JPS58107276A - Welding method for long tube - Google Patents

Abstract

PURPOSE:To reduce wavy distorsion generated in longitudinal direction and reduce hand work to remove the distorsion by progressing two lines of welding on the edges of both ends in longitudinal direction of plates simultaneously, and at the same time, performing waste welding along longitudinal direction in the center of the plates keeping pace with above-mentioned welding. CONSTITUTION:When welding long tubes, upper and lower plates 3, 4 are clamped to the upper and lower edges (a), (b) of long, thin side plates 1, 1', and the side plate 1 is welded simultaneously to the upper and lower plates 3, 4 as shown by weld lines P1, P2. At this time, waste welding is performed in the center along longitudinal direction of the side plate 1. The distances between weld lines P1 and Q1 and Q2, Q2 and P2 are made nearly equal and these weldings are progressed simultaneously. Similar welding is performed for the side plate 1'. Further, even when reinforcement is provided in the center of the side plate 1 by a weld line along longitudinal direction, welding of the reinforcement is performed with upper and lower welding of the side plate 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of welding a long tube. □The long tube A shown in Figure 1 shows the entire boom tube of the crane, but there are upper and lower plates 3 on the upper and lower edges a and b of the thin long side plates 1 and 1', respectively.
, 4 are arranged, and these side plates 1, (and upper and lower plates 3, 4) are arranged.
is welded as shown in welding line P, , P, , Karasu, 3. In this welding, after the side plate 1' is clamped (temporarily attached) to the upper and lower plates 3 and 4, the side plate 1 is attached to the upper and lower plates 3 and 4 as shown by welding lines R and R. Perform welding at the same time. Next, the side plate 1' and the upper and lower plates 3 and 4 are all welded at the same time as indicated by weld lines Pg and Pa, but during this welding, the shrinkage of the base metal and weld metal at the welded area during solidification is avoided. As a result, wavy distortion occurs in the longitudinal direction of the side plates 1' and 1'. This distortion phenomenon will be described in detail regarding the side plate 1 as follows. That is, in the side plate 1, the shrinkage phenomenon of the member itself occurs at and near the weld lines p, Ps, but the weld line P
In the central part separated from i and Ps, the member itself does not undergo thermal formation *'e, so it does not contract, and is subjected to compressive force in the longitudinal direction due to the above shrinkage phenomenon, so it has a wavy shape in the longitudinal direction. In order to remove this wavy distortion, the conventional practice was to perform manual hammering or heating work after welding.

h3 The present invention provides a novel method for welding long tubes that reduces the manual labor as much as possible. In FIG. The weld line of the sacrificial welding performed is shown. and welding lines P+ and Qt
The distances between the welding lines Q1 and Qs, and between the welding lines Q1 and Qs are approximately equal. These welds are performed simultaneously.

In this way, at the same time, welding lines Ps, Qt, Qs,
When welding is performed at the location indicated by Pa, the side plate 1 has the effect that the above-mentioned wavy distortion does not occur because the member itself shrinks in the center portion as well. In addition, in the above embodiment, there are two waste welds.
In the case of articles, as shown above, even one article is effective, and it goes without saying that having three or more articles is even more effective. Furthermore, side 1f1
Even if a reinforcing material is welded with a welding wire along the longitudinal direction of the side plate 1 in the center of the side plate 1, the welding sound of the reinforcing material may be made at the same time as the welding of the upper and lower sides of the side plate 1. Of course.

Although the explanation has been given above, it goes without saying that the present invention can also be applied to long tubes other than boom tubes.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of conventional welding of a long cylinder, and FIG. 2 is an explanatory diagram of welding of the present invention.

Claims (1)

[Claims] A method for welding a hollow elongated cylinder made of a plurality of elongated plates by welding both end edges in the longitudinal direction of each plate to the edges of the adjacent plates, the method comprising: When welding both longitudinal edges to the edge of the plate that is in contact with them, weld these two strips simultaneously, and as welding progresses, welding is applied to the center of the plate along the longitudinal direction of the plate. A method for welding a long cylinder, characterized in that a reinforcing material is welded to the central part of the plate along a weld line along the longitudinal direction of the plate.