Disclosed is a duplex ferritic austenitic stainless steel of 40-60 volume % ferrite and 40-60 volume % austenite, with improved cold workability and impact toughness. It contains less than 0.07% carbon (C), 0.1-2.0% silicon (Si), 3-5% manganese (Mn), 19-23% chromium (Cr), 1.1-1.9% nickel (Ni), 1.1-3.5% copper (Cu), 0.18-0.30% nitrogen (N), optionally molybdenum (Mo) and/or tungsten (W) according to the formula (Mo+½W)<1.0%. It optionally contains 0.001-0.005% boron (B), up to 0.03% of each of cerium (Ce) and/or calcium (Ca), with the balance being iron (Fe) and impurities where the chromium equivalent (Cr.sub.eq) and the nickel equivalent (Ni.sub.eq): 20<Cr.sub.eq<24.5 and Ni.sub.eq>10, where Cr.sub.eq=Cr+1.5Si+Mo+2Ti+0.5Nb Ni.sub.eq=Ni+0.5Mn+30(C+N)+0.5(Cu+Co).

Provided herein is a dual-phase stainless steel having excellent carbon dioxide corrosion resistance, excellent sulfide stress corrosion cracking resistance, and excellent sulfide stress cracking resistance. The dual-phase stainless steel contains, in mass %, C: 0.03% or less, Si: 1.0% or less, Mn: 0.10 to 1.5%, P: 0.030% or less, S: 0.005% or less, Cr: 20.0 to 30.0%, Ni: 5.0 to 10.0%, Mo: 2.0 to 5.0%, Cu: 2.0 to 6.0%, N: less than 0.07%, and the balance Fe and unavoidable impurities, and has a structure that is 20 to 70% austenite phase, and 30 to 80% ferrite phase in terms of a volume fraction.

Provided is a grain-oriented electrical steel sheet having better transformer iron loss property than conventional grain-oriented electrical steel sheets. A grain-oriented electrical steel sheet comprises: a steel substrate; a forsterite film on a surface of the steel substrate; and a Cr-depleted layer at a boundary between the steel substrate and the forsterite film, the Cr-depleted layer having a Cr concentration that is 0.70 times to 0.90 times a Cr concentration of the steel substrate.

The entirety or a part of this hot stamped product includes, as a chemical composition, by mass %, C: 0.001% or more and less than 0.080%, Si: 2.50% or less, Mn: 0.01% or more and less than 0.50%, P: 0.200% or less, S: 0.0200% or less, sol.Al: 0.001% to 2.500%, N: 0.0200% or less, Cr: 0.30% or more and less than 2.00%, and a remainder: Fe and impurities, in which a metallographic structure contains, by vol %, ferrite: more than 60.0%, martensite: 0% or more and less than 10.0%, and bainite: 0% or more and less than 20.0%, a tensile strength is less than 700 MPa, and ΔTS, which is a decrease in the tensile strength after a heat treatment at 170° C. for 20 minutes, is 100 MPa or less.

The present disclosure relates generally to a method for improving the performance of sintered NdFeB magnet. A method of preparing a sintered NdFeB magnet therefore comprises the steps of: a) preparing alloy flakes from a raw material of the NdFeB magnet by a strip casting process; and b) preparing a coarse alloy powder from the alloy flakes by a hydrogen decrepitation process, the hydrogen decrepitation process including treatment of the alloy flakes under a hydrogen pressure of 0.10 MPa to 0.25 MPa for a duration of 1 to 3.5 hours, then degassing the hydrogen at a predetermined temperature between 300° C. to 400° C. for a duration time of 0.5 to 5 hours, and then mixing the resulting coarse alloy powder with a lubricant.

A non-oriented electrical steel sheet according to an embodiment of the present invention includes, in wt%, Si: 2.2 to 4.5 %, Mn: 0.5 % or less (excluding 0 %), AI: 0.001 to 0.5 %, Sn: 0.07 to 0.25 %, and N: 0.0010 to 0.0090 %, and the balance of Fe and inevitable impurities.

A surface layer portion existing in an inner direction from a surface of the steel sheet and a central portion existing inside the surface layer portion are included, and the central portion includes N at 0.005 wt% or less, and the surface layer portion further includes N at 0.001 wt% or more compared to the central portion; and the surface layer portion has an average grain size of 60 .Math.m or less, while the central portion has an average grain size of 70 to 300 .Math.m.

Disclosed are high-strength ferritic stainless steel STS430, which has a yield strength of 350 MPa or greater and can be applied to a clamp of a vehicle or a common hose, and a manufacturing method thereof. The high-strength ferritic stainless steel for a clamp, according to one embodiment of the present invention, comprises, by weight, 0.04-0.1% of C, 0.2-0.6% of Si, 0.01-1.5% of Mn, 14.0-18.0% of Cr, 0.005-0.2% of Al, 0.005-0.2% of V, 0.02-0.1% of N, and the remainder as Fe and inevitable impurities, satisfies Expressions (1) and (2), and has at least 2.5×10.sup.6 precipitates having a mean diameter of 0.5 μm or less per mm.sup.2. (1) 0.35%≤Si+Al+V≤0.6% (2) 0.09%≤C+N≤0.12%

A method for manufacturing a grain-oriented electrical steel sheet according to an embodiment of the present invention comprises the steps of: hot-rolling a slab to prepare a hot-rolled sheet, the slab containing, in wt %, 2.0 to 6.0% of Si, 0.04 to 0.12% of Mn, 0.001 to 0.022% of N, 0.027 to 0.060% of C, 0.01 to 0.08% of Nb, 0.01% or less of Ti, and the balance of Fe and other inevitable impurities; cold-rolling the hot-rolled sheet to prepare a cold-rolled sheet; and subjecting the primarily recrystallization-annealed cold-rolled sheet to secondary recrystallization annealing.

The present invention provides a steel sheet having excellent wear resistance and composite corrosion resistance, and a method of manufacturing same. According to one example of the present invention, a corrosion-resistant steel sheet having excellent wear resistance and composite corrosion resistance comprises, in wt %: 0.04-0.10% of carbon (C); 0.10% or less (excluding 0%) of silicon (Si); 0.20-0.35% of copper (Cu); 0.1-0.2% of nickel (Ni); 0.05-0.15% of antimony (Sb); 0.07-0.22% of tin (Sn); 0.05-0.15% of titanium (Ti); 0.01% or less (excluding 0%) of sulfur (S); 0.005% or less (excluding 0%) of nitrogen (N); 0.05-0.15% of molybdenum (Mo); and the balance of iron (Fe) and inevitable impurities, and satisfies formula 1 and formula 2 below.

[Ni]/[Cu]≥0.5   [Formula 1]

48×([Ti]/48−[S]/32−[N]/14)≥0.04   [Formula 2]

Here, in formula 1 and formula 2, [Ni], [Cu], [Ti], [S], and [N] represent Ni, Cu, Ti, S, and N content (wt %) in the steel sheet, respectively.

The present disclosure relates to a thick steel material that can be appropriately used as a line pipe, a sour-resistant material and, more particularly, to a high-strength steel material having excellent sulfide stress corrosion cracking resistance and excellent resistance against propagation of sulfide stress corrosion cracking, and a method of manufacturing the steel material.