The invention relates principally to a welded steel part with a very high mechanical strength characteristics 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 consisting at least in part of a steel substrate and a pre-coating which is constituted by an intermetallic alloy layer in contact with the steel substrate, topped by a metal alloy layer of aluminum or aluminum-based alloy. This welded steel part claimed by the invention is essentially characterized in that the metal alloy layer (19, 20) has been removed from the edges (36) in direct proximity to the weld metal zone (35), while the intermetallic alloy layer (17, 18) has been left in place, and in that over at least a portion of the length of the weld metal zone (35), the ratio between the carbon content of the weld metal zone (35) and the carbon content of the substrate (25, 26) of either the first or the second sheet (11, 12) having the higher carbon content (Cmax) is between 1.27 and 1.59. The invention likewise relates to a method for the fabrication of a welded steel part as well as the use of this welded steel part for the fabrication of structural or safety parts for automotive vehicles.

A method for producing a part includes providing a first and a second precoated sheet (1,2), butt welding the first and second precoated sheets (1) to obtain a blank (15), and heating the blank (15) to a heat treatment temperature at least 10 C. lower than the full austenitization temperature of the weld joint (22) and at least 15 C. higher than a minimum temperature T

[00001]$T_{\min }\left(.Math..Math.C.\right)=\mathrm{AC}.Math..Math.3.Math.\left(\mathrm{WJ}\right)-\frac{{}_{\mathrm{IC}}^{\max }}{100}.Math.\left(\mathrm{Ac}.Math..Math.3.Math.\left(\mathrm{WJ}\right)-673-40\mathrm{Al}\right).$ where Ac3(WJ) is the full austenitization temperature of the weld joint (22)

[00002]$ IC max = ( 1 - ( 1 + ) .Math. ( max ( 1 .Math. ; .Math. ) .Math. Ts 2 - 350 ) ( 1 - ) .Math. ( .Math. .Math. Ts 2 + Ts 1 ) + ( 1 + ) .Mat HOT-ROLLED STEEL SHEET WITH EXCELLENT LOW-TEMPERATURE TOUGHNESS, STEEL PIPE, AND MANUFACTURING METHOD THEREFOR 20210054485 · 2021-02-25 · Jin-Ho Bae A preferable aspect of the present invention provides a hot-rolled steel sheet with excellent low-temperature toughness, a steel pipe using the same, and a manufacturing method therefor, wherein the hot-rolled steel sheet contains, by weight, 0.35-0.65% C, 0.01-0.4% Si, 13-26% Mn, 0.01-0.3% Ti, 0.01% or less B, 4% or less Al, 1-6% Cr, 0.05% or less P, 0.02% or less S, 0.01% or less N, 0.01-2% Cu, 0.001-0.015% Nb, and the balance Fe and other unavoidable impurities, the alloy elements satisfying the following relational formulas[Relational formula 1] 70<[10*(C/12)+(Mn/55)+(Al/27)]*100<95 and [Relational formula 2] 4<100*(Cr/52+100*(Nb/93))<9; wherein a microstructure comprises, by area fraction, 97% or more (including 100%) of austenite and 3% or less (including 0%) of a carbide, the crystal grain size of the austenite being 18-30 m or less; and wherein the size of the carbide is 0.5 m or less. SOLID WIRE FOR GAS-SHIELDED ARC WELDING OF THIN STEEL SHEET 20210086313 · 2021-03-25 · Nippon Steel Corporation · Shinji Kodama, Masahiro MATSUBA, Masafumi Azuma, Yoichiro Mori, Kenichiro Otsuka, Tetsuro NOSE, Tomokatsu IWAKAMI, Kazutaka MARUYAMA This wire for gas-shielded arc welding is a wire for joining a plurality of thin steel sheets by gas-shielded arc welding, the wire including, in mass %, with respect to a total mass of the wire: C: 0.06 to 0.15%; Si: more than 0 to 0.18%; Mn: 0.3 to 2.2%; Ti: 0.06 to 0.30%; Al: 0.001 to 0.30%; and B: 0.0030 to 0.0100%, in which Si, Mn, Ti, and Al satisfy Expressions (1) and (2).SiMn0.30Expression (1)(Si+Mn/5)/(Ti+Al)3.0Expression (2) MULTI-MATERIAL COMPONENT AND METHODS OF MAKING THEREOF 20210060712 · 2021-03-04 · Jianxun Hu, Eric Walker, Zhenzhen Yu, Abdelrahman Abdelmotagaly, Benjamin Schneiderman A multi-material component joined by a high entropy alloy is provided, as well as methods of making a multi-material component by joining materials with high entropy alloys to reduce or eliminate liquid metal embrittlement (LME) cracks. Consumable electrode type gas shield arc welding method and arc welding portion 10898967 · 2021-01-26 · Nippon Steel Corporation · Shinji Kodama, Tasuku ZENIYA, Shoko Oami, Masahiro MATSUBA The present invention provides a consumable electrode type gas shield arc welding method for performing arc welding of two steel sheets using a welding torch having a consumable electrode. The consumable electrode type gas shield arc welding method includes performing arc welding while a shielding gas having an oxygen potential which is indicated by the following Expression (1) and ranges from 1.5% to 5% is supplied from the welding torch toward the consumable electrode, and blowing an oxidation promotion gas having an oxygen potential which is indicated by the following Expression (2) and ranges from 15% to 50% at a flow velocity ranging from 1 to 3 m/sec over a weld bead and a weld toe portion which are formed by arc welding and are in a state of 700 C. or higher,=100([V.sub.1(O.sub.2)]+[V.sub.1(CO.sub.2)]/5)/([V.sub.1(X)]+[V.sub.1(O.sub.2)]+[V.sub.1(CO.sub.2)])Expression (1)=100[V.sub.2(O.sub.2)]/([V.sub.2(X)]+[V.sub.2(O.sub.2)]+[V.sub.2(CO.sub.2)])Expression (2) here, [V.sub.1(X)] is a mixing ratio (volume %) of an inert gas included in the shielding gas, [V.sub.1(O.sub.2)] is a mixing ratio (volume %) of oxygen included in the shielding gas, [V.sub.1(CO.sub.2)] is a mixing ratio (volume %) of carbon dioxide included in the shielding gas, [V.sub.2(X)] is a mixing ratio (volume %) of an inert gas included in the oxidation promotion gas, [V.sub.2(O.sub.2)] is a mixing ratio (volume %) of oxygen included in the oxidation promotion gas, and [V.sub.2(CO.sub.2)] is a mixing ratio (volume %) of carbon dioxide included in the oxidation promotion gas. Systems and methods for low-manganese welding wire 10898966 · 2021-01-26 · HOBART BROTHERS LLC · Mario Anthony Amata, Joseph C. Bundy, Steven Edward Barhorst The invention relates generally to welding and, more specifically, to welding wires for arc welding, such as Gas Metal Arc Welding (GMAW) or Flux Core Arc Welding (FCAW). In one embodiment, a tubular welding wire includes a sheath and a core. The tubular welding wire is configured to form a weld deposit on a structural steel workpiece, wherein the weld deposit includes less than approximately 2.5% manganese by weight. SINGLE LAYER ZINC ALLOY PLATED STEEL MATERIAL EXHIBITING EXCELLENT SPOT WELDABILITY AND CORROSION RESISTANCE, AND FABRICATION METHOD THEREFOR 20200399745 · 2020-12-24 · Young-Jin Kwak, Tae-Yeob Kim Provided are a single layer zinc alloy plated steel material and a fabrication method therefor, the single layer zinc alloy plated steel material comprising a base iron and a zinc alloy plating layer formed on the base iron, wherein the zinc alloy plating layer contains 13-24 wt % of Mg, and the adhesion amount of the zinc alloy plating layer is at most 40 g/m.sup.2 (excluding 0 g/m.sup.2). High strength welding joint having excellent impact toughness at very low temperature, and flux-cored arc welding wire therefor 10864605 · 2020-12-15 · Posco · Bong-Keun Lee, Sang-Chul Lee, Il-Wook Han, Jeong-Kil Kim A high strength welding joint having excellent toughness at low temperature obtained by welding a cryogenic high-strength high-Mn steel, comprising 0.1-0.61 wt % of C, 0.23-1.0 wt % of Si, 14-35 wt % of Mn, 6 wt % or less of Cr, 1.45-3.5 wt % of Mo, 0.02 wt % or less of S, 0.02 wt % or less of P, 0.001-0.01 wt % of B, 0.001-0.2 wt % of Ti, 0.001-0.3 wt % of N, and balance of Fe and inevitable impurities; and a flux-cored arc welding wire comprising 0.15-0.8 wt % of C, 0.2-1.2 wt % of Si, 15-34 wt % of Mn, 6 wt % or less of Cr, 1.5-4 wt % of Mo, 0.02 wt % or less of S, 0.02 wt % or less of P, 0.01 wt % or less of B, 0.1-0.5 wt % of Ti, 0.001-0.3 wt % of N, 4-15 wt % of TiO.sub.2, 0.01-9 wt % of at least one of SiO.sub.2, ZrO.sub.2 and Al.sub.2O.sub.3, 0.5-1.7 wt % of at least one of alkali elements including K, Na, and Li, 0.2-1.5 wt % of at least one of F and Ca, and balance of Fe and inevitable impurities. Super high strength gas protection welding wire containing V and manufacturing method therefor 10835997 · 2020-11-17 · BAOSHAN IRON &amp; STEEL CO., LTD. · Zhaoxia Qu, Lei Xu, Liqian Xia Provided is a superhigh strength gas shielded welding wire containing V, the mass percentage contents of the chemical elements thereof being: 0.08-0.12% of C, 0.65-0.80% of Si, 1.80-1.95% of Mn, 0<Cu0.25%, 0.20-0.40% of Cr, 0.2-0.6% of Mo, 1.30-1.80% of Ni, 0.08-0.20% of Ti, 0.01-0.05% of V, 0.0070-0.0130% of N, and the balance of Fe and other inevitable impurities. Also provided is a method for manufacturing the welding wire. A weld metal obtained after welding with said welding wire has a higher strength and toughness, and also has a good crack resistance, weldability and plasticity. $