JPS5942595B2 - Manufacturing method of fitting flange - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a flange for joints such as concrete piles, etc. Conventionally, in order to manufacture this type of flange, a long flat steel was wound into a perfect circular coil. After cutting one side in the axial direction and separating each roll, both end faces of the cut part of the winding ring are crimped and arc welded, but the cut part loses its perfect circle after welding due to the cut margin. be exposed.

Therefore, a separate work process is required to correct the roundness after welding, which increases the cost accordingly. In addition, the welding rod seeps into the welded area during arc welding, which impedes safety in terms of strength and deteriorates the quality of the product. In view of such conventional difficulties, the present invention makes it possible to easily form a perfect circle after welding the cut portion, thereby omitting the work process for correcting the cut portion to a perfect circle, and without causing the welding rod to seep into the cut portion during welding. The present invention aims to provide a method for manufacturing a flange that can stabilize the strength of the welded part. Next, embodiments of the present invention will be described in detail with reference to the drawings.

As a material, a long flat steel as shown in FIG. 1 is used.
This flat steel is formed to be slightly thicker from the inner peripheral surface side l to the outer peripheral surface side l' so that the plate thickness becomes uniform when it is bent into an annular shape. The above-mentioned flat steel is passed through a coil winder having a core metal having a slightly elliptical cross section, and wound several times to form an elliptical coil shape as shown in FIG.

Next, the coiled material is cut with saw teeth at a position where the cutting section 8 is perpendicular to the major axis a of the ellipse, as shown in FIG. 3, to separate the annular body of each turn as shown in FIG.

Then, the cut portions of the annular body are welded together using a flash butt welder.

That is, first, as shown in FIG. 5, both end surfaces of the cut section are butted against each other and preheated, and then, as shown in FIG. Welding occurs with burrs around the welded area as shown in the figure.
Finally, the burrs are removed from both sides of the flange under the soil and on both sides of the flange using a deburring device to obtain a nearly perfectly circular flange as shown in FIG.

Also, instead of winding a long flat steel into a coil like in the case of clay,
It is also possible to perform flash butt welding after cutting to a required length in advance and forming one piece into an elliptical annular body in which the diameter a perpendicular to the cut portion is slightly longer than the diameter b at the cut portion.

In any of the above cases, the ratio of the major axis a to the minor axis b of the elliptical annular body may be determined as appropriate to the extent that a perfect circle is formed after the cut portion is welded. .

As described above, in the present invention, by forming a slightly elliptical annular body in which the cut portion is located at a position substantially perpendicular to the major axis, both end faces of the cut portion can be welded and at the same time a substantially perfect circle can be formed. Since a flange can be formed, it is possible to omit the troublesome process of correcting the weld to a perfect circle after welding, which was previously required, which is very helpful in reducing costs.

In addition, as in the past, when a perfectly circular annular body is formed from the beginning, if flat butt welding is performed, the circularity will be severely distorted and correction work after welding will be extremely time-consuming, making it practically impossible. However, in the present invention, the cut portion can be welded by flash butt welding instead of conventional arc welding.
It has the advantage that the welding rod does not penetrate into the welding area, and the strength of the joint is extremely stable.

[Brief explanation of drawings]

The drawings show embodiments of the present invention, and FIGS. 1 to 6 are explanatory diagrams showing the order of the manufacturing process. a: Long axis of the ellipse, b: Short axis of the ellipse.

Claims (1)

[Claims] 1. A long flat steel piece that is gradually thickened from the inner circumferential side to the outer circumferential side and formed into a ladder-like cross-section, forming a slightly elliptical annular body with the cutting part located at a position almost perpendicular to the major axis. rear,
A method for manufacturing a flange for a joint, characterized by flash butt welding both end faces of the cut part.