Abstract: A process to manufacture an oilfield component comprises selectively reinforcing a base material with an age-hardenable clad material and age-hardening the clad material for a selected time and at a selected temperature profile, wherein the age-hardening results in the clad material developing a selected strength gradient. A body of a ram blowout preventer comprises, a low-ally base material, a vertical bore through the body, and a horizontal bore through the body intersecting the vertical bore, wherein at least a portion of the body is selectively reinforced with a clad material, and wherein the clad material is age-hardened for a selected time and at a selected temperature profile resulting in the clad material developing a selected strength gradient.

Abstract: The present invention relates to a method for heat treatment of a columnar work. In order to provide the method for heat treatment of a columnar work being able to attain a high productivity, a reduction of cost, and an improvement of quality, as compared with the prior art, the method for heat treatment of a columnar work of the present invention includes a quench-hardening step (S1) and a tempering step (S2) being carried out after the quench-hardening step (S1), the quench-hardening step (S1) includes a first quench-hardening step (S11) and a second quench-hardening step (S12) being carried out after the first quench-hardening step (S11), the entire region of the columnar work (3) from an outer circumferential surface (31f) to a core thereof (32), or a partial region thereof, is heated up to a temperature not lower than a transformation temperature Ac3, and then, the work is quench-hardened.

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.

Abstract: There is provided a heat treatment method in which high-quality tempering treatment can be performed in a short period of time. In this method, when an object to be treated is tempered after being quenched, the object to be treated is rapidly cooled to a 90% martensite transformation finishing temperature without being cooled to the ordinary temperature after quench heating, and then is subjected to 100% martensite transformation by using a 100° C. liquid, and thereafter, tempering treatment is performed after the whole of the object to be treated is soaked by using the 100 ° C. liquid.

Abstract: Provided are a steel having excellent rolling contact fatigue life and the manufacturing method thereof. The steel consists essentially of 0.7 to 1.1% C, 0.2 to 2.0% Si, 0.4 to 2.5% Mn, 1.6 to 4.0% Cr, 0.1% or more and less than 0.5% Mo, 0.010 to 0.050% Al, bymass, and balance of Fe and inevitable impurities, is treated by quenching and tempering, has residual cementite grain sizes ranging from 0.05 to 1.5 ?m, and has prior-austenite grain sizes of 30 ?m or smaller. When the steel is used to bearing steel, the bearing life extends even under service in more severe environments.

Abstract: The invention concerns weldable steel building components whereof the chemical composition comprises, by weight: 0.10%?C?0.22%, 0.50%?Si?1.50%, AI?0.9%, 0%?Mn?3%, 0%?Ni?5%, 0%?Cr?4%, 0%?Cu?1%, 0%?Mo+W/2?1.5%, 0.0005%?B<0.010%, N?0.025%, optionally at least one element selected among V, Nb, Ta, S et Ca, in contents less than 0.3%, and/or among Ti and Zr in contents not more than 0.5%, the rest being iron and impurities resulting from preparation, the aluminium, boron, titanium and nitrogen contents, expressed in thousandths of %, of said composition further satisfying the following relationship: B??×K+0.5, (1) with K=Min (I*; J*), I*=Max (0; I) and J*=Max (0; J), I=Min (N; N?0.29(Ti?5)), J=Min {N; 0.5 (N 0.52 AI+?j(N 0.52 AI)2+283)}, the silicon and aluminium contents of the composition additionally verifying the following conditions: if C>0.145, then Si+AI<0.95 and whereof the structure is bainitic, martensitic or martensitic/bainitic and further comprises 3 to 20% of residual austenite.

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

Abstract: This invention relates to a method of manufacturing a martensitic stainless steel. The method comprises the following steps (a) to (c): (a) preparing a steel having a chemical composition consisting of, by mass %, C: 0.003 to 0.050%, Si: 0.05 to 1.00%, Mn: 0.10 to 1.50%, Cr: 10.5 to 14.0%, Ni: 1.5 to 7.0%, V: 0.02 to 0.20%, N: 0.003 to 0.070%, Ti: not more than 0.300% and the balance Fe and impurities, and P and S among impurities are not more than 0.035% and not more than 0.010% respectively, and that it also satisfies the following equation: ([Ti]?3.4×[N])/[C]>4.5 wherein [C], [N] and [Ti] mean the content (mass %) of C, N and Ti, respectively, (b) heating the steel at a temperature between 850 and 950° C., (c) quenching the steel, and (d) tempering the steel at a temperature between Ac1?35° C. and Ac1+35° C. and in a condition of not more than 0.5 of the value of variation ?LMP1 in the softening characteristics LMP1, which is defined by the following equation: LMP1=T×(20+1.

Abstract: The invention provides a Martensite wear-resistant cast steel with film Austenite for enhancement of toughness comprises 0.25˜0.34 wt % C, 1.40˜2.05 wt % Si, 0.90˜1.20 wt % Mn, 1.80˜2.50 wt % Cr, 0.0005˜0.005 wt % B, 0.01˜0.06 wt % Ti, 0.015˜0.08 wt % Rare Earth, 0.015˜0.06 wt % Al, less than 0.035 wt % S, less than 0.035 wt % P, and the balance of iron. The method of producing the cast steel includes smelting and heat-treatment, after smelting as normal operation, adding Ferro-Rare Earth and Ferro-Boron in the ladle in sequence, then high temperature normalizing, water quenching and low temperature tempering. TEM structure of the cast steel is martensite lath with film austenite between martensite laths. Cast steel of the invention exhibits high hardenability and toughness, and low cost without precious Molybdenum and Nickel, applied to a range of wear-resistant castings, especially to heavy-section castings, i.e. heavy-section tooth.

Abstract: A steel alloy for cutting tools, wherein the alloy comprises C, Si, Mn, Cr, Mo, W, V, Al, P, S and N within the concentration ranges recited in the claims. 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: The present invention provides a method for manufacturing high tensile strength steel plate having 570 MPa (N/mm2) or larger tensile strength and having also extremely superior balance of strength and toughness both before PWHT and after PWHT to that of the conventional steel plates, by specifically specifying the temperature-rising rate at the plate thickness center portion of a quenched and tempered material during tempering, and to be concrete, the method has the steps of: casting a steel consisting essentially of 0.02 to 0.18% C, 0.05 to 0.5% Si, 0.5 to 2.0% Mn, 0.005 to 0.1% Al, 0.0005 to 0.008% N, 0.03% or less P, 0.

Abstract: Austempered ductile iron (ADI) for components requiring high strength and/or ductility, which has a silicon content of 3.35 weight-% to 4.60 weight-%, and which is obtainable by performing an ADI-heat treatment using an austenitization temperature of at least 910° C.

Abstract: A method of heat treating stainless steel in the form of blanks, piping, tubing, strip, or wire-like material, after rolling the material, and in a heat treatment furnace at a temperature higher than about 900° C. The material is subjected to a preheating stage and a final heating stage, wherein in the preheating stage flames from burners are directed toward the surface of the material to impinge on the surface. Burners situated in the preheating stage are supplied with a fuel that burns with the aid of an oxidizing gas that contains gaseous oxygen. The material is held in the preheating stage long enough to obtain at least some degree of oxidation on the surface of the material, and the material is heated further in a following, final heating stage by burners situated in a furnace and that are supplied with a fuel and an oxidizing gas.

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

Abstract: The present invention provides a method for heat-treating seam-welded constructions of hardenable steel and ferrous alloys with reduced weld-zone hardness and improved weld-zone ductility and toughness. This method consists of heating the seam weld rapidly with a secondary heat source to a temperature greater than the martensitic start temperature but not greater than the lower critical temperature, followed by immediately allowing the seam weld to air-cool. The rapid tempering of this invention is particularly suited to the production of high strength hardenable alloy seam-welded pipe and tubing and other structures.

Abstract: The present invention provides a link chain superior in low temperature toughness comprised of low carbon steel, said link chain characterized in that two-stage high frequency quenching-tempering is performed to give a link chain which has a martensite single phase structure, has an austenite grain size of 9 to 12, further contains in said structure a precipitate comprised of 40 nm or smaller TiC in 90% or more and 80 nm or smaller Ti(C,N) in 10% or less, contains AlN in not more than 0.0003%, and has a ?40° C. Charpy impact value of at least 45 J.

Abstract: This invention related to a high carbon and high molybdenum/tungsten martenisitic type iron base alloy with excellent hot hardness and wear resistance for making valve seat insert. The alloy comprises of 2.05-3.60 wt % carbon, 0.1-3.0 wt % silicon, 0-2.0 wt % manganese, 3.0-10.0 wt % chromium, 11.0-25.0 wt % molybdenum and tungsten, 0.1-6.5 wt % nickel, 0-8.0 wt % vanadium, 0-6.0 wt % niobium, 0-8.0 wt % cobalt, and the balance being iron with impurities.

Abstract: The invention concerns an article of a steel which is characterized in that it consists of an alloy which contains in weight-%: 1.2-2.0 C, 0.1-1.5 Si, 0.1-2.0 Mn, max. 0.2 N, max. 0.25 S, 4-8 Cr, 0.5-3.5 (Mo+W/2), 5-8 V, max. 1.0 Nb, balance essentially only iron and unavoidable impurities, and that the steel has a micro-structure obtainable by a manufacturing of the steel which comprises spray forming of an ingot, the micro-structure of which contains 8-15 vol-% carbides of essentially only MC-type where M substantially consists of vanadium, of which carbides at least 80 vol-% have a substantially rounded shape and a size in the longest extension of the carbides amounting to 1-20 ?m.

Abstract: The invention relates to a method for continuously creating a bainite structure in a carbon steel, especially a strip steel. The method comprises the following steps: the carbon steel (1) is austenitized (3) at a temperature exceeding the austenitizing temperature; the austenitized carbon steel (1) is introduced into a bath (2) containing a quenching agent (21) in order to cool the carbon steel (1) to a temperature lying below the austenitizing temperature; the carbon steel (1) is adjusted to the transformation temperature for bainite and is maintained (13) at the transformation temperature for a certain period of time; and the carbon steel is then cooled (17).

Abstract: The present invention relates to a low alloy, low to medium carbon content, high strength, and high ductility steel composition. The present invention contains relatively low nickel content, yet exhibits high performance characteristics and is manufactured at a substantially lower cost than alloy compositions containing high levels of nickel.

Abstract: The present invention provides a method for manufacturing an ultra high strength cold-rolled steel sheet, comprising the step of continuously annealing a cold-rolled steel sheet consisting essentially of, in terms of weight percentages, 0.07 to 0.15% C, 0.7 to 2% Si, 1.8 to 3% Mn, 0.02% or less P, 0.01% or less S, 0.01 to 0.1% Sol. Al, 0.005% or less N, 0.0003 to 0.003% B, and the balance being Fe, in which such continuous annealing comprises the steps of: heating the cold-rolled steel sheet at from 800° C. to 870° C. for 10 seconds or more; slowly cooling the heated steel sheet down to from 650° C. to 750° C.; rapidly cooling the slowly cooled steel sheet down to 100° C. or less at a cooling speed of over 500° C./sec; reheating the rapidly cooled steel sheet at from 325° C. to 425° C. for from 5 minutes to 20 minutes; cooling the reheated steel sheet down to room temperature; and coiling the cooled steel sheet.

Abstract: In a martensitic stainless steel tube according to the present invention, the content is determined by each of elements C, Si, Mn and Cr, and the bubble content ratio is further prescribed in accordance with the scale thickness on the outer surface of the steel tube, so that defects can be detected with high precision in the non-destructive inspection, such as ultrasonic test or the like. This allows the non-destructive inspection to be carried out with high efficiency. Moreover, there is another advantage that the weather resistance can be enhanced. The steel tube according to the present invention and the manufacturing method thereof can be suitably used in all of the technical fields in which a martensitic stainless steel tube having equal chemical composition is treated.

Abstract: Disclosed is a steel sheet including 0.10 to 0.20 mass % of C, 0.8 to 2.5 mass % of Si, 1.5 to 2.5 mass % of Mn, and 0.01 to 0.10 mass % of Al, wherein P is limited to less than 0.1 mass %, and S is limited to less than 0.002 mass % and more than 0 mass %, and the structure includes bainitic ferrite and residual austenite such that area percentage of the bainitic ferrite in relation to the entire structure is at least 70%, area percentage of the residual austenite is 2 to 20%, and total area percentage of polygonal ferrite and quasi-polygonal ferrite is up to 15%, and proportion of the residual austenite having an average particle size of up to 5 ?m in the residual austenite is at least 60%. The steel sheet is a TRIP steel sheet which has bainitic ferrite as its matrix, and it has a tensile strength (TS) of at least 980 MPa as well as an excellent stretch flangeability.

Abstract: A common-rail injection system is provided for a diesel engine and has excellent internal pressure fatigue resisting characteristics, vibrational fatigue resisting characteristics and cavitation resisting property and sheet face flawing resisting property, and can be made thin and light in weight. A main pipe rail is manufactured by transformation induced plastic type strength steel. After the main pipe rail is processed, residual austenite is generated by heat treatment, and the reduction processing of stress concentration of a branch hole and a main pipe rail side flow passage crossing portion is performed. Further, it is preferable that an induced plastic transformation is generated on the inner surface of the main pipe rail by autofrettage processing, and compression residual stress is left.

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.

Abstract: The invention provides a high tensile strength steel material having a tensile strength of 600 MPa, which is excellent in delayed fracture resistance property, and a method of manufacturing the steel material. As means for this, a steel material contains, in mass percent, C of 0.02 to 0.25%, Si of 0.01 to 0.8%, Mn of 0.5 to 2.0%, Al of 0.005 to 0.1%, N of 0.0005 to 0.008%, P of 0.03% or less, and S of 0.03% or less. In addition, the steel material contains at least one element selected from Mo, Nb, V, and Ti, and contains at least one of Cu, Ni, Cr, W, B, Ca, REM and Mg, as needed. The remainder includes Fe and inevitable impurities. In addition, in the steel material, precipitates having an average grain size of 20 nm or less, which contains at least one of Mo, Nb, V and Ti, are contained in steel in the number of at least 5 per 250000 nm2, and a microstructure includes residual austenite in a volume fraction of 0.5 to 5%. When Ca to be added is specified to be 0.0010% to 0.

Abstract: A link has link connecting bores (15) and (16) at both ends thereof and a wear rail (13) disposed between the upper portions of the link connecting bores (15) and (16). Portions near the ends of the wear rail (13) are designed to have a hardness smaller than that of a center portion of the wear rail. Accordingly, the portions near the ends of the wear rail can be abraded more easily than the center portion of the wear rail. Since the portions near the ends of the wear rail, in which the portions are easily abraded, are positioned closer to the link connecting bores, abrasion loss in use is smaller than that of the center portion owing to its structure. So, the difference in abrasion amount makes it possible to lower a level irregularity of the wear rail.

Abstract: A rocker arm 1 made of sheet metal is formed so that Vickers hardness Hv of the surface layer portion 9a of the valve stem receiver 9 is set at Hv 650 to 800 and a quantity of the retained austenite ?R is set at 25 to 35 vol %.

Abstract: A high strength steel sheet having (2-1) a base phase structure, the base phase structure being tempered martensite or tempered bainite and accounting for 50% or more in terms of a space factor relative to the whole structure, or the base phase structure comprising tempered martensite or tempered bainite which accounts for 15% or more in terms of a space factor relative to the whole structure and further comprising ferrite, the tempered martensite or the tempered bainite having a hardness which satisfies the relation of Vickers hardness (Hv)?500[C]+30[Si]+3[Mn]+50 where [ ] represents the content (mass %) of each element, and (2-2) a second phase structure comprising retained austenite which accounts for 3 to 30% in terms of a space factor relative to the whole structure and optionally further comprising bainite and/or martensite, the retained austenite having a C concentration (C?R) of 0.8% or more.

Abstract: The high-strength race of the present invention comprises using A steel for a high-strength race comprising the following elements in percentage by weight: C: 0.30 to 0.60%, Si: 0.30 to 1.30%, Mn: 0.5 to 1.5%, B: 0.0050% or less, Cr: 0.1 to 0.5%, Mo: 0.1 to 0.5%, Si+Mo: 0.5 to 1.4%, Ni: 0.02 to 1.0%, the balance of Fe and unavoidable impurities, performing induction hardening to make the race have a surface hardness of 58 HRC or more and further a surface hardness of 52 HRC or more even after the surface is tempered at 300° C. The high-strength race is superior in rotating fatigue properties, anti-surface fatigue strength and productivity by a combination of composition control and induction hardening.

Abstract: A machinable austempered cast iron article has improved strength, machinability, fatigue performance, and resistance to environmental cracking. A method of making the machinable austempered cast iron article includes austenitizing an iron composition having a substantially pearlitic microstructure in an intercritical temperature range of between 1380° F. and 1500° F. This produces a ferritic plus austenitic microstructure. The ferritic plus austenitic microstructure is quenched into an austempering temperature range of between 575° F. and 750° F. within 3 minutes to prevent formation of pearlite. The ferritic plus austenitic microstructure is then austempered in the austempering temperature range of between 575° F. and 750° F. to produce a microstructure of a continuous matrix of equiaxed ferrite with islands of austenite. Finally, the microstructure of the continuous matrix of equiaxed ferrite with islands of austenite is cooled to ambient temperature to produce the machinable austempered cast iron article.

Abstract: A process for producing a component of metal includes a) carrying out a heat treatment to harden the component, which ends with a heating process, especially with a tempering or microstructural transformation process, at a given temperature (TE); b) carrying out at least machining of the component at room temperature (TU) in order to provide its desired geometrical shape; and c) subsequent heating of the component to a temperature (T) which is greater than room temperature (TU).

Abstract: A high-strength steel sheet comprises carbon: 0.06 to 0.25 mass %, Si: 0.5 to 3.5 mass % and Mn: 0.7 to 4 mass %. Its mother structure is ferrite, its second phase structure comprises martensite and the residual austenite and the second phase structure measured by image analysis has an area fraction of 25% or less based on the total structure. The steel sheet satisfies the following requirements (1) to (3): (1) the volume fraction (Vt?hd R) of the residual austenite is 5% or more; (2) the ratio (SF?R/Vt?R) of the area fraction (SF?R) of the residual austenite within ferrite to Vt?R is 0.65 or more; and (3) the ratio [?2/(?1+?R)] of the space factor (?2) of martensite to the second phase structure (?1+?R) is 0.25 to 0.60. The steel sheet has excellent balance between strength and local elongation, and a low yield ratio.

Abstract: A steel material and a steel pipe made by using the same are provided which are to be used in severe oil well environments. Such a highly tough oil well steel pipe can be produced by rolling the base material, quenching the rolling product from the austenite region and tempering the same so that the relationship between the content of Mo [Mo] in the carbides precipitated at austenite grain boundaries and the austenite grain size (according to ASTM E 112) can be defined by the formula (a) given below. In this manner, steel pipes suited for use even under oil well environments becoming more and more severe can be produced while satisfying the requirements that the cost should be rationalized, the productivity improved and energy saved.

Abstract: The method and apparatus for enhancing the metallurgical quality of products treated in a furnace with several zones, wherein the temperature and the atmospheric conditions can be controlled. The applies to any type of product treated in a furnace, such as billets, blooms, slugs or slabs. Alternatively, this may be used by iron and steel manufacturers in the production line for sheets, plates, tubes, etc.

Abstract: A steel to be air-hardened as part of heat treatments such as hardening-and-tempering, induction hardening, carburizing, carbonitriding or nitriding comprising, in weight %: C 0.10-0.55; Si 0.97-2.03; Mn 1.14-1.83; Cr 0.00-1.65; Mo 0.36-0.58; and the balance Fe + impurities.

Abstract: An iron based, fine-grained, martensitic stainless steel essentially free of delta ferrite has a nominal composition of (wt. %): 0.05<C<0.15; 7.5<Cr<15; 2<Ni<5; Co<4; Cu<1.2; Mn<5; Si<1; (Mo+W)<4; 0.01<Ti<0.75; 0.135<(1.17Ti+0.6Zr+0.31Ta+0.31Hf)<1; V<2; Nb<1; N<0.02; Al<0.2; Al and Si both present such that (Al+Si)>0.01; B<0.1; P<0.1; S<0.03; and the balance essentially iron and impurities. This steel is different from other martensitic stainless steels because thermal mechanical treatment is used to refine the grains and precipitate a relatively uniform dispersion of fine, coarsening-resistant, MX-type particles. The steel combines high strength and impact toughness with good corrosion resistance.

Abstract: Martensitic stainless steel whose steel composition is restricted within a specific range for each element is provided. The scale layer formed on the surface of the base material consists of an inner layer scale mainly including FeCr2O4 and an outer layer scale having a thickness of not more than 20 ?m, which outer layer is deposited on the inner layer scale at a surface coverage of not less than 1% and not more than 15%. The application of rust preventive oil onto the surface of the steel ensures an excellent weather resistance during a long term, and therefore a martensitic stainless steel forming no rust either in the outdoor depository or in the indoor depository can be provided. The steel can be used to manufacture, not only steel pipes, but also steel plates, steel rods and others in a wide application field.

Abstract: An iron based, fine-grained, alloy.

Abstract: In order to manufacture a steel pipe for an air bag which can cope with increase in the pressure of gas blown into an air bag and decreases in the wall thickness of an accumulator, a steel having a composition, mass %, of: C: 0.05-0.20%, Si: 0.1-1.0%, Mn: 0.20-2.0%, P: at most 0.025%, S: at most 0.010%, Cr: 0.05-1.0%, Al: at most 0.10%, if necessary at least one of Mo: at most 0.50%, Ni: at most 1.5%, Cu: at most 0.5%, V: at most 0.2%, Ti: at most 0.1%, Nb: at most 0.1%, and B: at most 0.005%, and also if necessary, at least one of Ca: at most 0.01%, Mg: at most 0.01%, and REM (rare earth elements): at most 0.01%, and a remainder of Fe and impurities is used to produce a steel pipe, and the pipe is then subjected to cold working to predetermined dimensions, then to heating to a temperature of at least the Ac1 transformation temperature followed by quenching, and then to tempering at a temperature no higher than the Ac1 transformation temperature.

Abstract: A method of austempering of steel parts is described. The steel parts are initially austenitized and subsequently quenched to a start temperature which is higher than the martensite start temperature. Then the steel parts are subjected to a first isothermal holding at the start temperature for a first time period. Subsequently the steel parts are held for a second isothermal time period at a finish temperature which is higher than the start temperature. The method described is particularly well suited for rapid austempering of steel parts, a pure bainitic structure being achievable, and the core hardness of the steel parts obtained being settable via the start temperature, the finish temperature, the duration of the first time period, and the duration of the second time period.

Abstract: The present invention relates to a low alloy, low to medium carbon content, high strength, and high ductility steel composition. The present invention contains relatively low nickel content, yet exhibits high performance characteristics and is manufactured at a substantially lower cost than alloy compositions containing high levels of nickel.

Abstract: A heat resistant carburized rolling bearing component is formed of a steel material at least containing, as alloy elements in a matrix, by mass %, at least 0.1% and at most 0.4% of C, at least 0.3% and at most 3.0% of Si, at least 0.2% and at most 2.0% of Mn, at most 0.03% of P, at most 0.03% of S, at least 0.3% and less tan 2.5% of Cr, at least 0.1% and less than 2.0% of Ni, at most 0.050% of Al, at most 0.003% of Ti, at most 0.0015% of O and at most 0.025% of N, and a remaining part of Fe and an unavoidable impurity, and the bearing component is prepared by performing carburizing carbo-nitriding process followed by quenching, and after quenching, tempering at a tempering temperature of at least 200° C. and at most 350° C., and surface hardness after tempering process is at least HRC57.

Abstract: A pushing block for the CVT belt has a hyper-eutectoid structure overall and exhibiting a structure in which spheroidal cementite having an area percentage of 0.4% or more are dispersed in a matrix of a martensite.

Abstract: A method for providing a steel product having a surface hardness of between about 360 Bhn and 420 Bhn is provided. The method includes steps of providing a steel product from a steel product comprising at least about 96 wt. % iron and between about 0.24 wt. % and about 0.30 wt. % carbon, heating the steel product to at least its austentizing temperature, quenching to below its martinsite finish temperature, and tempering the steel product at a temperature of at least about 800° F. Steel products prepared by this method are described.

Abstract: The objective of the present invention is to provide a forging method that improves workability in machining, by turning the metallographical structure of products subject to impact load to a fine ferrite-perlite structure, without adopting the method of quenching and tempering, to obtain, as strength, a yield point (YP value) exceeding that obtained by the method of quenching and tempering, and making the tensile strength (TS) smaller compared with the method of quenching and tempering. A material to be forged has at least one kind of group 5 metal added thereto and is heated to a temperature suitable for hot forging. After forging to prescribed shape, cooling, and holding for a prescribed set time in a furnace at a tempering temperature, the material is further cooled to normal temperature by natural cooling.

Abstract: An iron-based corrosion resistant and wear resistant alloy. The alloy can comprise (in weight percent) 0.005-0.5% boron, 1.2-1.8% carbon, 0.7-1.5% vanadium, 7-11% chromium, 1-3.5% niobium, 6-11% molybdenum, and the balance including iron and incidental impurities. Alternatively, the Nb content can be replaced or combined with Ti, Zr, Hf and/or Ta such that 1%<(Ti+Zr+Nb+Hf+Ta)≦3.5. The alloy has improved hot hardness and high temperature compressive strength and is suitable for use in elevated temperature applications such as in diesel valve seat inserts.

Abstract: There are provided a high-hardness prehardened steel for cold working having excellent machinability containing, by mass, not less than 0.3% but less than 0.5% C, 0.7 to 2.0% Si, and 0.08 to 0.25% S, a die for cold working which is fabricated by cutting this prehardened steel at a cutting speed not less than 50 m/min. This steel is hardened and tempered to have a hardness not less than 50 HRC. Preferably, this steel consists, by mass, not less than 0.3% but less than 0.5% C, 0.7 to 2.0% Si, 0.1 to 2.0% Mn, 0.08 to 0.25% S, 0.5 to 15.0% Cr, at least one selected from the group consisting of W and Mo an amount of which one is not more than 3.5% in total in terms of (Mo+1/2W), not more than 4.0% V, not more than 0.15% N, and the balance Fe and incidental impurities.

Abstract: Method of reheating metallurgical products, in which solid products, especially steel products, are reheated so as to bring them from a temperature substantially below 400° C. to a temperature of at least about 1000° C. by passing them through a furnace having an upstream zone in which the said products are preheated and a downstream zone in which the said products are brought to their final temperature on leaving the furnace, the downstream zone of the furnace being fitted with burners, at least some of which operate with an oxidizer which is air, the smoke (flue gases) generated by these burners flowing as a countercurrent to the products and preheating these products in the upstream preheating zone. According to the invention, at least one burner is placed in the upstream preheating zone of the furnace, this burner being fed with a mixture of oxidizer and fuel, the oxidizer containing more than 21 vol % and preferably more than 30 vol % oxygen.

Abstract: A grinding ball having a 55 to 65 Rockwell C hardened outer shell of tempered martensite is adapted for use in a heavy duty grinding environment by stress relieving to stabilize the ball against break-up and/or spalling.