DE856930C - Inductor for longitudinal seam welding of pipes - Google Patents

Description

Inductor for longitudinal seam welding of pipes "7.u111 longitudinal seam welding of pipes, starting from a flat band, (read to the pipe) or rolled, inductors have already been proposed, which are already bent into a slot tube Grasp your hand and have ladder branches that are parallel to the edges to be welded have a hairpin-like turning point running in the vicinity of the welding point.

Such inductors have proven themselves, but should according to the invention can be improved in their effectiveness. This happens in the way, <iaß im In contrast to the earlier proposal, the inductor's heating conductors are already in the vicinity of the rolled tape are arranged and up to the welding point in their vicinity get lost. The inference of the heating conductor is advantageously below or above the unrolled tape. The inductor follows the external shape of the Belt edges, while this is done by pressure rollers in a known and customary manner to the slot tube is rolled and moves in the direction of its longitudinal axis relative to the inductor.

In the drawing, an embodiment is shown in plan view of the invention shown. The tape t is made while it is in the direction of the arrow a moves, bent by rollers, not shown, to the slotted tube, which then on its longitudinal seam is welded.

The inductor is designed so that its conductor branches 3 and 3 'in Neighborhood of the edges 4 and 4 'of the tape run in such a way that they are the changing external shape of the belt follow. Branches 3 and 3 ' .may run next to or above the edges .4 and q 'and it may be advantageous, on the length of the heating conductor from one arrangement to the other switch.

In the vicinity of the weld 5 is the hair. needle-like reversal point, which is advantageously arranged somewhat beyond the actual welding point will. The latter measure not only promotes welding itself, but still has the advantage that the weld is remunerated.

In the drawing the hair lies; a, delsc, hleife 6 just behind the Welding point 5.

When the belt passes through this device, the cools down Welding point off relatively quickly, as the heat flows off to the sides.

To reduce the cooling rate of the weld and thus To achieve an afterglow of the same, the hairpin loop 6 can also be very long be carried out, from the welding point to the reversal point of the hairpin loop the conductor loops of the inductor are guided parallel to the weld seam will.

In order to have a slightly falling temperature characteristic within the Getting the weld seam through pulling through can reduce the magnetic coupling of the Welding point from where the heating conductor branches are close to the pipe, gradually through this be increased that the distance between the pipe and inductor branches above it is steadily increasing. However, the distance between the needle loop and the pipe should be 5 Do not exceed 7 mm as the largest coupling width.

The length of the hairpin loop used for post-treatment is aligned depending on the pipe dimensions (diameter, wall thickness), the material and above all according to the pulling speed. By changing the coupling factor is to achieve any temperature characteristic.

Call the branches of the ladder running in the vicinity of the strip edges a preheating of these edges emerges over a considerable distance, so that with can be welded with good efficiency at great speed and safety. The yoke 7, 7 'of the inductor is located in the area of the still unrolled Band.

The coupling and the cross section of this yoke 7; 7'- can be designed differently compared to the coupling and cross section of the conductor branches 3 and 3 '. In particular, the conductor cross-section can be reinforced and the coupling in this area be enlarged. In addition, the conductor sections 3, 3 'and 6 with: Magnet yokes be provided, while these are omitted in whole or in part in sections 7, 7 ' could be.

The heating of the strip over its cross-section through the branches 7, 7 'is at comparatively lower temperatures with regard to the rolling-in process advantageous.

In the example chosen, the inference is that also the two connecting rails 8, 8 'is carried out over the band i. In some cases, however, it is beneficial to to derive the inference 7, 7 'correspondingly under the volume i. The connection 8, 8 'can, as shown in the drawing, in the area of the still unrolled tape lie. However, it can also be placed in the tip 6 or on another one that appears suitable Place to be relocated.

Claims (3)

PATENT CLAIM: i. Inductor for longitudinal seam welding of pipes, at which the heating conductors on a certain distance - along the one to be welded Edges run, characterized in that the heating conductors are already in the vicinity of the edges of the unrolled tape and up to the weld point in whose aftermath run, while the inference is below or above the unrolled one Ribbon runs. 2. inductor according to: 'claim i, characterized in that for aftertreatment of the weld seam the heating conductor branches of the hairpin run parallel to the weld seam are lengthened. 3. inductor according to claim 2, characterized in that zuan Achieving a desired falling temperature characteristic in the weld seam the coupling factor of the elongated hairpin is reduced by increasing the distance the inductor branches in front of the tube in sighting at the turning point of the hairpin increases.