A method for manufacturing a dissimilar metal joint product includes: spraying a metal powder capable of being joined to a steel material to at least a part of a surface of an aluminum or aluminum-alloy material at a low temperature and at a high speed to form a coating thereon; disposing the aluminum or aluminum-alloy material and the steel material such that the coating and the steel material face each other; and performing brazing using a brazing material or welding using a welding material between the coating and the steel material.

A flux-cored wire for arc welding, including a steel sheath filled with flux, where the wire contains, relative to a total mass of the wire, Cr: 16.0 to 22.0 mass %, Ni: 6.0 to 11.0 mass %, Mn: 0.7 to 2.6 mass %, Si: 0.1 to 1.1 mass %, Zr: 0.2 to 0.8 mass %, Fe: 45.0 to 65.0 mass %, TiO.sub.2: 5.0 to 9.0 mass %, SiO.sub.2: 0.1 to 2.0 mass %, ZrO.sub.2: 0.5 to 3.0 mass %, and Bi: less than 0.0020 mass %. Where by mass %, a Si content is denoted by [Si] and a Zr content is denoted by [Zr], a value of parameter A expressed by A=[Si]+2×[Zr] satisfies 1.4 to 2.5.

An automobile undercarriage part of the present invention has a welded joint formed by base steel plate, wherein the chemical composition of a weld metal contains, with respect to a total mass of the weld metal, by mass %, C: 0.02% to 0.30%, Si: 0.10% to less than 1.0%, Mn: 1.2% to 3.0%, Al: 0.002% to 0.30%, Ti: 0.005% to 0.30%, P: more than 0% to 0.015%, and S: more than 0% to 0.030%, the following formula (1A), formula (1B), formula (2), and formula (3) are satisfied, and slag in a toe portion of the fillet weld satisfies a formula (4).

[Al]+[Ti]>0.05  Formula (1A)

[Ti]/[Al]>0.9  Formula(1B)

7×[Si]+7×[Mn]−112×[Ti]−30×[Al]≤12  Formula (2)

2.0<[Si]+[Mn]  Formula (3)

[Ti content on slag surface]>[Si content on slag surface]  Formula (4).

An arc welding method includes welding a steel sheet while alternately switching feeding of a welding wire between forward feeding and backward feeding. The welding wire contains, in mass % with respect to a total mass to the welding wire, C: more than 0 and 0.30 or less, Si: 0.01 to 0.30, Mn: 0.5 to 2.5, S: 0.001 to 0.020, Ti: 0.05 to 0.30, and optional elements with the remainder being Fe and unavoidable impurities, and a value obtained by 2×[Ti]/[Si]−50×[S] is more than 1.0. The welding is performed by using a shielding gas containing CO.sub.2 gas in an amount of 80 vol. % or more with respect to a total volume of the shielding gas at a frequency of 40 Hz or more and 200 Hz or less, where one cycle for determining the frequency is one forward feeding and one backward feeding.

According to an aspect of the present invention, there is provided a flux-cored wire including a steel sheath and a flux that fills the steel sheath. The flux contains fluorides of which a total value α of F-equivalent values is 0.21% or more, oxides of which the total value β of amounts ranges from 0.30% to less than 3.50%, and carbonates of which a total value of amounts ranges from 0% to 3.50%. An amount of CaO ranges from 0% to less than 0.20%. An amount of iron powder ranges from 0% to less than 10.0%. A X-value is 5.0% or less. The amount of CaF.sub.2 is less than 0.50%. The amount of Ti oxides ranges from 0.10% to less than 2.50%. A ratio of α to β ranges from 0.10 to 4.00. A total value of amounts of MgCO.sub.3, Na.sub.2CO.sub.3, and LiCO.sub.3 ranges from 0% to 3.00%. Other chemical composition is within a predetermined range. Ceq ranges from 0.45% to 1.20%.

The disclosure belongs to the technical field of surface coating, and particularly relates to a flux-cored welding wire, a preparation method and use thereof, a porous coating and a preparation method thereof. The disclosure provides a flux-cored welding wire, including a core wire and a sheath, where the core wire includes the following components by mass percentage: 15.0-30.0% of Cr, 1.5-2.5% of Si, 5.0-10.0% of Ni, 1.0-5.0% of TiH.sub.2, and Fe as balance; and the sheath is made of steel. Test results of examples show that, the porous coating obtained by supersonic arc spraying the flux-cored welding wire provided by the disclosure has a porosity of up to 46% and a coating adhesive strength of 45 MPa, which are desired.

According to an exemplary embodiment of the present disclosure, disclosed is an aluminum coated blank that includes a first coated steel sheet; a second coated steel sheet connected to the first coated steel sheet; and a joint portion that connects the first coated steel sheet to the second coated steel plate at a boundary between the first coated steel sheet and the second coated steel sheet.

An additively manufactured object formed by depositing weld bead layers, each of the weld bead layers being obtained by melting and solidifying a filler metal made of a mild steel, the additively manufactured object includes a plurality of the weld bead layers having a ferrite phase with an average grain diameter of 11 μm or less in a part except for a surface oxide film.

A screw element of a ball screw mechanism includes a lead screw which, at an axial end, is joined to a rod element using a friction welding process. In order to improve the friction-welded joint, prior to the friction welding process, the lead screw has a circumferential groove on the end face facing the rod element.

A metal-cored electrode for welding to form a weld bead on a ferrous material, which weld bead includes at least 35 wt. % nickel. The metal-cored electrode includes a metal sheath surrounding a core. The core includes greater than 35 wt. % nickel.