Provided is a non-oriented electrical steel sheet that contains substantially no Al and contains large amounts of Si and Mn and has low iron loss, comprising a chemical composition containing C: 0.0050% or less, Si: 2.0% or more and 6.0% or less, Mn: 1.0% or more and 3.0% or less, P: 0.20% or less, S: 0.0050% or less, N: 0.0050% or less, Al: 0.0050% or less, and one or more selected from B: 0.0001% or more and 0.0050% or less, Nb: 0.0001% or more and 0.0050% or less, and V: 0.0005% or more and 0.0500% or less, with a balance consisting of Fe and inevitable impurities, wherein a number density of Si—Mn nitrides with an average diameter of 50 nm or more and 500 nm or less is 1 or less per μm.sup.3.

Proposed is a Fe-based alloy and a filler metal including the same. The Fe-based alloy contains 15% to 25% by weight of nickel (Ni), 0.5% to 3% by weight of manganese (Mn), 2% to 8% by weight of cobalt (Co), 0.1% to 0.5% by weight of carbon (C), and the balance iron (Fe) and unavoidable impurities.

The present invention relates to a rail which has a predetermined chemical composition and in which at least 90% of a metallographic structure from an outer surface of the rail bottom portion, as the origin, to a depth of 5 mm is a pearlite structure, a surface hardness HC of a foot-bottom central portion is in a range of Hv 360 to 500, a surface hardness HE of a foot-edge portion is in a range of Hv 260 to 315, and HC, HE, and a surface hardness HM of a middle portion positioned between the foot-bottom central portion and the foot-edge portion satisfy HC≧HM≧HE.

A multicomponent FeCoSiM soft magnetic alloy is provided. M of the alloy is one or more of V, Cr and Ni. A sum of atomic percentages of alloy elements in the alloy is 100%. The atomic percents of the alloy elements meet the following conditions: Fe, 68˜78 at %; Co, 4˜12 at %; Si, 14˜18 at %; V, 0˜4 at %; Cr, 0˜4 at %; and Ni, 0˜4 at %. The preparation method of the alloy includes weighing raw materials according to the atomic percentages of the alloy elements and then performing melting and annealing heat treatment each in vacuum or a protective atmosphere. The alloy is obtained by a reasonable design of compositions and contents. A magnetocrystalline anisotropy constant of the alloy is low, a magnetostrictive coefficient of the alloy approaches zero and the alloy has characteristics of high saturation flux density and low coercivity.

In a steel sheet according to the present embodiment, a Ti content and a N content satisfy Ti−3.5×N≥0.003, at a sheet thickness ¼ position, a metallographic structure includes 90% or more of martensite in terms of volume fraction, at the sheet thickness ¼ position, a number density of TiC having a circle equivalent diameter of 1 to 500 nm is 3.5×10.sup.4 particles/mm.sup.2 or more, at the sheet, thickness ¼ position, a value of a median value of a Mn concentration+3σ is 5.00% or less, and a hardness measured at the sheet thickness ¼ position is 1.30 times or more a hardness measured at a position 50 μm deep from a surface of the steel sheet.

Disclosed is a mar aging steel containing, in combination in mass percent, C in a content from greater than 0% to 0.02%, Mn in a content from greater than 0% to 0.3%, Si in a content from greater than 0% to 0.3%, Ni in a content of 10% to 13%, Mo in a content of 0.5% to 3.5%, Co in a content of 9% to 12%, Cr in a content of 1.5% to 4.5%, Ti in a content of 1.5% to 4.5%, and Al in a content of 0.01% to 0.2%, where the total content of Mo and Ti is 5.0 mass percent or less, and the ratio ([Mo]/[Ti]) of the Mo content [Mo] to the Ti content [Ti] is 1.0 or less, with the remainder consisting of iron and inevitable impurities.

Provided is a steel sheet having a predetermined chemical composition, wherein precipitates having a diameter of less than 0.1 μm are present in a number density of 10 to 200/μm.sup.2 in a depth region of 1 to 10 μm from a surface, an amount of dissolved C in a depth region of 10 to 60 μm from the surface is less than 0.20 mass %, and a tensile strength is 1200 MPa or more. Further, provided is a method for producing a steel sheet comprising a step of hot rolling a steel slab having a predetermined chemical composition, then coiling it at 580° C. or less, a step of pickling the hot rolled steel sheet to remove oxide scale and remove the surface layer of the hot rolled steel sheet down to at least 5 μm, and a step of cold rolling the hot rolled steel sheet, then holding it in an atmosphere of a dew point of −20 to 20° C. at a temperature region of 200 to 400° C. for 20 to 180 seconds and holding it at a temperature region of 740 to 900° C. for 40 to 300 seconds.

Provided is a steel sheet having a predetermined chemical composition and microstructure, wherein a block size in a first depth region of 1 to 10 μm from the surface is 5.0 μm or less, a block size in a second depth region of 10 to 60 μm from the surface is 6.0 to 20.0 μm, and a block size in a third depth region of 60 μm to 1/4 thickness from the surface is less than 6.0 μm. Further, provided is a method for producing a steel sheet comprising a step of hot rolling a steel slab having a predetermined chemical composition, then coiling it at 500° C. or more, a step of pickling the hot rolled steel sheet to remove oxide scale, wherein an amount of removal of the surface layer of the hot rolled steel sheet is less than 5.00 μm, a step of cold rolling by a rolling reduction of 30 to 90%, and an annealing step of holding in an atmosphere of a dew point of −20 to 20° C. at a temperature region of 740 to 900° C. for 40 to 300 seconds.

The method includes a tension element, for example in the form of flat steel, that is placed on the structure or structural part and can be guided around a corner. The flat steel can also wrap as a band around the structure, in which the two ends of the flat steel are either connected to one another or are separately connected to the structure by the end anchors or intersect to produce a clamping connection. The flat steel contracts as a result of a subsequent active and controlled input of heat using a heating element and generates a permanent tensile stress and, correspondingly, a permanent prestress on the structure. The structure, as equipped, has at least one tension element as a shape memory alloy which extends along the outer side of the structure and is connected by one or more end anchors

Disclosed is a steel composition including specified ranges of Ni; Mo; Co; Mo+Co+Si+Mn+Cu+W+V+Nb+Zr+Ta+Cr+C; Co+Mo; Ni+Co+Mo; and traces of Al; Ti; N; Si; Mn; C; S; P; B; H; O; Cr; Cu; W; Zr; Ca; Mg; Nb; V; and Ta in specified ranges; the remainder being iron and impurities. The inclusion population, as observed by image analysis over a polished surface measuring 650 mm.sup.2 if hot-formed or hot-rolled; and measuring 800 mm.sup.2 if cold-rolled, does not contain non-metallic inclusions of diameter >10 μm, and, in the case of a hot-rolled sheet, does not contain more than four non-metallic inclusions of diameter 5-10 μm over 100 mm.sup.2, the observation being performed by image analysis over a polished surface measuring 650 mm.sup.2.