A method of forming a shaped steel object is provided. The method includes cutting a blank from an alloy composition including 0.05-0.5 wt. % carbon, 4-12 wt. % manganese, 1-8 wt. % aluminum, 0-0.4 wt. % vanadium, and a remainder balance of iron. The method also includes heating the blank until the blank is austenitized to form a heated blank, transferring the heated blank to a press, forming the heating blank into a predetermined shape to form a stamped object, and decreasing the temperature of the stamped object to a temperature between a martensite start (Ms) temperature of the alloy composition and a martensite final (Mf) temperature of the alloy composition to form a shaped steel object comprising martensite and retained austenite.

The present invention relates to an R-T-B sintered magnet and a preparation method thereof. The sintered magnet includes a grain boundary region T1, a shell layer region T2 and an R.sub.2Fe.sub.14B grain region T3; at 10 μm to 60 μm from a surface of the sintered magnet toward a center thereof, an area ratio of the shell layer region T2 to the R.sub.2Fe.sub.14B grain region T3 is 0.1 to 0.3, and a thickness of the shell layer region T2 is 0.5 μm to 1.2 μm; and an average coating percent of the shell layer region T2 on the R.sub.2Fe.sub.14B grain region T3 is 80% or more. In the present invention, by optimizing a preparation process and a microstructure of a traditional rare earth permanent magnet, diffusion efficiency of heavy rare earth in the magnet is improved, such that coercivity of the magnet is greatly improved, and manufacturing cost is reduced.

The present invention relates to an R-T-B sintered magnet and a preparation method thereof. The sintered magnet includes a grain boundary region T1, a shell layer region T2 and an R.sub.2Fe.sub.14B grain region T3; at 10 μm to 60 μm from a surface of the sintered magnet toward a center thereof, an area ratio of the shell layer region T2 to the R.sub.2Fe.sub.14B grain region T3 is 0.1 to 0.3, and a thickness of the shell layer region T2 is 0.5 μm to 1.2 μm; and an average coating percent of the shell layer region T2 on the R.sub.2Fe.sub.14B grain region T3 is 80% or more. In the present invention, by optimizing a preparation process and a microstructure of a traditional rare earth permanent magnet, diffusion efficiency of heavy rare earth in the magnet is improved, such that coercivity of the magnet is greatly improved, and manufacturing cost is reduced.

A cold-rolled sheet according to an example of the present invention comprises at most 0.004 wt % (exclusive of 0 wt %) of C, at most 0.02 wt % (exclusive of 0 wt %) of Si, 0.1 to 0.3 wt % of Mn, at most 0.05 wt % (exclusive of 0 wt %) of Al, at most 0.02 wt % (exclusive of 0 wt %) of P, at most 0.001 wt % (exclusive of 0 wt %) of S, at most 0.004 wt % (exclusive of 0 wt %) of N, 0.015 to 0.035 wt % of Ti, and 0.001 to 0.003 wt % of B, with the balance being Fe and other inevitable impurities, and has a microstructure in which the crystal grain aspect ratio defined by the following equation 1 is 1.4 to 4.0.

Crystal grain aspect ratio=average crystal grain diameter in the rolling direction/average crystal grain diameter in the thickness direction   [Equation 1]

A cold-rolled sheet according to an example of the present invention comprises at most 0.004 wt % (exclusive of 0 wt %) of C, at most 0.02 wt % (exclusive of 0 wt %) of Si, 0.1 to 0.3 wt % of Mn, at most 0.05 wt % (exclusive of 0 wt %) of Al, at most 0.02 wt % (exclusive of 0 wt %) of P, at most 0.001 wt % (exclusive of 0 wt %) of S, at most 0.004 wt % (exclusive of 0 wt %) of N, 0.015 to 0.035 wt % of Ti, and 0.001 to 0.003 wt % of B, with the balance being Fe and other inevitable impurities, and has a microstructure in which the crystal grain aspect ratio defined by the following equation 1 is 1.4 to 4.0.

Crystal grain aspect ratio=average crystal grain diameter in the rolling direction/average crystal grain diameter in the thickness direction   [Equation 1]

Provided are a non-heat treated wire rod having high drawability and impact toughness, and a method for manufacturing the non-heat treated wire rod. The non-heat treated wire rod includes, by wt%, C: 0.02% to 0.30%, Si: 0.05% to 0.8%, Mn: 0.5% to 2.0%, Cr: 1.0% or less, P: 0.03% or less, S: 0.03% or less, sol.Al: 0.01% to 0.07%, N: from greater than 0.01% to 0.02%, Nb: 0.1% or less, V: 0.5% or less, and Ti: 0.1% or less, and a balance of Fe and inevitable impurities, wherein the non-heat treated wire rod has a microstructure including ferrite and pearlite.

The present disclosure relates to an aluminum alloy-plated steel sheet having excellent workability and corrosion resistance and a method for manufacturing the same, and more particularly, to an aluminum alloy-plated steel sheet preventing microcracks generated during hot forming and has excellent seizure resistance and corrosion resistance, and a method for manufacturing the same.

The present disclosure relates to an aluminum alloy-plated steel sheet having excellent workability and corrosion resistance and a method for manufacturing the same, and more particularly, to an aluminum alloy-plated steel sheet preventing microcracks generated during hot forming and has excellent seizure resistance and corrosion resistance, and a method for manufacturing the same.

A Fe-based alloy represented by a composition of (Fe.sub.(1-a)M.sup.1.sub.a).sub.100-b-c-d-e-f-gM.sup.2.sub.bM.sup.3.sub.cB.sub.dP.sub.eCu.sub.fTi.sub.g, wherein M.sup.1 is at least one element selected from the group consisting of Co and Ni, M.sup.2 is at least one element selected from the group consisting of Nb, Mo, Zr, Ta, W, Hf, Ti, V, Cr, and Mn, M.sup.3 is at least one element selected from the group consisting of Si, Al, Ga, and Ge, and a, b, c, d, e, f, and g satisfy the following content conditions: 0≤a≤0.5, 0<b≤1.5, 0<c≤4, 7≤d≤13, 0.1≤e≤5, 0.6≤f≤1.5, and 0<g, is provided, wherein a full width at half maximum of an XRD main peak is 0.172 or more.

A Fe-based alloy represented by a composition of (Fe.sub.(1-a)M.sup.1.sub.a).sub.100-b-c-d-e-f-gM.sup.2.sub.bM.sup.3.sub.cB.sub.dP.sub.eCu.sub.fTi.sub.g, wherein M.sup.1 is at least one element selected from the group consisting of Co and Ni, M.sup.2 is at least one element selected from the group consisting of Nb, Mo, Zr, Ta, W, Hf, Ti, V, Cr, and Mn, M.sup.3 is at least one element selected from the group consisting of Si, Al, Ga, and Ge, and a, b, c, d, e, f, and g satisfy the following content conditions: 0≤a≤0.5, 0<b≤1.5, 0<c≤4, 7≤d≤13, 0.1≤e≤5, 0.6≤f≤1.5, and 0<g, is provided, wherein a full width at half maximum of an XRD main peak is 0.172 or more.