A sealing method that uses an electrostatic energy storage welding machine which includes an energy storage section including a plurality of energy storage parts is provided. A method of sealing a liquid inlet port of a power storage device includes burring in advance a through-hole of the liquid sealing port to raise a hole edge of the through-hole into a form of a projection, wherein the liquid sealing port of the power storage device to be sealed with electrolyte contained therein corresponds to an object to be welded; placing a spherical body that is a lid body on the projection; and performing resistance welding between the projection and the spherical body to seal the liquid inlet port.

A welding method for the manufacture of an assembly of at least two steel substrates spot welded together through at least one spot welded joint, including A. provision of substrates including a press hardened steel part obtained by press hardening of a steel sheet coated with an aluminium based coating, B. application of a spot-welding cycle with welding electrodes and a spot-welding power source applying a current, the cycle including: at least three pulsations, each having the same maximum pulsation current (Cp) applied through the substrates, each pulsation duration p being identical and set from 20 to 60 ms, each pulsation being followed by the same cooling time c set from 30 to 50 ms, wherein the welding parameter Wp value is at least 0.8, Wp being defined as Wp=(t?c)/p t being the average thickness of the substrate in mm, c being the cooling time in ms, p being the pulsation duration in ms.

A galvanized steel sheet includes: a steel sheet having a chemical composition satisfying an equivalent carbon content Ceq of 0.35% or more and less than 0.60%, and a specified steel microstructure; and a galvanized layer on a surface of the steel sheet. The retained austenite has a solute C content of 0.6% or more by mass, and retained austenite grains with an aspect ratio of less than 2.0 constitute 50% or more of all retained austenite grains. In 90-degree bending at a curvature radius/thickness ratio of 4.2 in a rolling (L) direction with respect to an axis extending in a width (C) direction, an L cross section in a 0 to 50 ?m region from a surface of the steel sheet on a compression side has a number density of voids of 1000/mm.sup.2 or less, and the galvanized steel sheet has a tensile strength of 590 MPa or more.

A joining device for connecting a metal member and a resign member with a metal fastener including a penetrating tip comprises: a cylindrical nosepiece; a high frequency electromagnetic induction coil around the nosepiece; an electrode punch for pressing the fastener into the resign member; a electronic chopper for producing a high frequency current; a high frequency power supply for supplying an induction current to the induction coil; a welding power supply for supplying a welding current between the electrode punch and the metal member; a contact detector for sensing when the fastener tip touches the metal member; and a switching unit for automatically switching from the induction current to the welding current when the contact detector senses that the tip has contacted the metal member.

A lap welding method of a steel sheet includes spot welding in a state in which the flange portion of a second steel sheet member having the flange portion and a standing wall portion is overlapped with the first steel sheet member, thereby forming a nugget between a first steel sheet member and a flange portion; and, after the spot welding, laser welding a region between an R stop of the standing wall portion and the nugget, thereby forming a weld bead, and, in the weld bead, a length dimension is equal to or longer than a diameter of the nugget, and a width dimension is 0.5 to 3.0 mm.

The invention relates to an apparatus and a method for the low-resistance welding of metal sheets with a high cycle rate.

A secondary battery includes: an electrode body including an electrode main body, a collector foil protrusion section, and a collector foil connection portion; a first collector terminal including a first extension part that is welded to the collector foil connection portion; and a second collector terminal that is a member separate from the first collector terminal and includes a second extension part welded to the collector foil connection portion. The first extension part and the second extension part are located on the opposite sides of the collector foil connection portion. The secondary battery includes a welded joint at which both the first extension part and the second extension part are welded to the collector foil connection portion such that the first extension part, the second extension part, and the collector foil connection portion are united. The first collector terminal and the second collector terminal are united through the welded joint.

For the determination of the welding current to be used for the resistance welding of the overlap seam of container bodies, welding with a test body is carried out with a changing strength of welding current which in the test body produces a varying welding of the seam. The current strength varies from welding of this seam with a too high temperature to welding with a too low temperature. Along with this the welding current strength used in the welding is determined so that it is further determined at which point of the seam the welding has been accomplished and with what strength of welding current. By means of a mechanical and/or optical investigation of the welded seam it can then be easily determined where the seam has been correctly welded for the series production of container bodies from the same sheet material as the test bodies. When such a point or such a region of the seam is known the welding current used in the test welding can be taken as the welding current for serial production.

A one-side spot welding device includes a base which is formed in a cylindrical shape, a welding head and a welding tip. The base has a push rod operable in an upward and a downward direction with respect to the base and has a slide groove in an upper inner circumferential surface thereof. The welding head is installed at an upper side of the base so as to be slidable in a radial direction and equally divided in a circumferential direction so as to include a plurality of unit welding heads in close contact with one another. The unit welding heads are capable of being spaced apart from one another in the radial direction by the push rod. The welding tip is formed in a cylindrical shape so as to be configured at an outer circumference of the base, operates in an upward and a downward direction and is capable of applying welding electric current to the welding head.

A vehicle body manufacturing apparatus includes: a jig that holds one work of the vehicle body, positions the one work to the another work, and joins the works together at a joint section; a welding gun that welds a weld portion in the joint section by an electrode that is moved along a pressure axis and pressed against the weld portion; and a welding position fixing member that regulates the pressure axis, along which the electrode is moved, within a setting area, the welding position fixing member being movable in a coaxial direction to the pressure axis along which the electrode is moved, being contactable with the joint section to interpose the joint section between the jig and the welding position fixing member, and having a controllable pressure at a time of welding the weld portion by the electrode, which is moved at the time of welding.