A resistance spot welding method includes the steps of: removing at least part of oil on a surface of a welding target material by energization between a pair of electrodes; and after the oil removal step, forming a nugget in an overlapped portion of the welding target material by energization between the pair of electrodes.

In a vehicle body structure, an end portion of a first vehicle body member having a plate shape is coupled to a second vehicle body member having a plate shape. The first vehicle body member is made of a first metal and the second vehicle body member is made of a second metal. The vehicle body structure includes a third vehicle body member made of the first metal. The third vehicle body member includes an interposed portion having general portions and a convex portion. The convex portion has a weld-joint portion configured to be joined to the end portion of the first vehicle body member by welding. Each of the general portion has a swage-joint portion configured to be swaged and jointed to the second vehicle body member in a circular shape viewed from a thickness direction, and a cutout portion.

A steel sheet with a tensile strength (TS) of 1180 MPa or more, a member, and a method for producing them. In a region of the steel sheet within 4.9 μm in the thickness direction, a region with a Si concentration not more than one-third of the Si concentration in the chemical composition of the steel sheet and with a Mn concentration not more than one-third of the Mn concentration in the chemical composition of the steel sheet has a thickness of 1.0 μm or more. The lowest Si concentration L.sub.Si and the lowest Mn concentration L.sub.Mn in the region within 4.9 μm in the thickness direction from the surface of the steel sheet and a Si concentration T.sub.Si and a Mn concentration T.sub.Mn at a quarter thickness position of the steel sheet satisfy the following formula (1):

L.sub.Si+L.sub.Mn≤(T.sub.Si+T.sub.Mn)/4  (1).

A method for producing a zinc or zinc-alloy coated steel sheet with a tensile strength higher than 900 MPa, for the fabrication of resistance spot welds containing in average not more than two Liquid Metal Embrittlement cracks per weld having a depth of 100 μm or more, with steps of providing a cold-rolled steel sheet, heating cold-rolled steel sheet up to a temperature T1 between 550° C. and Ac1+50° C. in a furnace zone with an atmosphere (A1) containing from 2 to 15% hydrogen by volume, so that the iron is not oxidized, then adding in the furnace atmosphere, water steam or oxygen with an injection flow rate Q higher than (0.07%/h×α), α being equal to 1 if said element is water steam or equal to 0.52 if said element is oxygen, at a temperature T≥T1, so to obtain an atmosphere (A2) with a dew point DP2 between −15° C. and the temperature Te of the iron/iron oxide equilibrium dew point, then heating the sheet from temperature T.sub.1 up to a temperature T.sub.2 between 720° C. and 1000° C. in a furnace zone under an atmosphere (A2) of nitrogen containing from 2 to 15% hydrogen and more than 0.1% CO by volume, with an oxygen partial pressure higher than 10.sup.−21 atm., wherein the duration t.sub.D of heating of the sheet from temperature T.sub.1 up to the end of soaking at temperature T.sub.2 is between 100 and 500 s., soaking the sheet at T.sub.2, then cooling the sheet at a rate between 10 and 400° C./s, then coating the sheet with zinc or zinc-alloy coating.

A bracket of a cylinder device includes: a tubular portion having a C-shaped cross section, holding an outer periphery of the outer shell, and having a slit in a front portion; and a pair of mounting portions and protruding outward in the radial direction from both ends of the tubular portion in the circumferential direction. The tubular portion includes a hole formed to permit insertion of the protrusion, from at least one side portion to the back portion of the tubular portion.

The present invention includes a laser-welded lap joint including a weld zone formed by laser lap welding in a lapped portion including a plurality of lapped steel sheets. The weld zone includes a main weld zone that penetrates the steel sheets in the lapped portion and a final weld zone formed at one end of the main weld zone and having a crater, and the weld zone satisfies formulas (1) to (4):
L≥15.0;  (1)
10.0≥L2≥2l.sub.c;  (2)
t1≥2d.sub.c;  (3)
w.sub.c>d.sub.c  (4).

A valve seat formed within an aluminum engine component includes a valve seat surface machined within the aluminum engine component, a layer of copper alloy material laser clad onto the valve seat surface of the aluminum engine component, the layer of copper alloy material having a thickness of less than 2.0 millimeters, and a layer of copper alloy/tool steel carbide material laser clad onto the layer of copper alloy material, the layer of copper alloy/tool steel carbide material having an average thickness of less than 0.5 millimeters, wherein the layer of copper alloy/tool steel carbide material has an outer surface that is machined to a final valve seat profile.

A method for producing a joining connection between at least two metal sheets or at least two components made of hot-workable sheet metal with a scaling-resistant coating, comprising is provided. The method includes at least one step in which a connection is produced between the at least two metal sheets or sheet-metal components by hot-press soldering, wherein the surface of the metal sheets or components to be connected is pretreated in order to break up the coating.

A method for joining first and second axle components is provided. In one example, the method includes forming an aperture in a first axle component that is mounted to a second axle component, where the aperture has a chamfer at one end thereof, inserting an object into the aperture, and resistance welding the aperture while applying pressure to the object so that the object fills the chamfer.

A welded steel part obtained by welding a first sheet with a second sheet, at least one with a coating of aluminum alloy. The welding uses a welding wire which, after melting and cooling, constitutes a weld bead connecting the first sheet to the second sheet and being part of said welded steel part. The respective peripheral edge of the first and second sheets are in a joggled edge type configuration in which the peripheral edge of the first sheet is arranged above, and on or near the upper face of an end portion of the peripheral edge of the second sheet which is extended by an inclined junction portion, at least one part of the upper face of the inclined junction portion delimits at least laterally with the edge of the peripheral edge of the first sheet a groove receiving the weld bead, the inclined joining portion extending by a welding portion in longitudinal continuity with the peripheral edge of the first sheet.