JPS6252675B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a technology for crushing and reducing the thickness of an overlap weld when joining thin steel strips together.

After cold rolling, a thin steel strip such as a tin plate that has been annealed is subjected to temper rolling and a refining line as shown in FIG. 1 to become a final product. In this continuous line, the thin steel strip 2 unwound from the bay-off reel 1 is first passed through a welding machine 3, in which the trailing end of the leading coil and the tip of the trailing coil are overlapped with each other. In this state, they are usually joined by electric resistance welding, and then temper rolling and finishing work is performed.

In this invention, when the overlapping portions of the leading and trailing coil ends are crushed and reduced in thickness using a roller pair while the overlapping portions are still hot, This paper attempts to propose a method of crush thickness reduction that can be carried out completely and efficiently across the board.

Prior art and its problems Conventionally, crushing and thinning of overlap welded parts of thin steel strips using a crushing and thinning roller has been carried out in the following manner.

In other words, in the conventional method, until the crushing thickness reduction roller reaches the overlapping part, back pressure is applied to the rolling down cylinder that applies a load to the roller to reduce the rolling force, and the rolling force is reduced. Only after the end is detected, the back pressure of the cylinder is released and the rolling force is increased while moving the steel strip in the width direction to reduce the thickness of the welded portion by crushing. However, in this conventional method, it took time after the end of the lap weld was detected until the back pressure in the cylinder was released and the rolling force by the rollers was actually applied to the weld, resulting in the collapse of the steel strip. There was a problem in that a portion that did not undergo the crushing thickness reduction remained at the end where the thickness reduction started.

In this regard, in order to eliminate the unprocessed area of the crushing thickness reduction, a welding part edge (width edge) detector is placed in advance to detect the welding part edge, and the leading distance of the detector and the moving speed of the crushing thickness reduction roller are A method was proposed to calculate the rolling start time from
It is inevitable that some degree of error will occur, and therefore the rolling force may be applied before the roller reaches the edge of the weld; in such cases, the steel strip may be torn by the roller. This caused a new problem: storage.

Purpose of the Invention This invention was developed in view of the above-mentioned current situation, and is a device that moves a crushing and thickness-reducing roller back and forth in the width direction of the steel strip when crushing and reducing the thickness of the overlapping welded portion of thin steel strips. By adding some ideas to the way it moves, it is possible to uniformly crush and reduce the thickness of the welded part across the width of the steel strip without causing defects such as tearing of the steel strip during thinning. The purpose of this paper is to propose a method of crushing and reducing the thickness of a lap welded joint of thin steel strips.

Structure of the Invention The above object is advantageously achieved by the following structure.

That is, when the overlapping welded part of a thin steel strip is sandwiched between rollers from above and below, and the roller pair is moved in the width direction of the steel strip while applying a rolling force, the overlapping welded part is crushed and reduced in thickness. The pair of rollers is moved back and forth in the width direction of the strip, and when moving back and forth, the edge of the width of the steel strip is detected, a rolling force is applied to the pair of rollers, the roller pair is moved until it passes the other end, and then it is rolled down. The force is released, and during the subsequent go-around, after detecting the opposite strip width edge, a rolling force is applied to the roller pair to move it to at least the other edge, so that the overlap weld is spread over the entire strip width of the thin steel strip. This is a method of crushing and reducing the thickness of a thin steel strip overlap weld, which involves crushing and reducing the thickness over a period of time.

Hereinafter, the method of crushing and reducing the thickness of the overlap weld according to the present invention will be explained in detail with reference to FIG. 2.

In the place shown in Fig. 2, 4 and 5 are a pair of upper and lower crushing and thickness-reducing rollers, 6 and 7 are crushing cylinders that apply loads to them, and the crushing and thickness-reducing rollers 4 and 5 are made of thin steel. In this example, it waits on the left side with respect to the overlapping welding portion of the bands 2a and 2b, and starts moving toward the right side some time after the start of welding. At this time, the crushing and thickness reducing rollers 4 and 5 are still under load, and the rolling cylinders 6 and 7 are driven only when the weld end is detected as they move to the right. Pairs 4 and 5 start collapsing and reducing the thickness of the welded part, and move it as it is to the stop position A beyond the right end. Next, at stop position A, the load on cylinders 6 and 7 is released, the gap between rollers 4 and 5 is expanded to a thickness greater than the thickness of the welded part, and then the return movement to the left is started. be. In this case, as in the case of forward movement, the end of the weld is detected and a rolling force is applied to start crushing and thinning, and the crushing and thinning operation continues until the left stop position B, and then the load is applied. , and waits in preparation for the next operation.

By crushing and reducing the thickness of the overlapping welded part of the thin steel strip by the reciprocating operation of the roller pair as described above, it is possible to crush and reduce the thickness of the welded part of the thin steel strip evenly over the entire plate width area, and moreover, the roller pair is welded. Since the roll cast will not become narrower than the plate thickness due to the load being applied before reaching the end of the steel plate, it is possible to completely eliminate tearing of the thin steel plate by the crushing and thickness reduction rollers.

By the way, if the thickness of the overlapping part is twice the specified thickness, with the conventional crushing method, both ends of the steel strip will still be about 20 to 30 mm thick, and the center will be about 1.6 times thicker. On the other hand, the crushing thickness reduction method according to the present invention results in a weld that is about 1.6 times thicker at both ends and about 1.5 times thicker at the center, which is much more uniform and good than the conventional method. Collapse thickness reduction was achieved.

Effects of the Invention According to the present invention, in crushing and reducing the thickness of an overlapping welded portion of a thin steel strip, the welded portion can be spread over the entire width of the steel strip without causing any adverse effects such as tearing of the thin steel strip. It is possible to crush and reduce the thickness evenly.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a steel strip skin pass rolling and refining line, and FIG. 2 is a diagram showing a method for crushing and reducing the thickness of a lap welded portion of thin steel strips according to the present invention.

Claims (1)

[Claims] 1 The overlapping welded portion of the thin steel strip is held between the upper and lower sides by rollers, and when the roller pair is moved in the width direction of the steel strip while applying a rolling force, the overlapping welded portion is crushed and thinned. A pair of rollers is moved back and forth in the strip width direction, and when moving back and forth, first, after detecting the strip width end of the steel strip, a rolling force is applied to the roller and the roller is moved until it passes the other end, and then it is rolled down. By releasing the force and applying a rolling force to the roller pair after detecting the opposite side plate width edge during the subsequent go-around to move it at least to the other end,
1. A method for crushing and reducing the thickness of a lap welded part of a thin steel strip, the method comprising crushing and reducing the thickness of the lap welded part over the entire width of the thin steel strip.