The present invention involves a graphene-containing rare earth permanent magnet material and preparation method thereof. The graphene-containing rare earth permanent magnet material, comprising: 20.6 to 23.4 weight percent of neodymium, 6.6 to 7.5 weight percent of praseodymium, 0.95 to 1.20 weight percent of boron, 0.4 to 0.6 weight percent of cobalt, 0.11 to 0.15 weight percent of copper, 2.0 to 2.4 weight percent of lanthanum, 1.7 to 2.1 weight percent of cerium, 1 to 5 weight percent of graphene, a remainder being iron. The graphene-containing rare earth permanent magnet material exhibits excellent temperature resistance, good conductivity and magnet properties even without any heavy rare earth elements like terbium or dysprosium, which dramatically reduces the cost, promotes the efficient utilization of rare earth resources and improves product quality. The preparation method within this invention is simple to realize, easy to control, cost-effective and has high production efficiency and stable product performances.

An object of the present invention is to provide a low thermal expansion cast steel having sufficient strength even at a high temperature and a low coefficient of thermal expansion. The low thermal expansion cast steel of the present invention is obtained by suitably heat treating a cast steel comprising, by mass %, C: 0 to 0.10%, Si: 0 to 1.00%, Mn: 0 to 1.00%, Co: 13.00 to 17.50%, Ni satisfying −3.5×% Ni+118%≤Co−3.5×% Ni+121 (% Ni and %≤Co respectively represent the contents of Ni and Co (mass %)), and a balance of Fe and unavoidable impurities so that the 0.2% proof stress in a tensile test at 400° C. becomes 100 MPa or more, the average coefficient of thermal expansion at 25 to 350° C. becomes 6.0 ppm/° C. or less, and the Curie temperature becomes 350° C. or more.

A non-oriented electrical steel sheet has a predetermined chemical composition. The chemical composition satisfies (2×[Mn]+2.5×[Ni]+[Cu])−([Si]+2×[sol.Al]+4×[P])≥1.50%. In a case where Ahkl-uvw represents the area ratio of crystal grains in an {hkl}<uvw> orientation to the entire visual field when a plane at a depth of ½ of a sheet thickness from a surface parallel to a rolled surface is measured by SEM-EBSD, A411-011 is 15.0% or more, and the average grain size is 50 μm to 150 μm.

An Fe-based alloy for melting-solidification shaping including, in mass %: 18.0≤Co<25.0; 12.0≤Mo+W/2≤20.0; 0.2≤Mn≤5.0; 0.5≤Ni≤10.0; and 0≤Si≤1.0, with the balance being Fe and unavoidable impurities, and satisfying the following expressions (1) and (2) when [M] represents a content of an element M expressed in mass % basis, 58≤[Co]+3([Mo]+[W]/2)≤95 (1), A/B≥1.6 (2) where A=[Co]+[Ni]+3[Mn], and B=[Mo]+[W]/2+[Si], in which when the Fe-based alloy includes no Mo, the expressions (1) and (2) are calculated using [Mo]=0, when the Fe-based alloy includes no Si, the expression (2) is calculated using [Si]=0, and when the Fe-based alloy includes no W, the expressions (1) and (2) are calculated using [W]=0.

A steel sheet with a tensile strength (TS) of 1180 MPa or more, a member, and a method for producing them. In a region of the steel sheet within 4.9 μm in the thickness direction, a region with a Si concentration not more than one-third of the Si concentration in the chemical composition of the steel sheet and with a Mn concentration not more than one-third of the Mn concentration in the chemical composition of the steel sheet has a thickness of 1.0 μm or more. The lowest Si concentration L.sub.Si and the lowest Mn concentration L.sub.Mn in the region within 4.9 μm in the thickness direction from the surface of the steel sheet and a Si concentration T.sub.Si and a Mn concentration T.sub.Mn at a quarter thickness position of the steel sheet satisfy the following formula (1):

L.sub.Si+L.sub.Mn≤(T.sub.Si+T.sub.Mn)/4  (1).

A steel sheet with a tensile strength (TS) of 1180 MPa or more, a member, and a method for producing them. In a region of the steel sheet within 4.9 μm in the thickness direction, a region with a Si concentration not more than one-third of the Si concentration in the chemical composition of the steel sheet and with a Mn concentration not more than one-third of the Mn concentration in the chemical composition of the steel sheet has a thickness of 1.0 μm or more. The lowest Si concentration L.sub.Si and the lowest Mn concentration L.sub.Mn in the region within 4.9 μm in the thickness direction from the surface of the steel sheet and a Si concentration T.sub.Si and a Mn concentration T.sub.Mn at a quarter thickness position of the steel sheet satisfy the following formula (1):

L.sub.Si+L.sub.Mn≤(T.sub.Si+T.sub.Mn)/4  (1).

An anisotropic rare earth sintered magnet represented by the formula (R.sub.1-aZr.sub.a).sub.x(Fe.sub.1-b CO.sub.b).sub.100-x-y(M.sup.1.sub.1-cM.sup.2.sub.c).sub.y where R is at least one element selected from rare earth elements and Sm is essential; M.sup.1 is at least one of V, Cr, Mn, Ni, Cu, Zn, Ga, Al, and Si; M.sup.2 is at least one of Ti, Nb, Mo, Hf, Ta, and W; and x, y, a, b, and c each satisfy certain conditions. The anisotropic rare earth sintered magnet includes 80% by volume or more of a main phase composed of a compound of a ThMn.sub.12 type crystal, the main phase having an average crystal grain size of 1 μm or more, and containing an R-rich phase and an R(Fe,Co).sub.2 phase in a grain boundary portion. A method for producing the anisotropic rare earth sintered magnet is also described.

An anisotropic rare earth sintered magnet represented by the formula (R.sub.1-aZr.sub.a).sub.x(Fe.sub.1-b CO.sub.b).sub.100-x-y(M.sup.1.sub.1-cM.sup.2.sub.c).sub.y where R is at least one element selected from rare earth elements and Sm is essential; M.sup.1 is at least one of V, Cr, Mn, Ni, Cu, Zn, Ga, Al, and Si; M.sup.2 is at least one of Ti, Nb, Mo, Hf, Ta, and W; and x, y, a, b, and c each satisfy certain conditions. The anisotropic rare earth sintered magnet includes 80% by volume or more of a main phase composed of a compound of a ThMn.sub.12 type crystal, the main phase having an average crystal grain size of 1 μm or more, and containing an R-rich phase and an R(Fe,Co).sub.2 phase in a grain boundary portion. A method for producing the anisotropic rare earth sintered magnet is also described.

A low thermal expansion cast steel having a sufficient strength even at a high temperature and having a low coefficient of thermal expansion, that is, a low thermal expansion cast steel comprising, by mass %, C: 0 to 0.100%, Si: 0 to 1.00%, Mn: 0 to 1.00%, Co: 8.0 to 13.0%, and Ni satisfying −2.5×% Ni+85.5≤% Co≤−2.5×% Ni+90.5 (% Ni and % Co respectively being contents of Ni and Co (mass %)) and having a balance of Fe and unavoidable impurities and having, upon being subjected to suitable heat treatment, a 0.2% proof stress of a tensile test at 300° C. of 125 MPa or more, having an average coefficient of thermal expansion at 25 to 300° C. of 4.0 ppm/° C. or less, and having a Curie temperature of 250° C. or more.

Provided are a laminate shaped article made of a maraging steel and having excellent toughness, a method for manufacturing the same, and a metal powder for laminate shaping. The laminate shaped article is made of a maraging steel comprising 0.1-5.0 mass % of Ti. When sis is performed on concentration distribution of Ti in a cross section parallel to a lamination direction of the above laminate shaped article, a length of a linear Ti-rich portion having a Ti concentration B of (1.5×A) or more with respect to an average Ti concentration A in the cross section is 15 μm or less. In addition, the method for manufacturing the laminate shaped article uses a metal powder made of a maraging steel comprising 0.1-5.0 mass % of Ti, and a heat source output is set to 50-330 W and a scanning speed is set to 480-3000 mm/sec during the laminate shaping.