The invention relates to a method for producing thermomechanically produced hot strip products in which a steel alloy is melted; the steel alloy is adjusted so that a recrystallization during the hot rolling is suppressed; the final rolling temperature is greater than 800° C.; the melted steel alloy is cast into slab ingots and after being heated to a temperature above Ac.sub.3, the slab ingots are hot rolled until they reach a desired degree of deformation and a desired strip thickness; after the rolling, the strip is cooled to room temperature and for hardening purposes, is briefly heated to a temperature >Ac3 and cooled again, characterized in that the heating takes place with a temperature increase of more than 5 K/s, more than 10 K/s, more than 50 K/s, or more than 100 K/s, and is kept at a desired target temperature for a period of 0.5 to 60 s before cooling to yield improved mechanical properties.

Systems and methods for low-manganese welding alloys are disclosed. An example arc welding consumable may comprise: between 0.4 and 1.0 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 present disclosure belongs to the technical field of welding materials, and in particular relates to a Fe—Ni based alloy welding wire for welding 800H alloy and a preparation method thereof and a method for welding 800H alloy. The Fe—Ni based alloy welding wire for welding 800H alloy provided by the present disclosure has a reasonable chemical components, and after being used to weld 800H alloy, the obtained weld has a tensile strength of 557.6 MPa and an elongation of 37.5% at ambient temperature, and has a tensile strength of 420 MPa and an elongation of 17.25% at a temperature of 650° C.

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%≤C≤0.23%, 2.0%≤Mn≤2.7%, with C+Mn/10≥0.420%, 0≤Cr≤0.40%, with Mn+Cr≥2.25%, 0.2%≤Si≤1.6%, 0.02%≤Al≤1.2%, with 1.0%≤Si+Al≤2.2%, 0≤Nb≤0.035%, 0≤Mo≤0.1%, 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.

A steel sheet for the manufacture of a press hardened part is provided, having a composition of: 0.15%≤C≤0.22%, 3.5%≤Mn<4.2%, 0.001%≤Si≤1.5%, 0.020%≤Al≤0.9%, 0.001%≤Cr≤1%, 0.001%≤Mo≤0.3%, 0.001%≤Ti≤0.040%, 0.0003%≤B≤0.004%, 0.001%≤Nb≤0.060%, 0.001%≤N≤0.009%, 0.0005%≤S≤0.003%, 0.001%≤P≤0.020%. A microstructure has less than 50% ferrite, 1% to 20% retained austenite, cementite, such that the surface density of cementite particles larger than 60 nm is lower than 10{circumflex over ( )}7/mm.sup.2, and a complement of bainite and/or martensite, the retained austenite having an average Mn content of at least 1.1*Mn %. Press-hardened steel part obtained by hot forming the steel sheet, and manufacturing methods thereof.

A flux-cored wire according to an aspect of the present invention includes: a steel sheath; and a flux filling the inside of the steel sheath, in which the flux contains 0.11% or more in total of a fluoride in terms of F-equivalent value, 4.30% to 7.50% of a Ti oxide in terms of TiO.sub.2 equivalent, 0.30% to 2.40% in total of an oxide in terms of mass %, and 0% to 0.60% in total of a carbonate in terms of mass %, the amount of a Ca oxide in terms of CaO is less than 0.20% in terms of mass %, the amount of CaF.sub.2 is less than 0.50%, a chemical composition of the flux-cored wire is within a predetermined range, a Z value is 2.00% or less, a V value is 5.0 to 27.0, and Ceq is 0.30% to 1.00% or less.

A flux-cored wire may be used with an Ar—CO.sub.2 mixed gas, the wire having a steel sheath filled with a flux. Such flux-cored wires may include, as a total of the steel sheath and the flux, relative to a total wire mass: Fe in 92 mass % or more, total Si in a 0.50 mass % or more and 1.50 mass % 15 or less, Mn in 1.00 mass % or more and 3.00 mass % or less, total Li in 0.010 mass % or more and 0.10 mass % or less, and total Mg in 0.02 mass % or more and less than 0.50 mass %, C in 0.15 mass % or less, P in 0.030 mass % or less, S in 0.030 mass % or less, and a slag forming agent in 0.50 mass % or less.

A flux-cored wire according to an aspect of the present invention includes: a steel sheath; and a flux filling the inside of the steel sheath, in which the flux contains 0.11% or more in total of a fluoride in terms of F-equivalent value, 4.30% to 7.50% of a Ti oxide in terms of TiO.sub.2 equivalent, 0.30% to 2.40% in total of an oxide in terms of mass %, and 0% to 0.60% in total of a carbonate in terms of mass %, the amount of a Ca oxide in terms of CaO is less than 0.20% in terms of mass %, the amount of CaF.sub.2 is less than 0.50%, a chemical composition of the flux-cored wire is within a predetermined range, a Z value is 2.00% or less, a V value is 5.0 to 27.0, and Ceq is 0.30% to 1.00% or less.

An arc welding method includes performing welding by using a gas and a solid wire. The gas contains Ar. The solid wire includes a steel core wire and a copper plating film formed on a surface of the steel core wire, and the copper plating film has an average grain diameter of 600 nm or less.

A tailored welded blank produced from at least two blank parts, where at least one is a press-hardenable manganese-boron steel and at least one has a coating of aluminum or an aluminum-based alloy. The parts are welded by laser-beam welding or hybrid laser/gas-metal-arc welding, while retaining the coating, using shielding gas and a filler wire having in % by weight: C: 0.41 to 0.9; Si: 0.4 to 4; Mn: 0.4 to 3; optionally Cr: 0 to 10; and with optional alloying of one or more of: Mo: 0.01 to 1.0; B: 0.0008 to 0.0040; Ti: 2.5×B<=Ti<=5×B; V: 0.01 to 0.4; Nb: 0.01 to 0.2; W: 0.01 to 0.2; the remainder Fe and unavoidable impurities. The high proportion of C and Cr or additionally or alternatively of Mo, V, Nb and/or W enables hardening by carbide formation in a weld-seam region after welding.