Abstract: An exemplary process includes determining a desired pore size, selecting an initial pore size greater than the target pore size, manufacturing a porous structure with the initial pore size, forging the porous structure to form a forged part having the desired pore size, and forming an orthopedic device from the forged part.

Abstract: A method for manufacturing a forged component includes: performing hot forging on a material; heating the hot forged material to a first set temperature; and performing warm coining to correctly shape the heated material. The material may be heated to a second set temperature before hot forging. The material heated to the second set temperature may be hot forged. The second set temperature may be higher than the first set temperature. The hot forged material may be subjected to controlled cooling to a third set temperature at a predetermined cooling rate. The controlled cooled material may be heated to the first set temperature. The third set temperature may be lower than or equal to the first set temperature.

Abstract: Disclosed is a high-strength sheet containing: C: 0.15% by mass to 0.35% by mass, a total of Si and Al: 0.5% by mass to 3.0% by mass, Al: 0.01% by mass or more, N: 0.01% by mass or less, Mn: 1.0% by mass to 4.0% by mass, P: 0.05% by mass or less, and S: 0.01% by mass or less, with the balance being Fe and inevitable impurities, wherein the steel structure satisfies that: a ferrite fraction is 5% or less, the total fraction of tempered martensite and tempered bainite is 60% or more, the amount of retained austenite is 10% or more, MA has an average size of 1.0 ?m or less, retained austenite has an average size of 1.0 ?m or less, retained austenite having a size of 1.5 ?m or more accounts for 2% or more of the total amount of retained austenite, and the amount of solute nitrogen in a steel sheet is 0.002% by mass or less.

Abstract: Disclosed is a high-strength sheet containing: C: 0.15% by mass to 0.35% by mass, a total of Si and Al: 0.5% by mass to 3.0% by mass, Mn: 1.0% by mass to 4.0% by mass, P: 0.05% by mass or less (including 0% by mass), S: 0.01% by mass or less (including 0% by mass), and Ti: 0.01% by mass to 0.2% by mass, with the balance being Fe and inevitable impurities, wherein the steel structure satisfies that: a ferrite fraction is 5% or less, a total fraction of tempered martensite and tempered bainite is 60% or more, a retained austenite fraction is 10% or more, a fresh martensite fraction is 5% or less, retained austenite has an average grain size of 0.5 ?m or less, retained austenite having a grain size of 1.0 ?m or more accounts for 2% or more of the total amount of retained austenite, and a prior austenite grain size is 10 ?m or less.

Abstract: A high-strength galvanized steel sheet having excellent formability and crashworthiness, including a component composition containing 0.03% to 0.13% C, 1.0% to 2.0% Si, 2.4% to 3.5% Mn, 0.001% to 0.05% P, 0.0001% to 0.01% S, 0.001% to 0.1% Al, 0.0005% to 0.01% N, and 0.0003% to 0.01% B on a mass basis, the remainder being Fe and unavoidable impurities, and a microstructure containing a tempered martensitic phase and a bainitic phase such that the sum of an area fraction of the tempered martensitic phase and an area fraction of the bainitic phase is 30% or more (the area fraction of the martensitic phase is 30% or more in the absence of the bainitic phase), wherein a distance of closest approach of the tempered martensitic phase is 10 ?m or less and the contents of C, Mn, and B satisfy (1): (% Mn)+1000×(% B)?35×(% C)??(1).

Abstract: A method of producing a forged steel part is disclosed. The method includes providing a steel billet that can be selectively hardened to different hardness levels by varying the air cooling rate. The method also includes heating the steel billet to an austenization temperature of the steel billet. The method further includes hot forging the steel billet to form the steel part including a first region and a second region. The method yet further includes selectively cooling the hot forged steel part by air cooling the first region at a first cooling rate and air cooling the second region at a second cooling rate that is less than the first cooling rate.

Abstract: A track link for a ground-engaging track includes an elongate link body having a lower hardness material forming a lower mounting surface for mounting a track shoe, and a sacrificial higher hardness material forming an upper rail surface for contacting rotatable track engaging elements. The lower hardness and higher hardness materials transition at a material interface within the elongate link body, and the material interface is longitudinally non-uniform, such that the sacrificial higher hardness material has a varying depth from the upper rail surface to retard scalloping.

Abstract: A high strength screw (2), especially an ultra high strength screw (2) having a tensile strength Rm of at least 1400 N/mm2, having a bainite structure has a yield ratio of at least 0.95. The screw (2) belongs to the new strength classes 14.10, 15.10, 16.10 or 17.10. The high yield ratio is realized by heat treatment of the screw (2).

Abstract: Provided is a mold steel for plastic injection that is excellent in fatigue strength and tensile strength and available for long term use, where the mold steel includes: 0.15 to 0.40 wt. % of carbon (C), 0.15 to 0.50 wt. % of silicon (Si), 0.70 to 1.50 wt. % of manganese (Mn), 0.50 to 1.20 wt. % of nickel (Ni), 1.50 to 2.50 wt. % of chrome (Cr), 0.25 to 0.70 wt. % of molybdenum (Mo), 0.20 wt. % or less of vanadium (V), 0.010 wt. % or less of boron (B), and a trace of iron (Fe) and a plurality of impurities.

Abstract: A forging heat resistant steel of an embodiment contains in percent by mass C: 0.05-0.2, Si: 0.01-0.1, Mn: 0.01-0.15, Ni: 0.05-1, Cr: 8 or more and less than 10, Mo: 0.05-1, V: 0.05-0.3, Co: 1-5, W: 1-2.2, N: 0.01 or more and less than 0.015, Nb: 0.01-0.15, B: 0.003-0.03, and a remainder comprising Fe and unavoidable impurities.

Abstract: A high strength press-formed member includes a steel sheet constituting the member including a composition including by mass %, C: 0.12% to 0.69%, Si: 3.0% or less, Mn: 0.5% to 3.0%, P: 0.1% or less, S: 0.07% or less, Al: 3.0% or less, N: 0.010% or less, Si+Al: at least 0.

Abstract: In a press-hardening plant, a contact-cooling press (12) is provided between the furnace (11) and the press-hardening press (13). Preselected parts of the blank (18) are contact-cooled such that corresponding parts of the finished product are softer and display a lower yield point.

Abstract: A steel material which is suitable for hot press working or hot three-dimensional bending and direct quench and which can be used to manufacture a high-strength formed article with sufficient quench hardening even by short time heating at a low temperature has a chemical composition comprising, in mass percent, C: 0.05-0.35%, Si: at most 0.5%, Mn: 0.5-2.5%, P: at most 0.03%, S: at most 0.01%, sol. Al: at most 0.1%, N: at most 0.01%, and optionally at least one element selected from the group consisting of B: 0.0001-0.005%, Ti: 0.01-0.1%, Cr: 0.18-0.5%, Nb: 0.03-0.1%, Ni: 0.18-1.0%, and Mo: 0.03-0.5% and has a steel structure in which the spheroidization ratio of carbides is 0.60-0.90.

Abstract: A forged roll for use, inter alia, in the cold rolling industry and a method of producing a forged roll as described. The roll has a steel composition, by weight, with 0.8 to less than 1% C, 0.2 to 0.5% Mn, 0.2 to 2.0% Si, 7.0 to 13.0% Cr, 0.6 to 1.6% Mo, more than 1.0 to 3.0% V, the remainder being Fe and impurities. The steel is tempered martensite with retained austenite at less than 5% per volume with eutectic carbides of less than 5% by volume, a hardness between 780-840 HV, and internal compressive stresses of between ?300 to ?500 MPa.

Abstract: A reduced nickel-chromium alloy component having by weight about 0.38% to about 0.43% C, about 0.15% to about 0.30% Si, about 1.00% to about 1.25% Mn, about 0.75% to about 0.90% Ni, about 1.00% to about 1.30% Cr, about 0.25% to about 0.35% Mo, about 0.05% to about 0.12% V, up to about 0.015% S, up to about 0.015% P, up to about 0.15% Cu, and balance iron and incidental impurities. The component has a hardenability corresponding to an ideal diameter of greater than about 10 inches.

Abstract: A method of producing a forged steel part is disclosed to include providing a steel billet having a composition including 0.25-0.40 wt. % C, 1.50-3.00 wt. % Mn, 0.30-2.00 wt. % Si, 0.00-0.150 wt. % V, 0.02-0.06 wt. % Ti, 0.010-0.04 wt. % S, 0.0050-0.0150 wt. % N, 0.00-1.00 wt. % Cr, 0.00-0.30 wt. % Mo, 0.00-0.003 wt. % B, and a balance of Fe and incidental impurities. The method may further include heating the steel billet to an austenization temperature of approximately 1150 degrees C. to 1350 degrees C., hot forging the steel billet to form the steel part, and controlled air cooling the forged steel part after the hot forging. The method may still further include induction heating select portions of the forged steel part after the controlled air cooling to increase the hardness of the select portions of the forged steel part, followed by quenching and tempering before the final machining.

Abstract: According to the method of production of a steel sheet pressed part with locally modified properties, the steel sheet blank is first heated in a device for heating to the austenitic temperature of the material. Next, the steel sheet blank is converted in a tool for deep drawing by deformation into a final drawn part. Subsequently, the final drawn part is cooled inside the tool for deep drawing. Various locations of the final drawn part are cooled to various temperatures and/or at various rates during the cooling process. Thereafter, the drawn part is placed in an annealing device, where retained austenite stabilization occurs by diffusion-based carbon partitioning within the material from which the drawn part is made. After stabilization, the final drawn part is removed from the annealing device and air cooled to ambient temperature.

Abstract: Disclosed is an alloy steel for hot forging and a heat treatment method thereof, more particularly, an alloy steel for hot forging and a heat treatment method thereof, which includes iron as a base material, and about 0.08 to 0.13% by weight of carbon (C), about 1.3 to 1.5% by weight of manganese (Mn), and about 0.1 to 0.3% by weight of molybdenum (Mo), based on a total weight of the alloy steel. As such, a tempering process can be omitted to reduce process costs, while still providing excellent strength and toughness as compared to the alloy steel in the related art.

Abstract: A method of producing a martensitic steel including a content of other metals such that it can be hardened by intermetallic compound and carbide precipitation, with an Al content of between 0.4% and 3%. The heat shaping temperature of a last heat shaping pass of the steel is lower than the solubility temperature of aluminum nitrides in the steel, and a treatment temperature for each potential heat treatment after the last heat shaping pass is lower than the solid-state solubility temperature of the aluminum nitrides in the steel.

Abstract: The invention relates to a crankshaft member having high fatigue strength and good bending correctability, and its method of manufacture. The steel made crankshaft member mainly consists of a two-phase structure of ferrite and perlite. The steel includes C, Ni, Mn, and Cr as required elements and Si, Cu, Mo, Ti, V, Nb, Ca, and S as optional elements that may be included, in the amounts of C within the range of 0.20 to 0.50 wt %, Si within the range of 0 to 0.6 wt %, Mn within the range of 0.5 to 1.5 wt %, Cu within the range of 0 to 0.7 wt %, Ni within the range of 0.05 to 1.5 wt %, Cr within the range of 0.05 to 0.45 wt %, and Mo within the range of 0 to 0.5 wt % to satisfy the condition 115?70C+8Si+23Mn+11Cu+128Cr+83Mo?50. A portion of the member surface is provided at least with a hard nitride layer having an average hardness within the range of 300 to 450 HV. Lamellar spacing of the perlite is 0.3 ?m or less.

Abstract: A hot-pressed steel sheet member has a composition containing, by mass, C: 0.09% to 0.38%, Si: 0.05% to 2.0%, Mn: 0.5% to 3.0%, P: 0.05% or less, S: 0.05% or less, Al: 0.005% to 0.1%, N: 0.01% or less, Sb: 0.002% to 0.03%, and the balance being Fe and inevitable impurities, and having a tensile strength TS of 980 to 2,130 MPa.

Abstract: Methods of refining the grain size of titanium and titanium alloys include thermally managed high strain rate multi-axis forging. A high strain rate adiabatically heats an internal region of the workpiece during forging, and a thermal management system is used to heat an external surface region to the workpiece forging temperature, while the internal region is allowed to cool to the workpiece forging temperature. A further method includes multiple upset and draw forging titanium or a titanium alloy using a strain rate less than is used in conventional open die forging of titanium and titanium alloys. Incremental workpiece rotation and draw forging causes severe plastic deformation and grain refinement in the titanium or titanium alloy forging.

Abstract: Disclosed are corrosion resistant, non-magnetic austenitic stainless steels containing alloying elements molybdenum, nickel, and copper and further containing small quantities of an additional element selected from the group consisting of a rare-earth element, calcium, cobalt, iridium, osmium, rhenium, rhodium, ruthenium, silver, and a combination thereof.

Abstract: The microstructure of a low alloy steel workpiece for cold forming may be beneficially modified by heating the workpiece to a temperature just above its austenite transformation temperature (Ac3 temperature). The steel workpiece is then cooled just below its Ac3 temperature to promote ferrite formation on and between the austenite grains. Heating and cooling, above and below the Ac3 temperature, is repeated a determined number of times to refine the austenite grains before the workpiece is quenched below its martensite transformation temperature to form a mixture of martensite with increased retained austenite. The workpiece may be further heated in its martensite region to increase the proportion of retained austenite before quenching the steel workpiece to an ambient temperature. The formability of the workpiece is improved, as is the strength of its formed shape.

Abstract: A process of fabricating a rotating component and components formed thereby. The process includes fabricating preforms corresponding to portions of the component. Each preform has an interface surface at which the preforms can be joined to locate a first of the portions in a radially outward direction from a second of the portions. The preforms are then inertia welded together to form a profile having a solid-state weld joint containing a finer-grained material than other portions of the profile. The profile is then forged with dies to produce a forging. At least one of the dies has a recess into which the finer-grained material from the weld joint is expelled during forging to purge a joint region of the forging between the forging portions of the finer-grained material. The joint region contains grains distorted in an axial direction of the forging.

Abstract: Disclosed are a high-strength, high-toughness hot-pressed steel plate member and a manufacturing method therefor. A specified hot-press process is performed on a steel plate member that, with respect to the chemical composition of the steel plate, includes: 0.15 to 0.4 wt % of C; 1.0 to 5.0 wt % of Mn or of a total of Mn and at least one of Cr, Mo, Cu, and Ni; 0.02 to 2.0 wt % of at least any one of Si and Al; and the remainder being Fe and unavoidable impurities, thus providing the physical properties of a martensite phase average grain diameter of 5 ?m or less and a tensile strength of 1200 MPa or higher.

Abstract: A mechanical steel part in steel with high characteristics, characterized in that its composition, comprising in weight percentages, is 0.05%?C?0.25%; 1.2%?Mn?2%; 1%?Cr?2.5%; wherein the contents of C, Mn and Cr are such that (830-270C %-90 Mn %-70Cr %)?560; 0<Si?1.55; 0<Ni?1%; 0<Mo?0.5%; 0<Cu?1%; 0<V?0.3%; 0<Al?0.1%; 0<B?0.005%; 0<Ti?0.03%; 0<Nb?0.06%; 0<S?0.1%; 0<Ca?0.006%; 0<Te?0.03%; 0<Se?0.05%; 0<Bi?0.05%; 0<Pb?0.1%; the remainder of the steel part being iron and impurities resulting from processing, and wherein the in that its structure of the steel is bainitic and contains no more than a total of 20% of martensite and/or pro-eutectoid ferrite and/or pearlite.

Abstract: A method for press-molding an embossed steel plate is able to cool even an embossed steel plate under conditions adequate for quenching. After a plate body with convex portions formed thereon is placed between an upper pressing die and a lower pressing die and the dies are closed, first and second circulation pumps are run to circulate cooling water.

Abstract: An air hardenable steel alloy is disclosed comprising, in percent by weight: 0.18 to 0.26 carbon; 3.50 to 4.00 nickel; 1.60 to 2.00 chromium; 0 to 0.50 molybdenum; 0.80 to 1.20 manganese; 0.25 to 0.45 silicon; 0 to less than 0.005 titanium; 0 to less than 0.020 phosphorus; 0 up to 0.005 boron; 0 up to 0.003 sulfur; iron; and impurities. The air hardenable steel alloy has a Brinell hardness in a range of 352 HBW to 460 HBW. The air hardenable steel alloy combines high strength, medium hardness and toughness, as compared with certain know air hardenable steel alloys, and finds application in, for example, any of a steel armor, a blast-protective hull, a blast-protective V-shaped hull, a blast-protective vehicle underbelly, and a blast-protective enclosure.

Abstract: This invention relates to a method of manufacturing non-quenched and tempered steel having an ultrafine grained pearlite structure, including hot forging a steel material so as to be high-temperature compression deformed, thus obtaining a hot forged body; rapidly cooling the hot forged body to a low-temperature pearlite transformation range, thus obtaining a supercooled hot forged body; isothermally holding the supercooled hot forged body in the low-temperature pearlite transformation range so as to be isothermally transformed; and air-cooling the hot forged body; and to non-quenched and tempered steel manufactured thereby.

Abstract: This invention relates to a method of manufacturing a non-quenched and tempered steel product, including hot forging a steel material at about 1150˜1250° C. so that the volume thereof is 120% or less, rapidly cooling the hot forged material to about 650˜700° C. at a cooling rate of about 10° C./s or more, and performing warm coining at a temperature of about 600° C. or higher.

Abstract: The present invention relates to a method of manufacturing ultra-high strength steel products and, more particularly, to a method of manufacturing ultra-high strength steel products suitable for production of articles having a complicated shape or a high processing depth. The method includes preparing a steel sheet by blanking the steel sheet having hardenability to form a rough shape of a final product, cold-pressing the steel sheet to form a 50˜80% shape of the final product, precisely trimming the cold-formed steel sheet along a contour line corresponding to an outer contour of the final product, and hot-pressing the trimmed product to form the remaining 20˜50% shape of the final product and quenching simultaneous with hot-pressing, after heating the trimmed product to an austenite region of 700° C. or more.

Abstract: The present invention, among other things, relates to a method for producing a workpiece by press hardening a semi-finished product, which is distinguished by the fact that the semi-finished product consists of a steel which has a high content of silicon of at least 0.9 wt. %, with a simultaneously small content of manganese of less than 0.9 wt. %, a small carbon content of less than 0.25 wt. %, and a high chromium content of more than 1.20 wt. %, and which by heating is brought to a state in which the structure of the steel that is used is at least partially transformed to austenite, also optionally fully transformed to austenite, and the thus-heated semi-finished product is hot shaped so that after the hot deformation shaping, a structure is present in the workpiece that has a complex phase structure with predominantly martensite and ferrite fractions. In addition, a workpiece is described, which is produced according to this method, as well as uses of such a workpiece.

Abstract: A fixed constant velocity universal joint includes an outer race having a spherical inner circumferential surface, the outer race including axially extending ball grooves formed in the spherical inner circumferential surface at regular circumferential intervals, and an inner race having a spherical outer circumferential surface, the inner race including axially extending ball grooves formed in the spherical outer circumferential surface at regular circumferential intervals. Balls are interposed between pairs of the ball grooves of the outer race and the ball grooves of the inner race. A cage has pockets for receiving the balls, the pockets being formed at predetermined circumferential intervals. The outer race is produced by hot forging or lathe-turning and subjected to thermal refining treatment.

Abstract: A non-heat treated connecting rod which comprises, by mass %, C: 0.25-0.35%, Si: 0.50-0.70%, Mn: 0.60-0.90%, P: 0.040-0.070%, S: 0.040-0.130%, Cr: 0.10-0.20%, V: 0.15-0.20%, Ti: 0.15-0.20% and N: 0.002-0.020%, and the balance Fe and impurities, with chemical compositions being less than 0.80 in the value of C+(Si/10)+(Mn/5)+(5Cr/22)+1.65 V?(5S/7) using the symbol of the element as its content, the microstructure of the Big end of the said connecting rod being ferrite-pearlite, all-region hardness of the said big end being 255 to 320 in Vickers hardness, the ferrite-region hardness in the said ferrite-pearlite of the Big end being 250 or more in Vickers hardness and the ratio of the said ferrite-region hardness to the said all-region hardness of the said Big end being 0.80 or more, is excellent in machinability, fracture splitting ability, and fatigue resistance, although no Pb at all is added.

Abstract: A press-hardened component and a method for producing press-hardened components, in particular a bodywork component, from a semi-finished product made from unhardened, hot-formable steel sheet. Various process steps are carried out in the process. A component blank is formed from the semi-finished product by a cold-forming process, in particular a drawing process. The component blank is trimmed at the margin side to a margin contour which approximately corresponds to the component to be produced. The trimmed component blank is heated and press-hardened in a hot-forming tool, and then the press-hardened component blank is covered with a corrosion-prevention layer in a coating step.

Abstract: Methods of refining the grain size of titanium and titanium alloys include thermally managed high strain rate multi-axis forging. A high strain rate adiabatically heats an internal region of the workpiece during forging, and a thermal management system is used to heat an external surface region to the workpiece forging temperature, while the internal region is allowed to cool to the workpiece forging temperature. A further method includes multiple upset and draw forging titanium or a titanium alloy using a strain rate less than is used in conventional open die forging of titanium and titanium alloys. Incremental workpiece rotation and draw forging causes severe plastic deformation and grain refinement in the titanium or titanium alloy forging.

Abstract: A method for manufacturing an axle is provided. The method includes heating a billet at a heating station to a predetermined temperature, forging the heated billet at a forging station to form an axle, and machining the axle at a machining station to form a machined axle. A product is automatically transported to and from each station using a product transport system, wherein the product includes the billet, the axle and the machined axle.

Abstract: The invention relates to a method for manufacturing of a flexible trailing arm for a wheel axle suspension of a vehicle such as a lorry or a trailer. In the method a steel blank is heated. Next, the blank is formed into the desired shape of the trailing arm by means of a suitable forming process. Following that the trailing arm is austempered by cooling it in a warm fluid medium.

Abstract: The present invention provides a tool steel containing, by mass percent, 0.55 to 0.85% of C, 0.20 to 2.50% of Si, 0.30 to 1.20% of Mn, 0.50% or less of Cu, 0.01 to 0.50% of Ni, 6.00 to 9.00% of Cr, 0.1 to 2.00% of Mo+0.5 W, and 0.01 to 0.40% of V, with the balance of Fe and inevitable impurities, in which, when an area rate of a coarse carbide having a circle equivalent diameter of 2 ?m or more in a cross section parallel to a forging direction is represented by L(%) and an area rate of the coarse carbide in a cross section perpendicular to the forging direction is represented by T(%), the area rate L is 0.001% or more, the area rate T is 0.001% or more, and the ratio L/T is within a range from 0.90 to 3.00. The tool steel of the invention exhibits an isotropic size change in quenching and tempering.

Abstract: Disclosed are a weldable steel of high strength and high toughness and a method of producing members of machine parts. The steel consists essentially of, by weight %, C: 0.10-0.16%, Si: 0.05-0.50%, Mn: 1.3-2.3%, Cu: up to 0.5%, Ni: up to 0.5%, Cr: up to 0.5%, Mo: up to 0.3% and Ti: 0.025-0.035%, and the balance of Fe and inevitable impurities, and satisfying the condition that the weld-cracking susceptibility, Pcm, defined by the formula 1A below is less than 0.35, and the condition that the manganese equivalent, Mneq, defined by the formula 2A below is larger than 2.0.

Abstract: A high-strength forged part is disclosed which comprises a base phase structure, comprising 30% or more of ferrite in terms of a space factor, and a second phase structure, comprising bainite and/or martensite, and retained austenite having an average gain diameter of 5 ?m or less and a content represented by 50X[C]<[V?R]<150x[C], wherein [V?R] represents a space factor of the retained austenite (?R) and [C] represents the mass % of C in the forged part. Furthermore, a high-strength forged part is disclosed which comprises a base phase structure, comprising 50% or more of tempered bainite or tempered martensite in terms of a space factor, and a second phase structure, comprising martensite and 3% to 30% retained austenite in terms of a space factor, wherein the portion of the retained austenite and martensite having an aspect ratio of 2 or less is 25% or less in terms of a space factor.

Abstract: The present invention provides a fine grain surface layer steel part having a high proof strength ratio equal to or higher than that of conventional quenched and tempered materials, that is, a fine grain surface layer steel part containing, by mass %, C: 0.45% to 0.70%, Nb: 0.01% to 0.60%, Si: 0.10% to 1.50%, Mn: 0.40% to 2.0%, P: 0.10% or less, S: 0.001% to 0.15%, and N: 0.003% to 0.025% and having a balance of Fe and unavoidable impurities, where the surface layer and inside at all or part of the part have structures of different average particle sizes of ferrite crystal grains surrounded by high angle grain boundaries of a misorientation angle of 15 degrees or more and a method of production of that part comprising warm forging locations where strength is required to a predetermined shape at 1000° C. to 800° C. during which working so as to give an equivalent strain of 1.5 or more.

Abstract: A hot forged product including hardened areas introduced by partial cooling after hot forging, and unhardened areas, wherein Vickers hardness V1 of the hardened areas on the surface and Vickers hardness V2 of the unhardened areas satisfy the following formula (1): (V1?V2)/V2: 0.1 to 0.8.

Abstract: A manufacturing method for a heavy munition casing is provided, in which steel is rolled as a rough sheet or is forged as a slab depending on the desired casing size. Steel plates (2) produced in this way have a thickness that is somewhat greater than the manufacturing diameter of the munition casing (5). The steel used for this purpose has longitudinally oriented manganese sulfides (3), which are also shaped in the lateral direction, in addition to main shaping in the longitudinal direction, by shaping to form the shaped steel plate (2), and assume a longitudinally extending plate-shape as well. The initial material for the casing (5) is taken from an approximately rectangular steel plate (2), transversely with respect to the deformation direction. The quadrilateral piece obtained in this way is then turned to be round and is mechanically processed to form the shape of the casing (5).

Abstract: Disclosed is a non-heat treated steel for hot forging, particularly suitable for producing connecting rods of automobile engines. The steel consists essentially of: by weight, C: 0.3-0.8%, Si: 0.1-2.0%, Mn: 0.3-1.5%, P: 0.01-0.15%, Cr: 0-1.0%, V: 0-0.4%, Al: 0-0.05%, N: 0.005-0.03% and the balance being Fe and inevitable impurities, provided that the contents of C, Mn and Cr fulfill the following condition: 1.40[C %]+0.28[Mn %]+0.50[Cr %]?0.75 Pearlite area fraction in this steel after hot forging is 50% or more. Notches are provided with laser beam on an intermediate part at the location from which fracture starts, and load is applied. Then, the intermediate is split to be two components (big end or cap and small end/rod for connecting rod). The components are adhered to form the parts.

Abstract: A method for designing a low cost, high strength, high toughness martensitic steel in which a mathematical model is used to establish an optimum low cost alloying concentration that provides specified levels of strength toughness. The model also predicts critical temperatures and the amount of retained austenite. Laboratory scale ingots of the optimum alloying composition were produced comprising by % wt. of about: 0.37 of C; 1.22 of Ni; 0.68 of Mn; 0.86 of Si; 0.51 of Cu; 1.77 of Cr; and 0.24 of V; and the balance Fe and incidental impurities were melted in an open induction furnace. After homogenized annealing, hot rolling, recrystallization annealing, and further oil quenching, refrigerating, and low tempering, a tempered martensite microstructure was produced consisting of small packets of martensitic laths, fine vanadium carbide, as centers of growth of the martensitic lathes, and retained austenite.

Abstract: A hot press-formed member having stable strength and toughness is manufactured from a high strength steel sheet by hot press forming. In the cooling stage during hot press forming, the cooling rate is at least the critical cooling rate until the Ms point is reached and it is then in the range of 25-150° C./s in the temperature range from the Ms point to 200° C. The Vickers hardness of the hot pressed member is less than the value of (maximum quenching hardness—10) and at least the value of (maximum quenching hardness—100).

Abstract: A forging stock formed by extrusion such that its cross section perpendicular to the direction of extrusion varies along the direction of extrusion. The forging stock is cut into portions in the direction of extrusion to be forged individually, each cut portion having cross sections varying along the direction of extrusion. Each cut portion includes a pair of first parallel parts at both ends thereof in the direction of extrusion, a second parallel part, which is between the first parallel parts, and which differs in thickness from said first parallel parts, and oblique parts each of which is between the first parallel parts and the second parallel part.

Abstract: The present invention provides a fine grain surface layer steel part having a high proof strength ratio equal to or higher than that of conventional quenched and tempered materials, that is, a fine grain surface layer steel part containing, by mass %, C: 0.45% to 0.70%, Nb: 0.01% to 0.60%, Si: 0.10% to 1.50%, Mn: 0.40% to 2.0%, P: 0.10% or less, S: 0.001% to 0.15%, and N: 0.003% to 0.025% and having a balance of Fe and unavoidable impurities, where the surface layer and inside at all or part of the part have structures of different average particle sizes of ferrite crystal grains surrounded by high angle grain boundaries of a misorientation angle of 15 degrees or more and a method of production of that part comprising warm forging locations where strength is required to a predetermined shape at 1000° C. to 800° C. during which working so as to give an equivalent strain of 1.5 or more.