A second member is made of a material difficult to be welded to a first member. A first step includes forming a third member by welding a first filler material to the first member through a through-portion of the second member. A second step includes forming a fourth member by covering a surface of the third member with a second filler material and welding the fourth member to the second member.

A resistance welded steel pipe is provided. A hot-rolled steel sheet having a composition containing, in mass %, C: 0.025 to 0.168%, Si: 0.10 to 0.30%, Mn: 0.60 to 1.90%, and one or at least two selected from Ca, Nb, V, and Ti such that Pcm is 0.20 or less is subjected to continuous cold roll forming to obtain a pipe-shaped body. Tapered grooves are formed in the steel sheet such that the ratio of the tapered portions to the wall thickness of the steel sheet is 10 to 80%. Then end surfaces of the pipe-shaped body are butted against each other and subjected to electric resistance welding. Ultrasonic waves are transmitted toward the electric resistance weld surface such that a beam width is within the range of 0.1 to 4.0 mm, and the reflected waves are used for ultrasonic flaw detection using an ultrasonic flaw detector.

A method and system to manufacture workpieces employing a high intensity energy source to create a puddle and at least one resistively heated wire which is heated to at or near its melting temperature and deposited into the puddle as droplets.

The invention relates to a method for manufacturing a sandwich panel as a semi-finished product where at least one layer of a non-metallic material is positioned between at least two metallic layers. At least one of the metal layers is shaped into a three dimensional layer, and the metal layers are in direct mechanical contact to enable resistance weldability of the semi-finished product in order to connect the semi-finished product to a desired combination of solutions in a subsequent manufacturing process.

There is provided a power supply device that supplies an output current to an electric processing device which performs electric processing on workpieces. The device includes: a first power supply; a magnetic energy recovery switch that receives a current supplied from the first power supply, and converts the received current into the output current; and a control unit that controls the magnetic energy recovery switch such that an electric current frequency of the output current includes a first electric current frequency and a second electric current frequency which are different from each other within a one-time electric processing time using the electric processing device.

Disclosed herein are a method and a device for forming a groove in a surface of a steel sheet. In the method for forming a groove in a surface of a steel sheet, in order to form grooves at a depth of 10% or less of a thickness of the steel sheet in the surface of the steel sheet by irradiating a laser beam, in the case in which laser beams are irradiated from a plurality of laser oscillators to a scan mirror, pass through the scan mirror, and are then irradiated to the surface of the steel sheet, two or more laser beams share one scan mirror with each other to minimize a thermal influence of groove portions at a high line speed of 20 mpm or more, thereby accomplishing iron loss improvement characteristics before (after) heat treatment.

A steel sheet assembly includes a plurality of lapped steel sheets which have a tensile strength of 1,470 MPa or less and a thickness of 0.3 mm to 5.0 mm, the steel sheet assembly being formed by applying, in advance, an adhesive and a carbon-supplying agent to a surface of either or both of the steel sheets to be lapped and then welding the steel sheets. A weld of the assembly has a nugget diameter of 2.8√t (mm) or more, where t (mm) denotes the thickness of a thinner one of the steel sheets on both sides of a weld interface, and the amount of C is increased by 0.02 % by mass or more as compared to the steel sheets before being applied with the adhesive and the carbon-supplying agent.

In a laser machining apparatus, a controller is configured to perform: supplying an initial drive current to a pump light emitting device during an initial drive current supply period; controlling a scanner to start scanning a laser beam emitted from a laser beam emitting device after a standby period has elapsed from a start of supplying the initial drive current; and supplying a prescribed drive current to the pump light emitting device after the initial drive current supply period has elapsed, a prescribed drive current value being smaller than an initial drive current value, the pump light emitting device emitting the pump light having prescribed light intensity upon receipt of the prescribed drive current, the laser beam emitting device emitting the laser beam having prescribed beam intensity when the pump light having the prescribed light intensity is incident upon the laser beam emitting device.

A welding electrode apparatus has an electrode base, and electrode tip, and a locking ring that clamps the tip to the base, and that, when released, permits the tip to be replaced when worn. The locking ring and electrode tip co-operate to define an accommodation for a machine fed nut. The locking ring has a non-electrically conductive end face, and stands proud of the tip of the electrode. The locking ring has an unobstructed outside peripheral face suitable for gripping and tightening or loosening with a wrench. The locking ring has an internal, annular fluid cooling gallery and inlet and outlet ports tapped into the gallery. The cross-section of the gallery is non circular. The wall thickness of the part is roughly constant. On assembly and installation, the locking ring clamps to the tip and base, and provides a thermal conduction heat path to each of them.

A process for preparing a multi-thickness welded steel vehicle rail, the process comprises the steps of: (a) forming a first tube having a first outer diameter, an inner diameter and a first wall thickness; (b) forming a second tube having the first outer diameter, a second inner diameter and a second wall thickness different than the first wall thickness; (c) swaging a first end of the first tube to a second outer diameter less than the second inner diameter of the second tube; (d) inserting the swaged first end of the first tube into an end of the second tube to form a joint; (e) welding the first tube and the second tube together to form a weld at the joint to form a tube blank with a heat affected zone of lower metal strength in the area of the weld; (f) preheating the tube blank to create a common crystalline microstructure along a length of the tube blank; (g) introducing the tube blank into a blow molding tool having inner molding walls; (h) molding the tube blank at an elevated temperature by expanding the tube blank against the inner molding walls of the molding tool by injecting a pressurized medium into an interior cavity of the tube blank; and (i) quenching the tube blank by replacing the pressurized medium with a cooling medium through the molding tool and the tube blank to achieve a rapid cooling effect on the tube blank and to create a completed vehicle rail with essentially uniform material strength across the weld. A completed vehicle rail has an overlapped welded structure and uniform microcrystalline structure along the length of the rail.