JPS59179277A - Welding method of end part of hot dip galvanized steel strip - Google Patents

Abstract

PURPOSE:To decrease the defect in the weld zone in end part welding by welding intermittently the part where the tail end and beginning end of hot dip galvanized steel strip are overlapped in the transverse direction of the strip. CONSTITUTION:Steel strip are let off alternately from two pieces of parallel galvanized steel sheet coils. The beginning end of the other steel strip is superposed on the tail end of the one coil and both ends are welded by disc-shaped electrodes 3, 3. The strip are intermittently welded in the transverse direction thereof by the repetition of the length H of the weld zone and the length C of the non-weld zone by conducting periodically electricity to the electrodes 3, 3 or other means. The welding current is concentrated effectively in the weld zone by such intermittent welding and the good result of welding is obtd.

Description

[Detailed description of the invention] The present invention relates to a method for welding the ends of hot-dip plated steel strips.

In conventional continuous coating equipment for galvanized steel sheets, for example, two steel sheet coils are arranged in parallel, and when one coil finishes unwinding the steel sheet, the other coil starts unwinding.
Painting continued without stopping the equipment even after one coil of steel plate had been fed out. Therefore, when welding the end of the steel plate of one coil and the tip of the steel plate of the other coil overlappingly, a disc-shaped electrode is rolled along the welding fin, and welding current is continuously applied to perform continuous welding.

However, in such continuous welding, the welding line is continuous, so the welding current is not concentrated in the welded part, but is branched to the already welded part. In addition, especially with thin plates, the welding surface and the electrode contact surface are close to each other, so if the welding current is even a little too low, the welding surface will not melt, resulting in poor welding.On the other hand, if it is even a little too much, the plate will reach the electrode contact surface. It melts and adheres to the electrode, causing tearing and holes in the weld. For this reason, the range of appropriate conditions is narrow, and even a slight change in conditions results in poor welding.

It is an object of the present invention to provide a method for solving the mJ defect and minimizing defects in welded parts.

To achieve this objective, the configuration of the present invention consists of two parallel
When welding strips alternately from two hot-dip plated steel coils and welding the end of the steel strip of one coil to the start end of the other coil, welding is performed intermittently in the width direction of the steel strip. be.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

Strip steel sheets W are alternately fed out from two parallel galvanized steel coils 1 and 2, and the steel plate feeding end of one coil is overlapped with the steel plate edge starting edge of the other coil to form a disc-shaped electrode 8.
Weld according to 8. Note that 4 is a direction change roll, 5 is a pretreatment device, and 6 is a coating device.

Now, when performing the above-mentioned welding, the electrode 3.8 is energized periodically to perform intermittent welding by repeating the length H9 of the welded part and the length C of the non-welded part. And plate thickness t(ff)=
QJ7. If overlap allowance S (silk) = 2.0, H = 25
Good results were obtained with m and C=5m.

Note that H=10 P-50ff is desirable; if it is less than 10, the welding strength will be insufficient, and if it exceeds 50, the effect of intermittent welding will be lost due to shunt. Also, C: 8 to 10ff is desirable, and if it is less than 8, there is a risk of continuous welding.
If it exceeds 0, welding strength will be insufficient.

The present invention is also applicable to aluminized steel sheets and zinc-aluminum alloy plated steel sheets.

As described above, in the present invention, since intermittent welding is performed, the welding current is effectively concentrated in the welded part, and a good welding result is obtained.

[Brief explanation of drawings]

FIG. 1 is an overall system diagram showing the implementation state of the present method, FIG. 2 is an enlarged view of the main part thereof, and FIG. W... Galvanized steel plate, 1.2... Coil, 8...
・Electrode agent: patent attorney Shinpei Inukai

Claims (1)

[Claims] When steel strips are alternately fed out from two parallel hot-dip plated steel coils and the steel plate feeding end of one coil is overlapped and welded with the steel plate feeding start end of the other coil, welding is performed intermittently in the width direction of the strip steel plate. A method for welding the ends of hot-dip plated steel strips.