Abstract: A vehicle underbody assembly may include a pair of front rails, a pair of hinge pillars, a pair of crush cans, a pair of bumper supports, and a bumper. Each of the front rails includes a front portion, a mid-portion, and a backup portion. Each of the hinge pillars may be attached to one of the backup portions. Each of the crush cans may be attached to one of the front portions. Each of bumper supports may be secured to one of the crush cans. The bumper may be attached to the bumper supports. The front portions and the backup portions may be heat treated to have a higher strength than the mid-portions. Each of the front portions and the backup portions may be heated to define a hard strength zone and the mid-portion may be heated to define a medium strength zone.

Abstract: A hot forming tool includes a top tool and a bottom tool, both of which can be moved towards each other. When the hot forming tool is closed, a mold cavity is formed between the top tool and the bottom tool, with the top tool and/or the bottom tool being divided into at least two segments. The hot forming tool has one segment designed as a heating segment. The heating segment includes a compensating element on a side thereof opposite the mold cavity, to compensate for a thermal expansion of the heating segment in the press stroke direction.

Abstract: A cast component includes a cast body that has a single crystal microstructure and an internal corner bounding an internal cavity. The single crystal microstructure defines a critical internal residual stress with respect to investment casting of the cast body using a refractory metal core beyond which the single crystal microstructure recrystallizes under a predetermined condition. The internal corner has a corner radius that is greater than a critical corner radius below which an amount of internal residual stress in the single crystal microstructure exceeds the critical internal residual stress. The internal cavity includes a cross section less than about 20 mils near the corner radius.

Abstract: In a press-hardening plant, a contact-cooling press (12) is provided between the furnace (11) and the press-hardening press (13). Preselected parts of the blank (18) are contact-cooled such that corresponding parts of the finished product are softer and display a lower yield point.

Abstract: The invention relates to a method for producing partially-hardened components from steel sheets, in which a component that is cold-formed from a hardenable steel sheet material is heated, in a furnace, to a temperature below the austenitisation temperature (<AC3), and a radiating element acts upon the component in sections where said component is to be austenitised (<AC3), this radiating element having a component-side contour that corresponds to the contour of the component in the section to be austenitised. The invention also relates to a device for carrying out said method.

Abstract: The invention relates to a method for manufacturing a ferritic-austenitic stainless steel having good formability, good weldability and high elongation. The stainless steel containing the sum of carbon and nitrogen C+N in the range 0.17-0.295 in weight % in which sum C+N a lower carbon content to avoid sensitisation during welding is compensated by an increased nitrogen content to maintain formability is heat treated so that the microstructure of the stainless steel contains 45-75% austenite in the heat treated condition, the remaining microstructure being ferrite, and the measured Md30 temperature of the stainless steel is adjusted between 0 and 50° C. in order to utilize the transformation induced plasticity (TRIP) for improving the formability of the stainless steel.

Abstract: A continuous heat treatment furnace is provided in which an atmosphere-control gas is introduced to a heating chamber having a heating zone, metal tubes are continuously charged along an axial direction from a furnace entrance, and the metal tube subjected to a heat treatment is taken out from a furnace. The continuous heat treatment furnace includes a front chamber which has a preheating zone on an entrance side of the heating chamber and seal curtains which are located on an entrance side and an exit side of the front chamber.

Abstract: A bearing component formed from a bearing steel, wherein the component has an outer surface and comprises through-hardened bainite and/or martensite and has a substantially homogeneous chemical composition, at least a part of the bearing component having a compressive residual stress profile comprising ?25 to ?1000 MPa at the near surface, wherein the near surface is defined as a region 500 microns or less below the outer surface.

Abstract: Improved induction heating methods are presented for induction hardening undercut fillets of crankshafts or other workpiece recesses or undercuts in which an active turn is energized to induce current in a passive turn translated toward a workpiece undercut for heating the undercut.

Abstract: A process is provided for producing a rotor which is made by welding together disk-shaped and/or drum-shaped elements, in particular disks, wherein a device is used to join the disks together axially in sequence along a longitudinal axis and the disks are welded in a two-stage welding process. As they are joined together, the disks are stacked axially in the vertical direction. A first welding process takes place in a vertical orientation of the stacked disks, followed by a second welding process in a horizontal orientation of the stacked disks.

Abstract: A shaped part with different microstructures is made by continuously conveying a succession of hardenable steel blanks having first and second regions through a furnace such that the blanks reach an outlet of the furnace each with both of the respective first and second regions heated to an austenitization temperature. Then the blanks are positioned with the second regions thereof in a chamber of a holding unit and the first regions outside the chamber, and, while holding the second regions in the chamber and the first regions outside the chamber the second regions are heated and maintained at the austenitization temperature and the first regions are cooled with air to a temperature at which their microstructures become ferritic-pearlitic. Thereafter the blanks are transferred from the holding unit to a press where they are hardened and finish shaped.

Abstract: The present invention provides a method for manufacturing a swash plate type piston pump motor in which: a plurality of pistons are arranged in a circumferential direction on a cylinder block configured to rotate with a rotating shaft; the pistons are guided along a swash plate to reciprocate by rotation of the rotating shaft; a convex portion of the swash plate is slidably supported by a recess of a swash plate support; and a wall formed integrally with the swash plate support is arranged on a normal to at least a part of a supporting surface of the recess, wherein: the supporting surface of the recess is quenched by irradiating the supporting surface with laser light while causing the laser light to scan the supporting surface; and outputs of the laser light are changed in accordance with incidence angles of the laser light with respect to the supporting surface.

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: A system and method for producing locally austempered ductile iron includes a computer program for closely controlling the heating and cooling of an iron part or workpiece. The process allows for the austempering of a relatively low cost iron workpiece to produce significantly higher quality end products. The locally austempered regions may be formed to a substantial controlled depth.

Abstract: The present invention is directed generally to tools that are made, at least in part, more durable, particularly one or more working surface(s) of the tools. For example, various tools such as trowels, knives, and scrappers may be made having at least a portion of their blades heat treated to make at least their working edges more durable and extend their useful lives. For example, in various embodiments, a putty knife, taping knife, or scrapper blade may have at least one working surface or edge that has been at heat treated while an area of the blade where a handle is permanently attached is not heat treated.

Abstract: A structural motor-vehicle element is made by hot-shaping and press-hardening a steel workpiece into the element and thereafter heating the hot-shaped and press-hardened workpiece to between 320° C. and 400° C. The steel workpiece constitutes in weight percent, Carbon (C) 0.18% to 0.3% Silicon (Si) 0.1% to 0.7% Manganese (Mn) 1.0% to 2.5% Phosphorus (P) max. 0.025% Chromium (Cr) up to 0.8% Molybdenum (Mo) up to 0.5% Sulfur (S) max. 0.01% Titanium (Ti) 0.02% to 0.05% Boron (B) 0.002% to 0.005% Aluminum (Al) 0.01% to 0.06% the rest iron including impurities caused by the smelting process.

Abstract: The method for manufacturing a martensitic stainless pipe includes heating the steel pipe until the external surface temperature thereof reaches a predetermined temperature not lower than A3 transformation point+20° C. and not higher than 980° C. The heated steel pipe is first water cooled until the external surface temperature thereof reaches a predetermined temperature not lower than 350° C. The water cooled steel pipe is air cooled until the external surface temperature thereof reaches a predetermined temperature not higher than 250° C. The air cooled steel pipe is either water or air cooled until the external surface temperature thereof reaches normal temperature. The cooling rate of the steel pipe in the first cooling step is determined according to the wall thickness of the steel pipe so that the amount of heat recuperation for the external surface temperature of the steel pipe in the second cooling step is not higher than 50° C.

Abstract: A method for producing a metallic component (B) allows adjoining zones (Z1, Z2, Z3) having differing material properties to be produced in a manner which is simple in terms of production. This is achieved in that a sheet metal element (E) heated to a forming temperature is shaped in a forming tool (1) into an end-shaped component (B), wherein the forming tool (1) has a temperature adjustment means for adjusting the temperature of at least one of the portions (5, 7, 16) thereof that comes into contact with the sheet metal element (E) during the forming process, and in that the forming speed is controlled in consideration of the time for which the portion (5, 7, 16) of the forming tool (1) that is regulated with regard to the temperature thereof is in contact with the respective region (E1, E2, E3) of the sheet metal element (E) that rests against said portion.

Abstract: A holder having a baseplate with a tang extending rearwardly therefrom, a plurality of openings for receiving fasteners and a plurality of legs extending from the baseplate, the tang being heat treated or work hardened to harden the tang and facilitate its detachment for non-friable substrate applications. Work hardening may be accomplished, for example, by heating and quenching the tang to increase both its hardness and its brittleness to a level that allows the tang to be broken off with an impact force but not when inserted into a friable substrate so that the holder retains greater functionality.

Abstract: To provide a vehicle which can move independently as an own independent vehicle and can run integrally in linkage with another vehicle. A plurality of single-seat vehicles which can move independently are combined and they move integrally while a predetermined formation is maintained through linkage among respective vehicles. One of all the vehicles moving in linkage serves as a host vehicle and an occupant in the host vehicle becomes a driver in the linkage moving. A host vehicle 1 runs with speed/direction according to running operation conducted by an occupant. Simultaneously therewith, the host vehicle 1 instructs following vehicles 2 to 4 to synchronize (follow) the host vehicle. The host vehicle 1 transmits a speed, a direction, and a relative position to the host vehicle to the following vehicles 2 to 4 as moving information in order to synchronize the following vehicles with the host vehicle (maintain linkage relationship).

Abstract: A steel part with regions of different ductility is made by first loading the part onto a heatable rack and then heating the rack with the part on it in a furnace to a temperature above the AC3 point of the part. The part is then removed from the rack and loaded while still above the AC3 point into a press where it is shaped and hardened. In the press the part is engaged by tools that deform it and that cool it quickly to well below the AC3 point. Finally, before the rack has cooled substantially, the shaped and hardened part is taken out of the press and placed on the rack with predetermined regions of the part in heat-conducting engagement with the rack such that the ductility of the predetermined regions is increased by transfer of the residual heat from the rack to the predetermined regions.

Abstract: Provided is a method for heat treating a precipitation-hardened article having a thick section and a thin section so that the thin section can be solution annealed while the metallurgical structure of the thick section is substantially unaffected by the solution-annealing process. The method restores the microstructure of the thin section uniformly by solution annealing the thin section to achieve a preselected microstructure but without affecting the microstructure of the thick section.

Abstract: A hot forged product including hardened areas introduced by partial cooling after hot forging, and unhardened areas, wherein Vickers hardness V1 of the hardened areas on the surface and Vickers hardness V2 of the unhardened areas satisfy the following formula (1): (V1?V2)/V2: 0.1 to 0.8.

Abstract: The present invention is directed generally to tools that are made, at least in part, more durable, particularly one or more working surface(s) of the tools. For example, various tools such as trowels, knives, and scrappers may be made having at least a portion of their blades heat treated to make at least their working edges more durable and extend their useful lives. For example, in one embodiment, a trowel blade may have at least one texturing edge that has been at least partially heat treated.

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 sliding surface 4A of a shoe 4 undergoes laser radiation in a shape of a large number of parallel lines to form a large number of swollen portions 6 and concave portions 7 in adjacent positions thereof. The swollen portions 6 and the inner side thereof become direct-hardened portions 11 with a high hardness and the concave portions 7 and the inner side thereof become double-hardened portions 12, which are lower in hardness than the swollen portions 6. After the laser hardening, the sliding surface 4A undergoes lapping up to a position of an imaginary line 15 to delete the relief and form a flat and smooth plane. Thereafter the sliding surface 4A undergoes buffing so that portions with a low hardness are chipped off more than portions with a high hardness to form a large number of minute irregularities on the sliding surface 4A.

Abstract: A raw steel is coated with or surrounded by a boron compound (step S1). A coating film of h-BN is formed on the surface of the raw steel. Then, the raw steel is nitrided by a nitriding gas while being heated (step S2). B from the boron compound and N from the nitriding gas are diffused into the raw steel, turning the raw steel into a steel material containing B and N. Most of B and N are present as an Fe (B, N) solid solution or an Fe (C, B, N) solid solution in the structure of the steel material. The raw steel is heated and nitrided under conditions such that B and N are contained ranging from 7 to 30 ppm by weight and ranging from 10 to 70 ppm by weight, respectively.

Abstract: An inner ring is configured to simultaneously ensure the strength thereof and the dimensional accuracy of a female spline portion of a shaft hole thereof in the case where the female spline portion is subjected to heat treatment. Also it is configured to suppress the backlash of spline fit with a shaft. The inner ring is mounted in a constant velocity universal joint for transmitting torque while the inner ring is allowed to be angularly displaced relative to an outer ring and is spline-fitted to a shaft inserted into a shaft hole formed through the inner ring. The inner ring has a hardened layer by means of heat treatment which is formed only in an axial central portion of the shaft hole, but is not formed in remaining inner diameter surface other than the axial central portion.

Abstract: The interior of a furnace is partitioned into two longitudinally extending and transversely adjacent zones, and one of the zones is heated to a substantially higher treatment temperature than the other of the zones, which may or may not be heated. A steel workpiece is conveyed longitudinally through the furnace with a region of the workpiece moving exclusively through the one zone and another region of the workpiece moving exclusively through the other of the zones such that the regions are heated to different temperatures. The treatment temperature in one of the zone is above the AC1 point for the workpiece and the temperature in the other of the zones is close to or below the AC1 point for the workpiece.

Abstract: The present invention provides a method for welding and 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 controlling the cooling rate of the seam weld with a secondary heat source, applied after the weld cools below the materials upper critical temperature (AC3), but prior to the weld cooling to ambient temperature. This invention is particularly suited to the production of high strength hardenable alloy seam-welded pipe and tubing.

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: A method is disclosed for rounding and/or flattening an annular part that is out of round and/or not flat due to non-uniform internal stresses. The part is first checked for out of round and/or out of flat conditions. Out of round parts are then rounded by introducing compressive stresses into selected surface sections of the part whereby the introduced compressive stresses cause deformation of the annular part thereby rounding the annular part. Alternatively, out of round parts are rounded by relieving compressive stresses in selected surface sections of the part whereby the relieving of compressive stresses causes deformation of the annular part thereby rounding the annular part. Out of flat parts are flattened by introducing compressive stresses into selected surface sections of the part whereby the introduced compressive stresses cause deformation of the annular part thereby flattening the annular part.

Abstract: The invention relates to a stator for an electric machine, which has a core comprised of laminated sheet metal (1), the pole teeth (2) of each laminated sheet metal (1) of the core being connected to one another via respective webs (3). The laminated metal sheets (1) of the core are made from a two-state steel and, in the area of the pole teeth (2), have a high relative permeability and, in the area of the webs (3), have a section (5, 6, 7) with a low relative permeability.

Abstract: A method for heat treating metallic strips inside a heat treatment chamber at a pressure greater than atmospheric pressure including passing the strips through at least one heating zone of the chamber and moving the strip through at least one cooling zone of the chamber. A first protective gas atmosphere containing nitrogen and hydrogen and/or helium is established in all but at least one cooling zone. The at least one cooling zone has a second protective atmosphere containing nitrogen and a second amount of hydrogen, the second amount of hydrogen is greater than the first amount. Nitrogen is introduced into the chamber, and a protective gas containing a third hydrogen content greater than the second hydrogen content is injected into the cooling zone, producing a gas exchange between one zone of the chamber having the first protective atmosphere and the cooling zone, and controlling the flow of introduction and injection.

Abstract: In a method for the treatment of metallic materials especially for the consolidation of the texture of the materials, a blank of the metallic material is heated to a transformation temperature and the blank is then subjected to twisting preferably while, at the same time, being compressed. In this way, the texture can be refined to a large degree in a simple and inexpensive manner.

Abstract: A workpiece having regions of different ductility is made by first coating opposite faces of a flat sheet-metal workpiece of low ductility and then stripping the coating from the faces in one region of the workpiece while leaving the coating on the faces in another region of the workpiece. The workpiece is then deformed into a three-dimensional profile. Only the one uncoated region of the workpiece is heated and thereby hardened while not significantly heating the other coated region of the workpiece.

Abstract: A variable capacity rotary compressor to prevent an eccentric bush and a locking pin from being deformed or worn out due to a variance in a pressure of a compression chamber as a rotating shaft rotates. The compressor includes upper and lower compression chambers having different interior capacities thereof, and a rotating shaft. Upper and lower eccentric cams are provided on the rotating shaft to be eccentric from the rotating shaft in a common direction. Upper and lower eccentric bushes are fitted over the upper and lower eccentric cams, respectively, with a slot provided at a position between the upper and lower eccentric bushes. The locking pin operates to change a position of the upper or lower eccentric bush to a maximum eccentric position. Further, surfaces of parts around first and second ends of the slot are heat-treated, thus increasing a hardness thereof.

Abstract: A method of forming a vehicle component, particularly an elongated impact beam, having an open section structure, in a manner to provide predetermined strategically strengthened portions, comprising the steps of cold forming unhardened steel into a workpiece having mounting surfaces, selectively fixturing the mounting surfaces, static induction heating the workpiece with lengthwise surface eddy currents on selected portions, followed by quenching of the fixtured heated workpiece to form strengthened portions, and unfixturing the resulting component. Also disclosed is apparatus to accomplish this, and the resulting novel vehicle component.

Abstract: The invention relates to semifinished and finished products made from special corrosion-resistant precipitation-hardened austenitic steel containing a large amount of intersticially dissolved nitrogen, comprising substantially smooth surfaces. The invention also relates to a method for producing corresponding semifinished and finished items. The aim of the invention is to produce semifinished and finished item and to provide an economical method for the production thereof, combining both solidity and resistance to corrosion. This is achieved by precipitation-hardening areas of the steel material.

Abstract: An apparatus for manufacturing a case hardened journal cross includes an inductor having an open side to allow the journal cross to be inserted and withdrawn from the induction process with relative ease. The conductive frame of the inductor is shaped in a cross-like pattern that outlines the outer perimeter of a journal cross on each side of the journal cross. Because the induction coil passes across both sides of the journal cross, heat treating may be enhanced at specific locations of the outer surface of the journal cross by adjusting the distance of the induction coil from the journal cross. Also, a method for manufacturing such a journal cross includes determining the maximum stress distribution for the journal cross and, based thereon, determining the desired depth and location of the case hardening.

Abstract: A method of performing manufacturing operations on a workpiece made of a high strength alloy is disclosed in which a local area of a workpiece is heated to microstructurally soften the local area. The local area of the workpiece becomes softened and more ductile. A manufacturing operation involving deformation of the heat softened area is performed with the metal in the heat softened region being more ductile and having less strength than the surrounding portions thereof. Manufacturing operations may include riveting, clinching, hydro-forming, and magnetic pulse joining.

Abstract: Method of manufacturing a product (1, 15) from steel, in which a steel with a metastable first phase in which the steel has first properties is manufactured and, by mechanical influences, is transformed into a second, thermodynamically more stable phase with second properties which are at least partly different from the first properties, and, for adapting the product to particular applications, the product (1, 15) is manufactured locally differently by modification with regard to said phases with different properties. A product according to the invention therefore has, over its surface and/or its thickness, at least two differently adapted areas (10, 11) with different properties of the steel.

Abstract: The interior of a furnace is partitioned into two longitudinally extending and transversely adjacent zones, and one of the zones is heated to a substantially higher treatment temperature than the other of the zones, which may or may not be heated. A steel workpiece is conveyed longitudinally through the furnace with a region of the workpiece moving exclusively through the one zone and another region of the workpiece moving exclusively through the other of the zones such that the regions are heated to different temperatures. The treatment temperature in one of the zone is above the AC1 point for the workpiece and the temperature in the other of the zones is close to or below the AC1 point for the workpiece.

Abstract: A method, which is used to make controlled defects corresponding to natural flaws and residual stresses in various kinds of test pieces. Defects identical to natural flaws are required to qualify non-destructive testing (NDT) procedures. In the method, sequential, repeated, heating-cooling cycles are used to create defects and residual stresses. The shape of the heating and cooling pattern, the duration of the heating and cooling, and the number of thermal cycles are used to control the size of the defects and residual stresses obtained. The defect is grown without initial flaw or other nucleator. The defects correspond to natural flaws in terms of morphology and also of the signals obtained with NDT methods, and are suitable for use in, for example, NDT-qualification blocks.

Abstract: A weldable structural steel product having fine complex precipitates of TiN and CuS is provided which contains, in terms of percent by weight, 0.03 to 0.17%C, 0.01 to 0.05% Si, 0.4 to 2.0% Mn, 0.005 to 0.2% Ti, 0.0005 to 0.1% Al, 0.008 to 0.030% N, 0.0003 to 0.01% B, 0.001 to 0.2% W, 0.1 to 1.5% Cu, at most 0.03% P, 0.003 to 0.05% S, at most 0.005% O, and balance Fe and incidental impurities while satisfying conditions of 1.2≦Ti/N≦2.5, 10≦N/B≦40, 2.5≦Al/N≦7, 6.5≦(Ti+2Al+4B)/N≦14, and 10≦Cu/S≦90, and having a microstructure essentially consisting of a complex structure of ferrite and pearlite having a grain size of 20 &mgr;m or less.

Abstract: This invention relates to a procedure for hardening the bearing surfaces (H1,H2,H3,H4) of a shaft or axle, in particular a crankshaft (2) or camshaft, in which the bearing surfaces (H1-H4) to be hardened are hardened sequentially with the shaft or axle turning around their longitudinal axis (L) by means of a heating and quenching device (3), in which the distortion of the shaft or axle that arises in the area of the respective bearing surface (H1) during the course of hardening is determined, in which the shaft or axle is supported by at least one supporting device (9) during hardening of a bearing surface (H1-H6), which is placed against a previously hardened bearing surface (H1), and in which the setting of the supporting device (9) is regulated taking into account the distortion determined for the bearing surface (H1), against which the supporting device (9) is placed, and a device which enables hardening of crankshafts with a minimal distortion.

Abstract: A method of performing a heat treatment on steel rings, in particular for bearings, whereby the outer surface and inner surface of a preheated ring are exposed to different flows of a cooling medium such that the regions of the ring adjacent those surfaces are subjected to different cooling processes. The flow supply of the cooling medium is controlled in such a way that a desired internal stress pattern is obtained in the ring. The cooling medium includes of a combination of liquid and gas. An apparatus for performing a heat treatment on steel rings includes a support means for a ring to be treated; first and second supply means for supplying a spray or mist of a liquid, gas or combination thereof to the outer surface or inner surface of the ring, control means for controlling the supply of the spray or mist is also disclosed.

Abstract: In CrMoV based heat resistant steels and tungsten-containing CrMoV based heat resistant steels, trace impurities, such as phosphorus, sulfur, copper, aluminum, arsenic, tin, and antimony are reduced lower than a specific level. Furthermore, alloy steels having increased creep strengths in a creep test on an unnotched test piece by addition of trace impurities such as cobalt, niobium, tantalum, nitrogen, boron, or the like is used. The production process therefor includes heating a turbine rotor member having the specific composition at a temperature between 980° C. and 1100° C. at a part corresponding to the high-pressure part thereof and at a temperature between 850° C. and 980° C.

Abstract: A method for producing a stainless steel with improved corrosion resistance includes homogenizing at least a portion of an article of a stainless steel including chromium, nickel, and molybdenum and having a PREN of at least 50, as calculated by the equation: PREN=Cr+(3.3×Mo)+(30×N), where Cr is weight percent chromium, Mo is weight percent molybdenum, and N is weight percent nitrogen in the steel. In one form of the method, at least a portion of the article is remelted to homogenize the portion. In another form of the method, the article is annealed under conditions sufficient to homogenize at least a surface region of the article. The method of the invention enhances corrosion resistance of the stainless steel as reflected by the steel's critical crevice corrosion temperature.

Abstract: In CrMoV based heat resistant steels and tungsten-containing CrMoV based heat resistant steels, trace impurities, such as phosphorus, sulfur, copper, aluminum, arsenic, tin, and antimony are reduced lower than a specific level. Furthermore, alloy steels having increased creep strengths in a creep test on an unnotched test piece by addition of trace impurities such as cobalt, tantalum, nitrogen, boron, or the like is used. The production process therefor includes heating a turbine rotor member having the specific composition at a temperature between 980° C. and 1100° C. at a part corresponding to the high-pressure part thereof and at a temperature between 850° C. and 980° C.