Abstract: This welded structure comprises a weld metal which contains C, Si, Mn, Cr, Mo, V, Nb, N and O in prescribed amounts respectively with the balance being Fe and unavoidable impurities and which exhibits an A value of 200 or more and a Z value of 0.05 or more. The A value is calculated from the element contents of the weld metal according to the formula: A value=([V]/51+[Nb]/93)/{[V]×([Cr]/5+[Mo]/2)}×104. The Z value is calculated according to the formula: Z value=N×[insol. V] [wherein N (particles/?m) is the number density of carbide particles present in a prior austenite grain boundary per unit grain boundary in the stress-relief annealed weld metal, and [insol. V] is the concentration of compound-type V as determined by analyzing an extraction residue of the stress-relief annealed weld metal].

Abstract: A weld metal according to the present invention has a specific chemical composition, contains carbide particles each having an equivalent circle diameter of greater than 0.5 ?m in a number of 0.25 or less per micrometer of grain boundary length, and has an A-value as specified by Formula (1) of 0.12 or more, Formula (1) expressed as follows: A-value=([V]/51+[Nb]/93)/([Cr]/52+[Mo]/96) ??(1) where [V], [Nb], [Cr], and [Mo] are contents (percent by mass) of V, Nb, Cr, and Mo, respectively, in the weld metal.

Abstract: This weld metal has excellent creep characteristics and has a given chemical composition. In the weld metal, the value A defined by equation (1) is 200 or greater, and carbide particles each having an equivalent-circle diameter of 0.40 ?m or more have an average equivalent-circle diameter less than 0.85 ?m. In the segments that connect the centers of three or more carbide particles which are present on a 6-?m straight line and which each has an equivalent-circle diameter of 0.40 ?m or more, the sum of the lengths of the portions where the segments intersect the carbide particles is 25% or more of the overall length of the segments. Value A=([V]/51+[Nb]/93)/{[V]×([Cr]/5+[Mo]/2)}×104??(1) In the equation, [V], [Nb], [Cr], and [Mo] respectively indicate the contents (mass %) of V, Nb, Cr, and Mo in the weld metal.

Abstract: This welded structure comprises a weld metal which contains C, Si, Mn, Cr, Mo, V, Nb, N and O in prescribed amounts respectively with the balance being Fe and unavoidable impurities and which exhibits an A value of 200 or more and a Z value of 0.05 or more. The A value is calculated from the element contents of the weld metal according to the formula: A value=([V]/51+[Nb]/93)/{[V]×([Cr]/5+[Mo]/2)}×104. The Z value is calculated according to the formula: Z value=N×[insol. V] [wherein N (particles/?m) is the number density of carbide particles present in a prior austenite grain boundary per unit grain boundary in the stress-relief annealed weld metal, and [insol. V] is the concentration of compound-type V as determined by analyzing an extraction residue of the stress-relief annealed weld metal].

Abstract: A weld metal of the present invention contains C: 0.05-0.12%, Si: 0.10-0.35%, Mn: 0.65-0.90%, Cr: 1.85-2.50%, Mo: 0.80-1.20%, V: 0.25-0.50%, Nb: 0.010-0.050%, B: 0.0005-0.0010%, N: 0.025% or less (exclusive of 0%), and O: 0.025-0.060% respectively, with the remainder consisting of iron and inevitable impurities.

Abstract: A weld metal according to the present invention has a specific chemical composition, contains carbide particles each having an equivalent circle diameter of greater than 0.5 ?m in a number of 0.25 or less per micrometer of grain boundary length, and has an A-value as specified by Formula (1) of 0.12 or more, Formula (1) expressed as follows: A-value=([V]/51+[Nb]/93)/([Cr]/52+[Mo]/96) ??(1) where [V], [Nb], [Cr], and [Mo] are contents (percent by mass) of V, Nb, Cr, and Mo, respectively, in the weld metal.

Abstract: This weld metal has a predetermined chemical composition, controls the number of oxides in accordance with size, and has an A value stipulated by the belowmentioned formula of no greater than 5.0. A value=(100×[C]?6×[insol.Cr]?2×[insol.Mo]?24×[insol.V]?13×[insol.Nb])×([Mo]?[insol.Mo]), where [insol.Cr], [insol.Mo], [insol.Nb], and [insol.V] are contents (in mass percent) of Cr, Mo, Nb, and V, respectively, present as a compound after stress-relief heat treatment, and [C] and [Mo] are contents (in mass percent) of C and Mo, respectively, contained in the weld metal.

Abstract: This weld metal has excellent creep characteristics and has a given chemical composition. In the weld metal, the value A defined by equation (1) is 200 or greater, and carbide particles each having an equivalent-circle diameter of 0.40 ?m or more have an average equivalent-circle diameter less than 0.85 ?m. In the segments that connect the centers of three or more carbide particles which are present on a 6-?m straight line and which each has an equivalent-circle diameter of 0.40 ?m or more, the sum of the lengths of the portions where the segments intersect the carbide particles is 25% or more of the overall length of the segments. Value A=([V]/51+[Nb]/93)/{[V]×([Cr]/5+[Mo]/2)}×104??(1) In the equation, [V], [Nb], [Cr], and [Mo] respectively indicate the contents (mass %) of V, Nb, Cr, and Mo in the weld metal.