Abstract: Method for reducing the segregated seams of a steel which has high mechanical strength and high wear resistance and whose composition comprises by weight: 0.30%?C?1.42%; 0.05%?Si?1.5%; Mn?1.95%; Ni?2.9%; 1.1%?Cr?7.9%; 0.61%?Mo?4.4%; optionally V?1.45%, Nb?1.45%, Ta?1.45% and V+Nb/2+Ta/4?1.45%; less than 0.1% of boron, less than 0.19% of (S+Se/2+Te/4), less than 0.01% of calcium, less than 0.5% of rare earths, less than 1% of aluminum, less than 1% of copper; the balance being iron and impurities resulting from the production operation. The composition further complies with: 800?D?1150 with D=540(C)0.25+245(Mo+3V+1.5Nb+0.75Ta)0.30+125Cr0.20+15.8Mn+7.4Ni+18Si. According to the method, the molybdenum is completely or partially replaced with double the proportion of tungsten so that W>0.21%, and Ti, Zr, C are adjusted so that, after adjustment, Ti+Zr/2?0.2W, (Ti+Zr/2)×C?0.07, Ti+Zr/2?1.49% and D is unchanged at approximately 5%. Steel obtained and method for producing a steel workpiece.

Abstract: The invention relates to a steel alloy for a low alloy steel for producing high-tensile, weldable, hot-rolled seamless steel tubing, in particular construction tubing. The chemical composition (in % by mass) is: 0.15-0.18% C; 0.20-0.40% Si; 1.40-1.60% Mn; max. 0.05% P; max. 0.01% S; >0.50-0.90% Cr; >0.50-0.80% Mo; >0.10-0.15% V; 0.60-1.00% W; 0.0130-0.0220% N; the remainder is made up of iron with production-related impurities; with the optional addition of one or more elements selected from Al, Ni, Nb, Ti, with the proviso that the relationship VIN has a value of between 4 and 12 and the Ni content of the steel is not more than 0.40%.

Abstract: The present invention provides high strength thick welded steel pipe for line pipe superior in low temperature toughness, and a method of production of the same. A base material steel plate containing C: 0.010 to 0.050%, Si: 0.01 to 0.50%, Mn: 0.50 to 2.00%, Al: 0.020% or less, Ti: 0.003 to 0.030%, and Mo: 0.10 to 1.50%, having a carbon equivalent Ceq of 0.30 to 0.53, having a crack susceptability parameter Pcm of 0.10 to 0.20, satisfying formula 3, comprised an area ratio of 20% or less of polygonal ferrite and an area ratio of 80% or more of bainite, and having an effective crystal grain size of 20 ?m or less is formed into a pipe shape, then seam welded to make the effective crystal grain size of the heat affected zone 150 ?m or less: 10C+100Al+5Mo+5Ni<3.3??formula 3.

Abstract: The present invention provides an induction-hardened hollow driving shaft that comprises, as a raw material, a steel pipe that contains, by mass %, 0.30 to 0.47% C, 0.5% or less Si, 0.3 to 2.0% Mn, 0.018% or less P, 0.015% or less S, 0.15 to 1.0% Cr, 0.001 to 0.05% Al, 0.005 to 0.05% Ti, 0.004% or less Ca, 0.01% or less N, 0.0005 to 0.005% B and 0.0050% or less O (oxygen) and the balance Fe and impurities and of which Beff defined by an equation (a) or (b) below is 0.0001 or more, wherein a prior austenite grain size number (JIS G0551) after the hardening is 9 or more. Here, in the case of Neff=N?14×Ti/47.9?0, Beff=B?10.8×(N?14×Ti/47.9)/14 . . . (a), and, in other cases, Beff=B . . . (b). According to the present invention, a hollow driving shaft that is simultaneously provided with excellent cold workability, hardenability, toughness and torsional fatigue strength and can exert stable fatigue lifetime can be obtained and can be widely utilized.

Abstract: A cobalt-free low cost high strength martensitic stainless steel, with concentration of Ni up to 3.0% and Mo up to 1.0% of weight, has HRC of 53, UTS of 297 ksi, YS of 220 ksi, Charpy V-notch impact energy of 17.8 ft-lb, corrosion resistance in salt spray test ASTM 117. The steel was melted in an open induction furnace and vacuum arc remelting (VAR) and/or electroslag remelting (ESR) were not used to refine the steel. Further processing included homogenized annealing, hot rolling, and recrystallization annealing. The steel was heat treated by oil quenching, refrigeration, and low tempering. The steel has a microstructure consisting essentially of small packets of fine martensite laths, retained austenite, and carbides as centers of growth of the martensite laths. The cost and energy in making the steel are substantially reduced.

Abstract: The invention is directed to providing, for application in automobiles, construction materials, household appliances and the like, high-strength sheets excellent in formability properties such as hole expansibility and ductility, and also in fatigue resistance, characterized in comprising, in specified contents expressed in mass %, C, Si, Mn, P, S, Al, N and O and a balance of iron and unavoidable impurities, and having a steel sheet structure composed mainly of ferrite and hard structures, a crystal orientation difference between some ferrite adjacent to hard structures and the hard structures of less than 9°, and a maximum tensile strength of 540 MPa or greater.

Abstract: A forging steel has a dissolved Mg concentration within the range of 0.04-5 ppm by mass and a dissolved Al concentration within the range of 50-500 ppm.

Abstract: Steel sheet having a composition of ingredients containing substantially, by mass %, C: 0.005 to 0.200%, Si: 2.50% or less, Mn: 0.10 to 3.00%, N: 0.0100% or less, Nb: 0.005 to 0.100%, and Ti: 0.002 to 0.150% and satisfying the relationship of Ti?48/14×N?0.0005, having a sum of the X-ray random intensity ratios of the {100}<001> orientation and the {110}<001> orientation of a ? sheet thickness part of 5 or less, having a sum of the maximum value of the X-ray random intensity ratios of the {110}<111> to {110}<112> orientation group and the X-ray random intensity ratios of the {211}<111> orientation of 5 or more, and having a high rolling direction Young's modulus measured by the static tension method and a method of production of the same are provided.

Abstract: A steel wire for a cold-formed spring according to the present invention contains a prescribed chemical component composition, wherein: a martensitic transformation start temperature MS1 shown by the following expression (1) is in the range from 280° C. to 380° C.; the austenite grain size number N of austenite grains is No. 12 or more; the grain boundary share of carbide precipitated along the austenite grain boundaries is 50% or less; the amount of retained austenite after austenitized and tempered is 20 vol. % or less; and the tensile strength is 2,000 MPa or more; MS1=550?361[C]?39[Mn]?20[Cr]??(1), where [C], [Mn] and [Cr] represent the contents (mass %) of C, Mn and Cr, respectively. Such a steel wire can: secure hot-rolling formability and subsequent drawability while aiming at higher strength and higher stress; moreover exhibit excellent corrosion resistance; and obtain a spring (mainly a suspension spring for an automobile) excellent also in fatigue strength which is a basic required characteristic.

Abstract: An iron-carbon master alloy is described, with a C content of 0.3 to 8 wt % and an upper limit of alloying metals Ni<10 wt %, P<4 wt %, Cr<5 wt %, preferably<1 wt %, Mn<5 wt %, preferably<1 wt %, Mo<3 wt %, W<3 wt %, Cu<1 wt %, a particle size of >20 ?m and a hardness of <350 HV 0.01, and a method for the manufacture of said master alloy.

Abstract: Gun barrel for firearms made from a deformed material and method for producing the gun barrel material. The material has a chemical composition in % by weight of: Content C Si Mn P S Cr Mo Min 0.28 0.08 0.15 3.6 1.2 Max 0.36 0.26 0.35 0.005 0.002 4.4 1.8 Content Ni V W Ti As + Sn + Sb Fe Min 0.42 Rest Max <0.5 0.5? 0.15 0.08 0.007 and impurities due to smelting. The material has a hardness of at least 46 to 48 HRC.

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 high strength welded steel pipe for line pipe inexpensive in cost and superior in low temperature toughness, and a method of production of the same, produced by forming a base material steel plate containing, by mass %, C: 0.010 to 0.050%, Si: 0.01 to 0.50%, Mn: 0.50 to 2.00%, S: 0.0001 to 0.0050%, and Ti: 0.003 to 0.030%, limiting Al to 0.020% or less and Mo to less than 0.10%, having a carbon equivalent Ceq of 0.30 to 0.53 and a crack susceptibility parameter Pcm of 0.10 to 0.20, comprised of polygonal ferrite and residual bainite of an area rate of 20% or less, and having an effective crystal grain size of 20 ?m or less, into a pipe shape, then seam welding it and making the effective crystal grain size of the heat affected zone 150 ?m or less.

Abstract: A seamless steel pipe of a low-alloy steel consisting, by mass %, of C: 0.10 to 0.20%, Si: 0.05 to 1.0%, Mn: 0.05 to 1.2%, Ni: 0.02 to 1.5%, Cr: 0.50 to 1.50%, Mo: 0.50 to 1.50%, Nb: 0.002 to 0.10%, Al: 0.005 to 0.10%, and either or both of Ti: 0.003 to 0.050% and V: 0.01 to 0.20%, the balance being Fe and impurities, the impurities containing 0.025% or less of P, 0.005% or less of S, 0.007% or less of N, and less than 0.0003% of B, wherein the tensile strength is 950 MPa or more and the yield strength is 850 MPa or more, and the Charpy absorbed energy at ?40° C. is 60 J or more. This seamless steel pipe may further contain one or more of Cu: 0.02 to 1.0%, Ca: 0.0005 to 0.0050%, and Mg: 0.0005 to 0.0050%. The present invention also provides a method for manufacturing the above-described seamless steel pipe.

Abstract: Steel for machine structure use excellent in tool lifetime in a broad range of cutting speeds regardless of continuous machining, intermittent machining, or other systems and further in various machining environments such as use of a cutting fluid or a dry, semidry, and oxygen enriched environment, having a chemical composition containing, by mass %, C: 0.01 to 1.2%, Si: 0.005 to 3.0%, Mn: 0.05 to 3.0%, P: 0.0001 to 0.2%, S: 0.0001 to 0.35%, N: 0.0005 to 0.035%, and Al: 0.05 to 1.0%, satisfying [Al %]?(27/14)×[N %]?0.05%, and having a balance of Fe and unavoidable impurities and forming an Al2O3 coating on the surface of a cutting tool by machining using a cutting tool coated on the surface contacting the machined material by metal oxides with a value of a standard free energy of formation at 1300° C. of that value of Al2O3 or more, and a machining method of the same.

Abstract: A casing is formed from an alloy which contains, by mass, 0.08-0.20% C, 0.05-0.45% Si, 0.10-0.30% Mn, 0.80-1.40% Ni, 1.00-1.40% Cr, 1.20-1.60% Mo, 0.10-0.30% V, 0.06-0.10% Ti, 0.0005-0.0010% B, not more than 0.01% P, not more than 0.01% S, and not more than 0.005% Al, the balance being Fe and unavoidable impurity elements. The casing has excellent high-temperature strength, high toughness and excellent weldability, and is applicable to casings used in high-temperature high-pressure steam environments.

Abstract: A transformation toughened, high-strength steel alloy useful in plate steel applications achieves extreme fracture toughness (Cv & gt; 80 ft-lbs corresponding to KId & equals; 200 ksi.in½) at strength levels of 150-180 ksi yield strength, is weldable and formable. The alloy is characterized by dispersed austenite stabilization for transformation toughening to a weldable, bainitic plate steel and is strengthened by precipitation of M2C carbides in combination with copper and nickel. The desired microstructure is a matrix containing a bainite-martensite mix, BCC copper and M2C carbide particles for strengthening with a fine dispersion of optimum stability austenite for transformation toughening. The bainite-martensite mix is formed by air-cooling from solution treatment temperature and subsequent aging at secondary hardening temperatures to precipitate the toughening and strengthening dispersions.

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: A steel has the following chemical composition (amounts in % by weight): 0.05-0.14 C, 8-13 Cr, 1-2.6 Ni, 0.5-1.9 Mo, 0.5-1.5 Mn, 0.15-0.5 Si, 0.2-0.4 V, 0-0.04 B, 2.1-4.0 Re, 0-0.07 Ta, 0-60 ppm Pd, remainder Fe and unavoidable impurities. The steel can be used effectively as a welding additive material and has outstanding properties at very high temperatures, in particular a good creep rupture strength/resistance and a good oxidation resistance.

Abstract: A low-alloy steel containing, by weight percent, C 0.03-0.13%, Mn 0.90-1.80%, Si?0.40%, P?0.020%, S?0.005%, Ni 0.10-1.00%, Cr 0.20-1.20%, Mo 0.15-0.80%, Ca?0.040%, V?0.10%, Nb?0.040%, Ti?0.020% and N?0.011% for making high-strength, weldable steel seamless pipe, characterized in that the microstructure of the alloy steel is a mixture of bainite and martensite and the yield stress is at least 621 MPa (90 Ksi). It is a second object of the present invention to provide a high-strength, weldable steel seamless pipe, comprising an alloy steel containing, by weight percent, C 0.03-0.13%, Mn 0.90-1.80%, Si?0.40%, P?0.020%, S?0.005%, Ni 0.10-1.00%, Cr 0.20-1.20%, Mo 0.15-0.80%, Ca?0.040%, V??0.10%, Nb?0.040%, Ti?0.020% and N?0.011% also characterized in that the microstructure of the alloy steel is predominantly martensite and the yield stress is at least 690 MPa (100 ksi).

Abstract: The present invention pertains to steel with high mechanical resistance at room temperature and up to 130° C., good toughness and good corrosion resistance in the metal base as well as good resistance to cracking in the heat affected zones (HAZ) once the tubing is welded together, and more specifically to heavy gauge seamless steel tubing with high mechanical resistance, good toughness and good corrosion resistance called catenary conduit. The advantages of the present invention with respect to those of an the state of technology reside in providing a chemical composition for steel used to manufacture heavy gauge seamless steel tubing with high mechanical resistance, good toughness, good fissure resistance in the HAZ and good corrosion resistance and a process for manufacturing this product. These advantages are obtained by using a composition made up basically of Fe and a specific chemical composition.

Abstract: The invention concerns a method for making an abrasion resistant steel plate having a chemical composition comprising: 0.1%?C<0.23%; 0%?Si?2%; 0%?Al?2%; 0.5%?Si+Al?2%; 0%?Mn?2.5%; 0%?Ni?5%; 0%?Cr?5%; 0%?Mo?1%; 0%?W?2%; 0.05%?Mo+W/2?1%; 0%?Cu?1.5%; 0%?B?0.02%; 0%?Ti?0.67%; 0%?Zr?1.34%; 0.05%<Ti+Zr/2?0.67%; 0%?S?0.15%; N<0.03%, optionally 0% to 1.5% of Cu; optionally Nb, Ta and V such that Nb/2+Ta/4+V?0.5%; optionally Se, Te, Ca, Bi, Pb contents ?0.1%; the rest being iron impurities. Additionally: 0.095%?C*=C?Ti/4?Zr/8+7×N/8, Ti+Zr/2?7×N/2?0.05% and 1.05×Mn+0.54×Ni+0.50×Cr+0.3×(Mo+W/2)1/2+K>1.8, with K=1 if B?0.0005% and K=0 if B<0.0005%. After austenitization, the method consists in: cooling at a speed >0.5° C./s between a temperature between AC3 and T=800?270×C*?90×Mn?37×Ni?70×Cr?83×(Mo+W/2) and about T?50° C.; then cooling at a speed 0.1<Vr<1150×ep?1.7 between T and 100° C., (ep=plate thickness in mm); cooling down to room temperature and optionally planishing.

Abstract: The present invention provides a steel sheet excellent in both a balance between strength and elongation and a balance between strength and hole expandability, in other words, a multi-phase steel sheet having an excellent balance between strength and hole expandability. The present invention is a multi-phase steel sheet excellent in hole expandability characterized in that: the steel sheet contains, as chemical components in mass, C: 0.03 to 0.15%, P: not more than 0.010%, S: not more than 0.003%, and either one or both of Si and Al in a total amount of 0.5 to 4%, and one or more of Mn, Ni, Cr, Mo and Cu in a total amount of 0.

Abstract: A ferrous abrasion resistant sliding material capable of improving seizing resistance, abrasion resistance and heat crack resistance is provided. The ferrous abrasion resistant sliding material has a martensite parent phase which forms a solid solution with carbon of 0.15 to 0.5 wt %, and the martensite parent phase contains one or more types of each special carbide of Cr, Mo, W and V dispersed therein in a total content of 10 to 50% by volume.

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: A high-strength steel pipe having a strength of API X65 grade or higher consisting essentially of, by mass %, 0.02 to 0.08% of C, 0.01 to 0.5% of Si, 0.5 to 1.8% of Mn, 0.01% or less of P, 0.002% or less of S, 0.01 to 0.7% of Al, 0.005 to 0.04% of Ti, 0.05 to 0.50% Mo, at least one element selected from 0.005 to 0.05% of Nb and 0.005 to 0.10% of V, and the balance being Fe, in which the volume percentage of the ferritic phase is 90% or higher, and complex carbides containing Ti, Mo, and at least one element selected from the group consisting of Nb and V are precipitated in the ferritic phase. The high-strength steel pipe has excellent HIC resistance and good toughness of a heat-affected zone, and can be manufactured stably at a low cost.

Abstract: An internal high hardness type pearlitic rail that has a composition containing 0.73% to 0.85% by mass C, 0.5% to 0.75% by mass Si, 0.3% to 1.0% by mass Mn, 0.035% by mass or less P, 0.0005% to 0.012% by mass S, 0.2% to 1.3% by mass Cr, and the balance being Fe and incidental impurities, in which the value of [% Mn]/[% Cr] is greater than or equal to 0.3 and less than 1.0, where [% Mn] represents the Mn content, and [% Cr] represents the Cr content, and in which the internal hardness of a rail head that is defined by the Vickers hardness of a portion located from a surface layer of the rail head to a depth of at least 25 mm is greater than or equal to 380 Hv and less than 480 Hv.

Abstract: Super Bainite Steel is described comprising between 90% and 50% bainite, the rest being austenite, in which excess carbon remains within the bainitic ferrite at a concentration beyond that consistent with equilibrium; there is also partial partitioning of carbon into the residual austenite. Such bainite steel has very fine bainite platelets (thickness 100 nm or less). In this specification the expression “Super Bainite Steel” is used for such steel. In particular, the impact of varying the manganese content to achieve fast transformation times, and hence low manufacturing costs without the presence of expensive alloying materials is discussed. In one embodiment of the invention a Super Bainite Steel comprises in weight percent: carbon 0.6 to 1.1%, silicon 1.5 to 2.0%, manganese 0.5 to 1.8%, nickel up to 3%, chromium 1.0 to 1.5%, molybdenum 0.2 to 0.5%, vanadium 0.1 to 0.2%, balance iron save for incidental impurities.

Abstract: High-strength steel of which the chemical composition comprises, by weight: 0.03%?C<0.2% Si?0.49% 3%<Mn?4% Ni?0.9% 1%?Cr?5% Mo+W/2?1% Cu?0.9% S+Se/2+Te/3<0.020% Al?0.1%, the remainder being iron and impurities resulting from production. Block and plates obtained.

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 thick-walled seamless steel pipe for line pipe which has a high strength and improved toughness and corrosion resistance in spite of the thick wall and which is suitable for use as a riser and flow line has a chemical composition comprising, in mass percent, C: 0.02-0.08%, Si: at most 0.5%, Mn: 1.5-3.0%, Al: 0.001-0.10%, Mo: greater than 0.4%-1.2%, N: 0.002-0.015%, at least one of Ca and REM in a total amount of 0.0002-0.007%, and a remainder of Fe and impurities, with the impurities having the content of P: at most 0.05%, S: at most 0.005%, and O: at most 0.005%, the chemical composition satisfying the inequality: 0.8?[Mn]×[Mo]?2.6, wherein [Mn] and [Mo] are the numbers equivalent to the contents of Mn and Mo, respectively, in mass percent.

Abstract: Provided are a steel sheet for an automotive muffler and a method for producing the steel sheet. The steel sheet includes 0.01% by weight or less of C, 0.1 to 0.3% by weight of Si, 0.3 to 0.5% by weight of Mn, 0.015% by weight or less of P, 0.015% or less by weight of S, 0.02 to 0.05% by weight of Al, 0.004% or less of N, 0.2 to 0.6% by weight of Cu, 0.01 to 0.04% by weight of Co, and a remainder of Fe and unavoidable impurities. The method includes 0.01% by weight or less of C, 0.1 to 0.3% by weight of Si, 0.3 to 0.5% by weight of Mn, 0.015% by weight or less of P, 0.015% or less by weight of S, 0.02 to 0.05% by weight of Al, 0.004% or less of N, 0.2 to 0.6% by weight of Cu, 0.01 to 0.

Abstract: A ferrous abrasion resistant sliding material capable of improving seizing resistance, abrasion resistance and heat crack resistance is provided. The ferrous abrasion resistant sliding material has a martensite parent phase which forms a solid solution with carbon of 0.15 to 0.5 wt %, and the martensite parent phase contains one or more types of each special carbide of Cr, Mo, W and V dispersed therein in a total content of 10 to 50% by volume.

Abstract: A high strength steel sheet and a method for manufacturing the same has superior phosphatability properties and hot-dip galvannealed properties besides a tensile strength of 950 MPa or more and a high ductility, and also having a small variation in mechanical properties with the change in annealing conditions.

Abstract: A spring steel and spring having superior corrosion fatigue strength and a strength on the order of HRC 53 to HRC 56 are disclosed. The spring steel comprises a tempered martensite and 2.1 to 2.4% Si in terms of percent by mass of the total mass of the spring steel.

Abstract: The present invention provides high strength thick steel plate superior in crack arrestability high in strength, free of deterioration of HAZ toughness, and free of anisotropy, that steel plate containing, by mass %, C: 0.03 to 0.15%, Si: 0.1 to 0.5%, Mn: 0.5 to 2.0%, P: ?0.02%, S: ?0.01%, Al: 0.001 to 0.1%, Ti: 0.005 to 0.02%, Ni: 0.15 to 2%, and N: 0.001 to 0.008% and having a balance of iron and unavoidable impurities as chemical components, having a microstructure of a ferrite and/or pearlite structure with bainite as a matrix phase, and having an average circle equivalent diameter of crystal grains with a crystal misorientation angle of 15° or more of 15 ?m or less in the regions of 10% of plate thickness from the front and rear surfaces and of 40 ?m or less in the other region including the center part of plate thickness.

Abstract: Disclosed is an iron-nickel alloy having the following composition, in % by mass: C 0.05 to 0.5%, Cr 0.2 to 2.0%, Ni 33 to 42%, Mn<0.1%, Si<0.1%, Mo 1.5 to 4.0%, Nb 0.01 to 0.5%, Al 0.1 to 0.8%, Mg 0.001 to 0.01%, V max. 0.1%, W 0.1 to 1.5%, Co max. 2.0%, the remainder Fe, and production-related impurities.

Abstract: Disclosed herein is a spring wire rod excelling in fatigue characteristics. It contains TiN inclusions having a specific size defined by the ratio of each group in all the visual fields as follows: (1) Visual fields in which the maximum thickness is no larger than 5 ?m: less than 5% (2) Visual fields in which the maximum thickness is larger than 5 ?m and no larger than 10 ?m: no more than 30% (3) Visual fields in which the maximum thickness is larger than 10 ?m and no larger than 25 ?m: no less than 70% (4) Visual fields in which the maximum thickness is larger than 25 ?m: less than 5% The visual field is the cross section passing through the center line of the wire rod.

Abstract: A seamless steel pipe for line pipe having a high strength and good toughness and corrosion resistance even though having a thick wall has a chemical composition comprising, in mass percent, C: 0.02-0.08%, Si: at most 0.5%, Mn: 1.5-3.0%, Al: 0.001-0.10%, Mo: greater than 0.4% to 1.2%, N: 0.002-0.015%, Ca: 0.0002-0.007%, and a remainder of Fe and impurities, wherein the contents of the impurities are at most 0.03% for P, at most 0.005% for S, at most 0.005% for O and less than 0.0005% for B and wherein the value of Pcm calculated by the following Equation (1) is at least 0.185 and at most 0.250. The steel pipe has a microstructure which primarily comprises bainite and which has a length of cementite of at most 20 micrometers: Pcm=[C]+[Si]/30+([Mn]+[Cr]+[Cu])/20+[Mo]/15+[V]/10+5[B]??(1) wherein [C], [Si], [Mn], [Cr], [Cu], [Mo], [V] and [B] are numbers respectively indicating the content in mass percent of C, Si, Mn, Cr, Cu, Mo, V and B.

Abstract: A steel sheet having (a) a dual phase microstructure with a martensite phase and a ferrite phase and (b) a composition containing by percent weight: 0.01% to 0.2% C; 0.3% to 3% Mn; 0.05% to 2% Si; 0.1% to 2% Cr; 0.01% to 0.10% Al; and 0.0005% to 0.01% Ca, with the balance of the composition being iron and incidental ingredients. Also, the steel sheet is made by a batch annealing method, and has a tensile strength of at least approximately 400 MPa and an n-value of at least approximately 0.175.

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 2.6% molybdenum (Mo), 0.4 to less than about 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 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-pinnning dispersion.

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: The present invention provides a spring steel that has superior hardenability, undergoes less pitting in a corrosive environment, and can achieve higher stress and toughness. More specifically, the present invention provides a high-strength and high-toughness spring steel with improved hardenability and pitting resistance, containing, in mass percent, 0.40 to 0.70% carbon, 0.05 to 0.50% silicon, 0.60 to 1.00% manganese, 1.00 to 2.00% chromium, 0.010 to 0.050% niobium, 0.005 to 0.050% aluminum, 0.0045 to 0.0100% nitrogen, 0.005 to 0.050% titanium, 0.0005 to 0.0060% boron, no more than 0.015% phosphorus and no more than 0.010% sulfur, the remainder being composed of iron and unavoidable impurities, the steel having a tensile strength of at least 1700 MPa in 400° C. tempering after quenching and a Charpy impact value of at least 40 J/cm2 for a 2 mm U-notched test piece of JIS 2202 and the parameter Fce being at least 1.70.

Abstract: Disclosed is a hot rolled steel sheet in which it includes a steel having a chemical composition of 0.03 to 0.10% (the percent hereinafter representing % by mass) of C, 0.2 to 2.0% of Si, 0.5 to 2.5% of Mn, 0.02 to 0.10% of Al, 0.2 to 1.5% of Cr, 0.1 to 0.5% of Mo, and the residue of iron and inevitable contaminants, and in this steel sheet, at least 80% by area in longitudinal cross section has a martensitic structure. As a consequence, a high strength hot rolled steel sheet having a tensile strength of the level as high as 980 MPa or higher simultaneously with an excellent forming workability, and in particular, excellent stretch flangeability is provided at a relatively low cost.

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 invention deals with a hot-dip galvanized or galvannealed steel sheet wherein, the composition of the steel sheet comprises, by weight: 0.01?C?0.22%, 0.50?Mn?2.0%, 0.2?Si?3.0%, 0.005?Al?2.0%, Mo<1.0%, Cr?1.0%, P<0.02%, Ti?0.20%, V?0.40%, Ni?1.0%, Nb?0.20%, the balance of the composition being iron and unavoidable impurities resulting from the smelting, and the steel sheet comprises a layer of an internal nitride of at least one type of nitride selected from a Si nitride, Mn nitride, Al nitride, complex nitride comprising Si and Mn, or Al and Si, or Al and Mn, or complex nitride comprising Si, Mn and Al, said steel sheet comprising no further outer layer of iron nitride.

Abstract: The present invention relates to the following seamless steel pipes excellent in strength, toughness and weldability, particularly suitable for submarine flow lines, and a manufacturing method thereof. An as-quenched seamless steel pipe having a chemical composition consisting of, by mass%, C: 0.03 to 0.08%, Mn: 0.3 to 2.5%, Al: 0.001 to 0.10%, Cr: 0.02 to 1.0%, Ni: 0.02 to 1.0%, Mo: 0.02 to 0.8%, Ti: 0.004 to 0.010%, N: 0.002 to 0.008%, Ca: 0.0005 to 0.005%, and the balance Fe and impurities, with not more than 0.25% of Si, not more than 0.05% of P, not more than 0.005% of S, less than 0.005% Nb, and less than 0.0003% of B as the impurities, and having a microstructure consisting of not more than 20 volume% of polygonal ferrite, not more than 10 volume% of a mixed microstructure of martensite and retained austenite, and balance bainite. B can be 0.0003 to 0.001%. Mg and/or REM can be contained. The manufacturing method is characterized by the cooling rate during quenching.

Abstract: A hot rolled dual phase steel strip with Thickness® 1.0 mm can be used for producing cold pressed and cut pieces, in particular for the car manufacturing industry, by replacing with the same mechanical performances the cold rolled dual phase steel strip usually employed for these purposes. Said hot rolled strip in peritectic steel has a carbon percentage between 0.06 and 0.15% with chemical analysis without any important addition of chromium and phosphorous, with a constant geometrical profile on the whole length and tolerances, particularly with respect to the thickness, which are typical of a cold rolled strip with parallelism <0.05 mm, crown between strips centre and side edges <0.07 mm, while showing a structure with a microcrystalline fineness better than grade 10 of the ASTM 112 standard in a percentage higher than 80% of the whole structure.

Abstract: An oil country tubular good for expansion according to the invention is expanded in a well. The oil country tubular good for expansion has a composition containing, in percentage by mass, 0.05% to 0.08% C, at most 0.50% Si, 0.80% to 1.30% Mn, at most 0.030% P, at most 0.020% S, 0.08% to 0.50% Cr, at most 0.01% N, 0.005% to 0.06% Al, at most 0.05% Ti, at most 0.50% Cu, and at most 0.50% Ni, and the balance consisting of Fe and impurities, and a structure having a ferrite ratio of at least 80%. The oil country tubular good for expansion has a yield strength in the range from 276 MPa to 379 MPa and a uniform elongation of at least 16%. Therefore, the oil country tubular good according to the invention has a high pipe expansion characteristic.