A method of joining a first work piece and a second workpiece. The first and second workpieces may be rotor wheels of a rotor for a turbomachine. At least one of the workpieces includes an oxide dispersion strengthened alloy material and the first and second work pieces may be joined by welding a cladding on at least one of the workpieces to the other of the workpieces, without welding a substrate of the at least one workpiece which includes an oxide dispersion strengthened alloy material.

Disclosed is a hot-pressed member that can exhibit very high tensile strength after hot pressing as high as TS: 1780 MPa or more, and excellent indentation peeling strength at projection welds by properly adjusting its chemical composition and its microstructure such that a prior austenite average grain size is 7 μm or less within a range of 50 μm or less in a thickness direction from a surface of the member, a volume fraction of martensite is 90% or more, and an average intergrain distance of Nb and Ti carbonitrides having a grain size of less than 0.10 μm within a depth range of 20 μm to 100 μm in the thickness direction from the surface of the member is 5 μm or less.

The present invention relates to a mold steel having a composition including, in terms of mass %: 0.220%≦C≦0.360%; 0.65%≦Si<1.05%; 0.43%≦Mn≦0.92%; 0.43%≦Ni≦0.92%; 0.67%≦0.5Mn+Ni≦1.30%; 10.50%≦Cr<12.50%; 0.05%≦Mo<0.50%; 0.002%≦V<0.50%; 0.001%≦N≦0.160%; and 0.300%≦C+N≦0.420%, with the remainder being Fe and unavoidable impurities.

A soft magnetic material that is sheet-shaped or foil-shaped and has a high saturation magnetic flux density, contains iron, carbon, and nitrogen, and includes a martensite containing carbon and nitrogen, and γ-Fe, wherein the γ-Fe includes a nitrogen-containing phase. The soft magnetic material is produced by steps of heating an iron-based material that is sheet-shaped or foil-shaped, carburizing the iron-based material with a carburizing gas, dispersing a granular carbide in α-Fe in the iron-based material at a temperature equal to or lower than a eutectoid temperature, transforming the α-Fe into γ-Fe at a temperature higher than the eutectoid temperature, diffusing nitrogen into the γ-Fe using a nitrogen supply gas to form γ-Fe—N—C, and rapidly heating and then rapidly cooling the γ-Fe—N—C to transform the γ-Fe—N—C into a martensite. The result is a thermally stable soft magnetic material having a saturation magnetic flux density higher than that of pure iron.

A steel material according to the present disclosure has a chemical composition consisting of, in mass %: C: 0.15 to 0.45%, Si: 0.05 to 1.00%, Mn: 0.01 to 1.00%, P: 0.030% or less, S: 0.0050% or less, Al: 0.005 to 0.100%, Cr 0.55 to 1.10%, Mo: 0.70 to 1.00%, Ti: 0.002 to 0.020%, V: 0.05 to 0.30%, Nb: 0.002 to 0.100%, B: 0.0005 to 0.0040%, N: 0.0100% or less, O: less than 0.0020%, and the balance being Fe and impurities, and satisfying Formula (1) described in the specification. A grain diameter of a prior-austenite grain is 15.0 μm or less, and an average area of precipitate which is precipitated in a prior-austenite grain boundary is 12.5×10.sup.−3 μm.sup.2 or less. A yield strength is 758 to 862 MPa.

A martensitic stainless alloy comprising, in percent by weight (wt. %) C >0.50 to 0.60; Si 0.10 to 0.60, Mn 0.40 to 0.80; Cr 13.50 to 14.50; Ni 0 to 1.20; Mo 0.80 to 2.50; N 0.050 to 0.12; Cu 0.10 to 1.50; V max 0.10; S max 0.03; P max 0.03; the balance being Fe an unavoidable impurities.

Provided are a non-quenched and tempered wire rod having excellent drawability and impact toughness suitable for materials for automobiles or mechanical parts and a method of manufacturing the same. According to an embodiment of the present disclosure, the non-quenched and tempered wire rod includes, in percent by weight (wt %), 0.05 to 0.35% of carbon (C), 0.05 to 0.5% of silicon (Si), 0.5 to 2.0% of manganese (Mn), 1.0% or less of chromium (Cr), 0.03% or less of phosphorus (P), 0.03% or less of sulfur (S), 0.01 to 0.07% of soluble aluminum (sol.Al), 0.01% or less of nitrogen (N), at least one of 0.1% or less of niobium (Nb), 0.5% or less of vanadium (V), and 0.1% or less of titanium (Ti), and the remainder of iron (Fe) and inevitable impurities, and includes a ferrite-pearlite layered structure, as a microstructure, in a rolling direction.

A steel material for a low yield ratio, high-strength steel pipe having excellent low-temperature toughness according to an aspect of the present invention comprises, by weight %, 0.03-0.065% of C, 0.05-0.3% of Si, 1.7-2.2% of Mn, 0.01-0.04% of Al, 0.005-0.025% of Ti, 0.008% or less of N, 0.08-0.12% of Nb, 0.02% or less of P, 0.002% or less of S, 0.05-0.3% of Cr, 0.4-0.9% of Ni, 0.3-0.5% of Mo, 0.05-0.3% of Cu, 0.0005-0.006% of Ca, 0.001-0.04% of V, and the balance of Fe and inevitable impurities, wherein a number of deposits having an average diameter of 20 nm or less per unit area in a cross section of the steel material may be 6.5*10.sup.9/mm.sup.2 or greater.

The invention is intended to provide a duplex stainless steel and a method for manufacturing same. A duplex stainless steel pipe is also provided. A duplex stainless steel of the present invention has a specific composition, and has a microstructure containing an austenitic phase and a ferrite phase. The duplex stainless steel satisfies the following contents for C, Si, Mn, Cr, Mo, Ni, N, Cu, and W in the formula (1) below, and has a yield strength YS of 655 MPa or more, and an absorption energy vE.sub.−10 of 40 J or more as measured by a Charpy impact test at a test temperature of −10° C.

0.55[% C]−0.056[% Si]+0.018[% Mn]−0.020[% Cr]−0.087[% Mo]+0.16[% Ni]+0.28[% N]−0.506[% Cu]−0.035[% W]+[% Cu*F]≤0.94  (1)

According to one aspect of the present invention, what is provided is a rail including, by mass %: C: 0.75% to 1.20%; Si: 0.10% to 2.00%; Mn: 0.10% to 2.00%; Cr: 0.10% to 1.20%; V: 0.010% to 0.200%; N: 0.0030% to 0.0200%; P≤0.0250%; S≤0.0250%; Mo: 0% to 0.50%, Co: 0% to 1.00%; B: 0% to 0.0050%; Cu: 0% to 1.00%; Ni: 0% to 1.00%; Nb: 0% to 0.0500%; Ti: 0% to 0.0500%; Mg: 0% to 0.0200%; Ca: 0% to 0.0200%; REM: 0% to 0.0500%; Zr: 0% to 0.0200%; Al: 0% to 1.00%; and a remainder consisting of Fe and impurities, in which a structure ranging from an outer surface of a head portion as an origin to a depth of 25 mm includes 95% or greater of a pearlite structure by area ratio, the hardness of the structure is in a range of Hv 360 to 500, and in ferrite of the pearlite structure at a position at a depth of 25 mm from the outer surface of the head portion as the origin, the number density of a V nitride having a grain size of 0.5 to 4.0 nm and including Cr is in a range of 1.0×10.sup.17 to 5.0×10.sup.17 cm.sup.−3.