fixes two metal plates with a predetermined protrusion margin to accurately form an overlapping margin W between the two plates. Reference numeral 5 denotes a pine seam welding machine, in which a main body frame 6 is used as a truck, and is configured to move along a reciprocating path 7 that traverses the line direction of the metal strip. 8 is a seam electrode device, in which at least one seam electrode ring can move up and down to apply pressure;
As shown in FIG. 4, the stacked plates are sandwiched between the seam electrode wheels 8a and 8b from above and below, and pressurized and energized to form weld nuggets 9 continuously along the stacking margin W by moving the main body frame 6. Welding progresses while reducing the thickness of the weld joint to a certain extent by the pressure of the seam electrode wheel.

10 and 11 are rolling devices each having a pair of rolling rolls 10a, 10b, 11a, and 11b;
It is arranged at the rear of the seam electrode device 8.

As shown in FIG. 5, the rolling down device 10 has rolling down rolls 10a and 10b whose outer circumferential pressing surfaces are arcuate, and crush the approximately central area of the welded joint into an R shape by rolling after welding. In this case, a small amount of metal is extruded from both sides of the arcuate roll pressure surface, resulting in the formation of a small metal ridge S along both sides of the weld joint.

The next rolling down device 11 is for rolling down and completely flattening the metal protrusions S left on both sides of the joint, and as shown in FIG. It has a flat shape with a sufficient area in the width direction.

Immediately after welding, the reduction devices 10 and 11 described above advance between the clamp devices 3 and 4 to reduce the welded joint.

As explained above, the present invention crushes a welded joint in which welded nuggets are continuously stacked and welded using a pair of upper and lower reduction rolls having an arcuate outer peripheral pressure surface, and then The metal ridges left behind on the top and bottom 1 with a flat outer pressure surface.
Since the joint is continuously crushed by the pair of reduction rolls, even joints that could not be crushed sufficiently in the past can be easily crushed to the same thickness as the base material other than the welded part without causing deformation or breakage. Furthermore, with the method of the present invention, no excessive pressure is required at all, and the life of not only the lowering device but also the electrode device can be greatly extended, and the pressurizing device can be downsized.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a seam welding machine for carrying out the method of the invention. 2 to 4 are cross-sectional views showing a series of seam welded joints. FIGS. 5 and 6 are enlarged sectional views of main parts showing the shape of the reduction roll. [Explanation of symbols], 1, 2...Metal band plate, 3, 4...
Clamping device, 5... Seam welding machine, 6... Main body frame, 8... Electrode device, 10, 11... Lowering device, 1
0a, 10b, 11a, 11b...reduction roll, S
...metal ridges.

Claims (1)

[Claims] 1. When welding a welded joint in which welded nuggets are continuously stacked and welded, we roll a welded joint after welding to reduce the thickness. After rolling down the central area of the welded joint, the metal protrusions left on both sides of the joint are further rolled and pressed using a pair of upper and lower rolling rolls with flat outer pressure surfaces. A method for reducing the plate thickness of a lap welded joint, characterized by crushing it.