A shielding gas, apparatus, and method are provided for laser welding workpieces comprising aluminum or aluminum alloy. The shielding gas includes argon (Ar); and active gas components in a range of 0.5% to 3% by volume of the shielding gas. The active gas components include a combination of oxygen (O.sub.2) and at least one of nitrous oxide (N.sub.2O) and nitrogen (N.sub.2).

A system for welding pipe sections together includes first and second disks, each having a central portion and a resilient material outer portion. The central portion is more rigid than the outer portion. An outside dimension and shape of each outer portion is configured to engage an interior of a pipe having an inner dimension that is smaller than the outside dimension of the outer portion to establish a sealed interface between the outer portion and the interior of the first pipe section. The disks establish a chamber that overlaps a weld seam between abutting pipe sections. An inert gas introduced into the chamber effectively removes any air in the chamber so that a weld can be completed without any undesired gas near the weld seam.

Properties and performance of weld material between metals in a weldment is controlled by modifying one or more of the nitrogen content and the carbon content to produce carbide (e.g. MC-type), nitride and/or complex carbide/nitride (e.g. MX-type) type precipitates. Fusion welding includes (i) adjusting shield gas composition to increase nitrogen/carbon gas and nitride/carbide species, (ii) adjusting composition of nitrogen/carbon in materials that participate in molten welding processes, (iii) direct addition of nitrides/carbides (e.g. powder form), controlled addition of nitride/carbide forming elements (e.g. Ti, Al), or addition of elements that increase/impede solubility of nitrogen/carbon or nitride/carbide promoting elements (e.g. Mn), and (iv) other processes, such as use of fluxes and additive materials. Weld materials have improved resistance to different cracking mechanisms (e.g., hot cracking mechanisms and solid state cracking mechanisms) and improved tensile related mechanical properties.

A method for joining a plated steel sheet includes forming a plurality of protrusions, overlapping a first steel sheet, and performing arc welding, by which first and second steel sheets, at least one of which is a plated steel sheet, are arc welded. In the forming, the plurality of protrusions that is substantially perpendicular to an edge portion of the first steel sheet and is positioned along the edge portion is formed in an overlapping surface of the first steel sheet. In the overlapping, the first and second steel sheets are overlapped such that the protrusions protrude in a direction toward an overlapping surface of the second steel sheet. In the performing the arc welding, an arc welding is performed linearly in the edge portion of the first steel sheet or second steel sheet.

A method of refurbishing worn diaphragm rails for turbo machines. This method comprises machining the worn part of the diaphragm rails such that a clean and geometrically exact machined surface is achieved. Welding one or more layers on these machined surfaces builds up a cladding that overtops the nominal dimensions of new diaphragm. The method further comprises machining the cladding such that it has the nominal dimensions of a new diaphragm.

The present invention relates generally to welding gas compositions used as shielding gases in an electric arc welding process. More particularly, the invention is directed a shielding gas compositions used in gas metal or tungsten metal arc welding processes for welding aluminum or aluminum alloy containing work pieces. The compositions comprise from 200 to less than 400 ppm oxygen; from 200 to less than 400 ppm of a second gas selected from nitrous oxide, nitrogen, and combinations thereof; and the remainder being an inert gas preferably selected from argon, helium, and mixtures thereof.

A pulse welding period alternately includes a first peak period in which a first peak current whose peak value is a first current value is caused to flow through a welding wire and a base period in which a base current having a second current value is caused to flow through the welding wire. During the base period, a second peak current whose peak current value is a sum of a second current value and a third current value and is smaller than the first current value is superimposed on the base current at a second pulse frequency. A second peak period in which the second peak current is caused to flow once is shorter than the first peak period. During the first peak period, a droplet is transferred from the welding wire toward a base material.

Base materials of a butt welded joint with a welded portion have a carbon concentration of 0.1 mass % or greater and 0.35 mass % of less. The welded portion is formed by heating by keyhole welding and then reheating by heat conduction welding, and the welded portion has a melted and solidified portion by the keyhole welding, a reheated solidified portion by the heat conduction welding, and a remelted and solidified portion. A width W0 and a depth d0 of the melted and solidified portion and a width W1 and a depth d1 of the remelted and solidified portion have the following relationships: 0.46W0≤W1; and 0.14d0≤d1≤0.73d0.

A method for producing a surface of a base material, wherein the base material has spheroidal graphite cast iron, wherein firstly a partial surface is located, in a further step a two-ply buffer layer is used by means of TIG welding with the welding additive NiFe, wherein in a further step a fill layer is applied to the buffer layer, wherein the MIG welding method is used in conjunction with NiFe-2 in accordance with EN ISO 107 as welding additive 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.WJ−0.9FT.sub.BM≥0, 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+1553×C+55×Mn+267×Si+49×Ni+5×Cr−79×Al−2×Ni.sup.2−1532×C.sup.2−5×Mn.sup.2−127×Si.sup.2−40×C×Ni−4×Ni×Mn, and (b) a carbon content C.sub.WJ<0.15 wt. % or, if C.sub.WJ≥0.15 wt. %, a softening factor FA.sub.WJ such that FA.sub.WJ>5000, where FA=10291+4384.1×Mo+3676.9Si−522.64×Al−2221.2×Cr−118.11×Ni−1565.1×C−246.67×Mn.