One embodiment of the present disclosure provides an abrasion resistant steel having excellent hardness and impact toughness, and a manufacturing method therefor, the steel comprising, by wt %, 0.33-0.42% of C, 0.1-0.7% of Si, 0.6-1.6% of Mn, 0.05% or less of P, 0.02% or less of S, 0.07% or less of Al, 0.55-5.0% of Ni, 0.01-1.5% of Cu, 0.01-0.8% of Cr, 0.01-0.8% of Mo, 50 ppm or less of B, and 0.02% or less of Co, further comprising one or more selected from the group consisting of 0.02% or less of Ti, 0.05% or less of Nb, 0.05% or less of V and 2-100 ppm of Ca, and comprising the balance of Fe and other inevitable impurities, wherein C and Ni satisfy the following relation 1, and the microstructure comprises 95 area % or more of martensite and 5% or less of bainite (including 0%). [Relation 1] [C]×[Ni]≥0.231

A steel material for a low yield ratio, high-strength steel pipe having excellent low-temperature toughness according to an aspect of the present invention comprises, by weight %, 0.03-0.065% of C, 0.05-0.3% of Si, 1.7-2.2% of Mn, 0.01-0.04% of Al, 0.005-0.025% of Ti, 0.008% or less of N, 0.08-0.12% of Nb, 0.02% or less of P, 0.002% or less of S, 0.05-0.3% of Cr, 0.4-0.9% of Ni, 0.3-0.5% of Mo, 0.05-0.3% of Cu, 0.0005-0.006% of Ca, 0.001-0.04% of V, and the balance of Fe and inevitable impurities, wherein a number of deposits having an average diameter of 20 nm or less per unit area in a cross section of the steel material may be 6.5*10.sup.9/mm.sup.2 or greater.

Disclosed is a non-heat-treated steel that has low deformation resistance during cold forging in bolt head forming and excellent product yield, and that can be manufactured without the need to perform heat treatment for controlling strength variation. The disclosed steel has a chemical composition containing C: 0.18-0.24%, Si: 0.10-0.22%, Mn: 0.60-1.00%, Al: 0.010-0.050%, Cr: 0.65-0.95%, Ti: 0.010-0.050%, B: 0.0015-0.0050%, N: 0.0050-0.0100%, P: 0.025% or less inclusive of 0, S: 0.025% or less inclusive of 0, Cu: 0.20% or less inclusive of 0, and Ni: 0.30% or less inclusive of 0, in a range satisfying: 0.45≤C+Si/24+Mn/6+Ni/40+Cr/5≤0.60 and N≤0.519A1+0.292Ti, with the balance being Fe and inevitable impurities; and a microstructure in which bainite is present in an area ratio of 95% or more, where the microstructure contains prior austenite grains with a grain size number of 6 or more, and strength variation is 100 MPa or less.

A catalyst used for dehydrogenation of an organic hydrogen-storage material to generate hydrogen, a support for the catalyst, and a preparation process thereof are presented. A hydrogen-storage alloy and a preparation process thereof are also provided. A process for providing high-purity hydrogen, a high-efficiently distributed process for producing high-purity and high-pressure hydrogen, a system for providing high-purity and high-pressure hydrogen, a mobile hydrogen supply system, and a distributed hydrogen supply apparatus are also described.

This hot-rolled steel sheet has a predetermined chemical composition, in which in a case where the thickness is denoted by t, a metallographic structure at a t/4 position from the surface includes, by area fraction, 77.0% to 97.0% of bainite or tempered martensite, 0% to 5.0% of ferrite, 0% to 5.0% of pearlite, 3.0% or more of residual austenite, and 0% to 10.0% of martensite, in the metallographic structure, the average grain size excluding the residual austenite is 7.0 μm or less, the average number density of iron-based carbides having a diameter of 20 nm or more is 1.0×10.sup.6 carbides/mm.sup.2 or more, a tensile strength is 980 MPa or more, and an average Ni concentration on the surface is 7.0% or more.

Disclosed are a ferritic stainless steel capable of inhibiting high temperature oxidation through generation of an effective oxide scale, and manufacturing method thereof. The ferritic stainless steel excellent in oxidation resistance at high temperature according to an embodiment of the present disclosure includes, in percent (%) by weight of the entire composition, Cr: 10 to 30%, Si: 0.2 to 1.0%, Mn: 0.1 to 2.0%, W: 0.3 to 2.5%, Ti: 0.001 to 0.15%, Al: 0.001 to 0.1%, the remainder of iron (Fe) and other inevitable impurities, and satisfies a following equation (1).
W/(Ti+Al)≥10  (1)

The present disclosure belongs to the technical field of alloy preparation and provides a nickel-based superalloy and a preparation method thereof. In the present disclosure, the nickel-based superalloy includes the following components by mass percentage: C: 0.07% to 0.10%, 0<Si≤1.00%, 0<Mn≤1.50%, P≤0.020%, S≤0.005%, Cr: 19.0% to 23.0%, Ni: 31.0% to 34.5%, 0<Cu≤0.75%, Al: 0.15% to 0.60%, Ti: 0.15% to 0.60%, and Fe as a balance. In terms of mass percentage, Ni is adjusted to 31.0% to 34.5%, while P is controlled at less than or equal to 0.020% and S is controlled at less than or equal to 0.005%, thereby improving mechanical properties. The examples show that the nickel-based superalloy has a tensile strength of greater than or equal to 460 MPa, a specified plastic elongation strength of greater than or equal to 180 MPa, and an elongation at break of greater than or equal to 35%.

A process for manufacturing a flat steel product having a prealloyed corrosion-resistant coating, comprises providing a coated flat steel product comprising a steel substrate having, at least on one side of the steel substrate, and an aluminum-based corrosion-resistant coating. The coated flat steel product is heat-treated, comprising the following substeps: Heating the coated flat steel product in a furnace at a furnace temperature T of between 950° C. and 1150° C. with a furnace dwell time tv of between 40 seconds and 150 seconds, the furnace temperature being chosen such that the heating rate of the coated flat steel product in the temperature range from 500° C. to 700° C. is more than 10 K/s. The coated flat steel product is held at a temperature above Ac3 for a hold time of between 20 seconds and 60 seconds.

Disclosed are an alloy steel including boron (B) to provide improved hardenability, cobalt (Co) to provide improve strength, and the method of preparing the alloy steel. In particular, components of the alloy steel composition are appropriately mixed to form 100 vol % of tempered martensite as a constituent structure, thereby exhibiting excellent hydrogen embrittlement resistance and strength.

The invention relates to a steel wire suitable for making a spring or medical wire products which remarkably improve the performance of conventional stainless steel wire. The steel comprises (in wt. %): C: 0.02 to 0.15, Si: 0.1 to 0.9, Mn: 0.8 to 1.6, Cr 16 to 20, Ni: 7.5 to 10.5, Mo: ≤3, Al: 0.5 to 2.5, Ti: ≤0.15, N: ≤0.05, optional elements, and impurities, balance Fe, wherein the total amount of Cr and Ni is 25 to 27 wt. %, and wherein the steel has a microstructure including, in volume % (vol. %), martensite: 40 to 90, austenite: 10 to 60, and delta ferrite: ≤5.