Abstract: A spring steel having a high strength of 1900 MPa or more and superior in the brittle fracture resistance, as well as a method for manufacturing the same, are provided. The high strength spring steel comprises, as basic components in mass %, C: 0.4-0.6%, Si: 1.4-3.0%, Mn: 0.1-1.0%, Cr: 0.2-2.5%, P: 0.025% or less, S: 0.025% or less, N: 0.006% or less, Al: 0.1% or less, and O: 0.003% or less, the amount of solute C being 0.15% or less, the amount of Cr contained as a Cr-containing precipitate being 0.10% or less, and a TS value represented by the following equation being 24.8% or more, and in point of structure, the pre-austenite grain diameter being 10 ?m or smaller, wherein TS=28.5*[C]+4.9*[Si]+0.5*[Mn]+2.5*[Cr]+1.7*[V]+3.7*[Mo] where [X] stands for mass % of element X.

Abstract: The present invention provides a steel sheet excellent in workability, which may be used for components of an automobile or the like, and a method for producing the same. More specifically, according to one exemplary embodiment of the present invention, a steel sheet excellent in workability, including in mass, 0.08 to 0.25% C, 0.001 to 1.5% Si, 0.01 to 2.0% Mn, 0.001 to 0.06% P, at most 0.05% S, 0.001 to 0.007% N, 0.008 to 0.2% Al, at least 0.01% Fe. The steel sheet having an average r-value of at least 1.2, an r-value in the rolling direction of at least 1.3, an r-value in the direction of 45 degrees to the rolling direction of at least 0.9, and an r-value in the direction of a right angle to the rolling direction of at least 1.2.

Abstract: Steel, characterised in that the composition thereof is, in percentages by weight: C=0.20-0.30% Co=trace levels-1% Cr=2-5% Al=1-2% Mo+W/2=1-4% V=trace levels-0.3% Nb=trace levels-0.1% B=trace levels-30 ppm Ni=11-16% with Ni?7+3.5 Al Si=trace levels-1.0% Mn=trace levels-2.0% Ca=trace levels-20 ppm rare earths=trace levels-100 ppm if N?10 ppm, Ti+Zr/2=trace levels-100 ppm with Ti+Zr/2?10 N if 10 ppm<N?20 ppm, Ti+Zr/2=trace levels-150 ppm O=trace levels-50 ppm N=trace levels-20 ppm S=trace levels-20 ppm Cu=trace levels-1% P=trace levels-200 ppm the remainder being iron and inevitable impurities resulting from the production operation. Method of producing a component from this steel and a component obtained in this manner.

Abstract: The invention relates to a steel and a processing method for high-strength fracture-splittable machine components that are composed of at least two fracture-splittable parts. The steel and method are characterized in that the chemical composition of the steel (expressed in percent by weight) is as follows: 0.40%?C?0.60%; 0.20%?Si?1.00%; 0.50%?Mn?1.50%; 0%?Cr?1.00%; 0%?Ni?0.50%; 0%?Mo?0.20%; 0%?Nb?0.050%; 0%?V?0.30%; 0%?Al?0.05%; 0.005%?N?0.020%, the rest being composed of iron and smelting-related impurities and residual matter.

Abstract: A steel product or thin steel cast strip including, by weight, less than 0.25% carbon, between 0.20 and 2.0% manganese, between 0.05 and 0.50% silicon, less than 0.01% aluminum, and at least one of niobium between 0.01% and 0.20% and vanadium between 0.01% and 0.20%, and a microstructure of a majority bainite and acicular ferrite, and more than 70% niobium and/or vanadium in solid solution. The steel product may have an increase in elongation and an increase in yield strength after age hardening. The age hardened steel product may have niobium carbonitride particles with an average particle size of 10 nanometers and less, and may have substantially no niobium carbonitride particles greater than 50 nanometers. The steel product may have a yield strength of at least 380 MPa, a tensile strength of at least 410 MPa, or both. The product may have a total elongation of at least 6% or 10%.

Abstract: The invention relates to a steel and a processing method for producing machine components formed from solid stock, particularly for vehicle construction, having a primarily bainitic structure, characterized in that the chemical composition thereof has the following contents in weight percent: 0.10%?C?0.25%, 0.15%?Si?0.40%, 1.00%?Mn?1.50%, 1.00%?Cr?2.00%, 0.20%?Ni?0.40%, 0.05%?Mo?0.20%, 0.010%?Nb?0.040%, 0.05%?V?0.25%, 0.01%?Al?0.05%, 0.005%?N?0.025%, 0%?B?0.0050%, with the remainder being iron and the steel making-related accompanying elements and residual materials.

Abstract: Steel and steel shaped articles with an excellent delayed fracture resistance and a tensile strength of the 1600 MPa class or more, containing, by mass %, C: 0.20 to 0.60%, Si: 0.50% or less, Mn: over 0.10% to 3%, Al: 0.005 to 0.1%, Mo: over 3.0% to 10%, and, as needed, one or more of W: 0.01 to 10%, V: 0.05 to 1%, Ti: 0.01 to 1%, Nb: 0.01 to 1%, Cr: 0.10 to 2%, Ni: 0.05 to 1%, Cu: 0.05 to 0.5%, and B: 0.0003 to 0.01%, and a balance of Fe and unavoidable impurities and, further, a method of production comprising shaping the above steel to a desired shape (for example, a bolt shape), quenching it, then tempering it at 500 to 750° C. in temperature range.

Abstract: An austenitic TRIP steel consisting essentially of, in weight %, 0.14 to 0.18% Al, 2.8 to 3.2% Ti, 23.5 to 23.8% Ni, 3.8 to 4.2% Cr, 1.1 to 1.3% Mo, 0.29 to 0.31% V, 0.01 to 0.015% B, 0.01 to 0.02% C, and balance Fe and incidental impurities exhibits combined high yield strength and high strain hardening leading to improved stretch ductility under both tension and shear dynamic loading conditions.

Abstract: Cold rolled and continuously annealed high strength steel strip including (in wt %): 0.04-0.30% C, 1.0-3.5% Mn, 0-1.0% Si, 0-2.0% Al, 0-1.0% Cr, 0-0.02% P, 0-0.01% S, 0-0.25% V, 0-0.1% Nb, 0-0.20% Ti, 0-0.015% N, 0-0.010% B, unavoidable impurities, balance iron, provided with a hot dip galvanized or galvannealed zinc alloy coating layer, wherein the zinc alloy is 0.3-4.0% Mg and 0.05-6.0% Al; optionally at most 0.2% of one or more additional elements; unavoidable impurities; the remainder being zinc, and method for producing it.

Abstract: Various inexpensive rolling elements for use under high interface pressure such as induction hardened gears are provided, which have improved seizure resistance at tooth flanks and a temper hardness of HRC 50 or more at 300 ° C. To this end, a rolling element is made from a steel material which contains at least 0.5 to 1.5 wt % carbon and 0.2 to 2.0 wt % one or more alloy elements selected from V, Ti, Zr, Nb, Ta and Hf; and in which 0.4 to 4.0% by volume one or more compounds selected from the carbides, nitrides and carbonitrides of the above alloy elements and having an average particle diameter of 0.2 to 5 ?m are dispersed. In such a rolling element, the soluble carbon concentration of a martensite parent phase of a rolling contact surface layer is adjusted to 0.3 to 0.8 wt %, the martensite parent phase having been subjected to induction hardening and low temperature tempering, and one or more of the above carbides, nitrides and carbonitrides are dispersed in an amount of 0.4 to 4.

Abstract: A maraging heat-treatment steel includes 8.5 to 9.5% by weight of Cr, 0.15 to 0.25% by weight of Mn, 2 to 2.7% by weight of Ni, 0.5 to 2.5% by weight of Mo, 0.4 to 0.8% by weight of V, 0.001 to 0.15% by weight of Si, 0.06 to 0.1% by weight of C, 0.11 to 0.15% by weight of N, 0.02 to 0.04% by weight of Nb, maximum 0.007% by weight of P, maximum 0.005% by weight of S, maximum 0.01% by weight of Al, iron and standard impurities, wherein a weight ratio of vanadium to nitrogen V/N is in a range between 4.3 and 5.5.

Abstract: A method for locally heat-treating a gas turbine engine superalloy article to improve resistance to strain-induced fatigue of the article is disclosed. The method comprises providing a gas turbine engine superalloy article having a gamma prime solvus temperature; and locally over aging only a selected portion of the article to locally improve fatigue resistance at the selected portion of the article, wherein the local over age cycle includes heating at about 843° C. for about 3 to 4 hours.

Abstract: A method of processing a workpiece of maraging steel includes receiving a workpiece of maraging steel that has been subjected to thermomechanical processing at an austenite solutionizing temperature and then directly aging the workpiece of maraging steel at an aging temperature to form precipitates within a microstructure of the workpiece of maraging steel, without any intervening heat treatments between the thermomechanical processing and the direct aging.

Abstract: A thermal mechanical treatment method includes hot working a precipitation hardening martensitic stainless steel, quenching the stainless steel, and aging the stainless steel. According to certain embodiments, the thermal mechanical treatment does not include solution heat treating the stainless steel prior to aging or cryogenically cooling the stainless steel. An article includes a precipitation hardening martensitic stainless steel having a process history that includes hot working the stainless steel, quenching the stainless steel, and aging the stainless steel. According to certain embodiments, the process history does not include solution heat treating the stainless steel prior to aging or cryogenically cooling the stainless steel.

Abstract: A steel product for a line pipe according to the invention has a composition containing, in mass %, C : 0.03% to 0.15%, Si: 0.05% to 1.0%, Mn: 0.5% to 1.8%, P: 0.015% or less, S: 0.004% or less, O: 0.01% or less, N: 0.007% or less, sol. Al: 0.01% to 0.1%, Ti: 0.024% or less, Ca: 0.0003% to 0.02%, and the balance consisting of Fe and impurities. The size of TiN in the steel product for a line pipe is at most 30 ?m. The steel product has high HIC resistance and its crack area ratio can be reduced to 3% or less.

Abstract: A steel for high-strength springs contains, on the mass basis, 0.35% to 0.65% of C, 1.4% to 2.5% of Si, 0.1% to 1.0% of Mn, 2.0% or less (exclusive of 0%) of Cr, 1.0% or less (exclusive of 0%) of Ni, 1.0% or less (exclusive of 0%) of Cu, 0.020% or less (exclusive of 0%) of P, 0.020% or less (exclusive of 0%) of S, 0.006% or less (exclusive of 0%) of N:, and 0.1% or less (exclusive of 0%) of Al, with the remainder being iron and inevitable impurities, in which Wp(Fe) and W(C) satisfy the following condition: Wp(Fe)>5×W(C), wherein Wp(Fe) is the content of Fe (percent by mass) constituting Fe-containing precipitates in the steel; and W(C) is the carbon content (percent by mass) of the steel. The steel is excellent in cold workability and quality stability.

Abstract: An age hardenable martensitic steel alloy is disclosed. The alloy has the following composition in weight percent. C 0.30-0.36 Mn 0.05 max. Si 0.05 max. P 0.01 max. S 0.0010 max. Cr 1.30-3.2? Ni 10.0-13.0 Mo ?1.0-2.70 Co 13.8-17.4 Ti 0.02 max. Al 0.005 max. Ce 0.030 max. La 0.010 max. The balance is iron and the usual impurities. The composition of this alloy is balanced to provide a unique combination of very high strength, together with good toughness, ductility, and resistance to fatigue.

Abstract: This disclosure relates to a high strength cold rolled steel sheet composed of ferrite grains having an average grain diameter of 10 ?m or less, in which the average number per unit area of Nb(C, N) precipitates having a diameter of 50 nm or more is 7.0×10?2/?m2 or less, and a zone having a width of 0.2 to 2.4 ?m and an average area density of NbC precipitates of 60% or less of that of the central portion of the ferrite grains is formed along grain boundaries of the ferrite grains, for example, the steel sheet consisting of 0.004 to 0.02% of C, 1.5% or less of Si, 3% or less of Mn, 0.15% or less of P, 0.02% or less of S, 0.1 to 1.5% of sol.Al, 0.001 to 0.007% of N, 0.03 to 0.2% of Nb, by mass, and the balance of Fe and inevitable impurities. The steel sheet is most preferably used for automobile panel parts since it has the TS of 340 MPa or more and the superior surface strain resistance and press formability.

Abstract: This DR steel sheet includes the following steel components: C: 0.02 to 0.06 mass %, Si: equal to or less than 0.03 mass %, Mn: 0.05 to 0.5 mass %, P: equal to or less than 0.02 mass %, S: equal to or less than 0.02 mass %, Al: 0.02 to 0.10 mass %, and N: 0.008 to 0.015 mass %. The amount of solute N (Ntotal?NasAlN) in the steel sheet containing a residual iron and inevitable impurities, is equal to or more than 0.006%; and the total stretchability in a rolling direction after aging is equal to or more than 10%, total stretchability in a sheet width direction after aging is equal to or more than 5%, and an average Lankford value after aging is equal to or less than 1.0.

Abstract: A dual phase steel sheet with good bake-hardening properties is provided. The steel sheet is characterized in containing (in terms of percent by mass) C: no less than 0.06% and less than 0.25%; Si+Al: 0.5 to 3%; Mn: 0.5 to 3%; P: no more than 0.15%; and S: no more than 0.02%; and also meeting the following condition (in terms of space factor) that retained austenite is at least 3%, bainite is at least 30%, and ferrite is no more than 50%, and further characterized in differing in stress larger than 50 MPa before and after application of 2% pre-strain and ensuing heat treatment for paint baking at 170° C. for 20 minutes. The steel sheet has well-balanced strength and workability, exhibits good bake-hardening properties at the time of paint baking, and offers good resistance to natural aging.

Abstract: A ferritic stainless steel sheet has a composition of C up to 0.02 mass %, Si up to 0.8 mass %, Mn up to 1.5 mass %, P up to 0.050 mass %, S up to 0.01 mass %, 8.0-35.0 mass % of Cr, N up to 0.05 mass %, 0.05-0.40 mass % of Ti and 0.10-0.50 mass % of Nb with a product of (% Ti % N) less than 0.005. Precipitates of 0.15 ?m or more in particle size except TiN are distributed in a steel matrix at a rate of 5000-50000/mm2. The steel sheet is manufactured by hot-rolling a slab at a finish-temperature of 800° C. or lower, annealing the hot-rolled steel sheet at 450-1080° C., cold-rolling the hot-rolled steel sheet in accompaniment with intermediate-annealing at a temperature within a range of from (a recrystallization-finishing temperature ?100° C.) to (a recrystallization-finishing temperature) and then finish-annealing the cold-rolled steel sheet at 1080° C. or lower.

Abstract: Disclosed is a spring steel which contains, by mass, 1.2% or less C; 0.1% to 2% Mn; 0.2% to 3% Si; 0.0003% to 0.005% Al; to 8 ppm Li; 30 ppm or less (excluding 0 ppm) Ca; and 10 ppm or less (excluding 0 ppm) Mg. The steel contains oxide inclusions satisfying the following conditions (1) to (3) in a number of 1×10?4 or more per square millimeter: (1) containing a total of 80 percent by mass or more of Al2O3 and SiO2 based on the inclusion composition excluding Li2O; (2) having a ratio by mass of Al2O3 to SiO2 of from 1:4 to 2:3; and (3) containing lithium (Li). The spring steel gives a spring that exhibits superior fatigue properties without strict control of the average composition of inclusions.

Abstract: The invention relates to a hot-rolled steel sheet having a tensile strength of greater than 1200 MPa, an Re/Rm ratio of less than 0.75 and an elongation at break of greater than 10%, the composition of which contains, the contents being expressed by weight: 0.10%?C?0.25%; 1%?Mn?3%; Al?0.015%; Si?1.985%; Mo?0.30%; Cr?1.5%; S?0.015%; P?0.1%; Co?1.5%; B?0.005%; it being understood that 1%?Si+Al?2%; Cr+(3×Mo)?0.3%, the balance of the composition consisting of iron and inevitable impurities resulting from the smelting, the microstructure of the steel consisting of at least 75% bainite, residual austenite in an amount equal to or greater than 5% and martensite in an amount equal to or greater than 2%.

Abstract: The present invention provides a steel sheet with low aluminum content, which includes: between 0.050 and 0.080% by weight of carbon, between 0.25 and 0.40% by weight of manganese, less than 0.020% by weight of aluminum, and between 0.010 and 0.014% by weight of nitrogen, the remainder being iron and inevitable trace impurities, wherein when in an aged condition the sheet includes a percentage elongation A% satisfying the relationship: (750?Rm)/16.5?A%?(850?Rm)/17.5 where Rm is the maximum rupture strength of the steel, expressed in Mpa. Another embodiment of the invention provides a container, which includes or is made from the above-mentioned steel sheet.

Abstract: A method of making a steel composition includes the steps of: a. providing a steel composition that includes up to 15% Cr, up to 3% Mo, up to 4% W, 0.05-1% V, up to 2% Si, up to 3% Mn, up to 10% Co, up to 3% Cu, up to 5% Ni, up to 0.3% C, 0.02-0.3% N, balance iron, wherein the percentages are by total weight of the composition; b. austenitizing the composition at a temperature in the range of 1000° C. to 1400° C.; c. cooling the composition of steel to a selected hot-working temperature in the range 500° C. to 1000° C.; d. hot-working the composition at the selected hot-working temperature; e. annealing the composition for a time period of up to 10 hours at a temperature in the range of 500° C. to 1000° C.; and f. cooling the composition to ambient temperature to transform the steel composition to martensite, bainite, ferrite, or a combination of those microstructures.

Abstract: A low yield ratio, high toughness steel plate which can be manufactured at high manufacturing efficiency and low cost, without increasing material cost by adding large amount of alloy elements and the like, and without degrading toughness of a welding heat affected zone, a low yield ratio, high strength and high toughness steel pipe using the steel plate, and a method for manufacturing those are provided. Specifically, the steel plate and the steel pipe contain C of 0.03% to 0.1%, Si of 0.01 to 0.5%, Mn of 1.2 to 2.5% and Al of 0.08% or less, wherein a metal structure is a substantially three-phase structure of ferrite, bainite and island martensite, and an area fraction of the island martensite is 3 to 20%, in addition, a complex carbide is precipitated in the ferrite phase.

Abstract: Disclosed is a stainless steel containing, by mass, 0.05% or less carbon, 1.5 to smaller than 3.5% Si, 3.0% or less Mn, 6.0 to 12.0% Cr, 4.0 to 10.0% Ni, 10.0% or less Co, 6.0% or less Cu, 0.5 to 3.0% Ti, 0 to 2.0% Al, not more than 1.0% Mo, not more than 0.01% nitrogen, and the balance of Fe and unavoidable impurities. Preferably, it has a hardness of not lower than 59 HRC and may contain not more than 1.0% Nb and/or not more than 1.0% Ta. Alternatively, the stainless steel may further contain not more than 0.1% of Zr. The process for producing the steel includes producing a steel having a composition as described above by a consumable electrode remelting process, and then subjecting the steel to a solution treatment at a temperature of 1000 to 1150° C. and an aging treatment at a temperature of 400 to 550° C., thereby aging the stainless steel to a hardness of not lower than 59 HRC.

Abstract: To provide a steel pipe as a fuel injection pipe with high material strength, high internal pressure limit free from fatigue failure, prolonged fatigue life, and high reliability. A steel pipe as a fuel injection pipe of 500 N/mm2 or higher tensile strength comprising, by mass, C: 0.12 to 0.27%, Si: 0.05 to 0.40%, and Mn: 0.8 to 2.0%, and the balance being Fe and impurities, the contents of Ca, P, and S in the impurities being Ca: 0.001% or less, P: 0.02% or less, and S: 0.01% or less, respectively, characterized in that the maximum diameter of nonmetallic inclusions present in at least in a region extending from the inner surface of the steel pipe to a depth of 20 ?m is 20 ?m or less. Further, this steel pipe may contain, in place of a portion of Fe, at least one selected from among Cr: 1% or less, Mo: 1% or less, Ti: 0.04% or less, Nb: 0.04% or less, and V: 0.1% or less.

Abstract: The present invention provides an ultra soft high carbon hot-rolled steel sheet. The ultra soft high carbon hot-rolled steel sheet contains 0.2% to 0.7% of C, 0.01% to 1.0% of Si, 0.1% to 1.0% of Mn, 0.03% or less of P, 0.035% or less of S, 0.08% or less of Al, 0.01% or less of N, and the balance being Fe and incidental impurities and further contains 0.0010% to 0.0050% of B and 0.05% to 0.30% of Cr in some cases. In the texture of the steel sheet, an average ferrite grain diameter is 20 ?m or more, a volume ratio of ferrite grains having a grain diameter of 10 ?m or more is 80% or more, and an average carbide grain diameter is in the range of 0.10 to less than 2.0 ?m. In addition, the steel sheet is manufactured by the steps, after rough rolling, performing finish rolling at a reduction ratio of 10% or more and at a finish temperature of (Ar3?20° C.) or more in a final pass, then performing first cooling within 2 seconds after the finish rolling to a cooling stop temperature of 600° C.

Abstract: The present invention provides a hot-rolled high strength steel sheet in which, without using expensive Mo, by effectively using Ti which is an inexpensive element and the amount of precipitation hardening of which is large, both ductility and stretch-flangeability are improved at a tensile strength of 780 MPa or higher, and excellent tensile fatigue properties are exhibited; and a method for producing the hot-rolled high strength steel sheet. A hot-rolled high strength steel sheet having a composition including, in percent by mass, C: 0.06% to 0.15%, Si: 1.2% or less, Mn: 0.5% to 1.6%, P: 0.04% or less, S: 0.005% or less, Al: 0.05% or less, and Ti: 0.03% to 0.

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: 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.

Abstract: The present invention provides steel superior in machinability comprised of, by wt %, C: 0.005 to 0.2%, Si: 0.001 to 0.5%, Mn: 0.2 to 3.0%, P: 0.001 to 0.2%, S: 0.03 to 1.0%, T.N: 0.002 to 0.02%, T.O: 0.0005 to 0.035%, and the balance of Fe and unavoidable impurities, said steel satisfying one or both of Mn/S in the steel being 1.2 to 2.8 or an area ratio of pearlite over a grain size of 1 ?m in a microstructure of the steel being not more than 5%.

Abstract: A steel product with a high austenite grain coarsening temperature having less than 0.4% carbon, less than 0.06% aluminium, less than 0.01% titanium, less than 0.01% niobium, and less than 0.02% vanadium by weight, and having fine oxide particles containing silicon and iron distributed through the steel microstructure having an average particle size less than 50 nanometers and may be between 5 and 30 nanometers. The steel product may have fine oxide particles distributed through the microstructure capable of restricting ferrite recrystallisation for strain levels up to at least 10.0%, for temperatures up to 750° C. with holding times up to 20 minutes. The steel product may be made by continuous casting of steel strip introduced between the casting rolls to form a casting pool of molten carbon steel having a total oxygen content of at least 70 ppm usually less than 250 ppm, and a free oxygen content 20 and 60 ppm, counter rotating the casting rolls.

Abstract: Thermo-mechanical properties of welds in stainless steel is substantially improved by the implementation of a post weld heat treatment that iliminates sigma phase in the heat treated zone and favors niobium carbonitride precipitate formation in a desirable size range. In most cases, post weld heat treated material can be employed in pressurized devices at temperatures exceeding 550° C., which is currently regarded the upper safe temperature limit, and material according to the inventive subject matter was tested at temperature of up to 850° C. without reheat cracking.

Abstract: A cold rolled steel sheet, and a method of manufacturing the same, designed to have aging resistance and excellent formability suitable for use in automobile bodies, electronic appliances, and the like. The cold rolled steel sheet comprises in weight %: 0.003% or less of C, 0.003˜0.03% of S, 0.01˜0.1% of Al, 0.02% or less of N, 0.2% or less of P, at least one of 0.03˜0.2% of Mn and 0.005˜0.2% of Cu, and a balance of Fe and other unavoidable impurities. When the steel sheet comprises one of Mn and Cu, the composition of Mn, Cu, and S satisfies at least one relationship: 0.58*Mn/S?10 and 1?0.5*Cu/S?10, and when the steel sheet comprises both Mn and Cu, the composition of Mn, Cu, and S satisfies the relationship: Mn+Cu?0.3 and 2?0.5*(Mn+Cu)/S?20. Participates of MnS, CuS, and (Mn, Cu)S in the steel sheet have an average size of 0.2 ?m or less.

Abstract: The steel wire material for a spring of the invention contains; C: 0.37-0.54%, Si: 1.7-2.30%, Mn: 0.1-1.30%, Cr: 0.15-1.1%, Cu: 0.15-0.6%, Ti: 0.010-0.1%, Al: 0.003-0.05%, and the balance including iron with inevitable impurities, wherein ferrite decarburized layer depth is 0.01 mm or less, whole decarburized layer depth is 0.20 mm or less, and fracture reduction of area is 25% or more. It alternately may contain; C: 0.38-0.47%, Si: 1.9-2.5%, Mn: 0.6-1.3%, Ti: 0.05-0.15%, Al: 0.003-0.1%, and the balance including iron with inevitable impurities, wherein ferrite decarburized layer depth is 0.01 mm or less, Ceq1 in the equation (1) below is 0.580 or more, Ceq2 in the equation (2) below is 0.49 or less, and Ceq3 in the equation (3) below is 0.570 or less. Ceq1=[C]+0.11[Si]?0.07[Mn]?0.05[Ni]+0.02[Cr]??(1) Ceq2=[C]+0.30[Cr]?0.15[Ni]?0.70[Cu]??(2) Ceq3=[C]?0.04[Si]+0.24[Mn]+0.10[Ni]+0.20[Cr]?0.89[Ti]?1.92[Nb]??(3) (In the above equations, [ ] shows the content (mass %) of each element in steel.

Abstract: There are provided a high silicon stainless steel with a high elongation at break, a spring made thereof, and a process for manufacturing the high silicon stainless steel. The high silicon stainless steel of the invention is characterized in: mainly comprising a microstructure with a grain size of 15 ?m or less and having an elongation at break of 12% or higher; mainly comprising a microstructure with a grain size of 7 ?m or less and having an elongation at break of 14% or higher; or having an elongation at break of 7% or higher after thermal aging. The process of the invention for manufacturing the high silicon stainless steel is characterized in comprising a load application step for applying an impact load and/or a static load to the high silicon stainless steel or the master alloy, wherein the surface temperature is in a temperature range of 950° C. or below and not so low as to break the high silicon stainless steel or the master alloy.

Abstract: A coated metal article such as, e.g., a tool, which article comprises a body part comprising a substantially carbon-free precipitation-hardened iron-cobalt-molybdenum/tungsten-nitrogen alloy and carries a coating. The coating has been applied by a PVD method and/or a CVD method and comprises a substantially single-phase crystalline, cubic face-centered structure. This abstract is neither intended to define the invention disclosed in this specification nor intended to limit the scope of the invention in any way.

Abstract: A precipitation-hardened stainless maraging steel which exhibits a combination of strength, toughness, and corrosion resistance comprises by weight about: 8 to 15% chromium (Cr), 2 to 15% cobalt (Co), 7 to 14% nickel (Ni), and up to about 0.7% aluminum (Al), less than about 0.4% copper (Cu), 0.5% to 2.5% molybdenum (Mo), 0.4 to 0.75% titanium (Ti), up to about 0.5% tungsten (W), and up to about 120 wppm carbon (C), the balance essentially iron (Fe) and incidental elements and impurities, characterized in that the alloy has a predominantly lath martensite microstructure essentially without topologically close packed intermetallic phases and strengthened primarily by a dispersion of intermetallic particles primarily of the eta-Ni3Ti phase and wherein the titanium and carbon (Ti) and (C) levels are controlled such that C can be dissolved during a homogenization step and subsequently precipitated during forging to provide a grain-pinning dispersion.

Abstract: The subject of the invention is a process for manufacturing a part made of steel having a multiphase microstructure, said microstructure comprising ferrite and being homogeneous in each of the regions of said part, which process comprises the steps consisting in: cutting a blank from a strip of steel, the composition of which is typical of that of steels having a multiphase microstructure; said blank is heated so as to reach a soak temperature Ts above Ac1 but below Ac3 and held at this soak temperature Ts for a soak time ts adjusted so that the steel, after the blank has been heated, has an austenite content equal to or greater than 25% by area; said heated blank is transferred into a forming tool so as to hot-form said part; and said part is cooled within the tool at a cooling rate V such that the microstructure of the steel, after the part has been cooled, is a multiphase microstructure, said microstructure comprising ferrite and being homogeneous in each of the regions of said part.

Abstract: A shaped steel, such as H-shaped steel, excellent in fire resistance, where a flange portion has 50% or more of a ratio of strength, 80% or less of yield ratio, and 100 J or more of impact strength of Charpy impact test at 0° C., wherein the ratio of strength=(proof stress of 0.2% at 600° C.)/(yield strength at room temperature), and a producing method thereof are provided. The shaped steel comprises in mass percent (%): C: 0.03-0.15; Mo: 0.1-0.6; V?0.35; and N: 0.002-0.012, and the balance being iron and residual impurities, wherein (x) a mol fraction of precipitate of alloy carbides and alloy carbonitrides at 600° C. is 0.3% or more, and (y) the ratio of the mol fraction of precipitate of alloy carbides and alloy carbonitrides at 300° C. to the mol fraction of precipitate of alloy carbides and alloy carbonitrides at 600° C. is 2.0 or less.

Abstract: A steel strip made of martensitic steel contains C+N at not more than 0.12 wt %, Si at not more than 1 wt %, Mn at not more than 7 wt %, Ni at 2 to 24 wt %, Cr at 2 to 16 wt %, Mo at not more than 2.5 wt %, and Ni-Bal value and Ms value defined by the following equations shown by weight percentage of each composition are respectively Ni-Bal?1.2, Ms??28. Ni-Bal=Ni+0.5Mn+30(C+N)?1.1(Cr+1.5Si)+8.

Abstract: The present invention provides steel plate or steel pipe with small occurrence of the Bauschinger effect and methods of production of the same, particularly steel pipe used for steel pipe for oil wells or line pipe with a small drop in the compression strength in the circumferential direction due to the Bauschinger effect when expanded and methods of production of the same, that is steel plate or steel pipe with small occurrence of the Bauschinger effect characterized by having a dual-phase structure substantially comprising a ferrite structure and fine martensite which is dispersed in the ferrite structure. Further, this steel plate or steel pipe contains, by mass %, C: 0.03 to 0.30%, Si: 0.01 to 0.8%, Mn: 0.3 to 2.5%, P: 0.03% or less, S: 0.01% or less, Al: 0.001 to 0.01%, and N: 0.01% or less and a balance of iron and unavoidable impurities.

Abstract: The present invention provides hot dip galvanized high strength steel sheet excellent in plating adhesion and hole expandability and a method of production of the same, that is, hot dip galvanization steel sheet excellent in plating adhesion and hole expandability containing, by mass %, C: 0.08 to 0.35%, Si: 1.0% or less, Mn: 0.8 to 3.5%, P: 0.03% or less, S: 0.03% or less, Al: 0.25 to 1.8%, Mo: 0.05 to 0.35%, and N: 0.010% or less and having a balance of Fe and unavoidable impurities, said hot dip galvanized high strength steel characterized in that the steel sheet has a metal structure having ferrite, bainite, by area percent, 0.5% to 10% of tempered martensite, and, by volume percent, 5% or more of residual austenite, and a method of production comprising annealing by a continuous annealing process at 680 to 930° C. in temperature, then cooling to the martensite transformation point or less, then hot dip galvanizing the steel during which heating the steel to 250 to 600° C., then hot dip galvanizing it.

Abstract: The present invention provides spring steel used for spring steel wire achieving both high strength and cold coilability and spring steel wire, that is, spring steel containing, by mass %, C: 0.45 to 0.70%, Si: 1.0 to 3.0%, Mn: 0.05 to 2.0%, P: 0.015% or less, S: 0.015% or less, N: 0.0015 to 0.0200%, and t-O: 0.0002 to 0.01 and further limiting Al?0.01% and Ti?0.003%. Further, it is characterized by satisfying the following regarding the cementite-based spherical carbides present at an observed plane, an occupied area ratio of grains with a circle equivalent diameter of 0.2 ?m or more of 7% or less, a density of presence of grains with a circle equivalent diameter of 0.2 to 3 ?m of 1/?m2 or less, and a density of presence of grains with a circle equivalent diameter 3 ?m or more of 0.

Abstract: The present invention provides a spring steel wire which has a tempered martensitic structure brought about by quenching-tempering. The present spring steel wire has a 40% or higher reduction of area and a 1,000 MPa or higher shear yield stress after subjected to heat treatment for at least hours at a temperature ranging from 420° C. to 480° C. The present steel wire preferably constitutes, based on mass %, C: 0.50-0.75%, Si: 1.80-2.70%, Mn: 0.1-0.7%, Cr: 0.70-1.50%, Co: 0.02-1.00%, and remnants consisting of Fe and impurities, or constitutes, based on mass %, C: 0.50-0.75%, Si: 1.80-2.70%, Mn: over 0.7-1.50%, Cr: 0.70-1.50%, and remnants consisting of Fe and impurities.

Abstract: The invention relates to a tool steel, the composition of which comprises (the percentages being expressed in % by weight): 0.8 ? C ? 1.5 5.0 ? Cr ? 14 0.2 ? Mn ? 3 Ni ? 5 V ? 1 Nb ? 0.1 Si + Al ? 2 Cu ? 1 S ? 0.3 Ca ? 0.1 Se ? 0.1 Te ? 0.1 1.0 ? Mo + ½W ? 4 0.06 ? Ti + ½Zr ? 0.15 0.004 ? N ? 0.02 the balance of the composition consisting of iron and impurities resulting from the smelting, it being furthermore understood that: 2.5×10?4%2?(Ti+½Zr)×N, to a process for manufacturing parts made in this steel and to the parts obtained.

Abstract: The present invention develops a manufacture method, via conventional liquid metallurgy, of finished and semi-finished metallic parts as casting, ingot, blooms and slabs in alloys base Fe, base Ni and base Co, microstructurally reinforced with complex molybdenum and titanium carbide particles, by means of their previous elaboration and latter addition to the molten alloy in the melting furnace. Then, when the alloy solidifies, they are inserted and distributed within the grains of the base metallic matrix, enhancing their mechanical properties and behavior at room as well as at high temperatures.

Abstract: Disclosed herein is a precipitation hardening cold-rolled steel sheet and method for manufacturing the same, which can be used for structural components such as seat rails and the like of a vehicle body. The steel sheet comprises, by weight %, C: 0.07˜0.1%, Mn: 1.4˜1.7%, P: 0.05˜0.07%, S: 0.005% or less, acid-soluble Al: 0.1˜0.15%, Nb: 0.06˜0.09%, B: 0.0008˜0.0012%, Sb: 0.02˜0.06%, and the balance of Fe and other unavoidable impurities. The steel sheet has a yield strength of 750 MPa or more and a yield ratio of 85% or more, and is free from surface defects due to a very low degree of oxide enrichment on the surface thereof.

Abstract: There is provided an inexpensive rolling element used under high interface pressure such as induction hardened gears, the rolling element being improved in the seizure resistance of its tooth flanks and having a temper hardness of HRC 50 or more at 300° C. To this end, the rolling element is made from a steel material containing at least 0.45 to 1.5 wt % C and one or more alloy elements selected from 0.1 to 0.5 wt % V and 0.3 to 1.5 wt % Cr, and has a rolling contact surface layer having a structure tempered at low temperature in which 2 to 18% by volume cementite disperses in a martensite parent phase formed by induction heating and cooling and containing 0.25 to 0.8 wt % carbon solid-dissolving therein.