The invention relates to an apparatus for electric arc welding of two anschmelzender workpieces, preferably pipe ends, rings od Like On a closed seam path, in which at least two radially disposed in the welding plane, the same pole magnets 1 by a surrounding the weld path magnetic ring are combined In order to increase the field strength at such magnet assemblies, the invention provides that the weld path surrounding ring is formed by the weld path of the facing ends of the magnets Resistances which would otherwise occur with a separate, associated with the magnet ring, are thereby eliminated

Apparatus for electric arc welding

The invention relates to a welding device (1) for welding workpieces (3, 4) having a movable arc (8), wherein the welding device (1) comprises a controlled welding current source (25) having a current controller (27) and a positioning and compressing device (15) for the workpieces (3, 4), said device holding the workpieces (3, 4) at a distance (s) during heating and then compressing them. The welding device (1) comprises a device (28) for determining and analyzing process parameters, particularly the arc voltage, and a device for correspondingly controlling and changing (Δs) the distance (s) between the workpieces (3, 4) during heating. The welding device (1) can further comprise a driving device (21) for moving the arc (8), designed as a controllable magnet device having one or more inner and/or outer coils (22, 23) for electromagnetically moving the arc (S). The invention further relates to a method for welding workpieces (3, 4) having a movable arc (8), wherein the workpieces (3, 4) have a controlled welding current applied thereto by welding device (1) having a controlled welding current source (25), and are held at a distance (s) during warming and then compressed by a positioning and compressing device (15). Using the device (28), the arc voltage particularly can be determined and analyzed, wherein the distance (s) between the workpieces (3, 4) is correspondingly controlled and changed (Δs) by a device (16) during warming. Depending on the process parameter or parameters determined, the welding current and/or the distance (s) can be controlled during heating. Electrically conductive, particularly metal, workpieces (3, 4) made of different, particularly differently melting, materials can be welded.

Welding device and welding method having movable arc

of EP0288911A method and device for welding metallic hollow bodies (2, 3) with an arc moved magnetically along the weld path (10). Here, an inner coil arrangement (4) is used which has a radially orientated pole disc (8) at the level of the weld path (10). To influence the speed of the arc, the magnetic field in the gap (12) is locally varied. On the one hand, this is done by variation of the gap distance by appropriately profiled pole discs (8). On the other hand, the magnetic field can be varied by locally variable excitation. For this purpose, two or more magnet coils (5, 6) which can be excited differently are provided or locally variable permeability is provided.

Method and device for welding metallic hollow bodies

A magnet coil (7, 8) for using when welding with a magnetically moved arc, and in fact for welding with an arc moved between an auxiliary electrode (6) and a bead-like path (5) of a welding-edge seam, is improved by a coil core (7) adapted to the contours of the workpieces (3, 4) being slipped over these workpieces, a magnetic field (BL) directed perpendicularly to the welding plane being produced as a result of the applied coil winding. The magnet coil (7, 8) serves to increase the range of application of welding with a magnetically moved arc, and in fact in particular with regard to greater wall thicknesses.

Magnet coil for welding with magnetically moved arc.

Vorrichtung zum schweissen metallischer hohlkoerper mit magnetisch bewegtem lichtbogen

The same poles, pref. south poles, of the magnets surround the closed weld path and are pref. united in a closed path by connection to a radially split ring. The magnets may be electromagnets and individual magnets may be supplied with different currents. The appts is esp. for welding tube ends and rings and produces a strong field concn. even when welding small components.

Magnetically-moved-arc welding appts. - with individual magnets in welding plane and surrounding workpieces

Twometal workpieces or profiles are welded. The arc is moved in alternate directions (a,b) along the seam by a reversing the magnetic field or the welding current; and when the arc reaches the end of its travel in one direction, it creates a signal causing the reversal, so the arc moves in direction (b). A homogeneous magnetic field may be used along the seam; or one or more magnets may be moved along the seam. A further alternative is to use a row of magnets switches in sequence or with alteration in their amplitudes. The speed or frequency of the reversals may be varied. The pref. appts. includes a photocell located at each end of theseam and creating the signal when the arc is picked up by the photocell. A magnetically moved arc can be used for open seams; and the process can be automated.

Arc welding metals via open or closed seams - where arc is moved along seam by external magnetic field

In a method of welding metallic workpieces with an arc magnetically moved along a path of a welding-edge seam, welding current I and/or welding voltage U are readjusted by changing the distance between the workpieces 18, 19. With this method, the range of application of welding with a magnetically moved arc is increased.

Pache Norbert

Papers

Magnetically-moved-arc welding appts. - with individual magnets in welding plane and surrounding workpieces

Arc welding metals via open or closed seams - where arc is moved along seam by external magnetic field

Process for arc welding.

Magnet coil for welding with magnetically moved arc.