A spot welding process which uses a metal insert as an insert between the sheets to be welded which belongs to the field of industrial welding, in order to prevent the presence of mark or indentation on the surface of the welds. After the welding process, as the metal insert material melts and dissolves between the overlapped sheets, the state of the art does not provide for the use of metal insert as an insert between the sheets, the spot welding process with insert between (2), made of metal powder or solid metal, which is introduced between the interfaces of the sheets (3) to be welded by the spot welding process, the insert (2) (3), by inert adhesive (4) or other material and process which performs this function, wherein during the melting process the metal insert (2) melts and dilutes together with the base material, i.e. the opposing metal plates (3). The alloy of the metallic insert (2) has chemical and physical properties compatible with the properties of the base metal sheets (3), the spot welding equipment requires that its contact electrodes (5) have the fully flat surfaces (6) and Or special contact geometry.

The base member 3 can be attached to and detached from a base-holding member 5 without using tools and the like. The base-holding member 5 has a positioning mechanism that decides the position of the base member 3 on the base-holding member 5. Here, a reference part that decides the position of the base member 3 on the base-holding member 5 in a direction parallel to an optical fiber installation surface 2, which is an upper surface of the base member 3, is called a horizontal positioning reference part. Also, a reference part that decides the position of the base member 3 on the base-holding member in a direction vertical to the optical fiber installation surface 2 (the direction vertical to the horizontal positioning reference part), which is the upper surface of the base member 3, is called a vertical positioning reference part 6. That is, the horizontal positioning reference part and the vertical positioning reference part 6 are provided on the base-holding member 5.

The base member 3 can be attached to and detached from a base-holding member 5 without using tools and the like. The base-holding member 5 has a positioning mechanism that decides the position of the base member 3 on the base-holding member 5. Here, a reference part that decides the position of the base member 3 on the base-holding member 5 in a direction parallel to an optical fiber installation surface 2, which is an upper surface of the base member 3, is called a horizontal positioning reference part. Also, a reference part that decides the position of the base member 3 on the base-holding member in a direction vertical to the optical fiber installation surface 2 (the direction vertical to the horizontal positioning reference part), which is the upper surface of the base member 3, is called a vertical positioning reference part 6. That is, the horizontal positioning reference part and the vertical positioning reference part 6 are provided on the base-holding member 5.

In a welded joint manufactured by a method of resistance spot welding thin steel sheets, when the diameter of a nugget formed from the thin steel sheets is denoted by d, on a horizontal plane passing through a nugget surrounded by a corona bond, distribution of an amount of P in a region in the nugget surrounded by a closed curve at a distance d/100 from an end portion of a weld zone toward the inside of the nugget and a closed curve at a distance d/5 from the end portion of the weld zone toward the inside of the nugget is analyzed by area analysis, and the proportion of the region in terms of area in which the concentration m (mass %) of P is more than twice the concentration M (mass %) of P of a base metal composition is 5% or less.

In a welded joint manufactured by a method of resistance spot welding thin steel sheets, when the diameter of a nugget formed from the thin steel sheets is denoted by d, on a horizontal plane passing through a nugget surrounded by a corona bond, distribution of an amount of P in a region in the nugget surrounded by a closed curve at a distance d/100 from an end portion of a weld zone toward the inside of the nugget and a closed curve at a distance d/5 from the end portion of the weld zone toward the inside of the nugget is analyzed by area analysis, and the proportion of the region in terms of area in which the concentration m (mass %) of P is more than twice the concentration M (mass %) of P of a base metal composition is 5% or less.

Resistance spot welding of a thin-gauge steel workpiece to another steel workpiece is achieved through the combined use of specific spot welding electrodes and a pulsating welding current. Each of the spot welding electrodes has a weld face that is smaller in diameter than a typical steel spot welding electrode. And the pulsating welding current that is used in conjunction with the smaller-sized spot welding electrodes includes at least two stages of electrical current pulses.

Aluminum alloy workpieces and/or magnesium alloy workpieces are joined in a solid state weld by use of a reactive material placed, in a suitable form, at the joining surfaces. Joining surfaces of the workpieces are pressed against the interposed reactive material and heated. The reactive material alloys or reacts with the workpiece surfaces consuming some of the surface material in forming a reaction product comprising a low melting liquid that removes oxide films and other surface impediments to a welded bond across the interface. Further pressure is applied to expel the reaction product and to join the workpiece surfaces in a solid state weld bond.

The invention relates to a method for producing a composite sheet metal part having at least one metallic region from a composite sheet metal blank which has two outer cover sheets of metal and at least one layer which is arranged between the cover sheets and consists of plastics material. The invention provides an apparatus and method by which complex formed composite sheet metal parts can easily be produced in a few steps and which still have metallic regions which can be used for joining to further parts.

The invention relates to a method for producing a composite sheet metal part having at least one metallic region from a composite sheet metal blank which has two outer cover sheets of metal and at least one layer which is arranged between the cover sheets and consists of plastics material. The invention provides an apparatus and method by which complex formed composite sheet metal parts can easily be produced in a few steps and which still have metallic regions which can be used for joining to further parts.

A structural member is provided that includes a steel sheet with a tensile strength of 980 MPa or higher overlying another metal plate and joined thereto by welding, where a break initiating near a welded portion is less likely to be produced. A structural member (10, 10a, 10b, 10c) includes: a first member (1), the first member being a steel sheet with a tensile strength of 980 MPa or higher; a second member (2) overlying the first plate (1), the second member being a metal plate; a plurality of welded portions (3, 31, 32); a plurality of heat-affected zones (5, 51, 52) each formed to surround the corresponding one of the welded portions (3, 31, 32), the heat-affected zones having a Vickers hardness lower than that of the first member by 50 HV or more. A pair of edge sections (4) of the first member (1) are provided between adjacent heat-affected zones (5, 51, 52). The pair of edge sections (4) of the first member located between the adjacent heat-affected zones (5, 51, 52) extend to cross a line (LC1) linking the adjacent welded portions (3, 31, 32).