Nisshin Steel Co., Ltd.

Nippon Steel Nisshin Co., Ltd.

Nippon Steel Corporation

Takefumi Nakako

Kazuaki Hosomi

Tomokazu Nobutoki

Tsutomu Azuma

Hirohisa Mishima

Kouki Tomimura

Toshiharu Kittaka

Hiroshi Asada

Takeyuki Yoshida

Masahiro Nakata

Kenji Ooshima

Yasuhiro Sakurada

Keiji Yamamoto

Shigeo Matsubara

Kenji Ogawa

Hiroki Kanazawa

Akinobu Takezoe

Shoji Inoue

Tatsurou Iwasaki

Hiromichi Shiroma

Tetsuo Itou

Hiroyuki Tanase

A welded member includes a hot dip Zn-based alloy coated steel sheet as a base material and has excellent corrosion resistance and weld bead shear strength. In the welded member in which a lower sheet and an upper sheet, which are hot dip Zn-based alloy coated steel sheets, are stacked and arc-welded together, a weld bead is formed so that a cross-sectional width W satisfies the following formula 2T&#x2264;W&#x2264;6T, and a blowhole occupancy Br represented by the following formula becomes not more than 50%: Br=(&#x3a3;di/L)&#xd7;100, where T represents a thickness of the hot dip Zn-based alloy coated steel sheet, di represents a length of an i-th blowhole observed in X-ray radiography, and L represents a length of the weld bead.

Welded member and method for manufacturing same

Hot dip Zn-based alloy coated steel sheets (') are arc-weld in such a way that (a) a current waveform is a pulsed current waveform in which (i) a peak current and a base current alternate with each other at a pulse period of 1 ms to 50 ms and (ii) an average welding current is 100 A to 350 A and (b) an average welding voltage is 20 V to 35 V. Each of the hot dip Zn-based alloy coated steel sheets (&#x2032;) includes a coating layer that contains Zn as a main component and that contains Al at a concentration of 1.0% by mass to 22.0% by mass, and has a coating weight W of 15 g/mto 250 g/m.

Arc welding method for hot-dip galvanized steel plate having excellent appearance of welded part and high welding strength, method for manufacturing welding member, and welding member

The present invention provides a method for MIG brazing an Al alloy to a steel sheet so as to manufacture a lap joint member that excels in bonding strength with respect to the Al alloy. With the MIG brazing method, a bonding target sheet, specifically, an Al sheet or an Al alloy sheet is bonded to a hot dip Zn-based alloy coated steel sheet () whose coating layer contains Al in an amount of 1.0% by mass to 22.0% by mass. A target location of MIG brazing is a region between (i) an intersection (C) of one end of an end surface () of the bonding target sheet and the hot dip Zn-based alloy coated steel sheet and (ii) the other end (U) of the end surface of the bonding target sheet.

Method for MIG brazing, method for manufacturing lap joint member, and lap joint member

The present invention provides a method for laser brazing an Al alloy to a steel sheet so as to produce a lap joint member that excels in bonding strength with respect to the Al alloy. The laser brazing method includes a brazing step of forming a brazed part () for bonding an Al alloy () to a hot dip Zn-based alloy coated steel sheet () in which a coating layer () contains 1.0 to 22.0% by mass of Al and a coating weight per surface is 15 to 250 g/m.

Laser brazing method and production method for lap joint member

A vacuum insulation panel manufacturing method that makes it possible to manufacture low-cost, high-performance vacuum insulation panels, and a vacuum insulation panel are provided. This method of manufacturing a vacuum insulation panel () involves: a stacking step in which a first metal plate () is stacked on one side of an insulating core material (), and in which a backing member () having an opening () and a second metal plate () having an evacuation port () are stacked, with the opening () and the evacuation port () stacking, on the other surface of the core member () in the order of backing member () and second metal plate () from the core member () side; a first welding step for welding outwards of where the core member () is arranged in the first metal plate () and the second metal plate (); an evacuating step from the evacuation port () to create a vacuum in an inner area which is held between the first metal plate () and the second metal plate () and in which the core member () is arranged; and a laser welding step in which, in a state in which the inner area is made into a vacuum by the evacuating step, the evacuation port () is sealed by means of a sealing material () and the sealing material (), the second metal plate () and the backing member () are laser welded.

Vacuum insulation panel manufacturing method, and vacuum insulation panel

A vacuum insulation panel manufacturing method that makes it possible to manufacture low-cost, high-performance vacuum insulation panels, and a vacuum insulation panel are provided. This method of manufacturing a vacuum insulation panel involves: a stacking step in which a first metal plate is stacked on one side of an insulating core material, and in which a backing member having an opening and a second metal plate having an evacuation port are stacked, with the opening and the evacuation port stacking, on the other surface of the core member in the order of backing member and second metal plate from the core member side; a first welding step for welding outwards of where the core member is arranged in the first metal plate and the second metal plate; an evacuating step from the evacuation port to create a vacuum in an inner area which is held between the first metal plate and the second metal plate and in which the core member is arranged; and a laser welding step in which, in a state in which the inner area is made into a vacuum by the evacuating step, the evacuation port is sealed by means of a sealing material and the sealing material, the second metal plate and the backing member are laser welded.

A vacuum insulation panel manufacturing method that makes it possible to manufacture low-cost, high-performance vacuum insulation panels, and a vacuum insulation panel are provided. This method of manufacturing a vacuum insulation panel () involves: a stacking step in which a first metal plate () is overlaid on one side of a thermally insulating core material (), and in which a backing member () having an opening () and a second metal plate () having an exhaust port () are placed, with the opening () and the exhaust port () overlapping, overlaid on each other on the other surface of the core member () in the order of backing member () and second metal plate () from the core member () side; a first welding step for welding outwards of where the core member () is disposed in the first metal plate () and the second metal plate (); a vacuum creating step for evacuating air from the exhaust pert () to create a vacuum in an inner area which is held between the first metal plate () and the second metal plate () and in which the core member () is arranged; and a laser welding step in which, in a state in which the inner area is made into a vacuum by the vacuum creating step, the exhaust port () is sealed by means of a sealing material () and the sealing material (), the second metal plate () and the backing member () are laser welded.

Vacuum insulation panel manufacturing device

The present invention provides a method for producing a TIG-welded stainless steel tube without adding Hto a shielding gas, while inhibiting generation of a weld defect. The method is a method for producing a TIG-welded stainless steel tube and includes the steps of bending a stainless steel strip in a width direction so as to butt both edges against each other and TIG-welding the both edges thus butted. A pulse waveform of a pulse frequency of 40 Hz to 300 Hz is used as a current waveform of a welding power source.

Method for producing TIG welded stainless steel tube, TIG welded stainless steel tube, and TIG welded stainless member

A welded portion shape of a cross-section perpendicular to the shaped steel longitudinal direction is set to satisfy a&#x3e;0 mm, b&#x3e;0 mm, c&#x2265;0.14 Tw, d&#x2265;0 mm, e&#x2265;0 mm, a+d&#x2264;2 mm and b+e&#x2264;2 mm; where a is a front melting width of the web material (on the laser beam irradiation side), b is a rear melting width of the web material (on the laser beam non-irradiation side), c is a maximum weld penetration depth, in a plate pressure direction, into the flange material, d is a front melting width of the flange material (on the laser beam irradiation side), e is a rear melting width of the flange material (on the laser beam non-irradiation side), and Tw is the plate thickness of the web material.

Laser welded shaped steel

A laser welding method for welding materials having different thicknesses includes abutting two plates having different thicknesses such that one surface of the thin plate and one surface the thick plate are made flush with each other; and thereafter welding the plates by applying a laser beam to abutting surfaces thereof, wherein the laser beam is directed obliquely relative to an abutting end face of the thick plate, a target position of the laser beam is determined on the abutting end face of the thick plate, and a target position depth D on the abutting end face of the thick plate is determined based on the formula t/3&#x2264;D&#x2264;t where t is a thickness of the abutting end face of the thin plate.

Method for laser welding of materials having different thicknesses

A sleevefor introduction of a pressurized fluid, which is attached to a rockbolt main body, comprises a cylindrical projecting partof a large diameter and a bearing-plate-holding partof a diameter smaller than an aperture of a bearing plate. The projecting partand the bearing-plate-holding partpreferably has the same inner diameter. When the rockbolt main bodyis embedded in a bedrock or ground, the bearing platelocates on an edge of a rockbolt-setting hole of the bedrock or ground, and the bearing-plate-holding partextends through the bearing plateinto the rockbolt-setting hole. Since the projecting partand the bearing plateare disposed on a sprayed concrete layer, a projection height of the rockbolt is remarkably decreased. Consequently, lining concreteis applied onto the sprayed concrete layer with ease, and the bedrock or ground is reinforced with high reliability.

Rockbolts made of steel pipes

A high-strength steel pipe rockbolt has an expansive rockbolt main body prepared by processing a high-strength steel sheet of 1.8-2.3 mm in thickness with a tensile strength of 490-640 N/mmand an elongation of 20% or more into a welded pipe and roll-forming the welded pipe into a shaped pipe having one or more concavities extending along an axial direction. Use of the high-strength steel sheet ensures sufficient strength of the shaped pipe regardless of a decrease in thickness. The thin welded pipe is also advantageous in resistance to cracking caused by accumulation of strains introduced during roll-forming, swaging both ends of the welded pipe and hydraulic expansion. Moreover, expansive deformation of the shaped pipe is initiated by injection of a pressurized fluid at a low pressure, so that the expansive deformation is completed in a short time period with an improved working efficiency.

Rockbolt of high strength steel pipe and method of manufacturing the same

In a method for making thin-walled metal pipes, application of a pre-deformation to a metal sheet by plastic bending longitudinally perpendicular thereto, and forming the metal sheet into a pipelike shape by use of the widthwise curvature resulting from residual stress of the metal sheet receiving such plastic bending, when its lengthwise curvature is reduced to zero, the metal sheet being joined together at its junction.

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Tokyo, Japan

Takefumi Nakako