Abstract: The present invention relates to a roller bed (1) for rotating a generally circular work piece (5) in circumferential direction. The roller bed (1) comprises two supporting members (2) and each supporting member (2) comprises a top roller (3) and a bottom roller (4). The rollers (3, 4) are adapted for simultaneous mechanical drive in the same circumferential direction. Each top roller (3) is also connected to an electrical clutch which is adapted for disengaging the top roller (3) from the simultaneous mechanical drive. The present invention further relates to a system of roller beds (1).

Abstract: A method of automatically setting a welding parameter for MIG/MAG welding including the following steps: initiating (S1) a parameter setting welding operation; detecting (S2) a response welding current at a present wire feed speed during said parameter setting welding operation; determining (S4) a first function mapping said response welding current to said set wire feed speed; determining (S7) a desired wire feed speed from said first function and said desired welding current.

Abstract: A method of automatically setting a welding parameter for MIG/MAG welding including the following steps:—initiating (S1) a parameter setting welding operation;—measuring (S12) a welding voltage and retrieving (S13) a parameter representing a wire feed speed during said parameter setting welding operation; and—identifying (S14) a second function mapping said welding current to said welding voltage from said measured welding voltage and said retrieved parameter.

Abstract: A welding crane (1) for welding large structures is described. The welding crane (1) comprises a base part (2) which is arranged to be positioned on a ground (3), a mast (4) with a longitudinal axis (5). The mast (4) can be arranged in at least a first position in which the longitudinal axis (5) of the mast (4) extends substantially vertically from the base part (2). A boom (6) with a longitudinal axis (7) is arranged on the mast. The boom (6) can be arranged in at least a first position in which the longitudinal axis (7) of the boom (6) is substantially perpendicular to the longitudinal axis (5) of the mast (4). The boom (6) is arranged for receiving a welding head (13). The boom (6) is rotatable in relation to the mast (4) such that the boom (6) can be arranged in a second position in which the longitudinal axis (7) of the boom (6) is substantially parallel with the longitudinal axis (5) of the mast (4).

Abstract: A system for controlling a weld-current in an arc welding apparatus for short arc welding comprising a current regulator included in a voltage feedback loop from a power supply to a welding electrode and a ramp generator arranged to provide current ramps during a short circuit phase at said welding electrode.

Abstract: A welding power supply (1) for supply of current to a welding electrode (2), and a method and a computer program for controlling such a welding power supply is described. The welding power supply (1) comprises an output (3) for output of current from the welding power supply (1), and a control unit (9) for controlling the welding power supply (1). The control unit (9) is arranged to control the welding power supply (1) to supply current to the output (3) in the form of a series of alternating positive current pulses (11), having a positive top value (Imax+), and negative current pulses (12), having a negative top value (Imax), and to lower the current in the current pulses from the negative top value (Imax) and the positive top value (Imax+) to a negative switch value (Ix?) and a positive switch value (Ix+), respectively, before switch between a positive current pulse (11) and a negative current pulse (12).

Abstract: A system for controlling a weld-current in an arc welding apparatus for short arc welding comprising a current regulator included in a voltage feedback loop from a power supply to a welding electrode and a ramp generator arranged to provide current ramps during a short circuit phase at said welding electrode.

Abstract: The invention relates to an electric arc-welding welding head comprising a contact device and one or more wire feeder units, the contact device encompassing an electrode assembly, the electrode assembly comprising at least two fusible continuously-fed wire electrodes arranged in a contact device. An electrically insulated duct is provided for electric insulation of at least one of the electrodes so that the electrode is electrically insulated from other electrodes in the electrode assembly. The invention also relates to an electric arc-welding contact device and an electric arc-welding welding head assembly.

Abstract: A welding arrangement and a welding process for forming a weld seam between two edge portions, wherein the edge portions form a Y joint having a root portion and a bevel portion, said root portion being welded by a hybrid laser electric arc welding process including directing a laser beam and an electric arc in a single interaction zone of plasma and molten metal. A hybrid laser electric arc welding head and welding submerged arc welding head are arranged on a common carrier structure for welding the Y joint.

Abstract: An inverter provides alternating current (iout) to a load (130) containing a welding circuit. The inverter includes at least one commutation circuit (110) and a bridge circuit (120) connected to a bus forwarding power from a DC power source (100). The bus is also galvanically connected to the load (130) via the bridge circuit (120). The at least one commutation circuit (110) receives power from the DC power source (100); receives energy from inductive elements in the load (130) during a storage phase of a cyclic procedure, and controls energy feedback to the load (130) during a feedback phase of the cyclic procedure. The at least one commutation circuit (110) is a two-pole having a first pole (p1) connected to a first node (A) and a second pole (p2) connected to a second node (B). The at least one commutation circuit (110) is arranged to receive energy from the load (130) and feedback energy to the load (130) via the first and second nodes (A; B), either directly or via the bridge circuit (120).

Abstract: A contact fitting for a welding apparatus includes a housing, and first contact device, a second contact device, and a third contact device arranged between the first and second contact devices. The third contact device is movable relative to the first and second contact devices. The first contact device has an elongated form, is fixedly arranged in the housing, and extends from a first end, which is arranged between first and second ends of the housing, to a second end. The second contact device has an elongated form, is suspended spring-loaded to the housing, and extends from a first end, which is arranged between the first and second ends of the housing, to a second end.

Abstract: An inverter provides alternating current (iout) to a load (130) containing a welding circuit. The inverter includes at least one commutation circuit (110) and a bridge circuit (120) connected to a bus forwarding power from a DC power source (100). The bus is also galvanically connected to the load (130) via the bridge circuit (120). The at least one commutation circuit (110) receives power from the DC power source (100); receives energy from inductive elements in the load (130) during a storage phase of a cyclic procedure, and controls energy feedback to the load (130) during a feedback phase of the cyclic procedure. The at least one commutation circuit (110) is a two-pole having a first pole (p1) connected to a first node (A) and a second pole (p2) connected to a second node (B). The at least one commutation circuit (110) is arranged to receive energy from the load (130) and feedback energy to the load (130) via the first and second nodes (A; B), either directly or via the bridge circuit (120).

Abstract: A suggested welding crane for welding of objects comprises an arm, a stand and a welding head. The arm includes at least a first and a second segment, which are arranged with their length axes essentially parallelly and are telescopically movable along their length axes in relation to each other so that at least a first segment of said segments at least partly slides into at least a second segment of said segments. The welding head is arranged in a distal end of an outermost segment of the arm while an innermost segment of the arm is suspended in the stand. A linear guide is arranged on at least a first segment of said segments. A co-operating part of said at least one linear guide is arranged on at least a second segment of said segments, wherein the at least one linear guide is adapted to provide said telescopic movement.

Abstract: A method and an apparatus for friction stir spot welding together at least two metal sheets is described. A tool comprising a stepwise decreasing diameter towards the welding end is used. Each stepwise decrease in diameter defines a shoulder. The first shoulder is situated at a distance (x) from the welding end which is larger than zero and smaller than the minimum thickness (Wmin) of one of the metal sheets, and wherein a higher number of shoulders than the number of metal sheets to be joined, are situated within a distance (L) from the welding end that is smaller than the maximum thickness (Wmax) of a metal sheet times the number of metal sheets to be joined minus one.

Abstract: A welding device and a method for automatic multiple-bead welding, wherein a line illumination member is arranged to illuminate the joint by scanning a light beam across the joint line. A camera is arranged for the registration of line images of the joint when it is illuminated with the scanned light beam. The locations of the edges of the joint are determined by means of triangulation based on the registered line image. The welding device can include a stereo image member arranged to register photometric stereo images of the joint substantially simultaneously with the registration of the line images. The welding device is arranged to, during welding of a weld joint with a plurality of weld beads, control the welding head in dependence on both stereo images and line images.

Abstract: A welding device for powder welding is described, which comprises a welding head for transportation of at least one welding electrode to a welding area, and a powder transportation device for transportation of powder from a container to the welding area. The powder transportation device comprises at least a first pipe which at a first end has an opening which is arranged to be placed in the container in order to transport fluxing agent from the container. The powder transportation device comprises at least a first ejector which is connected to the second end of the first pipe and which is arranged to transport powder from the container via the first pipe using pressurized gas.

Abstract: An electric arc welding method is provided, wherein an electrode assembly comprises at least two fusible continuous electrodes acting on a workpiece for generating a weld pool via electric arcs, wherein the at least two electrodes are arranged in sequential order relative to a welding direction and laterally separated relative to each other, wherein steps are performed of monitoring at least one stability parameter (Stab_par) for each electrode of the electrode assembly; determining if one electrode of the electrode assembly violates a stability criterion (Crit); separating at least temporarily the one electrode violating the stability criterion (Crit) from one or more adjacent electrodes when a violation of the stability criterion (Crit) of the one electrode is detected.

Abstract: A welding device applies weld material between two work pieces such that the work pieces are connected mechanically with one another. The welding device includes a welding head and a central element. The welding head performs a welding action during transport thereof along an operating direction between the work pieces. Two primary sensor members are arranged on the central element upstream of the welding head relative to the operating direction. The sensor members register geometric properties of a spacing between the work pieces in which spacing the weld material is to be applied. Each sensor member is configured to maintain contact with a respective wall of the two work pieces adjoining the spacing while allowing variation of lateral distances between the central element and the adjoining wall. This is accomplished by the sensor members being pivotally attached to the central element via at least one pivoting axis oriented essentially perpendicular to the operating direction.