The disclosure discloses a NdFeB permanent magnet and a preparation method thereof. The magnet is composed of main phase I, a shell structure, a grain boundary phase adjacent to the shell structure, a main phase II, a Ga rich region and a Cu rich region. The magnet has high remanence, high coercivity, and high magnetic energy. In addition, this method can significantly reduce the production cost.

A high-strength cold-rolled steel sheet comprises: a chemical composition that contains C, Si, Mn, P, S, N, Al, Ti, Nb, and B with a balance consisting of Fe and inevitable impurities, and satisfies [mol % N]/[mol % Ti]<1; and a steel microstructure in which: an area fraction of ferrite is 30% or more and 60% or less; a total area fraction of tempered martensite and bainite is 35% or more and 65% or less; an area fraction of quenched martensite is 15% or less; an area fraction of retained austenite is 1% or more and 10% or less; an area fraction of low-Mn ferrite having a Mn concentration of 0.8×[% Mn] or less is 5% or more and 40% or less; a result of subtracting the area fraction of the low-Mn ferrite from the area fraction of the ferrite is 10% or more; an area fraction of a residual microstructure is less than 3%; and an average grain size of the low-Mn ferrite is 10 μm or less.

Disclosed in the present invention is a manufacturing method for a carbon steel and austenitic stainless-steel rolling clad plate, comprising the steps of: (1) obtaining a blank material of a carbon steel layer and a blank material of a stainless-steel layer; (2) assembling blank materials; (3) cladding and rolling; (4) cold rolling; (5) first annealing; and (6) second annealing. The carbon steel and austenitic stainless-steel rolling clad plate has two unique annealing processes, so that the clad plate has the performance advantages of the austenitic stainless-steel and the carbon steel. In addition, further disclosed in the present invention is a carbon steel and austenitic stainless-steel rolling clad plate manufactured by this method.

A high-performance thermoformed component provided with a coating, and a manufacturing method therefor. The thermoformed component comprises a substrate and a coating thereon. The substrate comprises the following ingredients in percentage by weight: 0.01-0.8% of C, 0.05-1.0% of Si, 0.1-5% of Mn, 0.001-0.3% of P, 0.001-0.1% of S, 0.001-0.3% of Al, 0.001-0.5% of Ti, 0.0005-0.1% of B, 0.001-0.5% of Nb, 0.001-0.5% of V, and the remainder being Fe and other unavoidable impurities. The appearance of the thermoformed component has no color difference and no mottling. The surface oxygen content of the thermoformed component is 0.1-20 wt. %, and the ratio of the standard deviation to the average value of the surface oxygen content satisfies: 0<standard deviation of oxygen content/average value of oxygen content ≤0.3. In the manufacturing method, a coated steel plate that has undergone heat treatment, transfer processing, and hot stamping is not treated with oil.

The present invention provides a rare-earth sintered magnet that is characterized in that: R (R indicates one or more elements selected from rare-earth elements, wherein Nd is essential), T (T indicates one or more elements selected from iron-group elements, wherein Fe is essential), X (X indicates one or two elements selected from B and C, wherein B is essential), M.sup.1 (M.sup.1 indicates one or more elements selected from Al, Si, Cr, Mn, Cu, Zn, Ga, Ge, Mo, Sn, W, Pb, and Bi), 0.1 mass % or less of O, 0.05 mass % or less of N, and 0.07 mass % or less of C are contained; the average crystal grain size is 4.0 μm or less; and relational expression (1) 0.26×D+97≤Or≤0.26×D+99 is satisfied assuming that the degree of orientation is Or [%] and that the average crystal grain size is D [μm]. With this rare-earth sintered magnet, it is possible to achieve superior magnetic characteristics in which both high Br and high H.sub.cJ are achieved.

The present disclosure relates to a zinc plated steel sheet having excellent fatigue strength of electrical resistance spot welds and a method for manufacturing the same. According to an aspect of the present disclosure, a zinc plated steel sheet includes a base steel sheet and a zinc-based plating layer formed on a surface of the base steel sheet, wherein a concentration profile of one or two of oxygen, and silicon and manganese measured in a depth direction from the surface of the base steel sheet has a maximum point in the depth direction from the surface, and an absolute value of a difference between a depth at which the maximum point of the concentration profile of oxygen is formed and a depth at which the maximum point of the concentration profile of one of silicon and manganese is formed is 0.5 μm or less.

The present invention provides a tin blackplate for processing and a method for manufacturing the same.

The tin blackplate according to an exemplary embodiment of the present invention comprises: in % by weight, 0.0005 to 0.005% of carbon (C), 0.15 to 0.60% of manganese (Mn), 0.01 to 0.06% of aluminum (AI), 0.0005 to 0.004% of nitrogen (N), 0.0005 to 0.003% of boron (B), 0.01 to 0.035% of titanium (Ti), and the balance being iron (Fe) and inevitable impurities, and satisfies the following Formula 1.

4.8≤([Ti]+[Al])/[N]−[B]≤12.5  [Equation 1]

In this case, in Equation 1, [Ti], [Al], [N], and [B] mean each value obtained by dividing the content (% by weight) of Ti, Al, N, and B in the blackplate by each atomic weight thereof.

An embodiment of the present invention provides steel for hot forming, a hot-formed member, and methods for manufacturing same, the steel comprising, by wt %, 0.06-0.1% of C, 0.05-0.6% of Si, 0.6-2% of Mn, 0.05% or less of P, 0.02% or less of S, 0.01-0.1% of Al, 0.01-0.8% of Cr, 0.01-0.5% of Mo, 0.02% or less of N, and the remainder of Fe and inevitable impurities, wherein an alloy factor represented by relational expression 1 below is 7 or more, and the number of carbides having a circular equivalent diameter of 0.5 μm or greater is 10.sup.5/mm.sup.2 or less.

Alloy factor=I(Mn)×I(Si)×I(Cr)×I(Mo)  [Relational expression 1] where the I values for the components are I(Mn)=3.34×Mn+1, I(Si)=0.7×Si+1, I(Cr)=2.16×Cr+1, and I(Mo)=3×Mo+1, respectively, and the content of each component is expressed as wt %.

The present invention provides wear-resistant steel which has high hardness while having wear resistance and high impact toughness at low temperature, and a manufacturing method therefor.

This steel sheet has a specific chemical composition, the tensile strength is 1300 MPa or more, the ratio (R/t) of the limit bend radius to the sheet thickness is less than 3.5, when a depth position of 30 μm from the surface in the sheet thickness direction is defined as a position A and a depth position of ¼ of the sheet thickness from the surface in the sheet thickness direction is defined as a position B, the number density of AIN at the position A is 3000 pieces/mm.sup.2 or more and 6000 pieces/mm.sup.2 or less, a metallographic structure at the position B includes 90% or more of martensite by volume percentage, and the hardness at the position A is 1.20 times or higher than the hardness at the position B.