Abstract: A welding beveling of a T-joint of a member welded to a rib on a lower plate, the rib varying in thickness along its length, comprises a beveling on an upper plate partially overlapping the rib at the thicker portion of the rib and having a clearance between the upper plate and the rib at the thinner portion, and a part of the beveling at the thicker rib portion being provided with a detecting hole for detecting the overlap.

Abstract: A method for assembling narrow gap members by welding is described. In the method, separate narrow gap members having spaces therein when assembled are provided and a deformation-preventive material consisting of a water-soluble material or a material capable of being disintegrated with water is filled in each space and is formed with a through groove or hole in the filled preventive material. In this state, the separate narrow gap members are subjected to welding, and immersed in water to remove the deformation-preventive material from each space. The through grooves may have a width larger than a leg length of each penetration bead, in which a heat-resistant flux is filled in each groove. The deformation-preventive material may be covered with a heat-resistant ceramic backing member shaped in a specific form or with a heat-resistant particle layer and a copper member shaped in conformity with an intended size and shape of a penetration bead.

Abstract: During arc welding, optical radiation emitted from an arc is detected by means of a photoelectric device, and an electric detection signal from the photoelectric device is used for controlling the travel of a suction hood along a weld line so that the weld fumes may be exhausted through the suction hood and to insure that the weld metal zone is always covered by the suction hood.