Kobe Steel, Ltd.

Yoshihiko Kitagawa

Hidenori Nako

Wataru Urushihara

Takuya Kochi

Munenobu Sato

Masafumi Yamakami

Masayuki Nagami

Tomoko Sugimura

Keito Ishizaki

A solid wire for electroslag welding, including Fe and, by mass % based on a total mass of the wire: C: more than 0% and 0.03% or less; Si: more than 0% and 0.10% or less; Mn: more than 0% and 0.25% or less; Ni: 10.5%-14.0%; S: more than 0% and 0.010% or less; Al: more than 0% and 0.250% or less; REM: 0.002%-0.080%; and O: more than 0% and 0.0090% or less.

Solid wire for electroslag welding, and welding joint

Provided is a flux-cored wire for gas-shielded arc welding that contains specific amounts of C, Mn, TiO, and Ni and specific amounts or less of P and S. The TiOhas a ratio (&#x3b1;1/&#x3b1;2) of 0.90-1.50 when &#x3b1;1 (mass %) is the content per wire total mass of particles having a size of 106 &#x3bc;m or smaller and &#x3b1;2 (mass %) is the content per wire total mass of particles having a size exceeding 106 &#x3bc;m.

Flux-cored wire for gas-shielded arc welding

Provided is a flux-cored wire for gas-shielded arc welding that contains, per wire total mass, specific amounts of C, Mn, TiOand specific amounts or less of P and S, and contains, in the flux, a specific amount of Ni per wire total mass. The Ni has a ratio (&#x3b1;1/&#x3b1;2) of 0.50-1.00 when &#x3b1;1 (mass %) is the content per wire total mass of particles having a size of 106 &#x3bc;m or less and &#x3b1;2 (mass %) is the content per wire total mass of particles having a size exceeding 106 &#x3bc;m.

The present invention is a weld metal formed by gas shielded arc welding using a flux cored wire, the welded metal having a predetermined chemical composition, residual austenite particles being present in an amount of at least 2500 particles/mm, and the volume fraction of residual austenite particles being at least 4.0%.

Weld metal having excellent resistance to hydrogen embrittlement

Disclosed is a weld metal which is formed by gas-shielded arc welding using a flux-cored wire, and which has a specific chemical composition, in which retained austenite particles are present in a number density of 2500 per square millimeter or more and in a total volume fraction of 4.0% or more based on the total volume of entire structures of the weld metal. The weld metal has excellent hydrogen embrittlement resistance and is resistant to cracking at low temperatures even when the weld metal has a high strength.

Weld metal excellent in hydrogen embrittlement resistance

The weld metal of the present invention is formed by gas shield arc welding using a flux-cored wire, has a predetermined chemical component composition, and contains 20% or more of Ti. The amount of Ti-containing oxide particles having a circle-equivalent diameter of 0.15-1.0 &#x3bc;m is at least 5000 per square mm, the amount of V per total mass of weld metal present as a compound within the weld metal is 0.002% or more, and the average circle equivalent diameter of V-containing carbide present in the weld metal is 15 nm or less.

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Fujisawa, Japan

Yoshihiko Kitagawa