MANUFACTURING LAYING HEAD PIPE PATH BELOW TRANSFORMATION TEMPERATURE

Abstract

A rolling mill coil-forming laying head system elongated hollow pathway Or pipe structure defining an inner surface for transport of elongated materials is formed by the process of bending the pathway structure at near constant temperature, such as at near ambient temperature, preferably without application of external heat. In some embodiments, the method utilizes an automated bending machine, preferably under computer numerical control (CNC) that executes stored bending constructions to conform the pathway structure to a desired profile. The bending instructions may be modified so that the actual bending profile conforms to a desired profile. In this manner subsequent path structures may be formed, that have uniform physical properties.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority under 35 §119(e) to co-pending United States Provisional Patent Application Ser. No. 61/540,671, filed 29 Sep. 2011, and is entirely incorporated herein by reference as if fully set forth below.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the present invention relate to a coil-forming apparatus, also known as a laying head system, in a rolling mill, and more particularly to a novel method of manufacturing a laying head pathway structure or pipe path for a laying head system by automated bending of thick-walled tubing or other elongated pathway structure, including nested multi-layer tubing below the constituent material's transformation temperature.

2. Description of the Prior Art

The conventional method for producing a rolling mill coil-forming laying head system elongated hollow pathway structure/laying head path is by heating tubes of various materials to a temperature of approximately 1922° F. (˜4050° C.) sufficient to allow the tube to be bent in a manual fixture to a desired profile. This heating temperature is above the transformation temperature of many materials, where they undergo internal atomic changes that affect their physical properties. In the case of some metal alloys, heating them above their transformation temperatures increases grain sizes within their grain structures, and decreases metal hardness. Consistent adherence to desired profile dimension specifications (often tolerances within 1 mm (˜0.039 in) over a dimensional length of meters (yards) are required for proper engagement with the coil-forming laying head quill and path supports and rotational balance. As noted above, heating the tube material above its transition temperature and subsequent cooling has detrimental effects on the mechanical properties of the tube, e.g., material hardness, which results in a shorter service of the component. The hot-forming heating and cooling cycle also introduces undesirable variances in tubing mechanical properties including by way of non-example, material hardness, weight, center of rotating mass, surface finish and dimensions during the approximately one hour-long forming process. White the heated tube is extracted from an oven at 1922° F. (˜1050° C.) its temperature cools to approximately 1382° F. (˜7750° C.) by completion of the approximately 100 second bending phase of a one hour-long forming process for each individual path/tube structure. The laying head path elongated structure formation process of heating the tube, bending it and allowing it to cool before it can be post processed is time consuming and labor intensive. Subsequent localized manual re-bending may be required to conform the cooled tube to the desired dimensional profile specifications, for example to compensate for cooling cycle thermal distortion and/or structural “spring back” to pre-bending dimensions. Manual “hot” laying path structure formation introduces construction. variances between different tubes and requires varying remediation efforts to conform each individual tube to desired dimensional profile specifications. In addition, each time a new laying head path is developed new fixtures are required, which define this path and serve as the means by which the path is formed.

Conventional “hot” manual laying head system pathway structure formation is not readily compatible with a new generation of elongated pathway structures that may not have uniform tubular cross sections, or that may be constructed of multiple nested and/or adjoining lateral segments of materials having different physical properties as shown in the above-referenced provisional patent applications. For example, a multi-layered laying path elongated structure formed from two or more nested layers of steel, nonferrous superalloys, composite non-metallic structures and aluminum is not conducive to conventional “hot” bending at temperatures of approximately 922° F. (˜1050° C.), because of the lower melting or burning temperature of the aluminum or composite layers.

SUMMARY OF THE INVENTION

Briefly described, aspects of the present invention relate to a method of manufacturing a laying head pipe pathway. In some embodiments, the method can produce a laying head path below the transition temperature of its constituent material, and in other embodiments at near ambient temperature, thus eliminating the need for heating the tube to high temperatures, and reducing variances in the pathway physical properties. Elimination of heating facilitates usage of multi-layer and/or adjoined multi-segment elongated pathway structures constructed of materials having different physical properties. In some embodiments, the method utilizes automated computer numerical control (CNC) bending machines to define and form the path mathematically, so that future changes to the path simply require a change to the equipment program and not physical forming tooling. The automated bending machine instruction sets utilized in the CNC controller may be modified to correct and compensate for deviations between an actual bent profile of a pathway structure and the desired bent profile. The modified bending instructions are utilized to bend subsequently manufactured pathway structures that are in conformity with the desired bent profile.

Embodiments of the present invention feature an apparatus for retention and transport of elongated materials in a rolling mill coil-forming laying head system comprising an elongated hollow pathway structure defining an inner surface for transport of elongated materials therein. The apparatus is formed by the process of bending the pathway structure below its constituent material transition temperature.

Other embodiments of the present invention feature an apparatus for retention and transport of elongated materials in a rolling mill coil-forming laying head system comprising an elongated hollow pathway structure defining an inner surface for transport of elongated materials therein, with uniform physical properties along its length. The uniform properties may be facilitated by bending the pathway structure below the transition temperature of its constituent materials, and preferably at near ambient temperature.

Additional embodiments of the present invention feature a method for forming an apparatus for retention and transport of elongated materials in a rolling mill coil-forming laying head system, by providing an elongated hollow pathway structure defining an inner surface for transport of elongated materials therein; and bending the pathway structure below its constituent material transition temperature. Bending may be performed with an automated bending machine that executes bending instructions under control of an industrial or other controller, which in sonic embodiments is a CNC controller. The bending instructions may be modified to correct for differences between a desired bending profile and an actual bending profile, so that future manufactured pathway structures conform to the desired profile specifications.

The features of aspects of the present invention may be applied jointly or severally in any combination or sub-combination by those skilled in the art. Further features of aspects and embodiments of the present invention and the advantages offered thereby, are explained in greater detail hereinafter with reference to specific embodiments illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The teachings of the present invention can be readily understood by considering the following detailed description in conjunction with the accompanying drawings, in which:

FIG. 1 shows a coil-forming apparatus including a laying head pipe path formed via methods of the present invention;

FIG. 2 shows a perspective view of prototype laying head pipe path formed via methods of the present invention;

FIG. 3 shows a perspective view of an alternative embodiment laying head pipe path to be formed via methods of the present invention;

FIG. 4 shows a perspective view of another alternative embodiment laying head pipe path to be formed via methods of the present invention;

FIG. 5 shows a partially cut away axial cross-sectional view of the laying head pipe path of FIG. 4;

FIG. 6 shows an automated bending machine adapted to “cold bend” at near constant ambient temperature a laying head pipe path formed via methods of the present invention;

FIG. 7 shows a controller and control system adapted for operating the automated bending machine of FIG. 6;

FIG. 8 shows schematically a portion of a laying head pipe path formed via methods of the present invention, including compensation for spring back of the pipe during the bending process; and

FIG. 9 is a flowchart of the methods of the present invention for compensating for spring back of the pipe during the bending process.

To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures.

DETAILED DESCRIPTION

To facilitate an understanding of embodiments, principles, and features of the present invention, they are explained hereinafter with reference to implementation in illustrative embodiments. In particular, they are described in the context of being a method of manufacturing a laying head pipe path elongated structure to a desired profile or shape below its constituent material transition temperature, desirably below 572° F. (˜300° C.), and preferably near ambient temperature. “Near ambient temperature” means temperature change attributable to internal elongated structure heating during the bending process. The pathway structure or pipe temperature change during the present invention bending process is much lower than conventional hot bending temperature change, with starting temperature of approximately 1922° F. (˜1050° C.), subsequent temperature drop to approximately 1382° F. (˜750° C.) during the relatively slow manual bending process and ultimate cooling to ambient temperature. By forming pathway structure or pipe apparatuses below the transition temperatures of their constituent materials (preferably near ambient temperature) there is less likelihood of changes and variances in their physical properties, leading to more consistently manufactured products. Embodiments of the present invention, however, are not limited to use in the described systems or methods.

As wire rod mills attempt to produce product at higher speeds, the service life of the laying head path material becomes a critical factor. Attempts have been made throughout the years to modify the mathematical equation that defines the laying head path as well as modifying the material from which the laying head path is manufactured, but the process by which the laying head path is manufactured has not changed. It is known that the industry standard process currently being used (i.e., heating a tube to an elevated temperature above constituent material transition temperature and manually bending it on a fixture) can have detrimental effects on the mechanical properties of the base material. It is also known that changes in the base material of the pipe can result in different amounts of spring-back as the material cools, altering the elongated structure profile dimensions. These dimensional differences are not realized until the cooled, bent pipe is removed from the bending fixture and an attempt is made to install the elongated structure in the coil forming laying head system equipment. A failed installation attempt results in lost maintenance time and remediation effort to re-bend the path/pipe elongated structure to conform to the desired profile dimensions.

Laying Head System Overview

Referring to FIGS. 1-5, the coil-forming apparatus laying head system 30 coils rolled elongated material, such as for example hot rolled steel. Elongated material that is advancing at a speed that may be as high as or greater than approximately 500 feet/second (150 m/sec), is received in the laying head system 30 intake end 32 and discharged in a series of continuous coil loops at the discharge end 34, whereupon the coils are deposited on a conveyor (not shown).

The laying head system 30 comprises a rotatable quill 50 and elongated path structure 60 that is attached to a pipe path support 70 by claims 71. The path 60 defines a hollow elongated cavity to enable transport of the material elongated material. Aspects of the present invention allow the path to comprise a laying head pipe; indeed, the path 60 may occasionally be referred to as a laying head pipe herein.

The quill 50 can have a generally horn shape that is adapted to rotate about an axis. The path 60 has a generally helical axial profile of increasing radius, with a first end 62 that that is aligned with the rotational axis of quill 50 and receives elongated material. The path 60 has a second end 64 that is spaced radially outwardly from and generally tangential to the quill 50 rotational axis and thus discharges the elongated material generally tangentially to the periphery of the rotating quill. The path 60 is coupled to the pipe support 70 by clamps 71. The pipe support 70 is in turn coupled coaxially to the quill 50, so that all three components rotate synchronously about the quill rotational axis. As illustrated in FIG. 1, as elongated material is discharged from the second end 64, it is directed into a ring guide 80 and its guide trough channel 84, having a helical pitch profile, such as that described in commonly owned U.S. Pat. No. 6,769,641. As the elongated, material is advanced through the ring guide 80 it is continued to he conformed into a continuous loop helix. Ring guide 80 is coupled to the pipe support 70 and rotates coaxially with the quill 50.

Stationary end ring 90 has an inner diameter that is coaxial with the quill 50 rotational axis and circumscribes the laying path/pipe 60 second end 64 as well as the ring guide 80. The end ring 90 counteracts centrifugal force imparted on the elongated material M as it is discharged front the laying head pipe 60 second end 64 and advances along the ring guide 80 helical trough channel 84 by radially restraining the material within the end ring inner diameter guide surface.

When operating the coil-forming laying head system 30 the quill 50 rotational speed can be selected based upon, among other factors, the elongated material structural dimensions and material properties, advancement speed, desired coil diameter and number of tons of elongated material that can be processed by the laying head pipe without undue risk of excessive wear. The path/pipe 60 elongated structure is periodically replaced. As shown in FIG. 2 the laying head path/pipe 60 has an interior inner surface 66, which is subjected to relatively higher wear rates than other portions of the pipe.

The owner of the present application has other applications, cited above, which are directed to laying head path/pipe elongated structures that incorporate wear resistant zones. In FIG. 3 the laying head path/pipe 60′ is of laterally joined segmented construction, comprising three axially joined segments 61A′, 61B′ and 61C′ which may have different physical properties. For example, segments 61A′ and 61C′ may comprise steel tubing and segment 61B′ may comprise superalloy tubing, with the segments joined to each. other by weld beads. In FIGS. 4 and 5 the laying head path/pipe 60″ embodiment has a multi-layer nested construction, with three layers 61″, 65″ and 68″. The inner surface 66″ is defined by an axially joined segments 68A″, 68B″ and 68C″, though a unitary solid inner layer can be substituted for the shown segmented layer. In the FIGS. 4 and 5 embodiments the outer layer 61″ is relatively thin-walled steel construction. The intermediate layer 65″ is constructed of tubular aluminum and the inner layer 68″ is constructed of stainless steel, super alloy, hardened steel or segmented combinations of any of them. The laying head path/pipe pathway structure, including the embodiments 60, 60′, 60″ herein, is constructed of relatively thick-walled elongated material, such as pipe, typically having an outer diameter “OD” between approximately 50 mm-60 mm (1.97 in-2.36 in) and an inner diameter “ID” between approximately 10 mm-40 mm. (0.39 in-1.57 in). Given, the different physical properties between the steel, stainless steel, aluminum and superalloy portions, and the relatively large wall thickness, preheating and manually bending the joined segments into the desired path/pipe 60′ profile is challenging, for among other reasons different temperature/plasticity and melting point properties of each material.

Below Transition Temperature Laying Head Pipe Path Bending

Aspects of the present invention relate to a method of manufacturing a laying head pipe pathway, including pathways constructed of axially joined segments and/or multi-layer nested layers. In some embodiments, the method can produce a laying head path at constant, near ambient temperature, thus eliminating the need for heating the tube to high temperatures above its constituent material transition temperature, and resulting detrimental impact on the mechanical properties of the base material(s). Elimination of elongated pathway structure high temperature pre-heating facilities use of multi-layer and multiple abutting segment fabricated pathway construction, where respective portions have different materials and physical properties, such as melting temperature.

In some embodiments, shown in FIGS. 6 and 7, the manufacturing method of the present invention utilizes known automated bending machinery 200 under known computer numerical control (CNC) controller 210 to define the path 60 profile mathematically, so that future changes to the path profile simply require a change to the equipment controller program instruction set stored in the controller's physical or virtual controller platform 100. Once an automated bending instruction set is optimized to manufacture laying head path elongated structures that are in conformity with desired profile specifications, additional conforming structures can be readily fabricated quickly and easily, without construction variances inherent in manually hot-formed conventional laying head system paths.

Referring to FIG. 7, the physical or virtual controller platform 100 includes a processor 110 and a controller bus 120 in communication therewith. Processor 110 is coupled to one or more internal or external memory devices 130 that include therein operating system 140 and application program 150 software module instruction sets that are accessed and executed by the processor, and cause the automated bending machinery 200 to perform bending operations on the laying head path/pipe 60, 60′, 60″, etc.

While reference to an exemplary controller platform 100 architecture and implementation by software modules executed by the processor 110, it is also to be understood that the present invention may be implemented in various forms of hardware, software, firmware, special purpose processors, or a combination thereof. Preferably, aspects of the present invention are implemented in software as a program tangibly embodied on a program storage device. The program may be uploaded to, and executed by, a machine comprising any suitable architecture. Preferably, the machine is implemented on a computer platform having hardware such as one or more central processing units (CPU), a random access memory (RAM), and input/output (I/O) interface(s). The computer platform 100 also includes an operating system and microinstruction code. The various processes and functions described herein may be either part of the microinstruction code or part of the program (or combination thereof) which is executed via the operating system. In addition, various other peripheral devices may be connected to the computer/controller platform 100.

It is to be understood that, because some of the constituent system components and method steps depicted in the accompanying controller 210 and control platform 100 figures are preferably implemented in software, the actual connections between the system components (or the process steps) may differ depending upon the manner in which the present invention is programmed. Specifically, any of the computer platforms or devices may be interconnected using any existing or later discovered networking technology and may also all be connected through a larger network system, such as a corporate network, metropolitan network or a global network, such as the Internet.

Computer/controller platform 100 receives input communications from one or more external input devices via respective communications pathways I′ directly or indirectly through input interface 160, that in turn can distribute the input information via the controller bus 120. Output interface 180 facilitates direct or indirect communication with one or more output devices, such as the automated bending machine 200, via associated communications pathways O′. As shown in FIG. 7 the exemplary controller platform 100 has a communications interface 170 for communication with other external devices no a shared external data bus, such as the data bus 212, so that input communications I′ and output communications O′ are communicated among the CNC controller 210, the automated bending machine 200, a host communications server or workstation 214, instruction set storage device 216 and human machine interface (HMI) 216. Exemplary CNC controller 210 output communications O′ include instruction sets to the automated bending machine 200 for bending pipe or other elongated structures into a desired profile for a laying head pipe/path 60, 60′, 60″ and 160.

In some aspects of the present invention, an automated bending machine 200, such as a machine manufactured by Star Technology Srl, of Brescia Italy, can be used to bend a hollow pipe of one or more layers and/or of laterally joined segments into a particular shape for use as a laying head pipe path. Aspects of the present invention, utilizing an automated bending machine 200, permit the desired profile/shape of the laying head pipe/path 60, 60′, 60″ and 160, which is generated when the hollow pipe is at constant ambient temperature, removing the requirement of heating the hollow pipe and the bending it into the desired shape. The Star Technology automated bending machine can push the hollow pipe through a pair of opposing grooves that can rotate and angle as the hollow pipe is forced there between, whereby as the hollow pipe exits the grooves the desired shape of the laying head pipe is generated. A prototype of exemplary laying head path/pipe 60 was formed on an automated bending machine under CNC control, using thin-wailed steel tubing. However, in other embodiments, the automated bending machine should have sufficient push and bend arm power, for example 10,000 kg (about 22,000 pounds of push), in order to bend the exemplary, relatively thick walled laying head path/pipes 60′ and 60″, having an outer diameter between approximately 50 mm-60 mm (1.97 in-2.36 in) and an inner diameter between approximately 10 mm-40 mm (0.39 in-1.57 in).

The method of forming an exemplary laying head pipe pathway 60, 60′, 60″, 160 comprises, providing an elongated, hollow tube or other elongated structure and forcing the tube through a grooved channel in the automated bending machine 200 that can angle the tube to form a particular three-dimensional profile or shape. There is no need to heat the tube to generate the desired shape. This method has the additional advantage that elements in the forming machine 200 and/or the CNC controller 210 programming can be adjusted to compensate for different material characteristics, to insure that the actual final bent profile of the laying pipe matches the desired profile. For example, the laying head path/pipe 160, shown in FIG. 8, has suffered “spring-back” during the bending process, so that after the tube material relaxes or springs back partially to its prior straight, unbent profile, the final resultant actual bent profile angle θ_A is shallower than the desired bent profile angle θ_D by angle correction factor θ_C.

The laying head path/pipe 160 bending instructions utilized by the automatic bending machine 200 and provided by the CNC controller 210 are modified to include the correction factor θ_C, so that subsequently bent elongated pathway structures conform to the desired bending profile θ_D. Referring to FIGS. 7 and 9, an initial set of bending instructions are created at step 300, such as in the work station 214 or retrieved from storage device 216, and utilized by the bending machine 200 to bend a blank elongated structure into a laying head path/pipe 160 at near ambient temperature in step 310. If the laying head path/pipe 160 bending process requires initial pre-heating of the blank elongated structure below its constituent material transition temperature—for example below 572° F. (˜300° C.)—the laying head path/pipe 160 is formed at a sufficiently low temperature to minimize change in the pathway material properties. The now bent laying head path/pipe 160 is measured to determine whether the actual bend angle θ_A or other measured profile dimension differs from the desired bend angle θ_D at step 330. If the actual bend angle or other measured profile dimension meets desired specifications, the bending instructions are validated and confirmed for storage and future reference when bending any subsequent laying head paths/pipes 160 requiring the same dimensions. Thus future bent paths/pipes 160 can be bent with good confidence that they will meet desired dimensional specifications and that they will have uniform construction. Conversely if at step 330 it is determined that the measured profile dimension bend angle θ_A differs from. the desired bend angle θ_D the correction factor θ_C is determined at step 340 and used to modify the initial or prior bending instructions at step 350. The bending step 310 is repeated with the modified bending instructions of step 350 and the bent tube measured at step 320. The steps 310-350 are repeated sequentially to generate new modified bending instructions until the actual bending profile θ_A conforms to the desired bending profile θ_D. Thereupon the modified instructions that achieved the desired bending profile conformity are stored at step 360 for use in future laying head path/pipe elongated structure 160 bending operations.

Although various embodiments that incorporate the teachings of the present invention have been shown and described in detail herein, those skilled in the art can readily devise many other varied embodiments that still incorporate these teachings. The invention is not limited in its application to the exemplary embodiment details of construction and the arrangement of components set forth in the description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.

Claims

1. An apparatus for retention and transport of elongated materials in a rolling mill coil-forming laying head system comprising an elongated hollow pathway structure defining an inner surface for transport of elongated materials therein, the apparatus formed by the process of bending the pathway structure below its constituent material transition temperature.

2. The apparatus of claim 1 having an inner layer defining the inner surface and a retention layer for retaining the inner layer, formed by the process of nesting the inner and outer layers prior to the bending step.

3. The apparatus of claim 1, the elongated hollow pathway structure comprising a segmented construction formed by the process of laterally abutting adjoining segments prior to the bending step.

4. The apparatus of claim 1, the bending step performed on an automated bending machine.

5. The apparatus of claim 1, the bending step performed at near ambient temperature.

6. The apparatus of claim 1, the bending step performed below 572° F. (˜300° C.).

7. An apparatus for retention and transport of elongated materials in a rolling mill coil-forming laying head system comprising an elongated hollow pathway structure defining an inner surface for transport of elongated materials therein, with uniform physical properties along its length.

8. The apparatus of claim 7, the uniform physical properties comprising uniform hardness along the inner surface.

9. The apparatus of claim 8, the uniform physical properties selected from the group consisting of hardness, surface finish, center of rotating mass, dimensions, melting temperature and weight per unit length.

10. The apparatus of claim 7, the pathway structure comprising a pipe having an outer diameter between approximately 50 mm-60 mm (1.97 in-2.36 in) and an inner diameter between approximately 10 mm-40 mm (0.39 in-1.57 in).

11. A method for forming an apparatus for retention and transport of elongated materials in a rolling mill coil-forming laying head system, comprising:

providing an elongated hollow pathway structure defining an inner surface for transport of elongated materials therein; and

bending the pathway structure below its constituent material transition temperature.

12. The method of claim 11, the bending step performed at near ambient temperature.

13. The method of claim 11, the bending step performed without applying external heat to the pathway structure.

14. The method of claim 11, the bending step performed on an automated bending machine that executes stored bending instructions to conform the pathway structure to a desired profile.

15. The method of claim 14, the pathway structure comprising a pipe having an outer diameter between approximately 50 mm-60 mm (1.97 in-2.36 in) and an inner diameter between approximately 10 mm-40 mm (0.39 in-1.57 in).

16. The method of claim 14, further comprising after the bending step:

comparing the bent pathway structure actual bent profile with the desired profile;

modifying the stored bending instructions to correct for differences between the respective profiles, if the actual bent profile does not conform to the desired profile;

repeating the bending, comparing and instruction modifying steps until the pathway structure actual bent profile conforms to the desired profile;

storing modified second bending instructions that conform the actual and desired profiles; and

bending a plurality of pathway structures with the second bending instructions.

17. The method of claim 16, the bending step performed at near ambient temperature.

18. The method of claim 16, the bending step performed without applying external heat to the pathway structure.

19. The method of claim 16, further comprising bending the plurality of pathway structures with uniform physical properties along each of their respective lengths, selected from the group consisting of hardness, surface finish, center of rotating mass, dimensions, melting temperature and weight per unit length.

20. The method of claim 16, the pathway structure comprising a pipe having an outer diameter between approximately 50 mm-60 mm (1.97 in-2.36 in) and an inner diameter between approximately 10 mm-40 mm (0.39 in-1.57 in).