Abstract: Provided is an abrasion-resistant steel plate or sheet which exhibits excellent weld toughness and excellent delayed fracture resistance and is thus suitable for construction machines, industrial machines, and so on. Specifically provided is a steel plate or sheet which contains, in mass %, 0.20 to 0.30% of C, 0.05 to 1.0% of Si, 0.40 to 1.2% of Mn, 0.010% or less of P, 0.005% or less of S, 0.40 to 1.5% of Cr, 0.005 to 0.025% of Nb, 0.005 to 0.03% of Ti, 0.1% or less of Al, 0.01% or less of N, and, as necessary, one or more of Mo, W, B, Cu, Ni, V, REM, Ca and Mg, and has a DI* of 45 to 180 while satisfying the relationship: C+Mn/4?Cr/3+10P?0.47, and which has a microstructure that comprises martensite as the matrix phase. DI*=33.85×(0.1×C)0.5×(0.7×Si+1)×(3.33×Mn+1)×(0.35×Cu+1)×(0.36×Ni+1)×(2.16×Cr+1)×(3×Mo+1)×(1.75×V+1)×(1.

Abstract: Provided is bearing steel excellent in post spheroidizing-annealing workability and in post quenching-tempering hydrogen fatigue resistance property. The bearing steel has a chemical composition containing, by mass %: 0.85% to 1.10% C; 0.30% to 0.80% Si; 0.90% to 2.00% Mn; 0.025% or less P; 0.02% or less S; 0.05% or less Al; 1.8% to 2.5% Cr; 0.15% to 0.4% Mo; 0.0080% or less N; 0.0020% or less O; and the balance being Fe and incidental impurities, to thereby effectively suppress the generation of WEA even in environment where hydrogen penetrates into the steel, so as to improve the rolling contact fatigue life and also the workability such as cuttability and forgeability of the material.

Abstract: A low-alloyed steel, comprising about 0.3 to about 0.50 wt. % carbon, about 2.0 to about 5.0 wt. % silicon, and a remainder of iron, optionally containing low amounts of molybdenum, titanium and/or boron, with up to about 0.5 wt. % impurities. The low-alloyed steel is useful for making structural components having a tensile strength of greater than about 1000 to about 2000 MPa, a yield strength of greater than about 700 to approximately 950 MPa; a break elongation of greater than about 17% and a scaling resistance of greater than about 650° C.

Abstract: A steel for electron-beam welding according to the present invention includes at least C: 0.02% to 0.10%, Si: 0.03% to 0.30%, Mn: 1.5% to 2.5%, Ti: 0.005% to 0.015%, N: 0.0020% to 0.0060%, and O: 0.0010% to 0.0035%, further includes S: limited to 0.010% or less, P: limited to 0.015% or less, and Al: limited to 0.004% or less, with a balance including iron and inevitable impurities. An index value CeEBB obtained by substituting composition of the steel into following Formula 1 falls in the range of 0.42 to 0.65%, the number of oxide having an equivalent circle diameter of 1.0 ?m or more is 20 pieces/mm2 or less at a thickness center portion in cross section along the thickness direction of the steel, and the number of oxide containing Ti of 10% or more and having an equivalent circle diameter of not less than 0.05 ?m or more and less than 0.5 ?m falls in the range of 1×103 to 1×105 pieces/mm2 at the thickness center portion.

Abstract: Disclosed is a high-strength steel plate having a predetermined chemical composition, in which a microstructure of the steel plate at a depth of one-fourth to one half the thickness from a surface has an area fraction of bainite of 90% or more, an average lath width of bainite of 3.5 ?m or less, and a maximum equivalent circle diameter of martensite-austenite constituents in bainite of 3.0 ?m or less. The steel plate exhibits high strengths and good drop weight properties and is useful as structural materials for offshore structure, ships, and bridges, as well as materials for pressure vessels in nuclear power plants.

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

Abstract: An ingot steel for bearings has a composition containing C: 0.56% by mass or more and 0.70% by mass or less, Si: 0.15% by mass or more and less than 0.50% by mass, Mn: 0.60% by mass or more and 1.50% by mass or less, Cr: 0.50% by mass or more and 1.10% by mass or less, P: 0.025% by mass or less, S: 0.025% by mass or less, Al: 0.005% by mass or more and 0.500% by mass or less, O: 0.0015% by mass or less, N: 0.0030% by mass or more and 0.015% by mass or less, and a remainder of Fe and incidental impurities, wherein eutectic carbide formation index Ec satisfies 0<Ec?0.25.

Abstract: The present invention provides a fire-resistant steel material superior in HAZ toughness of a welded joint which is high in high temperature yield strength at an envisioned fire temperature of 700 to 800° C. and is free of embrittlement of the welded joint even if exposed at this envisioned fire temperature and a method of production of the same, that is, a fire-resistant steel material of a composition containing, by mass %, C: 0.005% to less than 0.03%, Si: 0.01 to 0.50%, Mn: 0.05 to 0.40%, Cr: 1.50 to 5.00%, V: 0.05 to 0.50%, and N: 0.001 to 0.005% and restricted in contents of Ni, Cu, Mo, B, P, S, and O obtained by heating a steel slab to 1150 to 1300° C., then hot working or hot rolling the slab to an end temperature of 880 degrees or more, acceleratedly cooling the worked or rolled steel material under conditions of a cooling rate at a position of the slowest cooling rate of at least 2° C.

Abstract: 1—“BAINITIC STEEL FOR MOULDS”, with a composition of alloy elements that consist, in mass percentage, of Carbon between 0.05 and 1.0; Manganese between 0.5 and 3.0; Phosphorous, Boron, Titanium and Vanadium given by the ratio NU=[Ti+P+10B+(V?0.10)], being the values of NU between 0.02 and 0.30, with titanium always above 0.005, boron always below 0.010 and Vanadium may be partially or totally replaced with Niobium, in the proportion of two parts in mass of niobium for one part of Vanadium; Nickel, Molybdenum and Chromium given by the ratio G=[0.13Ni+0.60Mo+0.26Cr], with values of G above 0.10 and below 1.0; Sulphur up to 0.10; Silicon between 0.05 and 3.0; Nitrogen below 0.10; Calcium with contents up to 0.02; Aluminum below 0.5, Cobalt lower than 2.

Abstract: A filler material for welding is characterized by the following chemical composition (amounts in % by weight): 0.05-0.15 C, 8-11 Cr, 2.8-6 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, 1-3 Re, 0.001-0.07 Ta, 0.01-0.06 N, 0-60 ppm Pd, max. 0.25 P, max. 0.02 S, remainder Fe and manufacturing-related unavoidable impurities. The material has outstanding properties, in particular a good creep rupture strength/creep resistance, a good oxidation resistance and a very high toughness.

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

Abstract: An abrasion resistant steel consisting essentially of, in weight %: 0.20-0.30% carbon, 0.40-1.25% manganese, 0.05% maximum phosphorous, 0.01% maximum sulfur, 0.20-0.60% silicon, 0.50-1.70% chromium, 0.20-2.00% nickel, 0.07-0.60% molybdenum, 0.010-0.10% titanium, 0.001-0.10% boron, 0.015-0.10% aluminum, balance iron, and incidental impurities. The steel may be melted and cast into a steel ingot or slab, hot rolled to a desired plate thickness; austenitized at 1650-1700° F.; water quenched; and tempered at 350-450° F. The resulting steel plate may have a surface hardness of at least 440 HBW, a mid-thickness hardness of at least 90% of the surface hardness, and toughness in the transverse direction at ?60° F. of at least 20 ft-lbs and at room temperature of at least 40 ft-lbs.

Abstract: A component of an air-hardenable steel composed of (contents in mass %): C<0.20; Al<0.08; Si<1.00; Mn 1.20 to <2.50; P<0.020; S<0.015; N<0.0150; Cr 0.30 to <1.5; Mo 0.10 to <0.80; Ti 0.010 to <0.050; V 0.03 to <0.20; B 0.0015 to <0.0060, with the remainder being iron including the usual elements present in steel, is produced by heating a hot- or cold-rolled steel sheet or steel tube section to a temperature of ?blank=800 to 1050° C. and then forming the sheet or tube into a component in a forming tool. After removal from the tool, the component is cooled down in air while the component still has a temperature above ?removal=200° C. and below 800° C. The component achieves the required mechanical properties during air-cooling.

Abstract: Disclosed is a low alloy steel for oil well pipes which has excellent sulfide stress cracking resistance and is suitable for casing and tubing for oil wells or gas wells. Specifically disclosed is a low alloy steel for oil well pipes containing, in mass %, 0.2-0.35% of C, 0.05-0.5% of Si, 0.05-1.0% of Mn, not more than 0.025% of P, not more than 0.01% of S, 0.005-0.10% of Al, 0.1-1.0% of Cr, 0.5-1.0% of Mo, 0.002-0.05% of Ti, 0.05-0.3% of V, 0.0001-0.005% of B, not more than 0.01% of N, not more than 0.01% of O (oxygen), 0-0.1% of Nb, 0-0.01% of Ca, 0-0.01% of Mg and 0-0.1% of Zr, and having a half-value breadth (H) and a hydrogen diffusion coefficient (D) (10?6 cm2/s) satisfying the following formula (1): 30H+D?19.5??(1).

Abstract: A weld metal of a high-strength Cr—Mo steel formed by shielded metal arc welding contains: 0.04 to 0.10% by mass C, 0.15 to 0.5% by mass Si, 0.5 to 1.0% by mass Mn, 2.00 to 3.25% by mass Cr, 0.9 to 1.2% by mass Mo, 0.01 to 0.03% by mass Nb, 0.2 to 0.7% by mass V, 0.003% by mass or below and above 0% by mass B, 0.02 to 0.05% by mass O, and the balance of Fe and inevitable impurities. A residual extracted by electrolytic extraction from only an unaffected zone of the weld metal contains precipitated Cr in a Cr content below 0.3% by mass, and precipitated Nb in a Nb content of 0.005% by mass or above.

Abstract: The present invention provides a wire rod with a composition at least including: C: 0.95-1.30 mass %; Si: 0.1-1.5 mass %; Mn: 0.1-1.0 mass %; Al: 0-0.1 mass %; Ti: 0-0.1 mass %; P: 0-0.02 mass %; S: 0-0.02 mass %; N: 10-50 ppm; O: 10-40 ppm; and a balance including Fe and inevitable impurities, wherein 97% or more of an area in a cross-section perpendicular to the longitudinal direction of the wire rod is occupied by a pearlite, and 0.5% or less of an area in a central area in the cross-section and 0.5% or less of an area in a first surface layer area in the cross-section are occupied by a pro-eutectoid cementite.

Abstract: The present invention provides an abrasion resistant steel having a hardness of HB400 to HB520, having little change of hardness during long term use, and superior in toughness, characterized by containing, by mass %, C: 0.21% to 0.30%, Si: 0.30 to 1.00%, Mn: 0.32 to 0.70%, P: 0.02% or less, S: 0.01% or less, Cr: 0.1 to 2.0%, Mo: 0.1 to 1.0%, B: 0.0003 to 0.0030%, Al: 0.01 to 0.1%, and N: 0.01% or less, further containing one or more of V: 0.01 to 0.1%, Nb: 0.005 to 0.05%, Ti: 0.005 to 0.03%, Ca: 0.0005 to 0.05%, Mg: 0.0005 to 0.05%, and REM: 0.001 to 0.

Abstract: A high strength steel sheet contains, in percent by mass, 0.03 to 0.2% of C, 0.5 to 2.5% of Si, 1 to 3.0% of Mn, 0.01 to 0.5% of Cr, 0.01 to 0.5% of Mo, 0.02 to 0.15% of Al, 0.15% or less of Ti, 0.15% or less of No, and 0.15% or less of V; wherein the remainder includes Fe and inevitable impurities, and the content of Si satisfies the following formula (1), ?-4.1[Si]?-2.4??(1), provided, ?=6.9×([C]+[Mn]/6+[Cr]/5+[Mo]/4+[Ti]/15+[Nb]/17+[V]/14)1/2 is given, wherein [ ] shows the quantity (mass percent) of each element contained in the steel sheet. The high strength steel sheet is improved in formability (particularly, elongation), and excellent in balance between strength and elongation.

Abstract: The present invention is steel for surface hardening for machine structural use which contains, by mass %, C: 0.3 to 0.6%, Si: 0.02 to 2.0%, Mn: 0.35 to less than 1.5%, and Al: 0.01 to 0.5%, is restricted to B: less than 0.0003%, S: 0.0001 to 0.021%, N: 0.003 to 0.0055%, P: 0.0001 to 0.03%, and O: 0.0001 to 0.0050%, has a ratio Mn/S of Mn and S satisfying 70 to 30,000, has a balance of Fe and unavoidable impurities, and, when nitrided, then induction hardened, has a surface hardenability of a Vicker's hardness when tempered at 300° C. of 650 or more.

Abstract: The invention provides a steel material with satisfactory hydrogen embrittlement resistance, and particularly it relates to high-strength steel with satisfactory hydrogen embrittlement resistance and a strength of 1200 MPa or greater, as well as a process for production thereof. At least one simple or compound deposit of oxides, carbides or nitrides as hydrogen trap sites which trap hydrogen with a specific trap energy is added to steel, where the mean sizes, number densities, and length-to-thickness ratios (aspect ratio) are in specific ranges. By applying the specific steel components and production process it is possible to obtain high-strength steel with excellent hydrogen embrittlement resistance.

Abstract: An ultra soft high carbon hot-rolled steel sheet has excellent workability. The steel sheet is a high carbon hot-rolled steel sheet containing 0.2 to 0.7% C, and has a structure in which mean grain size of ferrite is 20 ?m or larger, the volume percentage of ferrite grains having 10 ?m or smaller size is 20% or less, mean diameter of carbide is in a range from 0.10 ?m to smaller than 2.0 ?m, the percentage of carbide grains having 5 or more of aspect ratio is 15% or less, and the contact ratio of carbide is 20% or less.

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: The present invention relates to a steel material giving more effective case hardening for improving the fatigue strength and is characterized by containing, by mass %, C: 0.01 to 0.3%, Si: less than 0.1%, Mn: 0.4 to 3%, Cr: 0.5 to 3%, and Al: 0.01 to 0.3%, further containing one or both of Mo: 0.2 to 1.5%, and V: 0.05 to 1.0%, having a balance of Fe and unavoidable impurities, and comprising a structure having 50% or more of bainite.

Abstract: A steel for heat treatment, which exhibits high strength and high toughness even when the heat treatment (such as quenching and tempering) of the steel is conducted under conventional conditions in an after stage. The steel for heat treatment contains C: 0.10 to 0.70 mass %, Mn: 0.1 to 3.0 mass %, Al: 0.005 to 2.0 mass %, P: 0.050 mass % or less, S: 0.50 mass % or less, O: 0.0030 mass or less, N: 0.0200 mass % or less, and one or more selected from the group consisting of Ti: 0.30 mass % or less and Nb: 0.30 mass or less with the balance being Fe and unavoidable impurities, and has a TH value of 1.0 or above as calculated according to the formula: ({Ti}/48+{Nb}/93) 104 and grain diameters of 10 ?m or below. {Ti} and {Nb} refer respectively to the contents of Ti and Nb in precipitates of 5 to 100 nm in size as determined about their respective extraction residues.

Abstract: The present application provides a high strength spring steel and a high strength spring that have superior corrosion fatigue strength. The spring steel comprises, in terms of percent by mass, 0.35-0.55% C, 1.60-3.00% Si, 0.20-1.50% Mn, 0.10-1.50% Cr and at least one element selected from 0.40-3.00% Ni, 0.05-0.50% Mo 0.05-0.50% V, the balance being at least substantially Fe and incidental elements and impurities.

Abstract: An alloy suitable for use in a rotor, such as one or more regions of a steam turbine rotor, as well as a forged rotor formed with the alloy. The alloy consists of, by weight, 0.20 to 0.30% carbon, 0.80 to 1.5% chromium, 0.80 to 1.5% molybdenum, 0.50 to 0.90% vanadium, 0.30 to 0.80% nickel, 0.05 to 0.15% titanium, 0.20 to 1.0% manganese, and 0.005 to 0.012% boron, the balance iron, optionally low levels of other alloying constituents, and incidental impurities.

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 steel for high-strength components including bands, sheets or pipes having excellent formability and particular suitability for high-temperature coating processes above Ac3 (about 900° C.) is disclosed. The steel includes the following elements (contents in % by mass): C 0.07 to ?0.15, Al?0.05, Si?0.80, Mn 1.60 to ?2.10, P?0.020, S?0.010, Cr 0.50 to ?1.0, Mo 0.10 to ?0.30, Timin 48/14×[N], V 0.03 to ?0.12, B 0.0015 to ?0.0050, with the balance iron including usual steel-accompanying elements.

Abstract: The present invention provides a fire-resistant steel material superior in weld heat affected zone reheat embrittlement resistance and low temperature toughness when welded by large heat input and exposed to fire and a method of production of the same, that is, a material containing C: 0.012 to 0.050%, Mn: 0.80 to 2.00%, Cr: 0.80 to 1.90%, and Nb: 0.01 to less than 0.05%, restricting Cu to 0.10% or less, containing suitable quantities of Si, N, Ti, and Al, restricting the contents of Mo, B, P, S, and O, and having a balance of Fe and unavoidable impurities, having contents of C, Mn, Cr, Nb, and Cu satisfying ?1200C?20Mn+30Cr?330Nb?120Cu??80, having a steel structure as observed by an optical microscope of an area fraction of 80% or more of a ferrite phase, and having a balance of the steel structure of a bainite phase, martensite phase, and mixed martensite-austenite structure.

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: The present invention provides high burring, high strength steel sheet excellent in softening resistance of the weld heat affected zone and a method of production of the same, that is, high burring, high strength steel sheet excellent in softening resistance of the weld heat affected zone containing, by wt %, C: 0.01 to 0.1%, Si: 0.01 to 2%, Mn: 0.05 to 3%, P?0.1%, S?0.03%, Al: 0.005 to 1%, N: 0.0005 to 0.005%, and Ti: 0.05 to 0.5% and further containing C, S, N, Ti, Cr, and Mo in ranges satisfying 0%<C?(12/48Ti?12/14N?12/32S)?0.05%, Mo+Cr?0.2%, Cr?0.5%, and Mo?0.5%, the balance being Fe and unavoidable impurities, wherein the microstructure comprises ferrite or ferrite and bainite.

Abstract: An abrasion resistant steel excellent in bending formability and suitable for members, e.g., power shovels, which come into contact with earth and sand, and a production method thereof are provided. Specifically, the steel contains, on a percent by mass basis, 0.05% to 0.35% of C, 0.05% to 1.0% of Si, 0.1% to 2.0% of Mn, 0.1% to 1.2% of Ti, 0.1% or less of Al, at least one element of 0.1% to 1.0% of Cu, 0.1% to 2.0% of Ni, 0.1% to 1.0% of Cr, 0.05% to 1.0% of Mo, 0.05% to 1.0% of W, and 0.0003% to 0.0030% of B, if necessary at least one element of 0.005% to 1.0% of Nb and 0.005% to 1.0% of V, and the remainder including Fe and incidental impurities, where DI* represented by the following formula is less than 60: DI*=33.85×(0.1×C*)0.5×(0.7×Si+1)×(3.33×Mn+1)×(0.35×Cu+1)×(0.36×Ni+1)×(2.16×Cr+1)×(3×Mo*+1)×(1.5×W*+1)??(1) where C*=C?1/4×(Ti?48/14N), Mo*=Mo×(1?0.5×(Ti?48/14N)), and W*=W×(1?0.5×(Ti?48/14N)).

Abstract: The steel according to the invention is characterized in that, in order to keep its weight content of molybdenum below 0.45%, its chemical composition, besides the iron and the inevitable residual impurities that result from the smelting of the steel, corresponds to the following analysis, given as percentages by weight: 0.3?C %?0.5 0.20?Mo %<0.45 0.4?Mn %?1.0 0.4?Cr %?2.0 0.04?Ni %?0.8 0.02?Nb %?0.045 0.03?V %?0.30 0.02?Ti %?0.05, with Ti>3.5 N 0.003?B %?0.005% S %?0.015 P %?0.015, and optionally 0.05?Si %?0.20; Al %?0.05 and N %?0.015. By cold forming a hot-rolled wire rod resulting from continuous casting, it is possible to obtain, after heat treatment, “ready-to-use” coined parts, such as cap screws for example for the automotive industry, that offer a tensile strength from 1200 to more than 1500 MPa while having a good hydrogen embrittlement resistance, and this with a specially controlled “raw material” production cost.

Abstract: Disclosed is an improved low alloy high speed tool steel, which exhibits constant toughness with small dispersion of the properties after heat treatment and regardless of the size of the products. The steel consists essentially of, by weight %, C: 0.50-0.75%, Si: 0.02-2.00%, Mn: 0.1-3.0%, P: up to 0.050%, S: up to 0.010%, Cr: 5.0-6.0%, W: 0.5-2.0%, V: 0.70-1.25%, Al: up to 0.1%, O: up to 0.01% and N: up to 0.04% and the balance of Fe. In the steel [Mo+0.5W](Mo-eq.) is 2.5-5.0%, [Mo-eq.]/V is 2-4. In the annealed state the steel contains carbides of the types of MC+M6C and/or M23C6(M7C3), and after quenching from a temperature of 1100-1200° C. it contains substantially no remaining carbide or, even contains, almost all the carbides are of MC.

Abstract: A high strength cold-rolled steel sheet and a high strength plated steel sheet which have an excellent surface appearance required for outer panels of automobiles and which have an extremely high r value in a direction at 45° with respect to the rolling direction and which have excellent press formability and a tensile strength of at least 340 MPa and a process for their manufacture are provided. The steel sheets have a chemical composition consisting essentially of, in mass %, C: 0.0005-0.025%, Si: at most 0.2%, Mn: 0.3-2.5%, P: at most 0.15%, S: at most 0.02%, N: at most 0.006%, sol. Al: less than 0.005%, Ti: 0.005-0.05%, and Nb: 0.020-0.200% with the mass ratio (Nb/Ti) of the contents of Nb and Ti being at least 2, and a remainder of Fe and impurities, and they have an r value in a direction at 45° with respect to the rolling direction (r45) of at least 1.80 and/or a mean r value (0 of at least 1.60, and a tensile strength of at least 340 MPa.

Abstract: Low alloy steel for oil country tubular goods contains, in percentage by mass, 0.20% to 0.35% C, 0.05% to 0.5% Si, 0.05% to 0.6% Mn, at most 0.025% P, at most 0.01% S, 0.005% to 0.100% Al, 0.8% to 3.0% Mo, 0.05% to 0.25% V, 0.0001% to 0.005% B, at most 0.01% N, and at most 0.01% O, the balance comprising Fe and impurities, the steel satisfying Expression (1): 12V+1?Mo?0 (1) where the symbols of elements represent the contents of the elements in percentage by mass. In this way, the steel according to the present invention has high SSC resistance.

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: This invention provides a forging steel excellent in forgeability, which forging steel comprises, in mass %, C: 0.001 to less than 0.07%, Si: 3.0% or less, Mn: 0.01 to 4.0%, Cr: 5.0% or less, P: 0.2% or less, S: 0.35% or less, Al: 0.0001 to 2.0%, N: 0.03% or less, one or both of Mo: 1.5% or less (including 0%) and Ni: 4.5% or less (including 0%), and a balance of iron and unavoidable impurities; wherein Di given by the following Equation (1) is 60 or greater: Di=5.

Abstract: An object of the preset invention is to provide a spring steel wire that: shows excellent wire drawability not only when it is used as a spring steel wire for cold-winding formed into a steel spring by applying quenching and tempering treatment after wiredrawing but also when it is used as a spring steel wire for cold-winding formed into a steel spring as it is wiredrawn; and secures a spring having an excellent fatigue characteristic after the spring steel wire is formed into the spring. The spring steel wire according to the present invention is a spring steel wire excellent in fatigue characteristic and wire drawability, wherein: the contents of C, Si, Mn, Cr, Ti, B, and other elements are specified; the contents (mass %) of B, Ti, and N satisfy the expression (1) below; the amount of solid solute B is in the range of 0.0005% to 0.0040%; the remainder in the spring steel wire is composed of Fe and unavoidable impurities; and the solid solute B concentrates at the grain boundaries of pearlite nodules, 0.

Abstract: A low alloy steel, which has a chemical composition by mass %, of C: 0.1 to 0.55%, Si: 0.05 to 0.5%, Mn: 0.1 to 1%, S: 0.0001 to 0.005%, Al: 0.005 to 0.08%, Ti: 0.005 to 0.05%, Cr: 0.1 to 1.5%, Mo: 0.1 to 1%, O: 0.0004 to 0.005%, Ca: 0.0005 to 0.0045%, Nb: 0 to 0.1%, V: 0 to 0.5%, B: 0 to 0.005%, Zr: 0 to 0.10%, P?0.03%, and N?0.006%, with the balance being Fe and impurities, is manufactured by adjusting the value of ([Ti]/47.9)([N]/14)/([Ca])/40.1) satisfies not less than 0.0008 and not more than 0.0066, at the time of melting the said low alloy steel, wherein [Ti], [N] and [Ca] are the contents in the molten steel by mass % of Ti, N and Ca respectively. The thus-manufactured low steel alloy has a high SSC resistance with a yield stress of not less than 758 MPa.

Abstract: Provided is a weld metal for Cr—Mo steels which is suppressed in the formation of ferrite bands and therefore has heightened toughness and tensile strength and at the same time, good SR cracking resistance. The weld metal according to the present invention contains C: 0.02 to 0.06% (mass %, which will equally apply hereinafter), Si: 0.1 to 1.0%, Mn: 0.3 to 1.5%, Cr: 2.0 to 3.25%, Mo: 0.8 to 1.2%, Ti: 0.010 to 0.05%, B: 0.0005% or less (inclusive of 0%), N: 0.002 to 0.0120%, O: 0.03 to 0.07%, and the balance being Fe and inevitable impurities, wherein a ratio of the Ti content [Ti] to the N content [N] satisfies the following range: 2.00<[Ti]/[N]<6.25.

Abstract: The invention relates to an ultrahigh-strength thin steel sheet excellent in the hydrogen embrittlement resistance, the steel sheet including, by weight %, 0.10 to 0.60% of C, 1.0 to 3.0% of Si, 1.0 to 3.5% of Mn, 0.15% or less of P, 0.02% or less of S, 1.5% or less of Al, 0.003 to 2.0% of Cr, and a balance including iron and inevitable impurities; in which grains of residual austenite have an average axis ratio (major axis/minor axis) of 5 or more, the grains of the residual austenite have an average minor axis length of 1 ?m or less, and the grains of the residual austenite have a nearest-neighbor distance between the grains of 1 ?m or less.

Abstract: A steel material of 85 to 95 HRB exhibiting a ratio of area occupied by ferrite of 30% or higher, which steel material comprises given amounts of C, Si, Mn, S, Ti, Cr, Al and B and the balance of iron and unavoidable impurities, is subjected to induction hardening. After the hardening, the surface of the steel material exhibits an Hv value of 640 to 730. When t refers to the effective hardening depth, namely, the distance from the surface to a region exhibiting an Hv value of 392 and r refers to the radius of the steel material, the hardened layer ratio, t/r, is 0.4 or higher.

Abstract: A low alloy steel is provided for oil country tubular goods with a yield strength between 654 MPa and 757 MPa, and possessing excellent resistance to HIC and SSC in high-pressure hydrogen sulfides environment, and comprising, by mass %: 0.10 to 0.60% C; 0.05 to 0.5% Si; 0.05 to 3.0% Mn; 0.025% or less P; 0.010% or less S; 0.005 to 0.10% Al; 0.01% or less O (oxygen); 3.0% or less Cr; and 3.0% or less Mo, wherein the amount of Cr and Mo content is 1.2% or more, with the balance being Fe and impurities, and the number of nonmetallic inclusions whose major axis is 10 ?m or more is 10 per square millimeter in the inspected cross section. The present invention provides a low alloy steel for oil country tubular goods possessing excellent resistance to sulfide stress cracking, and a seamless steel pipe.

Abstract: The present invention provides steel plate for high strength line pipe suppressing the rise in yield strength in the longitudinal direction of expanded steel pipe due to the heating at the time of coating to prevent corrosion and superior in strain aging resistance and steel pipe for the material for the same, that is, high strength steel pipe for line pipe superior in strain aging resistance characterized in that a base material having a composition of chemical elements containing, by mass %, Mo: over 0% to less than 0.15% and Mn: 1.7 to 2.5%, satisfying Mo/Mn: over 0 to 0.08, containing C, Si, P, S, Al, Ti, N, and B, furthermore containing one or more of Ni, Cu, and Cr, having a balance of iron and unavoidable impurities, having a P value of 2.5 to 4.0 in range, and having a metallurgical structure comprised of bainite and martensite: P value=2.7C+0.4Si+Mn+0.8Cr+0.45(Ni+Cu)+2Mo. Furthermore, it may contain one or more of Nb, V, Ca, REM, and Mg.

Abstract: This invention provides a case-hardening steel excellent in cold forgeability and low carburization distortion property that exhibits low deformation resistance and high limit compressibility when cold, namely, a case-hardening steel excellent in cold forgeability and low carburization distortion property comprising, in mass %, C: 0.07% to 0.3%, Si: 0.01% to 0.15%, Mn: 0.1% to 0.7%, P: 0.03% or less, S: 0.002% to 0.10%, Al: 0.01% to 0.08%, Cr: 0.7% to 1.5%, Ti: 0.01% to 0.15%, B: 0.0005% to 0.005%, N: 0.008% or less, and the balance of Fe and unavoidable impurities, and having a metallographic structure comprising 65% or greater of ferrite and 15% or less of bainite.

Abstract: The present invention provides a fire-resistant steel material superior in HAZ toughness of a welded joint which is high in high temperature yield strength at an envisioned fire temperature of 700 to 800° C. and is free of embrittlement of the welded joint even if exposed at this envisioned fire temperature and a method of production of the same, that is, a fire-resistant steel material of a composition containing, by mass %, C: 0.005% to less than 0.03%, Si: 0.01 to 0.50%, Mn: 0.05 to 0.40%, Cr: 1.50 to 5.00%, V: 0.05 to 0.50%, and N: 0.001 to 0.005% and restricted in contents of Ni, Cu, Mo, B, P, S, and O obtained by heating a steel slab to 1150 to 1300° C., then hot working or hot rolling the slab to an end temperature of 880 degrees or more, acceleratedly cooling the worked or rolled steel material under conditions of a cooling rate at a position of the slowest cooling rate of at least 2° C.

Abstract: A low alloy steel comprising, by mass %, C: 0.10 to 0.20%, Si: 0.05 to 1.0%, Mn: 0.05 to 1.5%, Cr: 1.0 to 2.0%, Mo: 0.05 to 2.0%, Al: 0.10 % or less and Ti: 0.002 to 0.05%, and with a Ceq value obtained by the following formula (1) of 0.65 or more, with the balance being Fe and impurities, wherein in the impurities, P is 0.025% or less, S is 0.010% or less, N is 0.007% or less, and B is less than 0.0003%, and the number per unit area of M23C6 type precipitates (M: a metal element) whose grain diameter is 1 ?m or more is 0.1/mm2 or less. This invention provides a low alloy steel possessing both hardenability and toughness and improves the resistance to sulfide stress corrosion cracking. Ceq=C+(Mn/6)+(Cr+Mo+V)/5 ??formula (1) where C, Mn, Cr, Mo and V in the formula (1) denote the mass % of respective elements.

Abstract: Embodiments of the present application are directed towards steel compositions that provide improved properties under corrosive environments. Embodiments also relate to protection on the surface of the steel, reducing the permeation of hydrogen. Good process control, in terms of heat treatment working window and resistance to surface oxidation at rolling temperature, are further provided.

Abstract: The invention concerns a method for making an abrasion resistant steel plate having a chemical composition comprising: 0.35%?C?0.8%, 0%?Si?2%, 0%?Al?2%, 0.35%?Si+Al?2%, 0%?Mn?2.5%, 0%?Ni?5%, 0%?Cr?5%, 0%?Mo?0.50%, 0%?W?1.00%, 0.1%?Mo+W/2?0.50%, 0%?B?0.02%, 0%?Ti?2%, 0%?Zr?4%, 0.05%?Ti+Zr/2?2%, 0%?S?0.15%, N<0.03%; optionally from 0% to 1.5% of Cu; optionally Nb, Ta or V with Nb/2+Ta/4+V?0.5%; optionally less than 0.1% of Se, Te, Ca, Bi or Pb; the rest being iron and impurities; the composition satisfying: 0.1%?C*=C?Ti/4?Zr/8+7×N/8?0.55% and 1.05×Mn+0.54×Ni+0.50×Cr+0.3×(Mo+W/2)1/2+K>1.8, with K=0.5 if B?0.0005% and K=0 if B<0.0005% and Ti+Zr/2?7×N/2?0.05%; hardening after austenitization while cooling at a speed>0.5° C./s between a temperature>AC3 and ranging between T=800?270×C*?90×Mn?37×Ni?70×Cr?83×(Mo+W/2) and T?50° C.; then at a core speed Vr<115×ep?1.7 between T and 100° C., (ep=plate thickness in mm); cooling down to room temperature. The invention also concerns the resulting plate.