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.

A welding apparatus includes: a laser beam irradiation section that emits a laser beam; a spectroscopic apparatus that receives plasma emission from a molten pool formed by laser beam irradiation, and acquires optical spectral information; and an estimation section that estimates material components of a weld zone on the basis of the optical spectral information, and estimates a property of the weld zone on the basis of the material components.

A welding apparatus includes: a laser beam irradiation section that emits a laser beam; a spectroscopic apparatus that receives plasma emission from a molten pool formed by laser beam irradiation, and acquires optical spectral information; and an estimation section that estimates material components of a weld zone on the basis of the optical spectral information, and estimates a property of the weld zone on the basis of the material components.

A method of laser beam welding two pipes together, the method including the steps of arranging two pipes such that a gap is provided between opposed surfaces of the pipes, heating at least one of the pipes by induction heating while the gap is provided between the opposed surfaces of the pipes, and subsequently laser beam welding the opposed surfaces of the pipes together.

A tailored blank for hot stamping includes a welded portion formed by butt-welding a first aluminum-plated steel sheet and a second aluminum-plated steel sheet, an Average Al concentration of a weld metal in the welded portion is in a range of 0.3 mass % to 1.5 mass %, an Ac.sub.3 point of the weld metal is 1250 C. or lower, and furthermore, an aluminum layer formed during the butt-welding is present on a surface of the welded portion.

A tailored blank for hot stamping includes a welded portion formed by butt-welding a first aluminum-plated steel sheet and a second aluminum-plated steel sheet, an Average Al concentration of a weld metal in the welded portion is in a range of 0.3 mass % to 1.5 mass %, an Ac.sub.3 point of the weld metal is 1250 C. or lower, and furthermore, an aluminum layer formed during the butt-welding is present on a surface of the welded portion.

A method for introducing a protective gas into an annular space of a receiver tube, in particular for solar collectors, is provided where the annular space is formed at least by one outer cladding tube and an inner absorber tube of the receiver tube and the outer cladding tube is connected to the absorber tube by a wall. The method includes producing an opening that penetrates the cladding tube or the wall, introducing protective gas through the opening into the annular space, and subsequently closing the opening.

A method for introducing a protective gas into an annular space of a receiver tube, in particular for solar collectors, is provided where the annular space is formed at least by one outer cladding tube and an inner absorber tube of the receiver tube and the outer cladding tube is connected to the absorber tube by a wall. The method includes producing an opening that penetrates the cladding tube or the wall, introducing protective gas through the opening into the annular space, and subsequently closing the opening.

A welding or cladding apparatus in which one or more energy beam emitters are used to generate a wide beam spot transverse to a welding or cladding path, and one or more wide feeders feed wire to the spot to create a wide welding or cladding puddle.

A welding or cladding apparatus in which one or more energy beam emitters are used to generate a wide beam spot transverse to a welding or cladding path, and one or more wide feeders feed wire to the spot to create a wide welding or cladding puddle.