A steel sheet has a composition comprising 0.060%≤C≤0.085%, 1.8%≤Mn≤2.0%, 0.4%≤Cr≤0.6%, 0.1%≤Si≤0.5%, 0.010%≤Nb≤0.025%, 3.42N≤Ti≤0.035%, 0≤Mo≤0.030%, 0.020%≤Al≤0.060%, 0.0012%≤B≤0.0030%, S≤0.005%, P≤0.050%, 0.002%≤N≤0.007% and optionally 0.0005%≤Ca≤0.005%, the remainder of the composition being iron and unavoidable impurities. The microstructure consists of 34% to 80% bainite, 10% to 16% martensite, and 10% to 50% of ferrite. The surface fraction of unrecrystallized ferrite, with respect to the whole structure, is of less than 30%. The martensite consists of self-tempered martensite and fresh martensite, the surface fraction of self-tempered martensite being comprised between 4% and 10%.

An embodiment of the present invention provides a steel wire rod and a method for producing same, the steel wire rod comprising 0.3-0.5 wt % of C, 0.02-0.4 wt % of Si, 1.0-1.5 wt % of Mn, 0.3-0.7 wt % of Cr, 0.003 wt % or less of B, 0.03 wt % or less of Ti, 0.03 wt % or less of P, 0.01 wt % or less of S, 0.02-0.05 wt % of Al, and 0.001-0.01 wt % of N, with the balance being Fe and inevitable impurities, and having a microstructure in which the main phase thereof is a complex structure of ferrite+pearlite, and contains at most 5 area % (including 0 area %) of at least one of bainite or martensite, wherein the average pearlite colony size in a region extending from the ⅖ point to the ⅗ point of the diameter is at most 7 μm.

A method for manufacturing an R-T-B based sintered magnet according the present disclosure comprises: a step for preparing a coarse ground powder which is made from an alloy for R-T-B based sintered magnets and which has an average particle size of 10-500 μm; a step for obtaining a fine powder having an average particle size of 2.0-4.5 μm, by feeding the coarse ground powder to a jet mill device that has a grinding chamber filled with inert gas and grinding the coarse ground powder; and a step for producing a sintered body of the fine powder, wherein the inert gas has been humidified, and the oxygen content of the R-T-B based sintered magnet is 1000-3500 ppm by mass.

An alloy including an amorphous phase, and the alloy includes: an average Fe concentration in an entire alloy of 82.0 at. % or more and 88.0 at. % or less; an average Cu concentration in the entire alloy of 0.4 at. % or more and 1.0 at. % or less; an average P concentration in the entire alloy of 5.0 at. % or more and 9.0 at. % or less; an average B concentration in the entire alloy of 6.0 at. % or more and 10.0 at. % or less; an average Si concentration in the entire alloy of 0.4 at. % or more and 1.9 at. % or less; an average C concentration in the entire alloy of 0 at. % or more and 2.0 at. % or less; an average impurity concentration of an impurity other than Fe, Cu, P, B, Si, and C in the entire alloy of 0 at. % or more and 0.3 at. % or less; and a total of the average Fe concentration, the average Cu concentration, the average P concentration, the average B concentration, the average Si concentration, the average C concentration, and the average impurity concentration of 100.0 at. %.

A hot-stamping formed body has a predetermined chemical composition and includes microstructure which includes residual austenite of which an area ratio is in a range of 20% to 30%. Among grain boundaries of crystal grains of bainite and tempered martensite in the microstructure, a ratio of a length of a grain boundary having a rotation angle in a range of 55° to 75° to a total length of a grain boundary having a rotation angle in a range of 4° to 12°, a grain boundary having a rotation angle in a range of 49° to 54°, and a grain boundary having a rotation angle in a range of 55° to 75° to the <011> direction as a rotation axis is 30% or more.

This steel sheet for a can is a steel sheet for a can containing, by mass %, C: 0.010% to 0.050%, Si: 0.020% or less, Mn: 0.10% to 0.60%, P: 0.020% or less, S: 0.020% or less, Al: 0.050% or less, N: 0.0100% or less, Nb: 0% to 0.03%, Ti: 0% to 0.03%, B: 0% to 0.0020%, and a remainder including Fe and an impurity, in which, when the number of carbides having an equivalent circle diameter of 2 μm or more and 5 μm or less is indicated by a, and the number of carbides having an equivalent circle diameter of 0.1 μm or more and less than 2 μm is indicated by b, a/b satisfies a range of the following formula (1), a fracture strain is 1.6 or more, and a sheet thickness is 0.10 to 0.30 mm.

a/b<0.12  (1)

A high-strength steel sheet with excellent delayed fracture resistance, having a tensile strength of 1700 MPa or larger, including a predetermined component composition, having a martensite structure whose ratio accounts for 95 area % or more of the entire metallographic structure, and having a transition metal carbide whose ratio accounts for 0.8 volume % or more of the entire metallographic structure.

A hot-rolled steel sheet has, as a chemical composition, by mass %: C: 0.01% to 0.30%; Si: 0.01% to 3.00%; Mn: 0.20% to 3.00%; P: 0.030% or less; S: 0.030% or less; Al: 0.001% to 2.000%; N: 0.0100% or less; and Ni: 0.02% to 0.50%, in which among measurement points at which elemental analysis is performed at a measurement pitch of 1 μm using an EPMA in a region of 250 μm×250 μm on a surface, the percentage of measurement points having a Ni content of 0.5 mass % or more is 10% to 70%.

A steel sheet includes a predetermined composition, in which a microstructure at a ¼ thickness position from a surface in a sheet thickness direction includes, by vol %, ferrite: 80% or more, martensite: 2% or less, and residual austenite: 2% or less, a proportion of unrecrystallized ferrite in the ferrite of 5% or less, and in the microstructure of the steel sheet stretched by 10% at the ¼ thickness position from the surface in the sheet thickness direction, a number density of voids having a maximum diameter of 1.0 μm or more is 1.0×10.sup.9 pieces/m.sup.2 or less.

A Sm—Fe—N magnet includes Sm—Fe—N particles, wherein an inter-particle metal phase is present between at least two of the Sm—Fe—N particles, an average particle diameter of the Sm—Fe—N particles is less than 2.0 μm, and a percentage of the Sm—Fe—N particles having an aspect ratio of 2.0 or more is 10% or less, the inter-particle metal phase includes a Fe.sub.3Zn.sub.10 phase and an α-Fe phase in a particle form, and in the inter-particle metal phase, an area ratio of the Fe.sub.3Zn.sub.10 phase is 80% or more.