A method of laser welding structures having different steel grades together. The method includes providing a first structure made from a first steel grade and composition and providing a second structure made from a second steel grade composition. The first structure is positioned adjacent the second structure to create a weld zone area wherein at least a portion of the first structure overlaps at least a portion of the second structure. A filler material is selected that has a composition that will create a weld joint between the first structure, the second structure and the filler material such that the weld joint has a predetermined microstructure. The filler material is positioned adjacent the weld zone area. A laser beam is directed at the weld zone area to create a weld joint between the first structure, the second structure and the filler material, wherein the weld joint has a predetermined microstructure.

A method of production of a welded structure by butt welding two steel sheets (51, 52) by laser welding (11) while supplying assist gas (12) to a back surface of a melt pool (13), whereby it is possible to prevent formation of a through hole in the melt part (53), characterized in that a thickness of at least one steel sheet (52) of the two steel sheets (51, 52) is 0.6 mm or less, the assist gas (12) is a mixed gas (12) containing 10 to 50 vol % of O.sub.2 gas, and, when an O.sub.2 concentration in the mixed gas (12) is C (vol %), a flow rate L of mixed gas (12) (liter/min) satisfies 30 (liter/min)C(vol %)1 (liter/min/vol %)L (liter/min)<40 (liter/min).

A plate is continuously press-bent, into a shaped member having a recess opening at one surface (i.e., lower surface). Then, the plate is bent back by pressing, at the front and rear ends, covering the openings of the recess and a side frame having open cross sections, each with a gap, is thereby formed. In the forming step, the side frame is not welded and has open cross sections, each with a gap. The side frames are then subjected to the next step (i.e., step of assembling the seat frame). In the step of assembling the seat frame, the side frames and coupling members are welded together, constituting a substantially rectangular seat frame. As the side frames are so welded in step of assembling the seat frame, a rigid structure each having closed cross sections with no gaps is formed.

A method for joining and shaping flat materials. At least one first flat material and at least one second flat material are fed to a cutting and welding device in respective supply devices, each associated with one flat material.

A method for producing a welded blank (1) includes providing two precoated sheets (2), butt welding the precoated sheets (2) using a filler wire. The precoating (5) entirely covers at least one face (4) of each sheet (2) at the time of butt welding. The filler wire (20) has a carbon content between 0.01 wt. % and 0.45 wt. %. The composition of the filler wire (20) and the proportion of filler wire (20) added to the weld pool is chosen such that the weld joint (22) has (a) a quenching factor FT.sub.WJ: FT.sub.WJ0.9FT.sub.BM0, where FT.sub.BM is a quenching factor of the least hardenable substrate (3), and FT.sub.WJ and FT.sub.BM are determined: FT=128+1553C+55Mn+267Si+49Ni+5Cr79Al2Ni.sup.21532C.sup.25Mn.sup.2127Si.sup.240CNi4NiMn, and (b) a carbon content C.sub.WJ<0.15 wt. % or, if C.sub.WJ0.15 wt. %, a softening factor FA.sub.WJ such that FA.sub.WJ>5000, where FA=10291+4384.1Mo+3676.9Si522.64Al2221.2Cr118.11Ni1565.1C246.67Mn.

An aluminum-based blank comprises a first plated steel plate and a second plated steel plate, connected at their boundary by a joint.

A shear bonding device and a shear bonding method of metal plates are disclosed. The shear bonding device may include: an upper shear bonding mold having more than one upper perpendicular tooth and more than one upper slanted tooth formed alternately on a front end surface thereof; a lower shear bonding mold overlapped with the upper shear bonding mold in a vertical direction by a predetermined width below the upper shear bonding mold, and having more than one lower perpendicular tooth corresponding to the more than one upper slanted tooth and the more than one upper perpendicular tooth corresponding to the more than one lower slanted tooth formed alternately on a front end surface confronting the upper shear bonding mold; an upper heating clamper including a front end surface contacting with the upper perpendicular tooth of the upper shear bonding mold and adapted to generate heat by receiving power from a power supply; a lower heating clamper including a front end surface contacting with the lower perpendicular tooth of the lower shear bonding mold and adapted to generate heat by receiving power from the power supply; upper and lower pressing cylinders moving the upper and lower shear bonding molds upwardly or downwardly so as to apply load; and upper and lower clamping cylinders moving the upper and lower heating clampers upwardly or downwardly so as to apply clamping force and load, wherein the metal plates are disposed between the upper shear bonding mold and heating clamper, and the lower shear bonding mold and heating clamper.

A hat profile (11) has a tensile strength exceeding 1400 MPa and it has soft bands (20) with a tensile strength below 1100 MPa on its side flanges (15,16). The profile is welded to a cover (17) by single rows of weld dots (18). The side flanges have high strength zones (21,22) on both sides of the soft bands (20).

A method for manufacturing a strip having a variable thickness along its length, comprising the steps: an initial strip of constant thickness is provided; homogeneous cold rolling of the initial strip along its length in order to obtain an intermediate strip of constant thickness along the rolling direction; flexible cold rolling of the intermediate strip along its length in order to obtain a variable thickness strip, having, along its length, first areas with a first thickness (e+s) and second areas with a second thickness (e), less than the first thickness (e+s), continuous annealing of the strip.

The plastic deformation ratio generated, after an optional intermediate recrystallization annealing, by the homogeneous cold rolling and the flexible cold rolling steps in the first areas is greater than or equal to 30%.

Methods and systems for laser cutting of components are disclosed herein. Examples are specifically suited for laser cutting relatively large components of e.g. a vehicle framework such as a unitary side panel of a vehicle door. Multiple robots may perform laser cutting operations substantially simultaneously.