Abstract: In an arc welding method and apparatus, a plasma (13) is generated at a welding intended position on a base material (2) by a laser (16) irradiated to the base material (2). When a discharge electrode (12) is at a minus potential, an arc discharge (4) takes place in the direction of the plasma (13) and is induced at a position irradiated with the laser (16). When the electrode (12) is at a plus potential, arc electrons are generated from a laser irradiated point and discharged to the electrode (12). When a voltage applied between the electrode (12) and the base material (2) is alternating, the polarities of the electrode (12) and the base material (2) alternately change so that the foregoing phenomena alternately occur. When the base material (2) is at a minus potential, an arc discharge (4) takes place from a laser spot.

Abstract: Plate parts (1, 2) to be joined are formed with flat meeting surfaces (1A, 2A) and beveled surfaces (1B, 2B) at the respective joining ends, and fixed in a welding position with the flat meeting surfaces (1A, 2A) in abutting engagement with each other. In this state, a cladding material (4) is pressed against a groove (3) between the two plate parts (1, 2) and at the same time put in high speed rotation. Heat of high temperature is generated by friction between contacting surfaces of the plate parts (1, 2) and the cladding material (4). As the cladding material (4) is moved along the meeting surfaces (1A, 2A), part of plasticized cladding material at the lower end of the cladding material (4) is left and deposited on the front side of the groove (3), contributing to increase the cladding volume of a weld portion (5) on the front side of the groove (3) and to enhance the strength of bondage between the two plate parts (1, 2).

Abstract: It is an object of the present invention to provide, in the double wire type welding method, a consumable electrode type arc welding method and welding apparatus for which the welding speed is sufficiently increased, and in particular the melting of steel such as carbon steel is increased and hence the welding speed is increased.

Abstract: A narrow gap welding method by which V-shaped or single-bevel grooved multi-layer build-up welding is carried out, comprises the steps of welding a first layer by applying a welding current by which a globule transfer pattern is made into a spray pattern by a waveform in which a direct current and a pulse current are caused to overlap, and thereafter welding the second layer by applying a direct current.

Abstract: A core wire-connecting device has a reciprocative housing; a rotor rotatably mounted therein and having a plurality of front receptacles and the same number of rear receptacles formed in mutual alignment in the peripheral surface of the rotor equidistantly in a circumferential direction; a connector disengaging member for inserting a connector constituted by a sleeve and a conical wedge received therein into the front receptacle in a first position of the rotor; a wedge-removing member disposed ahead of the rotor in alignment with the front receptacle in the first position of the rotor so as to force the conical wedge received in the sleeve placed in the receptacle into the corresponding rear receptacle; a core cutting-off mechanism disposed close to the front end of the rotor at the second position of the rotor spaced through a prescribed phase angle from the first position thereof in the rotating direction; a core-holding unit provided in front of the housing to support core wires except when the rotor is r