Abstract: A cross-rolling mill for rolling a block over a mandrel forms a hollow block. It includes a plurality of working rollers, each of which exerts a substantially radially aligned rolling force onto the block. The working rollers are supported in a roll stand, and the gap between the working rollers and preferably also the alignment of the rolling axis of at least one of the working rollers relative to the block can be modified. Hydraulic actuators, preferably hydraulic capsules, are provided in order to modify the rolling gap and preferably also the alignment of the rolling axis of at least one of the working rollers relative to the block.

Abstract: A roll straightening machine for straightening an elongated string member includes at least one first straightening roll rotatably mounted around a first rotation axis, and at least one second straightening roll rotatably mounted around a second rotation axis. The first and second rotation axis and rolls are oblique with respect to a longitudinal axis of an elongated string member to be received in the roll straightening machine, and also oblique with respect to one another. In order to provide a roll straightening machine that can be set up flexibly for different requirement profiles, the first rotation axis is mounted on a first holding device and the second rotation axis is mounted on a second holding device. The first and the second holding devices are supported by a frame in a removable manner, which is arranged to receive a variable number of holding devices having the straightening rolls.

Abstract: A drawing and/or straightening unit for feeding one or more oblong metal products to a machine for working the metal products is included that has a first roller on which at least one metal product being fed is positioned longitudinally. Also included is a second contrasting roller, opposite the first roller. This keeps the metal product correctly positioned during feed. The drawing and/or straightening unit has actuators operationally associated with the second roller to initially move and position the second roller with respect to the first roller and to vary the distance between the rollers. The actuators have actuators for initial movement of the second roller to the first roller, and for selective and controlled movement of the second roller.

Abstract: A method for manufacturing a coating rod, comprising the steps of preparing a rod material, disposing a pair of form rolling dies having a plurality of helical convex threads, so that the closure angle of a main axis of each of the form rolling dies in the horizontal direction of the main axis is substantially 0.25° or larger but not larger than 0.35° with respect to an axial direction of the rod material, and form-rolling the rod material by feeding the rod material along the axial direction thereof and rotating the pair of form rolling dies around the main axes thereof, while clamping the rod material with the pair of form rolling dies.

Abstract: The present invention provides a mandrel mill and the like that is capable of not only enhancing the elongation ratio of the pipe or tube, but also suppressing a pinhole defect from occurring. The first means of the present invention provides a mandrel mill comprising a plurality of rolling stands in which two grooved rolls R11, R12 are disposed, respectively, the mandrel mill being characterized in that the roll diameter ratio for the first rolling stand and the second rolling stand is set at a value of 4.6 or over. The second means of the present invention provides a mandrel mill comprising a plurality of rolling stands in which three grooved rolls R21, R22 and R23 are disposed, respectively, the mandrel mill being characterized in that the roll diameter ratio for the first rolling stand and the second rolling stand is set at a value of 2.8 or over.

Abstract: A heat transfer tube can comprise a tube body, and outer fins integrated with the tube body which are formed by allowing material on the tube body to extend along radial direction of the tube body and wind and extend around the tube outer surface in helical manner, wherein microscale channels are formed on at least one lateral surface of the outer fin.

Abstract: In straightening a duplex stainless steel pipe on a multi-roll pipe straightener, the value of A defined by the formula (1) is set to not more than 2.0% when it is not necessary to improve the mechanical strength of the pipe, and the value of A is set to more than 2.0% but not more than 3% when it is necessary to improve the mechanical strength of the pipe. Thereby, the mechanical strength of the duplex stainless steel pipe is regulated, A=(Di?Hi)/Di??(1) where each of the symbols in the formula (1) indicates the following: Di: the outer diameter (mm) of the pipe at an entry side of an i-th stand in the straightener, and Hi: the gap (mm) between groove bottom portions of the rolls at an i-th stand in the straightener.

Abstract: A double-wall pipe includes an outer pipe, and an inner pipe disposed inside the outer pipe. An outer wall of the inner pipe has thereon a ridge portion, which defines a groove portion extending in a longitudinal direction of the inner pipe. The outer pipe and the inner pipe are bent to have a straight portion extending straightly, and a bend portion bent from the straight portion. In the straight portion, the outer pipe has an inside diameter that is larger than an outside diameter of an imaginary cylinder defined by an outer surface of the ridge portion of the inner pipe. Furthermore, the ridge portion of the inner pipe contacts an inside surface of the outer pipe to be readially squeezed and held by the outer pipe, in the bend portion. The double-wall pipe can be suitably used for a refrigerant cycle device.

Abstract: In straightening a tube using a roll straightening machine provided with drum type straightening roll pairs vertically opposingly disposed, at least an outer layer portion of a roll main body is made of elastic material having spring type hardness Hs (JIS K 6301 A type) of 50 to 100 in at least three pairs of straightening rolls on an outlet side of the roll straightening machine, and an offset amount is imparted to a tube engaged in the three pairs, at least, of straightening opposing rolls such that ? defined by an equation (1) ranges from 1.0×10?3 to 1.5×10?3. The offset amount is set at three positions along a tube axis where the upper and lower rolls of each pair horizontally cross. Therefore, an S/N ratio can be enhanced in an eddy current test from inside of the tube to improve inspection efficiency, and excellent quality accuracy can be ensured in a heat transfer tube used in a steam generator and the like.

Abstract: Disclosed herein is a forming disk for fabricating a fin tube. The forming disk comprises a substantially circular plate having a shaft connection hole formed adjacent a center thereof for receiving a shaft of a form rolling machine. A plurality of projections having a first length are formed along a circumference of said plate at substantially regular angular intervals in such a way as to protrude in a radial direction, and a round curvature is formed in the formed fin at certain axial pitch periodically in a radial direction. Also disclosed is a high-performance and high-efficiency fin tube having formed fins. Each formed fin comprises a generally circular plate having a crest and a valley formed in both side faces at certain angular intervals along the circumference thereof so as to form a continuous curvature.

Abstract: Device for forming of at least one groove (92, 93, 94, 95, 96, 97, 98) in a friction layer (91) of a covered disk (90) for a force transmission aggregate, in particular for a disk clutch, with a rolling device (1, 11, 21, 31) with at least one roller flange (7, 17, 27a . . . 27f, 37a . . . 37c) for rolling in the at least one groove (92, 93, 94, 95, 96, 97, 98).

Abstract: A post bearing and method of manufacture in which bearing balls are loaded into a series of pocket holes arranged along a helical pattern in a sleeve cage. A single groove is swaged into the outside diameter of the sleeve intermediate the ball turns to capture the balls in the pocket holes.

Abstract: A rolling die for a ball screw has: a cylindrical portion including a helical protrusion formed in an outer peripheral surface thereof for forming a helical ball groove in a raw material of a screw shaft of the ball screw; and a conical lead-in portion formed in one end portion of the cylindrical portion, the lead-in portion including a plurality of frustum-cone-shaped portions, wherein the contact angles of the frustum-cone-shaped portions with respect to the raw material of the screw shaft are each set so as to increase sequentially in the order starting at and from the frustum-cone-shaped portion adjoining the cylindrical portion.

Abstract: A machine may produce a tube having textured internal and external surfaces in a single operation. Inner and outer knurling tools may form the textured surfaces. The texturing of the internal and external surfaces may be helical patterns of ribs and grooves. The height of the ribs formed in the internal and external surfaces may be less than about 35 mils. The angles of the patterns relative to a longitudinal axis of the tube may be less than about 45°. The angle of the helical pattern allows textured tubes to be used as heat exchanger elements wherein flow is directed substantially coaxial to the longitudinal axes of the tubes. The helical pattern formed in the external surface may be oriented in a right hand or left hand helical orientation. Similarly, the helical pattern formed in the internal surface may be oriented in a right hand or left hand orientation.

Abstract: A method for manufacturing a tube made of a non-ferrous material, particularly a tube made of mainly copper, by rolling, in which method, in the first working step the tube billet is worked by rolling with conical rolls, so that mainly owing to the deformation resistance, the temperature of the billet under operation rises up to the recrystallization range, at least on the spot that is being worked. Essentially immediately after the first working step, the tube billet is subjected to at least one second working step with a second set of conical rolls, in which case the tube billet is maintained, at least during the first working step and at least a second working step in non-oxidizing conditions. The invention also relates to an apparatus.

Abstract: A method of forming a finned tube in which the fins are planar, paralleled and extend radially to the tube longitudinal axis, including the steps of positioning at least one rotating forming roll against the tube exterior surface, the forming roll being spaced from the tube and rotatable about an axis that is parallel to said tube longitudinal axis, the forming roll having on the surface thereof an elongated helically arranged fin forming protrusion, the helical protrusion having a pitch of “x” and linearly advancing the tube past the forming tool a distance of “x” for each revolution of the forming roll.

Abstract: A method for manufacturing a tube made of a non-ferrous material, particularly a tube made of mainly copper, in which method, in the first working step the tube billet is worked so that mainly owing to the deformation resistance, the temperature of the tube billet under operation rises up to the recrystallization range, at least on the spot that is being worked. Essentially immediately after the first working step, the tube billet is subjected to at least a second working step and the tube billet is maintained, at least during the first and second working step in non-oxidizing conditions. the invention also relates to an apparatus.

Abstract: A method of producing a sliding sleeve for gearshift mechanisms includes two forming steps. In the first forming step a preform, which has been pushed onto a tool mandrel with an external toothing, is formed by roller spinning so as to form on the inner circumferential surface of the preform the toothing implemented on the outer circumferential surface of the tool mandrel. Subsequently, the thus formed preform is formed by profile rolling on its outer circumferential surface so as to obtain a formed part. Finally, the tool mandrel is removed from the formed part.

Abstract: A rolled ball screw has a screw shaft having a ball screw groove so as to engaging with rolling elements of a ball screw, the screw shaft is formed by rolling while a thread rolling die is pressed against a cylindrical bar-shaped member to thereby roll the ball screw groove, wherein the number of waves per circumference per lead of said ball screw groove is set different from the integer multiples of the number of said rolling elements per lead of said ball screw groove.

Abstract: A metallic heat transfer tube, in particular for the evaporation of liquids from pure substances or mixtures on the outside of the tube. Fins are integrally formed on the outside of the tube. Recesses are arranged in the area of the base of the primary grooves and extend between the fins. The recesses are in the form of re-entrant secondary grooves. The mechanical stability of the tube is not negatively influenced because material is primarily removed from the fin flanks toward the base of the groove so that the re-entrant secondary grooves are radially open.

Abstract: This method refers to a method by which the physical and mechanical properties intrinsic to a fine-grain structure may be formed in metal billets using pressure treatment. The method is designed to treat rods, bars and other particularly long billets. This method is designed to lower the cost of deformational treatment for long rods and large diameter billets and creates a pre-specified microstructure, including micro-crystal structure, and specific physical and mechanical properties. This may be achieved using various treatment techniques, one of which includes the deformation of at least a part of the billet through reduction of the billets cross-section. In this method, a long rod shaped billet is used. Reduction of the cross-section is achieved using tools that permit movement along and across the billet's axis as well as being rolled about its surface, for example, a roller. In this case at least one support stand is employed for correct placement of the billet.

Abstract: In a rolling die for forming a ball screw by rolling for example, a biting portion is formed on one end of a straight portion while a relief portion is formed on the other end. Further, the helical protrusion on the biting portion and the helical protrusion on the relief portion each become continuously and gradually smaller as distancing away from the dancette portion on the straight portion. The dancette portion on the various portions are continuously formed using only one grinding wheel with its grinding lead being changed.

Abstract: The present invention relates to a metallic, precise columnar member having an outer diameter with high accuracy, wherein the columnar member comprises a plurality of flattened thread ridges having a predetermined outer diameter provided on the surface of a metallic columnar blank in an axial direction. The method of the present invention comprises the steps of using rolling to form a plurality of thread ridges on the surface thereof and using rolling or drawing to make the tops of the thread ridges flat.

Abstract: The invention relates to a method for the manufacture of a shaft with a larger diameter flange, particularly for a cone gear, a round stock as the workpiece being rotated about its longitudinal axis relative to at least one spinning roll and is axially compressed and the material occurring during axial upsetting is formed to the larger diameter flange under the action of the at least one spinning roll. The invention also relates to a cone gear.

Abstract: A process for producing a heat exchanger tube (1) with a highly porous surface structure, in particular for evaporating liquids from pure substances or mixtures on the outside of the tube. The process starts from a rolling operation, by means of which helical fins (2) are produced on the outside of the tube, which fins, in turn, are deformed in a plurality of compression steps by means of gearwheel-like compression wheels (6, 7) in such a manner that the projections (12a, 12b) formed in each case form a cover (3a) for the passages (3) which are situated between the fins (2). The high level of porosity is achieved as a result of the remaining pores (13) and/or slots (14).

Abstract: A machine for simultaneously forming helical threads or fins on the exterior of first, second and third elongated cylindrical workpieces, the machine having first, second and third arbor blocks arranged in a common plane and spaced about a center point in the plane, having first, second and third thread or fin forming discs rotatably affixed respectfully to the first, second and third arbor blocks, and having first, second and third guides longitudinally displaceably and rotationally receiving respectively the first, second and third workpieces so that the first workpiece is guided by the first guide between the first and second discs, the second workpiece is guided by the second guide between the second and third discs and the third workpiece is guided by the third guide between the first and third discs, rotary energy being coupled to at least one of the discs. In an alternate embodiment four elongated cylindrical members are provided with threads or fins.

Abstract: A metallic finned tube having multiple fins integrally formed on and extending helically on an outside of the tube. The fins number at least four and begin at fin run start locations spaced evenly about a circumference of the tube, with at least one group of side-by-side helical fins being formed which begin at substantially the same circumferential fin run start location on the tube exterior.

Abstract: A method includes the steps of compacting powder metal to form a powder metal blank, and forming gear teeth on the powder metal blank by rolling the powder metal blank between rolling dies rotating about parallel axes. The step of forming gear teeth on the powder metal blank by rolling includes the steps of rotating the rolling dies about parallel axes and maintaining the distance between the parallel axes constant during forming of the gear teeth on the powder metal blank. Powder metal gears having 45.degree. helical gear teeth are cold rolled. Herringbone gears and pinion gears are made with the 45.degree. helical powder metal gears.

Abstract: The invention relates to a process for reducing the outside diameter and wall thickness by rolling a cylindrical hollow ingot the front part of which is fed into an Assel rolling mill, in which connection, in front of the Assel rolling mill as seen in the direction of feed, a device is provided for reducing the diameter and/or wall thickness of the rear end part of the hollow ingot threaded onto a mandrel rod. In this process, the prereduction rolls are slowly and continuously pressed against the ingot at a predetermined point near the end of the ingot to produce a conically reduced end portion.

Abstract: A rod-straightening apparatus 28 includes a movable collet unit 30 for gripping a butt end 24 of a rod 20 to be straightened. The rod 20 extends from the collet unit 30 in a cantilevered fashion to a tip end 26 of the rod. An intermediate portion of the rod 20 is located in a straightener mechanism 32 which includes five spaced, non-rotatable, stationary, straightening blocks 96 located along one side of the intermediate portion of the rod. Four spaced, non-rotatable, movable, straightening blocks 99 are located the opposite side of the intermediate portion of the rod 20 opposite the spaces between the five stationary blocks. The movable blocks 99 are supported on a slide member 140 which is controlled to move the blocks into a position adjacent the intermediate portion of the rod 20 after the intermediate portion has been positioned adjacent the fixed blocks 96. Each of the blocks 96 and 99 is formed with a groove 106 of semi-circular cross section to form a confined passage.

Abstract: A device for the formation by rolling of helical fins on heat exchange tubes to increase the heat transfer capacity of the tubes. The device comprises four forming rolls (6, 7, 8, 9) which are arranged on two carriages (4, 5) which are moved together in translation fashion by a hydraulic jack which enables the four forming rolls to bear simultaneously on the wall of a tube (2). The four forming rolls operate around the tube and are rotatably driven at equal speed by a single motor (50). The forming rolls are oriented about an axis (X2, X4, X5) which is perpendicular to the fin shaping zone. The tube (2) is driven by the forming rolls along an axis of translation.

Abstract: A finning and thread rolling machine capable of producing an integral finned tube, an extended finned tube or a wrap-on finned tube, whichever is desired, the tubing to be used for extended surface heat transfer. Types of tubes produced are integral low finned tube, bi-metal fin tube with extruded high finned tube on the outer portion, and extruded integral/high finned tube and spiral strip helical wrap-on finned tube. The apparatus also provides a two and three die thread rolling machine for thru-feed threading and form rolling.

Abstract: Improved method and apparatus for making finned tubing from difficult to work materials such as titanium and stainless steel uses spaced sets of finning discs on a plurality of arbors to form a tube against a mandrel having different diameters under each set of discs. By forming the tube fin tips to their final O.D. in a first disc set and by deepening their roots to bring the fins to their final height in a second disc set, tubes with higher fin counts and/or higher fin heights can be achieved than were formerly possible. The process of separately cold working the tips and roots also permits tubes to be made which are dimensionally identical to prior art tubes but with higher quality and productivity since tube stresses are greatly reduced. An improved titanium tube is also disclosed which has at leasts 26 fins per inch, a fin height of at least 0.034" and an outside to inside surface area ratrio of at least 3.0.

Abstract: A method of manufacturing a metallic tube with a spiral fin for use as a heat transfer tube of a heat exchanger and the like. A solid metallic bar or metallic elementary hollow bar provided with a small hole is supplied to an inclined rolling mill having a plurality of rolls provided with a plurality of annular grooves formed on an outer circumferential surface thereof, and the solid metallic bar or metallic elementary hollow bar is worked into a pierced hollow bar by piercing rolling by means of a piercing plug and at the same time a fin is formed on an outer circumferential surface of the pierced hollow bar to integrate the fin with a body of the tube. Accordingly, the piercing rolling and the formation of the fin on the outer circumferential surface of the tube can be carried out at the same time, so that the manufacturing process can be remarkably shortened and the productivity can be high.

Abstract: A high performance heat transfer tube for use in the condenser of an air conditioning or refrigeration system is formed on a grooved mandrel which has a sufficient number of grooves i.e., thirty six to forty eight, with a suitable helix angle, such as thirty degrees, and a sufficiently small pitch, such as 0.10 inches or less, so that a Moire imprint is avoided in the external fin enhancement. This makes the fin height uniform over the exterior of the tube, which results in an increase in condenser efficiency.

Abstract: Disclosed is a metallic tubular structure having an improved collapse strength characterized in that the tubular structure has a circumferential residual tensile stress left in the inner peripheral surface thereof, said residual stress ranging between 0 and 15 % of the yield stress of the tubular structure. The material of the structure may be any one selected from a group consisting of plain steel, alloy steel, stainless steel and Fe--Ni--Cr alloy. The tubular structure of the invention can suitably be used as pipes under severe condition such as in deep oil wells.

Abstract: An apparatus for producing a high performance evaporator tube having a subsurface channel formed between adjacent helical fins with the subsurface channels having alternating closed portions and open pores above the subsurface channels. The fins of the tube are rolled-over toward the adjacent fin and then contacted with a notched disc to form the alternating closed portions and open pores.

Abstract: A cross-roll straightener adapted to straighten round metal stock, wire, rods, bars and tubes by rotatingly advancing the stock through a central curved pass such that it is flexed beyond the yield point in a substantially uniform and gradual manner. A three pair roll arrangement provides uniform guidance and flexure while avoiding marking or collapsing of the stock. Also provided is a method for maintaining the stock in the pass line of a cross-roll straightener having a female roll and a male roll of unequal diameters. In addition, positive guidance and considerably more capacity to straighten smaller stock sizes is obtained by providing adjustable outboard roll supports at each end of the basic six-roll straightener, thereby also reducing whipping of the stock.

Abstract: A cross-roll straightener adapted to straighten round metal stock, wire, rods, bars and tubes by rotatingly advancing the stock through a central curved pass such that it is flexed beyond the yield point in a substantially uniform and gradual manner. A three pair roll arrangement provides uniform guidance and flexure while avoiding marking or collapsing of the stock. Also provided is a method for maintaining the stock in the pass line of a cross-roll straightener having a female roll of larger diameter than the male roll.

Abstract: Improved method and apparatus for making finned tubing from difficult to work materials such as titanium and stainless steel uses spaced sets of finning discs on a plurality of arbors to form a tube against a mandrel having different diameters under each set of discs. By forming the tube fin tips to their final O.D. in a first disc set and by depending their roots to bring the fins to their final height in a second disc set, tubes with higher fin counts and/or higher fin heights can be achieved than were formerly possible. The process of separately cold working the tips and roots also permits tubes to be made which are dimensionally identical to prior art tubes but with higher quality and productivity since tube stresses are greatly reduced. An improved titanium tube is also disclosed which has at least 26 fins per inch, a fin height of at least 0.034" and an outside to inside surface area ratio of at least 3.0.

Abstract: In order to increase output of pipe straightening devices, there is provided a driving unit between a preparatory station for the pipes and a feeding station which advances the pipes from the preparatory station in axial direction one after the other in the feeding station. The feeding station includes a succession of rotation symmetrical guiding elements supported for rotation about axes which extend parallel to the feeding path for the pipes. The guiding bodies prevent striking of unbalanced pipes against the feeding unit and permit axial feeding of the pipes in a straightening station.

Abstract: Improved method and apparatus for making finned tubing from difficult to work materials such as titanium and stainless steel uses spaced sets of finning discs on a plurality of arbors to form a tube against a mandrel having different diameters under each set of discs. By forming the tube fin tips to their final O.D. in a first disc set and by deepening their roots to bring the fins to their final height in a second disc set, tubes with higher fin counts and/or higher fin heights can be achieved than were formerly possible. The process of separately cold working the tips and roots also permits tubes to be made which are dimensionally identical to prior art tubes but with higher quality and productivity since tube stresses are greatly reduced. An improved titanium tube is also disclosed which has at least 26 fins per inch, a fin height of at least 0.034" and an outside to inside surface area ratio of at least 3.0.

Abstract: A method and apparatus for rolling transversely ribbed pipe consists in that the rib after forming is deflected in the direction of rolling parabolically, the external pipe is pressed down to the core pipe, and deflecting the rib and pressing down the external pipe onto the core pipe is carried out during one revolution of the pipe, and afterwards the rib is straightened.The apparatus has three tools provided with roll-formed disks, for supporting and straightening, whereby the second - in the direction of rolling - part of the profile of supporting disks is concave, preferably parabolically, and the last - in the direction of rolling - tool is provided with a supporting disk the outer diameter of which is from 0.1 to 0.8 mm larger than the outer diameter of the other supporting disks.

Abstract: A method of forming ribs on tubes or pipes is characterized by applying to the material of the tube, from which the rib is formed, initial compressive stresses preferably ##EQU1## where Fo denotes the area of the cross-section of the tube before drawing, Fr denotes the area of the cross-section of the core of the tube after drawing the rib, and Re is the plasticity limit. Next, ribs are drawn by driven tools with roll-formed disks while maintaining said compressive stress.

Abstract: The invention relates to a process and an apparatus for repairing worn labyrinth seal flanges. The seal flanges are repaired by spin-forming them to increase their radial height to at least equal that of an unworn labyrinth seal. A tool for carrying out the process has a pair of parallel rollers displaced a constant distance which is advanced radially inwardly over the seal flange so as to deform the sides and cause the material to creep in a radially outward direction to increase the height of the flange. The flange may be ground to remove any residual defects caused by the spin-forming operation.

Abstract: Skewed-axis cylindrical-die rolling method for the production of combined screw-thread and gear-tooth forms on the external surface of bars using multi-element dies which progressively form the screw thread and then the gear teeth on a portion of the screw thread in which the gear-tooth forming die element is free-rotating and the other die elements are driven.

Abstract: A roll configuration for use in a roll type straightener including a concave surface of revolution formed on a roll for line contact of the roll with a cylindrical workpiece wherein the throat of the surface of revolution is offset longitudinally from the axial midpoint of the surface of revolution whereby a pair of such rolls may be employed in mutually-aligned or non-offset relationship with respect to the cylindrical workpiece axis to provide lateral restraint of such a workpiece being subjected to a bending moment.

Abstract: An apparatus for straightening pipe, round bars or similar elements, wherein the pipe moves between rolls which subjects the pipe to tensile and compressive stresses and forces as it rotates in the straightener apparatus, with the movement of the pipe being effected by rotation of the rolls. Certain of the rolls are vertically adjustable with respect to the pipe and others are horizontally adjustable with respect to the pipe and to each other while certain other rolls are adjustable both vertically and horizontally with respect to the pipe and to each other while the pipe is moving through the apparatus and the straightening operation is in progress, whereby the forces being applied to the pipe may be readily changed in accordance with the bends or other deformity in the pipe to assure that the required forces are applied to the proper pipe areas to accomplish effective straightening of the pipe.

Abstract: The invention concerns a tube release roll mill with four or more driven rolls, which in pairs form a pass opening. The diagonally positioned identically constructed rolls have an enlarged working surface width. A certain roll pair spacing is also provided, as well as an enlarged angle of attack of the rolls, which together result in the wall thickness of the tube bloom being more uniform, the development of fewer surface defects, and a quieter operation of the roll mill.

Abstract: A cross-roll straightener adapted to straighten round metal stock, wire, rods, bars and tubes by rotatingly advancing the stock through a central curved pass such that it is flexed beyond the yield point in a substantially uniform and gradual manner. A three pair roll arrangement provides uniform guidance and flexure while avoiding marking or collapsing of the stock.