A laser welding method of the present disclosure includes the step of irradiating a workpiece with a laser beam in a helical shape along a weld part of the workpiece. The helical shape is a combination of a circular trajectory in which a laser beam is moved circularly, and a movement trajectory in which the laser beam is moved in a proceeding direction along the weld part. Furthermore, first energy of the laser beam moving so as to have a component of the proceeding direction in the circular trajectory is larger than second energy of the laser beam moving so as to have a component of an opposite direction to the proceeding direction in the circular trajectory.

Laser welding method

There is provided a method for manufacturing a laser welded steel pipe in which the status of laser welding is accurately assessed, and the assessment is used to modify welding conditions, so that laser welded steel pipes can be manufactured at a high yield rate and in a stable manner. Irradiation point(s) of laser beam(s), with which the longitudinal edges are irradiated from the side of the outer surface, are monitored from the side of the inner surface of an open pipe, and then conditions of welding with the laser beam(s) are assessed to be kept unchanged if any keyhole is found penetrating out of the inner surface of the open pipe, or modified if no keyhole is found penetrating out of the inner surface of the open pipe.

Method for manufacturing laser welded steel pipe

A welding apparatus of an embodiment includes: a welding torch and a shape sensor attached to a welding robot; a shape data extraction unit extracting, from measured data measured by the shape sensor, shape data representing an outline of an object to be welded; a transformation data calculation unit calculating, based on a position and a posture of the shape sensor, coordinate transformation data for correcting the shape data; a shape data correction unit correcting the shape data based on the coordinate transformation data; an angle calculation unit calculating, based on the corrected shape data, an inclination angle of a groove of the object to be welded; and a welding position and posture determination unit determining, based on the inclination angle of the groove, a position and a posture of the welding torch.

Welding apparatus and welding method

In this method for producing a laser-welded steel tube by forming a steel plate into a tubular open pipe by means of a forming roll and then laser welding the edge section of the open pipe by radiating a laser beam while applying pressure to the edge section using a squeeze roll, welding is performed with two laser beams each transmitted using a different fiber and having a correctly focused spot diameter of over 0.3 mm being radiated from the top surface side of the open pipe along the edge section, a preceding laser beam that precedes in the direction of welding progress at the top surface side of the open pipe and a subsequent laser beam that is subsequent being provided with an angle of incidence from the perpendicular direction to the top surface of the open pipe, radiating while tilted in the direction of welding progress, the angle of incidence of the preceding laser beam being caused to be greater than that of the subsequent laser beam, and the gap between the center point of the preceding laser beam and the center point of the subsequent laser beam at the rear surface of the open pipe being at least 1 mm.

Method for producing laser welded steel pipe

The invention discloses a butt-welding method and welding device for phosphorus-containing high-strength steel strips with tensile strength of at least 450MPa. The butt-welding method comprises the following steps of: butting-joint end surfaces obtained after finely shearing two same phosphorus-containing high-strength steel strips; applying pressure on the thickness direction of two steel strip plates by using a pair of leveling rollers to shape a welded seam; synchronously moving a pair of heaters and the leveling rollers to heat steel strip parts pressed by the leveling rollers; synchronously moving a laser along with the leveling rollers and the heaters, and butt-welding butting-joint parts of the two steel strips; and shaping a welded joint of the two steel strips by using the other pair of heaters and leveling rollers in the laser moving process. The welding device comprises the laser, wherein two sides of the laser are respectively provided with the heaters and the leveling rollers, and the heaters are arranged between the laser and the leveling rollers. By using the butt-welding method and the welding device, phosphorus as a microalloy element in the welded joint can be sufficiently diffused, furthermore, the welded joint has favorable toughness, and the steel strips can be kept not to break when being repeatedly bent under the action of high tension.

Butt-welding method and welding device for phosphorus-containing high-strength steel strips with tensile strength of at least 450MPa

PROBLEM TO BE SOLVED: To provide a method of laser welding for a steel sheet, in which there can be attained reduction of morphological defects of a weld area of welded material and exhibition of satisfactory bonding strengthSOLUTION: The method of laser welding for the steel sheet causes multiple steel sheets adhering water to abut on each other at end faces thereof and irradiating the abutted area of the steel sheets brought into mutual abuttal with laser beams to thereby weld the abutted area The method includes: a cutting step of cutting the end faces of the steel sheets into forms suitable for mutual abuttal; an abutting step of bringing the end faces formed by the cutting step into mutual abuttal; a first heating step of heating the abutted area; and a laser welding step of welding by laser the abutted area having been heated by the first heating step

Method of laser welding for steel sheet, and laser welding apparatus

PROBLEM TO BE SOLVED: To provide a laser welding method which restrains recession of a weld zone and provides excellent welding quality without diminishing welding efficiency in laser butt welding using laser beam, and to provide a laser welding device therefor. SOLUTION: In the invented laser welding method, a butt portion is formed by making ends of steel plates 1 and 2 butt to each other, and the butt portion is irradiated with a laser beam which is emitted from an oscillator 11 composed of a plurality of oscillation media, is transmitted by means of optical fibers 12 and is condensed by an optical system 13 so as to weld the steel plates. The laser beam is condensed so that one beam spot or two circular beam spots standing in line in the direction of the weld line are formed on the surface of the steel plates. Welding is performed by making the beam spots move along the weld line, with a relation that the total lengths L, L' and L" of the beam spots in the direction of the weld line on the surface of the steel plates are greater than the beam spot widths W, W' and W" in the direction perpendicular to the weld line. COPYRIGHT: (C)2009,JPO&INPIT

Laser welding method and laser welding device

PROBLEM TO BE SOLVED: To provide a laser welding apparatus that makes stable and high quality welding possible without having complicated and large-sized apparatus and that also has easy maintenance and low cost. SOLUTION: The laser welding apparatus includes a plurality of oscillation mediums arranged in parallel, an optical fiber for transmitting a laser beam released from the oscillation mediums, and a machining head having the optical fiber attached and having a focusing lens and a collimator lens. The apparatus is constituted so that the wavelength of the laser beam is ≤2 μm and that the spot diameter d of the focal point of the laser beam is ≥0.3 mm. COPYRIGHT: (C)2009,JPO&INPIT

Laser welding apparatus, laser welding method, and manufacturing method of metallic plate material

PROBLEM TO BE SOLVED: To provide a laser beam welding method and its apparatus capable of preventing any damage of an optical component due to sputtering, and preventing the adhesion of sputtering to a workpiece to be welded. SOLUTION: In the method for welding butted steel plates by using laser beam which is emitted from an oscillator 11 consisting of a plurality of crystalline bodies, transmitted via optical fibers 12, and condensed by an optical system 14, a first gas jetting means 17 for jetting gas from the transverse direction to sputtering scattered from a molten pool C formed by irradiation with the laser beam is arranged between the optical system and the steel plates, and the laser beam is emitted to perform the welding while jetting the gas across just above the molten pool so that the vertical distance from an extension A k along a lower end of a jet port of the first gas jetting means and the molten pool is in a range of ≤3 mm. COPYRIGHT: (C)2009,JPO&INPIT

Laser beam welding method for steel plate, and its apparatus

PROBLEM TO BE SOLVED: To provide the laser beam welding method and the laser beam welding device of steel plates, and a method of manufacturing a welded steel plate, by which occurrence of weld defects is prevented, when performing laser beam welding after heating a butted part with an induction heating device which runs in a plate width direction and generates a magnetic flux penetrating the steel plate in parallel with the surface of the steel plate. SOLUTION: Heating is performed with the induction heating device with which the magnetic flux penetrating the steel plate in parallel with the surface of the steel plate is generated while being moved from one end part in the plate width direction of the steel plate which is narrower in the plate width among a plurality of the steel plates toward the other end part. The heating is performed so that, when the length of the coil of the induction heating device is defined as L, the average value E2' of energy per unit time, which is output by the induction heating device by the time when the tail end of the coil passes through a position of 0.6 L from the other end of the steel plate and reaches the other end of the steel plate, is smaller than the average value E1' of the energy per unit time which is output by the induction heating device by the time when the tail end of the coil reaches the position of 0.6L from the other end of the steel plate when viewed from the other end of the steel plate. COPYRIGHT: (C)2010,JPO&INPIT

Yujiro Tatsumi

Papers

Method of laser welding for steel sheet, and laser welding apparatus

Laser welding method and laser welding device

Laser welding apparatus, laser welding method, and manufacturing method of metallic plate material

Laser beam welding method for steel plate, and its apparatus

Laser welding method and laser welding device of steel plate, and method of manufacturing welded steel plate