Abstract: Provided is a tank cooling device that is capable of cooling a tank more quickly. A tank cooling device 4 has a nozzle 40. The nozzle 40 is comprised to supply cooling gas for cooling a tank 100 to an outer surface of the tank 100, with the cooling gas assisted by compressed gas in the nozzle 40. The tank 100 has a tank main body 101 made by using synthetic resin and an end member 102 made by using metal. The nozzle 40 supplies a gas flow to each of the tank main body 101 and the end member 102.

Abstract: A method for forming and treating a steel article of a high strength and ductile alloy. The method includes the steps of providing a starting steel composition for the steel article, preheating the composition, heating the starting material to a peak temperature range in less than forty seconds, holding the heated steel composition at the peak temperature range for between two and sixty seconds, quenching the heated steel composition from the peak temperature range to below 177° C. (350° F.) at a temperature rate reduction of 200 to 3000° C./sec (360 and 5400° F./sec), removing residual quench media from the surface of the quenched steel composition, tempering the quenched steel composition at a temperature of 100 to 704° C. (212 to 1300° F.); and air cooling the tempered steel composition to less than 100° C. (212° F.) to form a steel having desired mechanical properties.

Abstract: A high-strength cold-rolled steel sheet includes, by mass %, C: 0.10% to 0.40%, Mn: 0.5% to 4.0%, Si: 0.005% to 2.5%, Al: 0.005% to 2.5%, Cr: 0% to 1.0%, and a balance of iron and inevitable impurities, in which an amount of P is limited to 0.05% or less, an amount of S is limited to 0.02% or less, an amount of N is limited to 0.006% or less, the microstructure includes 2% to 30% of retained austenite by area percentage, martensite is limited to 20% or less by area percentage in the microstructure, an average particle size of cementite is 0.01 ?m to 1 ?m, and 30% to 100% of the cementite has an aspect ratio of 1 to 3.

Abstract: A method for treating high-strength, low-alloy steel includes controlling material responses, such as the crystal structure of the steel, through various processing steps. More specifically, the method includes cold treating the steel to achieve predictable increases in a minimum ultimate tensile strength or desired changes in the crystal structure of the steel. In one embodiment, cold treating the steel operates to controllably increase the minimum ultimate tensile strength of the steel within increasing a specified maximum ultimate tensile strength of the steel. Stated otherwise, cold treating the steel may reduce or narrow a minimum-to-maximum ultimate tensile strength range such that the minimum ultimate tensile strength is closer to the specified maximum ultimate tensile strength.

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: A high strength steel, including about 0.05 to about 0.25% of C, less than about 0.5% of Si, about 0.5 to about 3.0% of Mn, not more than about 0.06% of P, not more than about 0.01% of S, about 0.50 to about 3.0% of Sol. Al, not more than about 0.02% of N, about 0.1 to about 0.8% of Mo, about 0.02 to about 0.40% of Ti, and the balance of iron and unavoidable impurities, wherein the steel has a structure formed of at least three phases including a bainite phase, and a retained austenite phase in addition to a ferrite phase having a composite carbide containing Ti and Mo dispersed and precipitated therein, wherein the total volume of the ferrite phase and the bainite phase is not smaller than 80%, the volume of the bainite phase is about 5% to about 60%, and the volume of the retained austenite phase is about 3 to about 20%.

Abstract: A high-tensile-strength hot-rolled steel sheet is provided having a composition which contains 0.02 to 0.08% C, 0.01 to 0.10% Nb, 0.001 to 0.05% Ti and Fe and unavoidable impurities as a balance, wherein the steel sheet contains C, Ti and Nb in such a manner that (Ti+(Nb/2))/C<4 is satisfied, and the steel sheet has a structure where a primary phase of the structure at a position 1 mm away from a surface in a sheet thickness direction is one selected from a group consisting of a ferrite phase, tempered martensite and a mixture structure of a ferrite phase and tempered martensite, a primary phase of the structure at a sheet thickness center position is formed of a ferrite phase, and a difference ?V between a structural fraction (volume %) of a secondary phase at the position 1 mm away from the surface in the sheet thickness direction and a structural fraction (volume %) of a secondary phase at the sheet thickness center position is 2% or less.

Abstract: There is provided a rolled steel with excellent toughness, a drawn wire rod prepared by drawing the rolled steel, and a method for manufacturing the same, in which even if a heating step is omitted, the toughness of the steel can be improved by securing a degenerated pearlite structure in an internal structure of the rolled steel by controlling a content of Mn among components and cooling conditions, and then preventing C diffusion. The rolled steel according to the present invention includes C: 0.15˜0.30%, Si: 0.1˜0.2%, Mn: 1.8˜3.0%, P: 0.035% or less, S: 0.040% or less, the remainder Fe, and other inevitable impurites, as a percentage of weight, in which the microstucture of the rolled steel is composed of ferrite and pearlite including cementite with 150 nm or less of thickness.

Abstract: A method continuously creates a bainite structure in a carbon steel, especially a strip steel by austenitizing the carbon steel; introducing the austenitized carbon steel into a bath containing a quenching agent; adjusting the carbon steel to the transformation temperature for bainite and maintaining the transformation temperature for a certain period of time; and then cooling the carbon steel. The carbon steel stays in the bath until a defined percentage of the bainite structure relative to the total structure of the carbon steel has formed. Residues of the quenching agent are removed from the surface of the carbon steel by blowing the same off when the carbon steel is discharged from the bath, and the remaining structure components of the carbon steel are then transformed into bainite in an isothermal tempering station without deflecting the carbon steel at all.

Abstract: The invention relates to a method and equipment for controlling flatness of a stainless steel strip in connection with cooling after annealing in a finishing line.

Abstract: A method for quenching a steel pipe by water cooling from an outer surface thereof, where pipe end portions are not subjected to water cooling, and at least part of a main body other than the pipe end portions is subjected to water cooling. A region(s) that is not subjected to direct water cooling over an entire circumference thereof can be along an axial direction at least in part of the main body other than the pipe end portions. The start and stop of water cooling can be intermittent at least in part of the quenching. During the water cooling of the pipe outer surface, an intensified water cooling can be performed in a temperature range in which the pipe outer surface temperature is higher than Ms point. Thereafter, the cooling can be switched to moderate cooling so that the outer surface is cooled down to Ms point or lower.

Abstract: A steel sheet contains, on a mass percent basis, 0.03%-0.12% C, 0.5% or less Si, 0.8%-1.8% Mn, 0.030% or less P, 0.01% or less S, 0.005%-0.1% Al, 0.01% or less N, 0.035%-0.100% Ti, and the balance being Fe and incidental impurities and has microstructures with a fraction of polygonal ferrite of 80% or more, the polygonal ferrite having an average grain size of 5 to 10 ?m. The amount of Ti present in a precipitate having a size of less than 20 nm is 70% or more of the value of Ti* calculated using expression (1): Ti*=[Ti]?48×[N]/14??(1) where [Ti] and [N] represent a Ti content (percent by mass) and a N content percent by mass), respectively, of the steel sheet.

Abstract: The microstructure of a low alloy steel workpiece for cold forming may be beneficially modified by heating the workpiece to a temperature just above its austenite transformation temperature (Ac3 temperature). The steel workpiece is then cooled just below its Ac3 temperature to promote ferrite formation on and between the austenite grains. Heating and cooling, above and below the Ac3 temperature, is repeated a determined number of times to refine the austenite grains before the workpiece is quenched below its martensite transformation temperature to form a mixture of martensite with increased retained austenite. The workpiece may be further heated in its martensite region to increase the proportion of retained austenite before quenching the steel workpiece to an ambient temperature. The formability of the workpiece is improved, as is the strength of its formed shape.

Abstract: Embodiments of the present disclosure comprise carbon steels and methods of manufacture. In one embodiment, a double austenizing procedure is disclosed in which a selected steel composition is formed and subjected to heat treatment to refine the steel microstructure. In one embodiment, the heat treatment may comprise austenizing and quenching the formed steel composition a selected number of times (e.g., 2) prior to tempering. In another embodiment, the heat treatment may comprise subjecting the formed steel composition to austenizing, quenching, and tempering a selected number of times (e.g., 2). Steel products formed from embodiments of the steel composition in this manner (e.g., seamless tubular bars and pipes) will possess high yield strength, at least about 175 ksi (about 1200 MPa) while maintaining good toughness.

Abstract: A cooling device and a cooling method for a hot strip allow uniform and stable cooling of the strip at a high cooling rate when supplying the coolant to the upper surface of the hot strip. The cooling device includes an upper header unit 21 for supplying a rod-like flow to the upper surface of the strip 10. The upper header unit 21 is formed of the first upper header group including plural first upper headers 21a arranged in a conveying direction and a second upper header group including plural second upper headers 21b arranged in the conveying direction. The cooling device is provided with an ON-OFF mechanism 30 to allow each of the upper headers 21a and 21b of the first and the second upper header groups to independently execute the ON-OFF control (start/end injection control) of an injection (feeding) of the rod-like flow.

Abstract: One or more embodiments relates to a high-temperature, titanium alloyed, 9 Cr-1 Mo steel exhibiting improved creep strength and oxidation resistance at service temperatures up to 650° C. The 9 Cr-1 Mo steel has a tempered martensite microstructure and is comprised of both large (0.5-3 ?m) primary titanium carbides and small (5-50 nm) secondary titanium carbides in a ratio of. from about 1:1.5 to about 1.5:1. The 9 Cr-1 Mo steel may be fabricated using exemplary austenizing, rapid cooling, and tempering steps without subsequent hot working requirements. The 9 Cr-1 Mo steel exhibits improvements in total mass gain, yield strength, and time-to-rupture over ASTM P91 and ASTM P92 at the temperature and time conditions examined.

Abstract: A transformation toughened, high-strength steel alloy useful in plate steel applications achieves extreme fracture toughness (Cv > 80 ft-lbs corresponding to KId=200 ksi.in ½) 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: A cooling method of steel plate able to raise a cooling uniformity in a steel plate conveyance direction comprising, at a front stage part of a cooling apparatus, not spraying while a front end region of steel plate is passing, spraying by successively increasing the cooling water rate from 80 to 95 vol % (Qfront) of a standard water density when the front part region passes so that the amount of cooling water becomes the standard water density when a boundary part of the front part region and a center part region arrives, and continuing spraying by the standard water density while the center part region is passing, then, at a rear stage part of the cooling apparatus, spraying by making the amount of cooling water 80 to 95 vol % of the standard water density while the front end region of the steel plate is passing, successively increasing the amount of cooling water rate from 80 to 95 vol % of the standard water density when the front part region passes so that the amount of cooling water becomes the standard

Abstract: The present invention provides a high strength steel sheet with 780 MPa class tensile strength excellent in bending workability and fatigue strength. The high strength steel sheet is (1) a steel sheet whose steel composition contains: C: 0.05-0.20%; Si: 0.6-2.0%; Mn: 1.6-3.0%; P: 0.05% or below; S: 0.01% or below; Al: 0.1% or below; and N: 0.01% or below, the balance comprising iron and inevitable impurities, in which (2) a microstructure comprises a polygonal ferrite structure and a structure formed by low-temperature transformation, in which, when a sheet plane located at a depth of 0.1 mm from a surface of the steel sheet is in the observation under a scanning electron microscope with respect to twenty sights in total in different positions in the sheet-width direction, the maximum value of the areal proportion of the polygonal ferrite (Fmax) and the minimum value of the areal proportion of the ferrite (Fmin) in a 50 ?m×50 ?m area in each sight satisfy Fmax?80%, Fmin?10%, and Fmax?Fmin?40%.

Abstract: The invention relates to a composition and heat treatment for a high-temperature, titanium alloyed, 9 Cr-1 Mo steel exhibiting improved creep strength and oxidation resistance at service temperatures up to 650° C. The novel combination of composition and heat treatment produces a heat treated material containing both large primary titanium carbides and small secondary titanium carbides. The primary titanium carbides contribute to creep strength while the secondary titanium carbides act to maintain a higher level of chromium in the finished steel for increased oxidation resistance, and strengthen the steel by impeding the movement of dislocations through the crystal structure. The heat treated material provides improved performance at comparable cost to commonly used high-temperature steels such as ASTM P91 and ASTM P92, and requires heat treatment consisting solely of austenization, rapid cooling, tempering, and final cooling, avoiding the need for any hot-working in the austenite temperature range.

Abstract: A method for heat treatment of steel and a system thereof is provided. First the steel is austenitized at a suitable temperature and then the temperature is rapidly brought down to the austempering temperature. Here the cyclic austempering is carried out between two austempering temperatures by modulating the temperature with controlled heating and cooling and the controlled temperature modulation is obtained by controlling the temperature-time profile in a batch furnace or by controlling the zone temperatures in a continuous furnace. This method of cyclic austempering reduces the austempering time, reduces the energy consumption and emissions, enhances the productivity and reduces the process cost.

Abstract: A method for the production of steels is provided. A heat treatment is carried out, in which the steel is hardened in water twice at different high temperatures, and subsequently subjected to an annealing treatment. It has been shown that the steel 26NiCrMoV14-5 has a high subzero toughness. In one aspect, the steel is usable down to a temperature of at least minus 170° C.

Abstract: A martensitic stainless steel pipe, which comprises specified quantities of C, Si, Mn, P, S, Cr, Ni, Al, N, Cu, Ti, V, Mo, Nb, B and Ca, and the balance being Fe and impurities, has satisfactory toughness at a high strength of 650 MPa or more by yield strength and also excellent hot workability. Therefore, it can be used as a high-strength martensitic stainless steel pipe for carbon dioxide gas corrosion resistant use, to be used in oil and/or gas well environments containing no hydrogen sulfide but carbon dioxide gas. This high-strength martensitic stainless steel pipe is an inexpensive martensitic stainless steel pipe, which does not require an addition of large quantities of expensive elements such as Ni and Mo, and moreover does not require the control of the content of P to a value less than 0.010% by mass.

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: A method continuously creates a bainite structure in a carbon steel, especially a strip steel by austenitizing the carbon steel; introducing the austenitized carbon steel into a bath containing a quenching agent; adjusting the carbon steel to the transformation temperature for bainite and maintaining the transformation temperature for a certain period of time; and then cooling the carbon steel. The carbon steel stays in the bath until a defined percentage of the bainite structure relative to the total structure of the carbon steel has formed. Residues of the quenching agent are removed from the surface of the carbon steel by blowing the same off when the carbon steel is discharged from the bath, and the remaining structure components of the carbon steel are then transformed into bainite in an isothermal tempering station without deflecting the carbon steel at all.

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

Abstract: A method for treating high-strength, low-alloy steel includes controlling material responses, such as the crystal structure of the steel, through various processing steps. More specifically, the method includes cold treating the steel to achieve predictable increases in a minimum ultimate tensile strength or desired changes in the crystal structure of the steel. In one embodiment, cold treating the steel operates to controllably increase the minimum ultimate tensile strength of the steel within increasing a specified maximum ultimate tensile strength of the steel. Stated otherwise, cold treating the steel may reduce or narrow a minimum-to-maximum ultimate tensile strength range such that the minimum ultimate tensile strength is closer to the specified maximum ultimate tensile strength.

Abstract: This invention provides a high-strength hot-rolled steel sheet having strength of at least 980 N/mm2 at a sheet thickness of from about 1.0 to about 6.0 mm and excellent in hole expandability, ductility and ability of phosphate coating, which steel sheet is directed to automotive suspension components that are subjected to pressing. The high-strength hot-rolled steel sheet contains, in terms of a mass %, C: 0.01 to 0.09%, Si: 0.05 to 1.5%, Mn: 0.5 to 3.2%, Al: 0.003 to 1.5%, P: 0.03% or below, S: 0.005% or below, Ti: 0.10 to 0.25%, Nb: 0.01 to 0.05% and the balance consisting of iron and unavoidable impurities; satisfies all of the following formulas <1> to <3>: 0.9?48/12×C/Ti<1.7??<1> 50,227×C?4,479×Mn>?9,860??<2> 811×C+135×Mn+602×Ti+794×Nb>465??<3>, and has strength of at least 980 N/mm2.

Abstract: A method of cooling both surfaces of steel plate, which stably secures precision of cooling control from a start of cooling to an end so as to uniformly cool the top and bottom surfaces of the steel plate and thereby stably secures the steel plate quality and cools the steel plate down to a target temperature with a good precision. The method comprises dividing a steel plate cooling region into at least a spray impact part region and a spray non-impact part region, predicting a heat transfer coefficient for each divided region in advance, computing a predicted temperature history of the steel plate based on this predicted value, and setting and controlling amounts of sprayed coolant on the spray impact part regions by top and bottom surface nozzles.

Abstract: A method for producing a plate of steel which is resistant to abrasion and whose chemical composition includes, by weight: 0.24%?C<0.35%; 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%; 0.1%?Mo+W/2?1%; 0%?B?0.02%; 0%?Ti?1.1%; 0%?Zr?2.2%; 0.35%<Ti+Zr/2?1.1%; 0%?S?0.15%; N<0.03%, optionally up to 1.5% of copper; optionally at least one element selected from Nb, Ta and V at contents such that Nb/2 +Ta/4+V?0.5%; optionally at least one element selected from among Se, Te, Ca, Bi, Pb at contents which are less than or equal to 0.1%; and the balance being iron and impurities resulting from the production operation. The chemical composition further complying with the following relationships: C*=C?Ti/4?Zr/8+7×N/8?0.095% 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%.

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: 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: The invention concerns a method for making an abrasion-resistant steel part consisting of 0.1%?C?0.23%; 0%?Si?2%; 0%?AI?2%; 0.5%?Si+AI?2%; 0%?Mn?2.5%; 0%?Ni?5%; 0%?Cr?5%; 0%?Mo?1%; 0%?W?2%; 0.05%?Mo+W/2?1%; 0%?B?0.02%; 0%?Ti?0.67%; 0%?Zr?1.34%; 0.05%?Ti+Zr/2?0.67%; 0%?S?0.15%; N<0.030, 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 and 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+0.5O×Cr+0.3×(Mo++W1/2)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 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<150×ep?1.7 between T and 100° C., (ep=thickness of plate in mm); cooling down to room temperature and optionally planishing. The invention also concerns the resulting plate.

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%?AI?2%; 0.35%?Si+AI?2%; 0%?Mn?2.5%; 0%?Ni?5%; 0% ?Cr?5%; 0%?Mo?0.050; 0%?W?1%; 0,1%?Mo+W/2?0.5%; 0%?B?0.02%; 0%?Ti?2%; 0%?Zr?4%; 0.05%?Ti+Zr/2?2%; 0%?S?0.15%; N?0,03; optionally 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+0.5O×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*?9O×Mn?37×Ni?70×Cr?83×(Mo+W/2) and T?50° C.; then at a core speed Vr<1150×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.

Abstract: A method for the heat treatment of workpieces made of steel or cast iron involves quenching the workpiece to a temperature above the martensite starting temperature (i.e., the temperature below which martensite is formed) after a holding period at or above the austenitizing temperature. In the ensuing time period, austenite is transformed into bainite. The temperature of the workpiece is reduced during the time period when transformation occurs and the transformation of austenite into bainite is thus continued.

Abstract: The high carbon steel wire rod contains 0.65% to 1.20% of C, 0.05% to 1.2% of Si, 0.2% to 1.0% of Mn, and 0.35% or less (including 0%) of Cr, further contains P and S each in an amount restricted to 0.02% or less, where 80% or more of the metal structure is constituted by a pearlite structure; and an average tensile strength TS and an average lamellar spacing ? of the high carbon steel wire rod show the relation of TS?8700/?{square root over ( )}(?/Ceq)+290 in which Ceq=% C+% Mn/5+% Cr/4. The high carbon steel wire rod can omit a patenting treatment before or during wire drawing, is superior in wire drawability, and exhibits a low drawing resistance in a wire drawing die in an as-hot-rolled state.

Abstract: A carbon steel alloy that exhibits the combined properties of high strength, ductility, and corrosion resistance is one whose microstructure contains ferrite regions combined with martensite-austenite regions, with carbide precipitates dispersed in the ferrite regions but without carbide precipitates are any of the interfaces between different phases. The microstructure thus contains of four distinct phases: (1) martensite laths separated by (2) thin films of retained austenite, plus (3) ferrite regions containing (4) carbide precipitates. In certain embodiments, the microstructure further contains carbide-free ferrite regions.

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 method of post-solidification processing to minimize the content of extremely coarse grain-refining precipitates that may form during solidification is low-alloy and alloy high-strength steels containing approximately 0.09-0.17% by weight C so as to provide improved toughness in a wrought and heat-treated product. The method entails cooling an as-cast steel at a reduced rate in a furnace held at a temperature in excess of the equilibrium solution temperature for AlN in austenite. The steel is maintained at this temperature for a sufficient amount of time to effect the dissolution of coarse AlN precipitates in the microstructure, and the so-treated steel is then cooled at any desired rate to room temperature or to a hot-rolling temperature.

Abstract: The invention concerns a method for making a multiphase hot-rolled steel strip comprising an ultra-fast cooling operations, which consists in carrying out said ultra-fast cooling operation after controlled slow cooling of the strip on a conventional slow cooling table of the rolling mill. The controlled cooling constitutes a first slow cooling, at the output of the finishing mill, from an end-of-roll temperature to an intermediate temperature of about 750° C. to 500° C.; said first cooling determines the fraction of the first phase (ferrite) in the steel. The ultra-fast cooling (>150° C./s), which solidifies the resulting structure, lowers the temperature of the strip down to a coiling temperature, ranging between about 600° C. and room temperature, at which a second slow cooling is performed which results if the formation of the second phase (bainite or martensite).

Abstract: The invention relates to a method for producing especially shape-rolled products from rail steels that have a finely perlitic and/or ferritic/perlitic structure after cooling. The inventive method is characterized by guiding the workpiece through a cooling stretch that is composed of individual independent cooling modules (2a-e) having independently adjustable cooling parameters.

Abstract: Carbon steels of high performance are disclosed that contain a three-phase microstructure consisting of grains of ferrite fused with grains that contain dislocated lath structures in which laths of martensite alternate with thin films of austenite. The microstructure can be formed by a unique method of austenization followed by multi-phase cooling in a manner that avoids bainite and pearlite formation and precipitation at phase interfaces. The desired microstructure can be obtained by casting, heat treatment, on-line rolling, forging, and other common metallurgical processing procedures, and yields superior combinations of mechanical and corrosion properties.

Abstract: The present invention aims to produce a cold rolled metal coated multi-phase steel, characterized by a tensile strength of at least 500 MPa, a yield ratio (Re/Rm) lower than 0.65 in skinned conditions, lower than 0.60 in unskinned conditions, and with good metal coating adhesion behavior. In the case of the aluminized steel according to the invention, the steel also has superior resistance to temperature corrosion up to 900° C. and excellent mechanical properties at this high temperature. The hot metal coated steel product having a steel composition with a manganese content lower than 1.5%, chrome content between 0.2 and 0.5%, molybdenum content between 0.1 and 0.25%, and a relation between the chrome and molybdenum content as follows Cr+2 Mo higher than or equal to 0.7%, undergoes a thermal treatment in the hot dip metal coating line defined by a soaking temperature between Ac1 and Ac3, a primary cooling speed higher than 25° C./sec and a secondary cooling speed higher than 4° C./sec.

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.

Abstract: The invention concerns a method for making a multiphase hot-rolled steel strip comprising an ultra-fast cooling operations, which consists in carrying out said ultra-fast cooling operation after controlled slow cooling of the strip on a conventional slow cooling table of the rolling mill. The controlled cooling constitutes a first slow cooling, at the output of the finishing mill, from an end-of-roll temperature to an intermediate temperature of about 750° C. to 500° C.; said first cooling determines the fraction of the first phase (ferrite) in the steel. The ultra-fast cooling (>150° C./s), which solidifies the resulting structure, lowers the temperature of the strip down to a coiling temperature, ranging between about 600° C. and room temperature, at which a second slow cooling is performed which results if the formation of the second phase (bainite or martensite).

Abstract: A low-alloy heat-resistant steel may be used to manufacturing a large element which has uniform superior high temperature properties through a surface layer to a center part. The low-alloy heat-resistant steel comprises carbon in an amount of 0.20 to 0.35% by weight, silicon in an amount of 0.005 to 0.35% by weight, manganese in an amount of 0.05 to 1.0% by weight, nickel in an amount of 0.05 to 0.3% by weight, chromium in an amount of 0.8 to 2.5% by weight, molybdenum in an amount of 0.1 to 1.5% by weight, tungsten in an amount of 0.1 to 2.5% by weight, vanadium in an amount of 0.05 to 0.3% by weight, phosphorus in an amount not greater than 0.012% by weight, sulfur in an amount not greater than 0.005% by weight, copper in an amount not greater than 0.10% by weight, aluminum in an amount not greater than 0.01% by weight, arsenic in an amount not greater than 0.01% by weight, tin in an amount not greater than 0.01% by weight, antimony in an amount not greater than 0.

Abstract: A method for cooling hot reduced iron briquettes at low cost without degrading the strength is provided. The method includes a primary cooling step of cooling the hot reduced iron briquettes by steam at a cooling rate of 4.0° C./s or less, a secondary cooling step of cooling the reduced iron briquettes by steam and sprayed water at a cooling rate of 4.0° C./s or less, and a final cooling step of cooling the reduced iron briquettes by sprayed water at a cooling rate of 3.5° C./s or more to a temperature in a final product temperature range. The steam generated by evaporation of sprayed water during the final cooling step is used in the primary and/or secondary cooling step.

Abstract: A steel sheet having a composition comprising C: 0.05-0.20 mass %, Si: 0.3-1.8 mass %, Mn: 1.0-3.0 mass %, Fe of the balance and inevitable impurities is subjected to a primary step of primary heat treatment and subsequent rapid cooling to Ms point or lower, a secondary step of secondary heat treatment and subsequent rapid cooling, and a tertiary step of galvanizing treatment and rapid cooling, so as to turn the structure of the steel sheet into a composite structure of 20% or more by volume of tempered martensite, 2% or more by volume of retained austenite, ferrite and a low-temperature transformation phase. A galvanized layer is deposited on the surface of the steel sheet. It is preferred to cool the steel sheet to 300° C. at a cooling rate of 5 ° C./sec. or more after the galvanizing treatment. After the galvanizing treatment, alloying treatment may be conducted.

Abstract: Large sections of solution annealed, precipitation hardenable alloys which are resistant to internal cracking yet fully hardenable can be produced if, during rapid quenching, the temperature of the section is allowed to stabilize immediately above the alloy's solvus temperature before the section is rapidly quenched. Preferably, the temperature of the section is allowed to stabilize a second time, this time at an elevated temperature not so high that significant phase changes occur, before the section is cooled to ambient.

Abstract: In a heat treatment method for producing boundary layer-hardened long products and flat products of unalloyed or low-alloy steel, the workpiece is cooled for producing a martensitic grain within a boundary layer of the workpiece by repeating several sequential cooling process steps. Each sequential cooling process step has a cooling phase, in which the workpiece is cooled to a temperature below a martensite starting temperature for martensitic conversion of only a portion of the boundary layer of the workpiece, and a temporal stress-relief phase for relieving stress within already formed martensitic grain areas and already formed martensite/austenite boundary areas. Subsequently, the workpiece is cooled at a cooling rate below a lower critical cooling rate for cooling the workpiece core.