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.

Methods of producing high strength continuously cast hot rolled steel sheet products are disclosed. The methods include continuously casting a steel slab and then hot rolling with finish rolling on a hot strip mill, quenching on the hot strip mill to form a predominantly matrensitic microstructure, and performing a thermal cycling step including soaking at an intercritical temperature followed by holding at a lower temperature. The resultant hot rolled steel sheet products have a microstructure comprising ferrite and retained austenite. Steels processed in accordance with the present invention exhibit favorable combined ultimate tensile strength and total elongation (UTS.Math.TE) properties, and may fall into the category of Generation 3 advanced high strength steels, desirable in various industries including automobile manufacturers.

The disclosed martensitic stainless steel is defined in its composition is by specified ranges of weight percentages of C; Mn; Si; ≤Mn+Si; ≤S; 10,000×Mn×S; P; Cr, with [Cr−10.3−80*(C+N).sup.2]≤(Mn+Ni); Ni; Mo; Mo+2W; Cu; Ti; V; Zr; Al; O; Ta; Nb; (Nb+Ta)/(C+N); Nb; N; Co; Cu+Co; Cu+Co+Ni; B; rare earths+Y; Ca; the remainder being iron and impurities resulting from processing. Its microstructure includes at least 75% martensite, at most 20% ferrite and at most 0.5% carbides, the size of the ferrite grains being between 4 and 80 μm, preferably between 5 and 40 μm. Also disclosed is a method of manufacturing such steel.

A hot stamped article having excellent shock absorption having a predetermined chemical composition, having a microstructure containing prior austenite having an average grain size of 3 μm or less and further containing at least one of lower bainite, martensite, and tempered martensite in an area ratio of 90% or more, and having a grain boundary solid solution ratio Z defined by Z=(mass % of one or both of Nb and Mo at grain boundaries)/(mass % of one or both of Nb and Mo at time of melting) of 0.3 or more.

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.

Disclosed is a follow-up process-omitting type high-strength hot-rolled steel sheet having an excellent yield ratio and a method for manufacturing the same. The hot-rolled steel sheet includes, in percent by weight (wt %), 0.12% or more and less than 0.3% of C, 0.5% or less of Si (excluding 0), 0.1 to 2.5% of Mn, 0.0005 to 0.005% of B, 0.02% or less of P, 0.01% or less of S, and the balance of Fe and inevitable impurities, has a microstructure including at least 95 vol % of martensite, has a yield ratio (yield strength/tensile strength) of 0.75 or more, is manufactured by continuous hot rolling, and is manufactured without performing a follow-up process such as cold rolling and heat treatment.

Disclosed are a wire rod and a component, for cold forging, each having excellent delayed fracture resistance characteristics and applicable to high-strength bolts and the like and a manufacturing method therefor.

According to an embodiment, a heat-treated component having excellent delayed fracture resistance characteristics includes, in percent by weight (wt %), 0.3 to 0.5% of C, 0.01 to 0.3% of Si, 0.3 to 1.0% of Mn, at least two types selected from the group consisting of 0.3 to 1.5% of Cr, 0.3 to 1.5% of Mo, and 0.01 to 0.4% of V, and the balance being Fe and other impurities, includes, as a microstructure, a tempered martensite phase in an area fraction of 95% or more, and includes V-based carbides having a diameter of 300 nm or less at 10/100 μm.sup.2 or more.

The present invention relates to a method for producing an article out of a maraging steel, wherein the article is successively subjected to a solution annealing and heat treatment, wherein the steel has the following composition in Wt.-%: C=0.01-0.05 Si=0.4-0.8 Mn=0.1-0.5 Cr=12.0-13.0 Ni=9.5-10.5 Mo=0.5-1.5 Ti=0.5-1.5 Al=0.5-1.5 Cu=0.0-0.05

Residual iron and smelting-induced impurities.

A controller alters a cycle time of a die arrangement, configured to hot stamp metal into components and having an active cooling system, based on an amount of heat transferred from the components to the active cooling system such that a grain structure of the components transitions from an austenitic state to a martensitic state.

A carburized steel component, comprising a steel base including, by weight percent, from 0.08% to 0.35% carbon, 0.5% to 1.3% manganese, 0% to 0.35% silicon, 0.2% to 2.0% chromium, 0% to 4% nickel, 0% to 0.50% molybdenum, 0% to 0.06% niobium, and a remaining weight percent of iron, and a carburized layer of above 0.35% by weight carbon from a surface of the carburized layer to a carburized layer depth, wherein the carburized layer depth is from 0.5 mm to 3.0 mm, wherein the carburized layer comprises a microstructure including martensite, retained austenite, carbide, and less than 2% by volume non-martensitic transformation products (NMTP), and wherein the carburized layer includes a prior austenite average grain size of 3.0-8.0 microns from the surface to a depth of at least 0.2 mm.