There is provided a duplex stainless steel tube including a chemical composition consisting of, in mass %, C: 0.008 to 0.030%, Si: 0.10 to 0.70%, Mn: 0.80 to 2.60%, P: 0.030% or less, S: 0.0001 to 0.0050%, O: 0.0004 to 0.0150%, Sn: 0.0001% or more to less than 0.0100%, Cu: 0.10 to 2.50%, Ni: more than 2.50 to 5.50% or less, Cr: 21.5 to 25.5%, Mo: 0.10 to 0.50%, N: 0.050 to 0.200%, Al: 0.200% or less, and optional elements, with the balance: Fe and impurities, wherein 4S+8O+Sn is 0.0040 to 0.0900, and 4S+Sn is 0.0180 or less.

There is provided a duplex stainless steel tube including a chemical composition consisting of, in mass %, C: 0.008 to 0.030%, Si: 0.10 to 0.70%, Mn: 0.80 to 2.60%, P: 0.030% or less, S: 0.0001 to 0.0050%, O: 0.0004 to 0.0150%, Sn: 0.0001% or more to less than 0.0100%, Cu: 0.10 to 2.50%, Ni: more than 2.50 to 5.50% or less, Cr: 21.5 to 25.5%, Mo: 0.10 to 0.50%, N: 0.050 to 0.200%, Al: 0.200% or less, and optional elements, with the balance: Fe and impurities, wherein 4S+8O+Sn is 0.0040 to 0.0900, and 4S+Sn is 0.0180 or less.

An alloy particle contains: total content of Fe and Co: from 82.2 to 96.5 parts by mass; Co: 0 to 30.0 parts by mass; P: 0 to 4.5 parts by mass; B: more than 0 to 5.0 parts by mass; C: 0 to 3.0 parts by mass; Si: 0 to 6.7 parts by mass; Ni: more than 0 to 12.0 parts by mass; Cr: more than 0 to 4.2 parts by mass; total content of Mo, W, Zr, and Nb: 0 to 4.2 parts by mass; total content of P and Cr: 7.4 parts by mass or less; multiplication product of the parts by mass of Ni and Cr: 0.5 or more; and total content of Fe, Co, and Ni: 97.0 parts by mass or less. The alloy particle contains an amorphous phase, and a volume percentage of the amorphous phase is 70% or higher.

An alloy particle contains: total content of Fe and Co: from 82.2 to 96.5 parts by mass; Co: 0 to 30.0 parts by mass; P: 0 to 4.5 parts by mass; B: more than 0 to 5.0 parts by mass; C: 0 to 3.0 parts by mass; Si: 0 to 6.7 parts by mass; Ni: more than 0 to 12.0 parts by mass; Cr: more than 0 to 4.2 parts by mass; total content of Mo, W, Zr, and Nb: 0 to 4.2 parts by mass; total content of P and Cr: 7.4 parts by mass or less; multiplication product of the parts by mass of Ni and Cr: 0.5 or more; and total content of Fe, Co, and Ni: 97.0 parts by mass or less. The alloy particle contains an amorphous phase, and a volume percentage of the amorphous phase is 70% or higher.

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.

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.

Novel High-Entropy Alloy (HEA) compositions are particularly suited to welding applications. The mixtures contain at least the elements nickel, manganese, cobalt, chromium, vanadium, molybdenum, and iron. The % weight of the constituents varies in accordance with the detailed description contained herein, with tolerances in the range of ±4% for major alloying elements and ±1% for minor alloying elements. The mixture may also contain a small amount of Aluminum, Titanium, and Boron with a tolerance in the range of +/−1% or, more preferably, +/−0.5% In accordance with the invention, the compositions above may be integrated into HEA welding products using cored wire and welding electrode manufacturing techniques, preferably starting with vacuum melted rolled alloys. One manufacturing process uses the compositions as an alloyed strip formed around the appropriate ground/crushed alloys to make commercially viable fabricated welding products.

Novel High-Entropy Alloy (HEA) compositions are particularly suited to welding applications. The mixtures contain at least the elements nickel, manganese, cobalt, chromium, vanadium, molybdenum, and iron. The % weight of the constituents varies in accordance with the detailed description contained herein, with tolerances in the range of ±4% for major alloying elements and ±1% for minor alloying elements. The mixture may also contain a small amount of Aluminum, Titanium, and Boron with a tolerance in the range of +/−1% or, more preferably, +/−0.5% In accordance with the invention, the compositions above may be integrated into HEA welding products using cored wire and welding electrode manufacturing techniques, preferably starting with vacuum melted rolled alloys. One manufacturing process uses the compositions as an alloyed strip formed around the appropriate ground/crushed alloys to make commercially viable fabricated welding products.

An austenitic stainless steel material is provided that has high creep strength even when used at an average operation temperature of more than 600 to 750° C. after welding with higher heat input, and furthermore, has excellent stress relaxation cracking resistance even after use for a long time period at the average operation temperature after welding with higher heat input. The steel material has a chemical composition which consists of, in mass %, C: 0.030% or less, Si: 1.50% or less, Mn: 2.00% or less, P: 0.045% or less, S: 0.0300% or less, Cr: 15.00 to 25.00%, Ni: 8.00 to 20.00%, N: 0.050 to 0.250%, Nb: 0.10 to 1.00%, Mo: 0.05 to 5.00%, and B: 0.0005 to 0.0100%, with the balance being Fe and impurities, and a ratio of the dissolved N amount (mass %) with respect to the content of N (mass %) in the steel material is 0.40 to 0.90.

An austenitic stainless steel material is provided that has high creep strength even when used at an average operation temperature of more than 600 to 750° C. after welding with higher heat input, and furthermore, has excellent stress relaxation cracking resistance even after use for a long time period at the average operation temperature after welding with higher heat input. The steel material has a chemical composition which consists of, in mass %, C: 0.030% or less, Si: 1.50% or less, Mn: 2.00% or less, P: 0.045% or less, S: 0.0300% or less, Cr: 15.00 to 25.00%, Ni: 8.00 to 20.00%, N: 0.050 to 0.250%, Nb: 0.10 to 1.00%, Mo: 0.05 to 5.00%, and B: 0.0005 to 0.0100%, with the balance being Fe and impurities, and a ratio of the dissolved N amount (mass %) with respect to the content of N (mass %) in the steel material is 0.40 to 0.90.