A method of lap welding for producing a welded lap joint (110) having good integrity, high peel strength, high tensile strength, high fatigue resistance, where the overlapped sheets (30, 32) are fused together across their region of overlap (50). Before welding, one sheet (30) is overlapped with another sheet (32) forming a lap joint (94). Preferably, the width of overlap is at least 50 % of the thickness of the thinnest sheet and no greater than twice the thickness of the thickest sheet. During welding, a high energy density radiation beam (34) is trained on at least one of the sheets and is acutely angled relative to the plane of overlap (56), which coincides with the weld interface (48) of the sheets (30, 32). Preferably, the sheets (30, 32) can be oriented relative to the direction of gravity such that the plane of overlap (56) of the sheets (30, 32) is acutely oriented relative to gravity so that during welding the direction of gravity influences formation, geometry and flow of a molten weld nugget (102). To join the sheets (30, 32), the beam (34) is trained on at least one of the sheets for a sufficient period of time and with a sufficient energy density to weld the sheets (30, 32) together completely from front to back of the overlap (56) producing a weld (110) having high peel strength with no unfused lip across the overlapping area. After welding is completed, the sheets (30, 32) can be formed using any conventional forming or any shaping process.

Method of high energy density radiation beam lap welding

Slide contact unit

In forming a desired print gap between a sheet of paper fed on a platen and a print head by driving a moving mechanism for changing a space between the platen and the print head, a condition where the space between the platen and the print head becomes smaller than a predetermined value is detected, and in this case the space between the platen and the print head is increased by a driving portion for driving the moving mechanism. Accordingly, when a thin paper is used as the sheet of paper, cutting, wrinkling, etc. of the thin paper can be prevented.

Print gap adjusting device

An automatic welder is used in an internal welder unit which travels along the interior of a pipeline and welds the abutting ends of the pipe segments together. The automatic welder has a carriage assembly that contains a laser source for producing a laser beam, first and second line-up clamp assemblies for aligning the respective abutting ends of the pipe segments together, at least one laser beam conductor, or alternatively a reflecting surface positioned between said first and second line-up clamp assemblies along the axis of said beam, for directing said beam to the abutting ends of said first and second pipe segments, and a drive for rotating the reflecting surface around the axis of said beam to direct the beam to the abutting ends of said pipe segments for welding said pipe segments together. The automatic welder can also be configured as an external welder in which the automatic welder carrying a laser source is carried on a track mounted on the outside of the pipeline. As the external welder orbits around the pipeline, the laser source generates a laser beam which is directed at the junction of the abutting ends of the pipe segments for welding them together. Arc and laser beads can be combined to form a composite welding joint.

Arc and laser welding process for pipeline

Process for manufacturing a welded pipe from a metal strip having two longitudinal edges approximately parallel to each other, which are brought together so as to come approximately into contact with each other and thus form an unwelded pre-tube, the said pre-tube then being welded in order to join the said edges together. According to the invention, the two edges are welded together to obtain a welded metal pipe by using, approximately simultaneously, at least one laser beam and at least one electric arc, that is to say using a hybrid arc/laser, preferably plasma/laser, welding process. This process can be used to produce weld seams of rectilinear, helicoidal or spiralled shape.

Application of a hybrid arc/laser process to the welding of pipe

PURPOSE:To execute welding with high quality, high toughness and high efficiency by combining laser tack welding and submerged arc welding to execute said welding. CONSTITUTION:An open pipe 7 after UO working is moved toward an arrow 14 by a pipe mover 10 of a tack welding machine. On the other hand, laser light 8 to be used for laser welding is bent to a perpendicular direction by a mirror right above the weld point and is condensed by a lens so as to be irradiated onto the target weld point. The focus of the condensed light is so adjusted as to be positioned lower than the top point in the butt part of the pipe 7 in order to obtain deep penetration at a high speed. The weld point is shielded by the inert gas ejected from a welding torch in the direction coaxial with the beam. Since the laser welding is used for tack welding in the above-mentioned way, the stubbing and humping defects at the beginning and terminal ends of welding are thoroughly eliminated. The high-speed welding and penetration depth equal to or higher than by an MIG welding method are obtd. with the small molten area.

Welding procedure of steel material with high quality, high toughness and high efficiency

PURPOSE:To fusion-cut in an arbitrary shape and in a smooth cut surfaces, by injecting oxygen or oxygen containing gas coaxially with the laser beam and behind the laser beam. CONSTITUTION:The focus is aimed slightly lower than the surface of a condenser lens 1. As a cutting gas, oxygen or oxygen containing gas is introduced from a lead- in hole 2a, and this cutting gas in injected from a main opening 3 toward a silicon steel plate 4 so as to be coaxial with a laser beam 1a. A subsidiary opening 6 is provided behind the main opening 3, and the cutting gas introduced from the lead-in hole 2b is injected from the subsidiary opening 6. Thus, by heating and melting the silicon steel paltes 4 with the laser beam 1a, the plate can be easily fusion-cut by injecting cutting gas, so that a smooth fusion-cutting plane may be obtained.

Fusionncutting method of silicon steel plates

PURPOSE:To make laser welding easy, by utilizing a dummy plate which is excellent in cutting characteristic, and making a plate butting surface which becomes a weld line coincide with a laser scanning line easily, in case of butt-welding of a material which is inferior in laser cutting characteristic. CONSTITUTION:A preceding plate 3 of materials 3, 4 to be welded is made to pass through a laser welding and cutting device 2, is stopped, subsequently a dummy plate 12 is forwarded to a prescribed position of said device 2, and it is fused into two pieces 12a, 12b by a laser torch 7. 12a is removed, the cut surface of 12b is left on the running line of the laser torch 7, and after that, the preceding plate 3 is moved backward, and its rear end is butted against the cut surface of 12b and is clamped. 12b is removed, the following material to be welded 4 is forwarded to the laser welding and cutting device 2, and its front end is pressed against the rear end of the preceding plate 3 which has been fixed on the laser torch running line, which is made to a weld line. After the running line center of the laser torch has been aligned exactly with the weld line, the material to be welded 3, 4 are welded by the laser torch 7.

Laser welding method

PURPOSE:To manufacture inexpensively a steel sheet excellent in workability and vibration-damping properties by rolling the laminated stocks obtained by overlapping the coated layers of the stocks, having each a coated metal layer of specific thickness, formed by spraying metals on the sheet surfaces of rolling stocks respectively, after soaking them at a prescribed temperature. CONSTITUTION:One or more kinds of Ni, Cr, Co, Ti, Mg, Mn, A, Zn and Cu or an alloy of Fe and these metals are used for spraying materials. A sprayed metal layer 4 of 0.1-10mm thickness is formed on the sheet surface of a rolling stock 2, and the layers 4 of two stocks 2 are overlapped to join them together into a laminated stock by welding the circumferences of the overlapped parts to each other, etc. After soaking the laminated stocks in the ordinary heating furnace used for rolling within a range of 800-1,300 deg.C, they are rolled under a >=1.5 draft into a steel sheet. A composition-type vibration-damping steel sheet obtained in such manner, has the vibration-damping properties equal to those at normal temperature even at a high temperature of 400-500 deg.C.

Manufacture of composite type vibration-damping steel sheet

PURPOSE:To enable to obtain the weld metal having a high toughness at a high speed welding, by combining the flux having the composition of specific component, such as SiO2, CaO etc, with the wire containing Ti and welding at a specific welding condition and also, keeping Ti/N ratio in the welding metal constant. CONSTITUTION:Flux containing 8-28% SiO2, 15-35% CaO, 18-37% TiO2, 1-10% MnO, 1-8% AlO3, 5-15% CaF2 and 2-8% BaO and also, 37-53% total amount of basic component (CaO+MnO+CaF2+BaO), is used and welding is performed by combining said flux and welding wire containing Ti under the condition shown by the table. As a result of it, a high toughness weld metal containing 0.03-0.065% Ti, 0.0035-0.007% N, and 0.035-0.045% O and having the relation of Ti-4.3N=0.015-0.035(Ti, N is wt%), can be obtained.

Nishiyama Noboru

Papers

Welding procedure of steel material with high quality, high toughness and high efficiency

Fusionncutting method of silicon steel plates

Laser welding method

Manufacture of composite type vibration-damping steel sheet

High speed submerged arc welding