A welded steel part with a very high mechanical strength is provided. The welded steel part is obtained by heating followed by hot forming, then cooling of at least one welded blank obtained by butt welding of at least one first and one second sheet. The at least one first and second sheets including, at least in part, a steel substrate and a pre-coating which includes an intermetallic alloy layer in contact with the steel substrate, topped by a metal alloy layer of aluminum or aluminum-based alloy. A method for the fabrication of a welded steel part and the fabrication of structural or safety parts for automotive vehicles are also provided.

The disclosed technology generally relates to consumable electrode wires and more particularly to consumable electrode wires having a core-shell structure, where the core comprises chromium. In one aspect, a welding wire comprises a sheath having a steel composition and a core surrounded by the sheath. The core comprises chromium (Cr) at a concentration between about 12 weight % and about 18 weight % on the basis of the total weight of the welding wire, manganese (Mn) at a concentration between about 12 weight % and about 18 weight % on the basis of the total weight of the welding wire, nickel (Ni) at a concentration between zero and about 5 weight % on the basis of the total weight of the welding wire, and carbon (C) at a concentration greater than zero weight %, wherein concentrations of Ni, C and Mn are such that [Ni]+30[C]+0.5[Mn] is less than about 12 weight %, wherein [Ni], [C], and [Mn] represent weight percentages of respective elements on the basis of the total weight of the welding wire. The disclosed technology also relates to welding methods and systems adapted for using the chromium-comprising electrode wires.

A flux-cored wire with a steel sheath filled with flux, including based on a total mass of the wire, C: 0.026% to 0.060% by mass, Si: more than 0% to 0.50% by mass, Mn: 1.3% to 2.8% by mass, Cu: 0.20% to 1.50% by mass, Ni: 0.45% to 1.00% by mass, Mo: 0.15% to 0.65% by mass, Mg: 0.30% to 0.65% by mass, and B: 0.001% to 0.010% by mass. Provided that Cr: 0.10% by mass or less and Al: 0.10% by mass or less. A Nb content [Nb] of the wire expressed in % by mass based on the total mass of the wire and a V content [V] of the wire expressed in % by mass based on the total mass of the wire satisfy [Nb]+[V]=0.015 or less.

The present invention relates to a connecting element for non-detachably connecting at least two components by means of friction welding when the connecting element is rotated about a longitudinal axis of the connecting element. The connecting element includes a stem formed along the longitudinal axis with a stem face at a free end of the stem for penetrating at least one component, and a head connected to the stem for transmitting a torque about the longitudinal axis from a turning tool to the stem. The stem face has a stem end face which has a convex envelope with a blunt shape.

A method for producing a coated steel sheet having a tensile strength TS of at least 1100 MPa, a total elongation TE according to ISO standard 6892-1 of at least 12%, the product TSxTE of the tensile strength by the total elongation being at least 14200 MPa %, and a hole expansion ratio HER according to ISO standard 16630:2009 of at least 25%, the method including the following successive steps: providing a cold-rolled steel sheet, the chemical composition of the steel containing in weight %: 0.15%C0.23%, 2.0%Mn2.7%, with C+Mn/100.420%, 0Cr0.40%, with Mn+Cr2.25%, 0.2%Si1.6%, 0.02%Al1.2%, with 1.0%Si+Al2.2%, 0Nb0.035%, 0Mo0.1%, the remainder being Fe and unavoidable impurities, annealing the steel sheet at an annealing temperature T.sub.A so as to obtain a structure comprising at least 65% of austenite and at most 35% of intercritical ferrite, quenching the sheet from a temperature of at least 600 C. at a cooling rate comprised between 20 C./s and 50 C./s down to a quenching temperature QT between 200 C. and 270 C., heating the sheet up to a partitioning temperature PT comprised between 400 C. and 480 C. and maintaining the sheet at this partitioning temperature PT for a partitioning time Pt comprised between 50 s and 250 s, hot-dip coating the sheet at a temperature less than 515 C., cooling the coated sheet down to the room temperature,
the steel sheet having a microstructure consisting of, in surface fraction: between 3% and 15% of retained austenite, at least 30% of tempered martensite, at most 5% of fresh martensite, at most 35% of bainite, the sum of the surface fractions of tempered martensite, fresh martensite and bainite being comprised between 55% and 92%, and between 5% and 35% of ferrite.

The present invention relates to a method for the manufacture of a coated steel sheet comprising the following successive steps: A. the coating of the steel sheet with a first coating consisting of nickel and having a thickness between 600 nm and 1400 nm, the steel sheet having the following composition in weight: 0.10<C<0.40%, 1.5<Mn<3.0%, 0.7<Si<3.0%, 0.05<Al<1.0%, 0.75<(Si+Al)<3.0%, and on a purely optional basis, one or more elements such as Nb0.5%, B0.010%, Cr1.0%, Mo0.50%, Ni1.0%, Ti0.5%, the remainder of the composition making up of iron and inevitable impurities resulting from the elaboration, B. the recrystallization annealing at a temperature between 820 to 1200 C., C. the coating with a second coating based on zinc not comprising nickel.

Rolling support and guiding element (2) for a rail vehicle, comprising at least one upper portion forming the rolling surface, said portion being made from steel (1) having a composition comprising, in addition to Fe: 0.15C0.3%, 1Mn2%, 0.2%Ni1%, 0.5Cr2%, the steel (1) having a mixed structure of tempered martensite and residual austenite and bainite after having undergone a tempering heat treatment at a controlled speed and for a controlled length of time.

Systems and methods for low-manganese welding alloys are disclosed. An example arc welding consumable may comprise: less than 0.4 wt % manganese; strengthening agents selected from the group consisting of nickel, cobalt, copper, carbon, molybdenum, chromium, vanadium, silicon, and boron; and grain control agents selected from the group consisting of niobium, tantalum, titanium, zirconium, and boron. The grain control agents may comprise greater than 0.06 wt % and less than 0.6 wt % of the welding consumable. The resulting weld deposit may comprise a tensile strength greater than or equal to 70 ksi, a yield strength greater than or equal to 58 ksi, a ductility (as measured by percent elongation) of at least 22%, and a Charpy V-notch toughness greater than or equal to 20 ft-lbs at 20 F. The welding consumable may provide a manganese fume generation rate less than 0.01 grams per minute during the arc welding operation.

The purpose of the present invention is to provide a flux cored wire which has good high-temperature cracking resistance, and which enables the achievement of a welded part exhibiting excellent coating adhesion. The present invention relates to a metal flux cored wire for gas-shielded are welding, which contains, relative to the total mass of the wire, 0.02-0.30% by mass of C, 0.3-1.5% by mass of Si, 0.3-2.5% by mass of Mn, and oxide of at least one element selected from the group consisting of Si, Cr and Ni in an amount of 0.01-0.30% by mass in total, 0.020% by mass or less of S, and 0.3% by mass or less of Al, Ca, Mg, K and Na in total in the form of metals or alloys, with the balance made up of Fe and unavoidable impurities.

A laser welded joint has weld metal provided between a plurality of steel sheets. A chemical composition of the weld metal has predetermined components, and average hardness of the weld metal is 350 to 540 in Vickers hardness. In the weld metal, distribution density of porosities having a diameter of 2 m to 50 m is equal to or less than 5.0 pieces/mm.sup.2. In the weld metal, distribution density of oxide inclusions having a diameter of 3 m or more is 0.1 to 8.0 pieces/mm.sup.2.