Abstract: A case hardening steel, which has excellent cold forgeability and excellent crystal grain coarsening prevention characteristics after carburization, contains, in mass %, 0.05-0.20% of C, 0.01-0.1% of Si, 0.3-0.6% of Mn, 0.03% or less of P (excluding 0%), 0.001-0.02% of S, 1.2-2.0% of Cr, 0.01-0.1% of Al, 0.010-0.10% of Ti, 0.010% or less of N (excluding 0%), and 0.0005-0.005% of B, with the balance consisting of iron and unavoidable impurities. The density of Ti-based precipitates having circle-equivalent diameters less than 20 nm in the case hardening steel is 10-100 pieces/?m2; the density of Ti-based precipitates having diameters of 20 nm or more in the case hardening steel is 1.5-10 pieces/?m2; and the case hardening steel has a Vickers hardness of 130 HV or less.

Abstract: A steel foil for a solar cell substrate includes 7% to 40% by mass of Cr and has a tensile strength of 930 MPa or more in a direction perpendicular to the rolling direction.

Abstract: Provided is a steel sheet for a formed member having enhanced ductility, a formed member, and a method for manufacturing the formed member, and more particularly, to a steel sheet for making a formed member having high strength and ductility such as an automotive structural member and a reinforcing member, a formed member, and a method for manufacturing the formed member. The steel sheet for a formed member has enhanced ductility, and includes, by weight %, C: 0.1% to 1.0%, Si+Al: 0.4% to 3.0%, Mn: 0.1% to 5.0%, P: 0.0001% to 0.1%, S: 0.0001% to 0.03%, N: 0.03% or less (but not 0%), and the balance of Fe and inevitable impurities. The formed member having high strength and ductility that can be used for forming an automotive structural member, a reinforcing member, etc. In addition, the formed member can be used for a heat-treatable impact resistant member.

Abstract: A method for manufacturing an ultra high strength member includes heating a steel sheet at a first heating temperature within a temperature range of 700 to 1000° C.; forming the steel sheet into a shape of a member at the first heating temperature and simultaneously cooling the steel sheet; after completion of the cooling, shear punching the steel sheet into a desired shape to obtain an ultra high strength member; and after the shear punching, subjecting the ultra high strength member to a first heat treatment including heating the ultra high strength member at second heating temperature within a temperature range of 100° C. or higher, but lower than 300° C. and retaining the member at the second heating temperature for 1 second to 60 minutes, wherein the resulting ultra high strength member has a tensile strength of 1180 MPa or more.

Abstract: There is provided a useful method for producing a press-formed product without causing disadvantages such as hardness variation, which product has favorable formability in a level so as to be able to be produced by deep drawing, and which method is carried out by heating a thin steel sheet to a temperature not lower than an Ac3 transformation point thereof; and then cooling the thin steel sheet at a rate not lower than a critical cooling rate, during which the thin steel sheet is formed into the press-formed product, wherein the forming is started from a temperature higher than a martensitic transformation start temperature Ms thereof, the cooling rate is kept to be 10° C./sec. or higher during the forming, and the forming is finished in a temperature range not higher than the martensitic transformation start temperature Ms.

Abstract: A method of producing a seamless, tubular product includes centrifugally casting a corrosion resistant alloy into a tubular workpiece having an inner diameter and an outer diameter. The method then removes material from the inner diameter of the workpiece and subjects the workpiece to at least about a 25% wall reduction at a temperature below a recrystallization temperature of the workpiece using a metal forming process. The metal forming process includes radial forging, rolling, pilgering, and/or flowforming.

Abstract: A method of making a ductile iron article is disclosed. The method includes providing a ductile iron article preform. The method also includes deforming the ductile iron article preform by hot-working to provide a hot-worked portion of the article. The method further includes cooling the article to an austempering temperature. Still further, the method includes austempering the ductile iron article preform for a predetermined time sufficient to provide an austempered article preform comprising an austempered microstructure, wherein the austempered microstructure of the hot-worked portion is different than in other portions of the article. A ductile iron wind turbine shaft is also disclosed. The ductile iron wind turbine shaft has an austempered microstructure comprising an ausferrite matrix and a plurality of graphite nodules. The austempered microstructure has a deformed portion, the deformed portion has a microstructure that is different than the microstructure of the other portion of the shaft.

Abstract: A hybrid method manufacturing apparatus for a torsion beam according to an exemplary embodiment of the present invention includes a pair of side punch molds where a semi-finished product material heated to approximately 880 to 800° C. is molded and a press mold where a cooling water circulation line decreasing the temperature of the processed finished product to approximately 750 to 450° C. while the semi-finished product material is molded to a processed finished product is installed, an advantage of high-temperature molding having high dimensional accuracy is maintained at the time of manufacturing the torsion beam and additional heat treatment such as tempering is selectively performed only when additional heat treatment such as tempering increases toughness because only a martensite structure is not formed in quenching treatment.

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 processing method is provided integrating hot stamping and controllable subsequent heat treatment in the technical field of hot working for steels. It includes the steps of selecting and preparing a steel blank, hot stamping treatment, controllable temperature quenching, adjusting the temperature of the steel blank to a tempering temperature and fine stamping at the same time. The invention combines the hot stamping and controllable heat treatment to improve the strength of material with precise plastic deformation and save energy as well. The tensile strength of the processed steel is greater than 1900 Ma.

Abstract: A steel for an induction hardening including, by mass %, C: more than 0.75% to 1.20%, Si: 0.002 to 3.00%, Mn: 0.20 to 2.00%, S: 0.002 to 0.100%, Al: more than 0.050% to 3.00%, P: limited to 0.050% or less, N: limited to 0.0200% or less, O: limited to: 0.0030% or less, and the balance composing of iron and unavoidable impurities, wherein an Al content and a N content satisfy, by mass %, Al?(27/14)×N>0.050%.

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: A side rail and to a method for producing a side rail are disclosed. The side rail has a region of a first type and a region of a second type which have mutually different strengths. A transition region having a width of less than 50 mm is formed between the two regions. The side rail has in the region of the first type a bainitic structure and in the region of the second type a martensitic structure.

Abstract: A high strength bainitic steel and a process for producing seamless pipes for OCTG applications are described. In particular, the advantages ensuing to the steel of the invention are the improvement in strength-toughness over tempered martensitic steels, and a simplified thermal treatment. Quenching is not necessary and by avoiding the quenching treatment the microstructure results far more homogeneous, which allows thick walled tubes to be produced. For the same steel composition, in comparison to conventional tempered martensitic structures, a better combination of strength and toughness can be achieved, in particular by tempering as rolled carbide-free bainitic structures.

Abstract: The high-strength steel sheet includes, by mass %: C: 0.01% to 0.10%; Si: 0.15% or less; Mn: 0.80% to 1.80%; P: 0.10% or less; S: 0.015% or less; Al: 0.10% to 0.80%; Cr: 0.01% to 1.50%; N: 0.0100% or less; and a balance consisting of iron and inevitable impurities, in which a metallic structure is composed of ferrite and a hard second phase, the area fraction of the ferrite is 80% or more, the area fraction of the hard second phase is 1% to 20%, the fraction of unrecrystallized ferrite in the ferrite is less than 10%, the ferrite grain sizes are 5 ?m to 20 ?m, and the fraction of the ferrite crystal grains having an aspect ratio of 1.2 or less in the entire ferrite crystal grains is 60% 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 carbon steel sheet having high formability due to a microscopic and uniform carbide distribution and having a good characteristic of final heat treatment, and a manufacturing method thereof. The carbon steel sheet having excellent formability, includes, in wt %, C at 0.2-0.5%, Mn at 0.1-1.2%, Si at less than or equal to 0.4%, Cr at less than or equal to 0.5%, Al at 0.01-0.1%, S at less than or equal to 0.012%, Ti at less than or equal to 0.5×48/14×[N]% when the condition of B(atomic %)/N(atomic %)>1 is satisfied or by 0.5×48/14×[N]% to 0.03% when the condition of B and N is not satisfied, B at 0.0005-0.0080%, N at less than or equal to 0.006%, Fe, and extra inevitable elements; an average size of carbide is less than or equal to 1 ?m; and an average grain size of ferrite is less than or equal to 5 ?m.

Abstract: A process for producing a bearing seat or a drive journal having a large diameter on a rolled threaded spindle is disclosed. The blank of the threaded spindle is hot-upset in the longitudinal direction, such that it bulges radially with respect to the longitudinal direction, a first longitudinal region having an enlarged diameter being provided.

Abstract: A high strength steel plate containing 0.02 to 0.08% C, by mass, and has substantially a two phase microstructure of ferrite and bainite. The ferrite contains precipitates having a particle size of 30 nm or smaller grain size. The steel plate has a yield strength of 448 MPa or higher. A method for manufacturing the high strength steel plate which comprises hot rolling, accelerated cooling and reheating. The accelerated cooling is conducted down to a temperature of 300 to 600° C. at a cooling rate of 5° C./s or higher. The reheating is conducted up to a temperature of 550 to 700° C. at a heating rate of 0.5° C./s or higher.

Abstract: A method of designing low cost, high strength, high toughness martensitic steel uses mathematical modeling to define optimum low cost chemical compositions, the content of retained austenite, and critical temperatures; melting an ingot, processing same, making steel articles, and heat treating the articles using the critical temperatures and the content of retained austenite. The new steel comprises, by weight, about 0.3-0.45% of C; at most 2.5% of Cr; at most 1.0% of Mo; at most 3.50% of Ni; about 0.3 to 1.5% of Mn; about 0.1-1.3% of Si; about 0.1-1.0% of Cu; Cu being less than Si; about 0.1 to 1.0% of V+Ti+Nb; at most 0.25% of Al; the sum of alloying elements being less than about 11.5%; the balance being essentially Fe and incidental impurities. Procedures of melting, processing and heat treatment using the mathematical model are disclosed.

Abstract: In a method, a blank of unhardened steel sheet is subjected in a press tool to a hot forming and press-hardening process to produce a structural part. After press-hardening, at least one linear zone of the structural part is heat treated in order to increase ductility and reduce strength in the linear zone in relation to adjacent regions of the structural part. After heat treatment, a bending or cutting operation is carried out on the structural part along the linear zone.

Abstract: A steel part having a long rolling contact fatigue life and capable of further increasing the life of a bearing under severer using condition than usual conditions. The steel part includes steel having a composition containing 0.7% by mass to 1.1% by mass of C, 0.5% by mass to 2.0% by mass of Si, 0.4% by mass to 2.5% by mass of Mn, 1.6% by mass to 5.0% by mass of Cr, 0.1% by mass to less than 0.5% by mass of Mo, 0.010% by mass to 0.050% by mass of Al, less than 0.0015% by mass of Sb as an impurity, and the balance composed of Fe and inevitable impurities, the steel being hardened and tempered. In the steel structure of a portion from the surface to a depth of 5 mm, residual cementite has a grain diameter of 0.05 to 1.5 ?m, prior austenite has a grain diameter of 30 ?m or less, and the ratio by volume of the residual austenite is less than 25%.

Abstract: The invention relates to a method of and a plant for making hot-rolled strips of cast metal, wherein the cast strip is subjected as a rough strip to at least a first step for momogenizing the grain structure in a protective gas and the cast strip is then subjected to at least a further heat-treatment step before it is rolled to reduce its thickness. After the thickness reduction the cast strip is subjected to a second step of homogenization or recrystallization of its grain structure before finally the strip is passed to a cutter and a finished rolled hot piece is severed from the following strip.

Abstract: Provided is a stainless-steel seamless belt formed by subjecting a stainless-steel plate to a plastic forming process and having a thickness of 50 ?m or less. The seamless belt has a bending durability of 100,000 or more times in a specific bending test and has a Vickers hardness of 450 (Hv) or more.

Abstract: The present invention provides a line pipe of, e.g., the API standard X60 to X100 class. The line pipe has an excellent deformability, as well as excellent low temperature toughness and high productivity, a steel plate used as the material of the steel pipe. Methods for producing the steel pipe and the steel plate are also provided. In particular, a high-strength steel plate excellent in the deformability has a ferrite phase is dispersed finely, and accounts for 5% to 40% in area percentage in a low temperature transformation structure mainly composed of a bainite phase. For example, most grain sizes of the ferrite phase are smaller than the average grain size of the bainite phase. A high-strength steel pipe excellent in deformability is also provided, in which a large diameter steel pipe is produced through forming the steel plate into a pipe shape. The steel pipe has the above-referenced structure, and satisfies the conditions that YS/TS is 0.95 or less and YS×uEL is 5,000 or more.

Abstract: A crash box for installation between a bumper crossbeam and a side rail of a motor vehicle is made from a longitudinal beam made of a steel alloy having the following composition in weight-%, 0.15 to 0.30% of carbon (C), 0.10 to 0.70% of silicon (Si), 1.00 to 2.50% of manganese (Mn), 0.10 to 0.50% of chromium (Cr), 0.02 to 0.05% of titanium (Ti), 0.001 to 0.005% of boron (B), 0.01 to 0.06% of aluminum (Al), up to 0.50% of molybdenum (Mo), max. 0.025% of phosphorus (P), max. 0.015% of sulfur (S), remainder iron (Fe) including impurities resulting from smelting. The longitudinal beam is hot-formed and press-hardened and then heat-treated at a temperature of 200° C. to 800° C., with a material of the longitudinal beam having a bend angle of greater than or equal to 60° after heat treatment and measured in accordance with DIN EN ISO 7438.

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: 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: A high-strength hot-rolled steel sheet containing C: 0.05 to 0.15%, Si: no more than 1.50% (excluding 0%), Mn: 0.5 to 2.5%, P: no more than 0.035% (excluding 0%), S: no more than 0.01% (including 0%), Al: 0.02 to 0.15%, and Ti: 0.05 to 0.2%, which is characterized in that its metallographic structure is composed of 60 to 95 vol % of bainite and solid solution-hardened or precipitation-hardened ferrite (or ferrite and martensite) and its fracture appearance transition temperature (vTrs) is no higher than 0° C. as obtained by impact tests. (% in terms of % by weight).

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: A high-strength steel machined product giving excellent hardenability has a metal microstructure with excellent balance of strength and toughness and high stability of retained austenite. The product is composed of an ultra-high low-alloy TRIP steel having a metal microstructure which contains an appropriate quantity of two or more of Cr, Mo, and Ni, and an appropriate quantity of one or more of Nb, Ti, and V, and having an appropriate value of carbon equivalent; the metal microstructure has a mother-phase structure composed mainly of lathy bainitic ferrite with a small amount of granular bainitic ferrite and polygonal ferrite, and has a secondary-phase structure composed of fine retained austenite and martensite.

Abstract: Disclosed is a ball for a constant velocity joint, and a method for producing the same. The ball for a constant velocity joint is produced via a quenching step for heating a spherical body consisting of a material corresponding to a high carbon chromium bearing steel regulated by Japanese Industrial Standards (JIS) to 840-900° C. and then cooling the spherical body under such a condition as 10-25 vol. % of austenite remains up to a first part where the depth from the surface is 0.1 mm, a step for tempering the spherical body at 150° C. or more, and a step for shot peening the spherical body and imparting a compression residual stress of ?1000 MPa or more to a region reaching second part where the depth from the surface is 0.2 mm.

Abstract: The present invention provides a steel plate that exhibits excellent low-temperature toughness in a base material and a weld heat-affected zone and has small strength anisotropy, wherein the steel includes, by mass, C: 0.04%-0.10%; Si: 0.02%-0.40%; Mn: 0.5%-1.0%; P: 0.0010%-0.0100%; S: 0.0001%-0.0050%; Ni: 2.0%-4.5%; Cr: 0.1%-1.0%; Mo: 0.1%-0.6%; V: 0.005%-0.1%; Al: 0.01%-0.08%; and N: 0.0001%-0.0070%, with the balance including Fe and inevitable impurities, a Ni segregation ratio at a portion located at one-fourth of a thickness of the steel plate in a steel-plate thickness direction from a surface of the steel plate is 1.3 or lower, a degree of flatness of a prior austenite grain is in a range from 1.05 to 3.0, an effective diameter of crystal grain is 10 ?m or lower, and a Vickers hardness number is in a range of 265 HV to 310 HV.

Abstract: In a method to produce formed steel parts a primary steel material is provided, which (in % by weight) comprises C: 0.02-0.6%, Mn: 0.5-2.0%, Al: 0.01-0.06%, Si: max. 0.4%, Cr: max. 1.2%, P: max. 0.035%, S: max. 0.035%, and optionally one or more of the elements of the “Ti, Cu, B, Mo, Ni, N” group, with the proviso that Ti: max. 0.05%, Cu: max. 0.01%, B: 0.0008-0.005%, Mo: max. 0.3%, Ni: max. 0.4%, N: max. 0.01%, and the remainder as iron and unavoidable impurities. The primary material is heated through at a heating temperature (TA) lying between the Ac1 and the Ac3 temperature, such that at best incomplete austenitising of the primary material takes place, is placed into a press-form tool and formed therein into the formed steel part. The formed steel part is then heated to a bainite forming temperature (TB), which is above the martensite starting temperature (MS), however below the pearlite transformation temperature of the steel.

Abstract: Method for austempering at least one part of a work piece, which method comprises the steps of: a) heating at least one part of the work piece to an initial austenitizing temperature (T1); b) subjecting said at least one part of the work piece to one or more austenitizing temperatures (T1 . . . T1n) for a predetermined time to austenitize it; c) quenching said at least one part of the work piece; d) heat treating said at least one part of the work piece at one or more austempering temperatures (T2 . . . T2n) for a predetermined time to austemper it; e) cooling the at least one part of the work piece; whereby at least one of the steps a) to e) is/are at least partly carried out under Hot Isostatic Pressing (HIP) conditions.

Abstract: An austenitic, substantially ferrite-free steel alloy and a process for producing components therefrom. This Abstract is not intended to define the invention disclosed in the specification, nor intended to limit the scope of the invention in any way.

Abstract: A method of production of 780 MPa class high strength steel plate excellent low temperature toughness comprising heating a steel slab of containing, by mass %, C: 0.06 to 0.15%, Si: 0.05 to 0.35%, Mn: 0.60 to 2.00%, P: 0.015% or less, S: 0.015% or less, Cu: 0.1 to 0.5%, Ni: 0.1 to 1.5%, Cr: 0.05 to 0.8%, Mo: 0.05 to 0.6%, Nb: less than 0.005%, V: 0.005 to 0.060%, Ti: less than 0.003%, Al: 0.02 to 0.10%, B: 0.0005 to 0.003%, and N: 0.002 to 0.006% to 1050° C. to 1200° C. in temperature, hot rolling ending at 870° C. or more, waiting for 10 seconds to 90 seconds, then cooling from 840° C. or more in temperature by a 5° C./s or more cooling rate to 200° C., then tempering at 450° C. to 650° C. in temperature for 20 minutes to 60 minutes.

Abstract: The occurrence of delayed fracture which is found in a hot worked martensitic stainless steel is prevented by subjecting the steel, after hot working and prior to heat treatment for hardening by quenching from a temperature of at least Ac1 point of the steel, to preliminary softening heat treatment under such conditions that the softening parameter P defined below is at least 15,400 and the softening temperature T is lower than the Ac1 point: P(softening parameter):P=T(20+log t) T: softening temperature [K] t: duration of softening treatment [Hr]. The present invention is particularly effective for a martensitic stainless steel having a steel composition in which the amount of effective dissolved C and N (=[C*+10N*]) where C* and N* are calculated by the following formulas is larger than 0.45: C*=C?[12{(Cr/52)×(6/23)}/10, and N*=N?[14{(V/51)+(Nb/93)}/10]?[14{(Ti/48)+(B/11)+(Al/27)}/10].

Abstract: In a torsion beam manufacturing method using a hybrid method according to an exemplary embodiment of the present invention, dimensional accuracy is increased by high-temperature molding of performing molding by heating an internal structure up to A3 transformation point (950° C.) temperature at which the internal structure is austenited and tempering treatment is optionally performed only when the tempering treatment increases toughness because a ferrite structure is formed at a structural ratio of approximately 5% or less together with a martensite structure and a bainite structure by preventing quick cooling performed in a quenching treatment by lowering temperature through an indirect cooling method during the high-temperature molding process.

Abstract: Provided are a high strength thin steel sheet having tensile strength of about 800 MPa or more, and a manufacturing method thereof. The thin steel sheet is mainly used for construction materials, home appliances, and automobiles. The thin steel sheet has excellent plating characteristic, welding characteristic, bending workability, and hole expansion ratio. The thin steel sheet includes, in weight %, C: 0.02-0.20%, Si: 1.5% or less, Mn: 1.5-3.0%, P: 0.001-0.10%, S: 0.010% or less, SoLAl: 0.01-0.40%, N: 0.020% or less, Cr: 0.3-1.5%, B: 0.0010-0.0060%, Sb: 0.001-0.10%, and including at least one material selected from the group consisting of Ti: 0.003-0.08%, Nb: 0.003-0.08%, and Mo: 0.003-0.08%, and includes Fe and other inevitable impurities as a remainder. Here, Si, Mn, B, Sb, P, and S meet conditions of 5<(Si/Mn+150B)/Sb<20 and C+Mn/20+Si/30+2P+4S<0.27. Also, the manufacturing method can secure workability of the thin steel sheet.

Abstract: Steel is described having a chemical composition, in weight-%, of 0.3 to 0.5% carbon (C), from traces to a max. of 1.5% silicon (Si), 0.2 to 1.5% manganese (Mn), 0.01 to 0.2% sulfur (S), 1.5 to 4% chromium (Cr), 1.5 to 5% nickel (Ni), 0.5 to 2% molybdenum (Mo), which at least partially may be replaced by twice as much tungsten (W), 0.2 to 1.5% vanadium (V), from traces to a max. of 0.2% rare earth metals, and a balance essentially of only iron, impurities and accessory elements in normal amounts. In addition, a method for manufacturing a blank of the steel and a process for manufacturing a cutting tool body or holder for cutting tools of the steel is described.

Abstract: To provide a non-aging steel sheet for vitreous enameling, the steel sheet being excellent in resistance to bubbles and black spots, without the employment of decarbonization and denitrification annealing that raises the cost of production and also without the addition of expensive elements such as Nb, Ti, etc. that raise the cost of alloys. The steel sheet comprises, in mass, to C: 0.0050% or less, Si: 0.50% or less, Mn: 0.005 to 1.0%, P: 10×(B?11/14×N) to 0.10%, S: 0.080% or less, Al: 0.050% or less, N: 0.0005 to 0.020%, B: 0.60×N to 0.020%, and O: 0.002 to 0.0800%, and the shape of B nitrides is controlled mainly by adjusting hot-rolling conditions.

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: The present invention provides a ferritic stainless steel that has excellent strength at high temperature, oxidation resistance at high temperature, and salt corrosion resistance at high temperature and that can be used under high temperatures exceeding 900° C., and a method of producing the same. Specifically, the composition thereof is adjusted, on a % by mass basis, so as to include C: 0.02% or less; Si: 2.0% or less; Mn: 2.0% or less; Cr: from 12.0 to 40.0%; Mo: from 1.0 to 5.0%; W: more than 2.0% and 5.0% or less; wherein the total content of Mo and W: (Mo+W)?4.3%, Nb: from 5 (C+N) to 1.0%, N: 0.02% or less, and Fe and inevitable impurities as residual.

Abstract: A high speed tool steel, which is high in impact value and free from variations in tool performance, comprising, by mass %, of: 0.4?C?0.9; Si?1.0; Mn?1.0; 4?Cr?6; 1.6-6 in total of either or both of W and Mo in the form of (½W+Mo) wherein W?3; 0.5-3 in total of either or both of V and Nb in the form of (V+Nb); wherein carbides dispersed in the matrix of the tool steel have an average grain size of ?0.5 ?m and a dispersion density of particles of the carbides is of ?80×103 particles/mm2.

Abstract: A steel part having a long rolling contact fatigue life and capable of further increasing the life of a bearing under severer using condition than usual conditions. The steel part includes steel having a composition containing 0.7% by mass to 1.1% by mass of C, 0.5% by mass to 2.0% by mass of Si, 0.4% by mass to 2.5% by mass of Mn, 1.6% by mass to 5.0% by mass of Cr, 0.1% by mass to less than 0.5% by mass of Mo, 0.010% by mass to 0.050% by mass of Al, less than 0.0015% by mass of Sb as an impurity, and the balance composed of Fe and inevitable impurities, the steel being hardened and tempered. In the steel structure of a portion from the surface to a depth of 5 mm, residual cementite has a grain diameter of 0.05 to 1.5 ?m, prior austenite has a grain diameter of 30 ?m or less, and the ratio by volume of the residual austenite is less than 25%.

Abstract: Iron-based alloys and articles in strips, sheets, workpieces and the like are converted into high strength steel with a minimum of cost, time and effort, including producing dual phase materials. This is achievable by extremely rapid micro-treating of low, medium, and high carbon iron-based alloys and articles by rapid heating and rapid cooling at least a portion of the alloy/article. This heating step involves nearly immediately heating the iron-based alloy to a selected temperature above its austenite conversion temperature. Then, the alloy is immediately quenched, also at an extremely fast rate, on at least a portion of the iron-based alloy in a quenching unit adjacent the heating unit. This procedure forms high strength alloy in a desired area, depending upon where the treatment was performed.

Abstract: The present invention relates to ferritic-austenitic stainless steel oriented to have low Ni which is excellent in corrosion resistance, particularly in corrosion resistance in a neutral chloride environment, and has high “uniform elongation”—a factor governing workability—and a method of production for the same. There are independently provided ferritic-austenitic stainless steels and methods of production for the same particularly having a corrosion resistance in a neutral chloride environment satisfying PI value(=Cr+3Mo+10N—Mn)?18% and having a uniform elongation satisfying ?10?Md?110 (where Md=551?462({C}+[N])?9.2[Si]?8.1[Mn]?13.7[Cr]?29[Ni]?29[Cu]?18.

Abstract: The present invention provides a fire resistant steel material excellent in high temperature strength, toughness, and reheating embrittlement resistance containing, by mass %, C: 0.001% to 0.030%, Si: 0.05% to 0.50%, Mn: 0.4% to 2.0%, Nb: 0.03% to 0.50%, Ti: 0.005% to less than 0.040%, N: 0.0001% to less than 0.0050%, and Al: 0.005% to 0.030%, limiting P: 0.03% or, less and S: 0.02% or less, satisfying C—Nb/7.74?0.005 and 2?Ti/N?12, and having a balance of Fe and unavoidable impurities and, further, a process for production of a fire resistant material comprising heating a steel slab comprised of this chemical composition to 1100 to 1350° C. and hot rolling it by a cumulative reduction rate at 1000° C. or less of 30% or more.