JPS6054285A - Method for reducing plate thickness at lap weld joints - Google Patents

Abstract

PURPOSE:To decrease the thickness of a welded joint part to about the same thickness as the thickness of base metal by crushing the welded joint part in two stages by using a roll pair each having an arc-shaped pressing surface of outside circumference and a roll pair each having a flat pressing surface of outside circumference. CONSTITUTION:The lap welded joint part of metallic hoops 1, 2 formed continuously with a weld nugget is rolled by upper and lower rolling-down rolls 10a, 10b of which the pressing surface of outside circumference is formed into an arc shape to crush the roughly central area of the joint part to an R shape. The metallic build-up parts S slightly forced out both sides of the pressing surface are rolled down by upper and lower roll-down rolls 11a, 11b of which the pressing surface of outside circumference has a flat shape. Said parts are thus thoroughly flattened. The thickness of the welded joint part is thus decreased without requiring excessively large pressing force by the above-mentioned method.

Description

Detailed Description of the Invention The present invention reduces the thickness of a continuous lap-welded joint by rolling, and reduces the plate thickness of the welded joint (preferably to the same level as that of the base material other than the welded part). (reduction) method.

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 equal to the thickness of the base material other than the welded part. It becomes thicker.

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

That is, in the past, the joint part could not be pushed out to a sufficient degree with a mere rolling reduction blade. Therefore, if a considerable force is used to push out the weld, excessive pressure is required on the reduction roll, causing defects such as the welded joint being distorted in a wave-like manner and, in some cases, causing breakage.

The present invention is intended to solve the above-mentioned drawbacks, and the gist thereof is to weld a welded joint in which welding nuggets are continuously overlapped and welded in the first stage [1 is a welded joint in which the outer circumferential pressure surface is arc-shaped]. Then, in the second stage, the metal protrusions pushed out on both sides of the welded joint are crushed with a pair of upper and lower reduction rolls, and then, in the second stage, the raised parts of the metal extruded on both sides of the welded joint part are crushed with a pair of upper and lower rolling rolls having a flat outer circumferential pressure surface.
The objective is to reduce the plate thickness to a certain level by using a pair of downstream holes.

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, fil (2) is a metal band plate, and in FIG. 1, it is transported in a direction perpendicular to the plane of the paper in front/back relation. (31 (4) is a clamping device that aligns and fixes two metal plates with a predetermined extension margin, and accurately forms the overlapping margin (W) of both plates. (5) is a matsushi seam welding machine, Main body frame (6
) is used as a trolley, and is configured to move along a reciprocating path ( ) that crosses the line direction of the metal strip. (8) is a seam electrode device in which at least one seam electrode ring moves up and down to apply pressure, and as shown in Figures 2 to 4, the stacked drawing boards are moved from above and below. The seam electrode rings (8a) (8b) are used to press and apply electricity, and the overlapping margin (W) is removed by moving the main body frame (6).
) Welding progresses while continuously forming welding nuggets (9) along the welding joint while reducing the thickness of the welded joint to a certain extent by the pressing force of the seam electrode ring.

(10) (11) is the rJZ lower device, each of which has a pair of pressureless lower rolls αOa)αQ'tt), (11,a)(
llb) and is arranged at the rear of the seam electrode device (8).

As shown in No. 51, the downstream equipment (in) has a reduction roll (
The outer pressure surface of the 108x10b) is lined, and the center area of the welded joint is rounded by rolling after welding.
crush into shape. In this case, a small amount of metal is extruded from both sides of the circular 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 used to roll down the metal protrusions (S) left on both sides of the joint to make them completely flat, and as shown in Figure 6, the outer pressure surface has a flat shape with a sufficient area in the width direction of the welded joint.

Immediately after welding, the above-mentioned rolling down device (11) advances between the clamping devices (3×4) and rolls down the welded joint.

As explained above, the present invention involves crushing the mass of welded welded nuggets by continuously stacking them with a pair of upper and lower reduction rolls each having a pressure surface on the outer periphery of the lining, and then Since the metal protrusions left on both sides of the joint are continuously pressed down by a pair of upper and lower rolling rolls with flat outer pressure surfaces, even joints that could not be crushed sufficiently in the past can be deformed or broken. Easily align with the parent phase other than the welded part without
It can be crushed to a plate thickness of . In addition, with the method of the present invention, excessive pressure is not required, and the life of not only the reduction device but also the electrode device can be greatly extended, and the pressure device can be downsized.

[Brief explanation of the drawing]

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] (IX2)...Metal band TV (3X4)...Clamp device (5)...Seam welding machine (6)...Body frame (8)...Electrode device (IIIXII) ...
Lowering device Qoa)Qob), Qta)(txb),
,, Reduction roll (S)...Metal raised part

Claims (1)

[Claims] Welded joints made by continuously overlapping weld nuggets are
When reducing the thickness by rolling after welding, run a pair of upper and lower reduction rolls with circular arc-shaped outer pressure surfaces along the welded joint, and after rolling down the central area of the welded joint by rolling, The plate thickness of the lap welded joint is characterized in that the metal protrusions left on both sides of the joint are rolled and crushed by a pair of upper and lower reduction rolls having a flat outer peripheral pressure surface. Decrease method.