An embodiment of the present invention provides a steel plate for a pressure vessel having excellent hydrogen-induced cracking resistance and a method of manufacturing same, the steel plate comprising, in weight %, 0.2 to 0.3% of carbon (C), 0.05 to 0.50% of silicon (Si), 0.1% to 0.5% (exclusive) of manganese (Mn) , 0.005 to 0.1% of aluminum (Al), 0.010% or less of phosphorus (P) , 0.0015% or less of sulfur (S), 0.001 to 0.03% of niobium (Nb), 0.001 to 0.03% of vanadium (V) , 0.001 to 0.03% of titanium (Ti), 0.01 to 0.20% of chromium (Cr), 0.01 to 0.15% of molybdenum (Mo) , 0.01 to 0.50% of copper (Cu) , 0.05 to 0.50% of nickel (Ni), 0.0005 to 0.0040% of calcium (Ca), and the balance of Fe and other inevitable impurities, wherein the average grain size of ferrite is 5-20 μm.

A steel with high hardness and excellent toughness contains, in mass %, 0.55-1.10% C, 0.10-2.00% Si, 0.10-2.00% Mn, 0.030% or less P, 0.030% or less S, 1.10-2.50% Cr, and 0.010-0.10% Al, with the balance consisting of Fe and unavoidable impurities. The structure of the steel after quenching is a dual phase structure of martensitic structure and spheroidized carbide. Spheroidized cementite particles with an aspect ratio of 1.5 or less constitute at least 90% of all cementite particles. The proportion of the number of spheroidized cementite particles on the prior austenite grain boundaries to a total number of cementite particles is 20% or less.

There is provided a precipitation-strengthened stainless steel plate having a chemical composition: by mass %, C: 0.01 to 0.10%; Si: 0.02 to 3.0%; Mn: 0.02 to 2.0%; Ni: 20 to 30%, Cr: 14 to 25.0%; Mo: 1.0 to 4.0%; Cu: 0.01 to 2.0%; Co: 0.01 to 0.5%; V: 0.1 to 1.0%; B: 0.001 to 0.01%; N: 0.02% or less; Ti: 2.0 to 5.0%; Al: 0.002 to 5.0%; Ti+Al: 3.3 to 6.0%; and the balance being Fe and impurities, the precipitation-strengthened stainless steel plate having a Vickers hardness Hv of 300 or higher, wherein the number density γ′: Ni.sub.3(Al, Ti), which is an intermetallic compound, is 0 to 5/μm.sup.2. As a heat resistant component material, the precipitation-strengthened stainless steel plate is less expensive than conventional Ni-based alloys such as NCF625 and NCF718, and more excellent in high temperature properties than a precipitation-strengthened heat-resistant stainless steel such as SUH660.

There is provided a precipitation-strengthened stainless steel plate having a chemical composition: by mass %, C: 0.01 to 0.10%; Si: 0.02 to 3.0%; Mn: 0.02 to 2.0%; Ni: 20 to 30%, Cr: 14 to 25.0%; Mo: 1.0 to 4.0%; Cu: 0.01 to 2.0%; Co: 0.01 to 0.5%; V: 0.1 to 1.0%; B: 0.001 to 0.01%; N: 0.02% or less; Ti: 2.0 to 5.0%; Al: 0.002 to 5.0%; Ti+Al: 3.3 to 6.0%; and the balance being Fe and impurities, the precipitation-strengthened stainless steel plate having a Vickers hardness Hv of 300 or higher, wherein the number density γ′: Ni.sub.3(Al, Ti), which is an intermetallic compound, is 0 to 5/μm.sup.2. As a heat resistant component material, the precipitation-strengthened stainless steel plate is less expensive than conventional Ni-based alloys such as NCF625 and NCF718, and more excellent in high temperature properties than a precipitation-strengthened heat-resistant stainless steel such as SUH660.

A high-yield-ratio high-strength electrogalvanized steel sheet having an electrogalvanized coating layer formed on a surface of a base steel sheet, in which the base steel sheet has a certain chemical composition, and a steel microstructure, in which a total area fraction of one or both of bainite containing carbides having an average grain diameter of 50 nm or less and tempered martensite containing carbides having an average grain diameter of 50 nm or less is 90% or more in the whole of the steel microstructure, and in which a total area fraction of one or both of the bainite containing and the tempered martensite containing carbides is 80% or more in a region from the surface of the base steel sheet to a position located at ⅛ of a thickness of the base steel sheet, and diffusible hydrogen in steel in an amount of 0.20 mass ppm or less.

A 3-D printing method and a 3-D printout are provided. In an embodiment, the 3-D printing method includes laser-scanning a printing material according to a 3-D printing model so that the printing material starts to be sintered into a printout in a shape, layer by layer from the bottom up; and feeding a treatment gas into a 3-D printing device and laser-scan a local area of the printout so that the treatment gas reacts with the surface of the local area of the printout and a hardened layer is formed. The laser scanning and the feeding of the treatment gas are performed alternately until a printout with local hardened layers is formed. By adjusting the gas environment, the components can be manufactured by selective laser melting equipment to have a wear- and corrosion-resistant nitrided surface layer and keep the expected ductility of the central area.

A high-strength ferritic stainless steel for clamp includes, in percent (%) by weight of the entire composition, C: 0.04 to 0.1%, Si: 0.2 to 0.6%, Mn: 0.01 to 1.5%, Cr: 14.0 to 18.0%, Al: 0.005 to 0.2%, V: 0.005 to 0.2%, N: 0.02 to 0.1%, the remainder of iron (Fe) and other inevitable impurities, and satisfies following formulas (1) and (2), and the number of precipitates with an average diameter of 0.5 μm or less is 2.5×10.sup.6 pieces/mid or more: (1) 0.35%≤Si+Al+V≤0.6% and (2) 0.09%≤C+N≤0.12%.

The invention relates to the technical field of microstructure refinement and homogenization of bearing steel, and specifically relates to a high-carbon bearing steel and a method of preparing same. The high-carbon bearing steel of the invention has the following chemical composition: C: 0.80˜1.20 wt %, Cr: 0.40˜2.0 wt %, Mn: 0.15˜0.75 wt %, Si: 0.15˜0.75 wt %, Nb: 0˜0.20 wt %, Mo: 0˜0.20 wt %, V: 0˜0.20 wt %, P≤0.015 wt %, S≤0.01 wt %, the remaining is Fe and unavoidable impurities; the contents of Nb, Mo and V are not 0 at the same time. According to the invention, microalloying elements such as Nb, Mo and V, in combination with other elements, are added into the high-carbon bearing steel to effectively refine the bearing steel matrix and promote the precipitation of a large amount of nano-carbides, thereby enhancing the contact fatigue life of the high-carbon bearing steel.

A precipitation hardenable, martensitic stainless steel is disclosed. The alloy has the following broad composition in weight percent.

TABLE-US-00001 Ni 10.5-12.5 Co 1.0-6.0 Mo 1.0-4.0 Ti 1.5-2.0 Cr  8.5-11.5 Al Up to 0.5 Mn  1.0 max. Si 0.75 max. B 0.01 max.

The balance of the alloy is iron and the usual impurities found in commercial grades of precipitation hardenable martensitic stainless steels as known to those skilled in the state of the art in melting practice for such steels. A method of making parts from the alloy and an article of manufacture made from the alloy are also described.

An optimized Gamma-prime (γ′) strengthened austenitic transformation induced plasticity (TRIP) steel comprises a composition designed and processed such that the optimized γ′ strengthened austenitic TRIP steel meets property objectives comprising a yield strength of 896 MPa (130 ksi), and an austenite stability designed to have M.sub.s.sup.σ(sh)=−40° C., wherein M.sub.s.sup.σ(sh) is a temperature for shear, and wherein the property objectives are design specifications of the optimized γ′ strengthened austenitic TRIP steel. The optimized γ′ strengthened austenitic TRIP steel is Blastalloy TRIP 130.