An electric resistance welded steel pipe or tube comprises: a base metal being a steel sheet having a specific chemical composition and an electric resistance weld portion having a bond width of 40×10.sup.−6 m or more and 120×10.sup.−6 m or less, wherein C.sub.0-C.sub.1 is 0.05 mass % or less, where C.sub.0-C.sub.1 is a difference between C.sub.1 in mass % which is a minimum C content of the electric resistance weld portion and Co in mass % which is a C content of the steel sheet, and a depth of a total decarburized layer in each of an inner surface layer and an outer surface layer of the electric resistance welded steel pipe or tube is 50×10.sup.−6 m or less.

A method for manufacturing structural steel components with local reinforcement is provided. The method comprises selecting at least a zone of the component to be reinforced, providing a steel blank and deforming the blank in a press tool to form a product, wherein the blank and/or the product comprises a groove in the zone to be reinforced, the groove comprising an inner surface and an outer surface. The method further comprises depositing a reinforcement material on the inner surface of groove and locally heating the reinforcement material and the groove of the steel blank or product, to mix the melted reinforcement material with the melted portion of the steel blank or product.

According to one aspect of the present invention, there is provided a T-joint including a first steel sheet, a second steel sheet, and a fillet welded part, in which the sheet thickness of the second steel sheet is 6.0 mm or less, the second steel sheet is stood on a first surface of the first steel sheet, the fillet welded part joins the first surface of the first steel sheet and a first surface of the second steel sheet to each other, at least one of the first surface of the first steel sheet or the first surface of the second steel sheet includes a zinc-based plating, an abutting end portion of the second steel sheet on a second surface side of the second steel sheet has an inclined surface, and in a cross section taken along a sheet thickness direction of the first steel sheet and a sheet thickness direction of the second steel sheet, the inclined surface forms an acute angle with respect to the first surface of the first steel sheet.

A gas shield arc welding method that reduces the number of joints, which are the sites where defects occur more readily, and that enables automatic welding with a welding robot. A gas shield arc welding method in which a steel pipe Wo is welded by multi-pass welding with a steel frame erection adjusting tool attached to an erection piece on the steel pipe Wo to immobilize an open end section of the steel pipe. An initial single or several layers are welded to the open end section, after welding, the steel frame erection adjusting tool is removed; and remaining layers are welded with a welding robot such that two bead joints are formed at no more than two sites.

A steel joined body includes a plurality of steels joined together, the plurality of steels including a joint interface having a carbon concentration of 0.20 mass % or more and 2.10 mass % or less, and the steel joined body including a concentration gradient layer having a carbon concentration decreasing with distance from the joint interface.

A pipe processing tool that is configured to deform the end of a pipe so that the circumferential shape of the end of the pipe generally matches the circumferential shape of an adjacent pipe end. Matching the circumferential shapes of the pipe ends is advantageous during a pipe attachment process. The pipe processing tool can include a deformation ring with a plurality of pipe deformation members. Each pipe deformation member faces radially inward and is actuatable in a radial direction toward and away from the center of the deformation ring in order to permit engagement with the pipe. Each pipe deformation member is individually and separately actuatable from the other pipe deformation members so that the circumferential shapes of the pipes can be altered by controlling suitable ones of the pipe deformation members.

The invention relates to a device (2) for welding hard material elements (4) onto teeth (6) of a saw blade (8), comprising a saw blade feed device (12) for moving the saw blade (8) in a feed direction (14), such that a tooth (6a) of the saw blade (8) can be brought into a target position (16) in a working region (10) of the device (2), comprising a first centering device (30) for centering the saw blade (8) transversely to the feed direction (14), comprising a second centering device (32) for centering a respective hard material element (4) transversely to the feed direction (14), comprising a resistance welding device (24) having a welding electrode (26) that can be deployed into and withdrawn from the working region (10), comprising a supply device (28) for supplying and transferring a respective hard material element (4) to the welding electrode (26), and it being possible for the welding electrode (26) to be deployed in such a way that the hard material element (4) can be brought toward the tooth (6a) to abut the tooth (6a). According to the invention, the hard material element (4) can be centered relative to the centered and fixed saw blade (8) by means of the second centering device (32), and the first and second centering device (30) are provided in a common assembly (38), such that the centering of the saw blade (8) by the first centering device (32) predetermines a centering position for the subsequent centering of the hard material element (4) by the second centering device (32).

The present invention relates to steel used for a sash component and the like of a vehicle and, more specifically, to a hot-rolled steel sheet for a high-strength electric resistance welded steel pipe having excellent expandability and a method for manufacturing same, the hot-rolled steel sheet having a smaller decrease in the strength of a welding heat-affected zone (HAZ) formed during electric resistance welding, in comparison with a base material.

Provided is a laser machining method that causes no degradation in magnetic properties for thin electrical steel sheets. An electrical steel sheet machining method comprises machining an electrical steel sheet to a predetermined shape by melt-cutting the electrical steel sheet using a laser, wherein a scanning rate of the laser in the melt-cutting is 10000 mm/min or more.

A joint body includes first and second metal members and a joint portion including a welded portion where the first and second metal members are joined together, the welded portion having a line shape. The joint portion includes first and second longitudinal portions and a plurality of connecting portions. The first longitudinal portion has first intersecting portions arranged in a first direction and extends in the first direction. The second longitudinal portion has second intersecting portions arranged in the first direction and extends in the first direction. The welded portion intersects itself at the first and second intersecting portions. The connecting portions are arranged in the first direction. The connecting portions extend in a first direction and connect the first and second longitudinal portions.