Cold Forged Stub End
Apparatus for forming and shaping a stub end fitting and methods for forming the stub end fitting, are provided. The apparatus can include application of a multi-part die including first and second die parts which both together contain a preformed stub end fitting having an annular shaped flange, and a third die part (“push bullet”) used to land upon an end of a tubular member opposite the flange of the stub end fitting in order to cause portions of the stub end fitting to extrude into a cavity between the first and second die portions not already filled by the stub end fitting during initial containment. The resulting stub end fitting has enhanced material and operational properties. Additional material can be added to the outer diameter portion of the stub end fitting between the tubular main body and the flange to build or enhance an existing annular fillet to further enhance the material and operational properties of the stub end fitting.
1. Field of the Invention
The present invention relates to pipes and pipe fittings. More particularly, the present invention relates to systems, apparatus, and related methods for forming a stub end fitting.
2. Description of Related Art
Flare fittings on the ends of adjacent pipes, are used in conjunction with an external compression assembly to connect adjacent pipes together. In order to connect soft copper tubing such as, for example, that used in plumbing or break lines, etc. the end of the copper tubing is first cut to have a smooth surface, and a dowel or punch is used to flare or bend the prepared end of the tubing into a conical shape, typically having a 45 degree angle. A flare nut is then threadingly connected to an adjacent threaded nipple to compress the end of the tubing sufficient to form a leak-tight seal between the conical end of the copper pipe and a surface within the nipple, but not to an extent that the conical end of the tubing is bent normal to the axis of the copper tubing. Notably, such process is effective in typical plumbing and automotive break lines, etc., but would not be effective in connecting adjacent pipes in a plant or facility where the pipes are made of steel or other less pliable material, are generally much larger, function under higher flow rates and pressures, and require substantially non-turbulent fluid flows.
In a typical connection between, for example, 304L grade stainless steel pipe used in a facility or plant, each of a pair of adjacent pipe ends are fitted with a washer-like flange referred to as a flare fitting, stub end, or stub end fitting having a relatively flat in-line surface normal to the longitudinal axis of the pipe and configured to be held against the stub end of the adjacent pipe with a connection assembly to form a leak-tight seal. In a typical manufacturing process, a washer-like piece of steel or other material to form the flange of the stub end fitting is cut from a flat metal work piece having a thickness matching the desired thickness of the stub end. The washer-like piece forming the flange of the stub end is then welded to the end of a tubular member of the stub end. The stub end fitting is then welded to the end of the pipe. A connection assembly having a complementary pair of connectors are then fitted together such that inner portions press tightly against the stub end of each adjacent pipe end. A series of bolts are inserted through the pair of connectors to compressibly hold the two ends of the pipe together.
Notably, such arrangement can have some substantial disadvantages. For example, the weld connecting the flange of the stub end to the respective tubular member end extends into the inner diameter of the junction between the tubular member and the flange, making weld inspection a difficult and/or expensive process, which can require substantial interruption of plant or facility operations. Further, imperfections in and between the inner diameter of the flange of the stub end, the portion of the tubular member welded to the pipe end, and in the weld, itself, can result in disruption of what would otherwise remain a laminar flow. Accordingly, recognized by the inventor is the need for a method and apparatus for forming a stub end for the end of the pipe which does not require an annular weld be placed on the inner diameter of the tubular member/stub end, which provides a uniform inner diameter between portions of the stub end and portions of the pipe end adjacent to the stub end that minimizes or limits flow disruption beyond that conventionally capable, and which can be made inexpensively.
SUMMARY OF THE INVENTIONIn view of the foregoing, various embodiments of the present invention advantageously provide a method and apparatus for forming a stub end fitting for use on the end of a pipe, such as, for example, ASA/ANSI 304L grade stainless steel pipe, which does not require the use of a weld to attach the flange of the stub end fitting to the end of the tubular member of the stub end fitting, and/or which does not require an annular weld be placed on the inner diameter of the tubular member/flange conjunction. Various embodiments of the present invention advantageously also or alternatively provide a method and apparatus for forming a stub end fitting for use on the end of a pipe which provides a uniform inner diameter between portions of the flange of the stub end and portions of the tubular member of the stub end that minimizes or limits flow disruption beyond that conventionally capable, and which can be provided a substantial reduction in manufacturing costs.
Specifically, an embodiment of the present invention provides a method of forming a metal stub end fitting for a pipe. The method can include forming a circumferentially extending flange on a distal end of a tubular member, with the flange and the tubular member defining a junction with an interior radius. The method can also include providing a die having a cylindrical chamber with proximal and distal ends, inserting the tubular member into the distal end of the chamber with the flange in contact with the distally facing surface, and securing a closure plate to a distal side of the die, trapping the flange within a cavity between a distally facing surface located within an annular chamber having a cylindrical inner diameter substantially equal to an outer diameter of the flange, and a face on the closure plate having a frusto-conical shape. The method can also include providing a plunger having a cylindrical portion and an external annular shoulder, inserting the cylindrical portion of the plunger into the tubular member and past the flange, engaging a proximal end of the tubular member with the external shoulder, and applying a force that shortens a length of the tubular member and causes metal at the junction to flow, decreasing the interior radius and causing the distally facing surface of the flange to become frusto-conical. The method further includes the steps of machining the distally facing surface of the flange to a flat surface, applying a weld bead around an exterior fillet joining the flange with the tubular member, and machining the weld bead to a desired radius for the exterior fillet.
An embodiment of the present invention provides an apparatus for shaping an annular shaped flange on an end of a tubular member. The apparatus can include a multi-part die including first and second die parts which can be connected together to contain a preformed shaped stub end fitting, and a third die part defining a push bullet which can be used to modify the stub end fitting through application of the force on an end of the tubular member opposite the flange of the stub end fitting to cause portions of the flange and/or portions of the adjacent tubular member to extrude into a cavity (e.g., gaps) between the first and second die portions not already filled by the stub end fitting during initial containment.
According to an exemplary configuration, the first die part has: a first proximal facing surface shaped to receive a first distal facing surface of a second die part; a second proximal facing surface adjacent the first proximal facing surface and positioned to receive a distal facing surface of a stub end fitting when positioned in the multi-part die; a distal surface; and a cylindrical shaped bore extending at least partially therebetween along a main axis thereof, with at least substantial portions of the cylindrically shaped bore having inner surface dimensions substantially matching inner surface dimensions of a bore extending through a main body and a preformed stub end fitting. According to the exemplary configuration, the first proximal facing surface is longitudinally separated from and coaxially located with the second proximal facing surface and has an inner diameter at least as large as, but more preferably matching the outer diameter of the second proximal facing surface. The second proximal facing surface has an outer diameter substantially matching an outer diameter of the flange of the stub end fining when completed and has a uniform inward slope extending between surfaces forming an outer perimeter of the second proximal facing surface and surfaces forming an inner perimeter of the second proximal facing surface adjacent the bore to form a conical face.
Further, according to an exemplary configuration, the second die part has a first distal facing surface being shaped to land on the first proximal facing surface of the first die part; a second distal facing surface adjacent the first distal facing surface and positioned to land on at least portions of a proximal facing surface of the stub end fitting when positioned in the multi-part die; a proximal facing surface; and a cylindrically shaped central bore extending along a main axis of the second die part between the proximal facing surface and the second distal facing surface. At least substantial portions of the bore of the second die part have inner surface dimensions substantially matching outer surface dimensions of the main body of the tubular member. The second die part also includes an annular shaped recess extending axially inward from the inner perimeter of the first distal facing surface to form the second distal facing surface. According to the exemplary configuration, the first distal facing surface is longitudinally separated from and coaxially located with the second distal facing surface and has an inner diameter at least as large as but preferably matching the outer diameter of the second distal facing surface, and has an outer diameter substantially matching an outer diameter of the stub end fitting when completed. The recess is coaxially located with the central bore and includes portions having an inner perimeter dimension matching an outer perimeter dimension of the second distal facing surface and outer perimeter dimension of the stub end fitting when completed and a diameter that is larger than the diameter of the central bore, such that the larger diameter recess in conjunction with a smaller diameter central bore form an annular shoulder having a rounded corner having a specified radius being smaller than a radius of the stub end fitting when completed.
Still further, according to an exemplary configuration, the push bullet (third die part) includes a cylindrically shaped first main body portion having a cylindrically shaped side outer surface being shaped to match the inner surface dimensions of the cylindrically shaped bore extending at least partially through the first die part along a main axis thereof and substantially matching inner surface dimensions of the bore extending through the main body and the stub end fitting of the preformed tubular member. The push bullet further includes a cylindrically shaped second main body portion having side outer surface dimensions matching inner surface dimensions of the cylindrically shaped central bore of the second die part and outer surface dimensions of the main body of the tubular member, whereby the larger side outer surface dimensions of the cylindrically shaped second main body portion in conjunction with a smaller side outer surface portions of the first main body portion form an annular shoulder having a distal facing surface configured to land upon an annular shaped proximal facing surface of the preformed tubular member.
According to the exemplary method of use of the above described multi-part die, the cylindrically shaped first and second main body portions of the push bullet can be slidably positioned within the centrally shaped central bore of the second die part so that the second main body portion provides compression of the tubular member along the main axis of the first and second die parts, the main axis of the push bullet, and the main axis of the preformed tubular member to thereby induce metal flow to fill gaps between portions of the proximal facing surface of the first die part and distal facing surface of the flange and/or gaps between portions of the annular shoulder of the second die part and portions of the tubular member between an outer surface of the main body of the tubular member and the proximal facing surface of the stub end fitting of the tubular member. Advantageously, the first main body portion of the push bullet is slidably positioned within the bore of the first die part and the bore of the tubular member during compression to prevent radially inward flow of tubular member material during compression of portions of the tubular member. A proximal portion of the push bullet can have outer surface dimensions being larger than the outer surface dimensions of the first main body portion of the push bullet to form a shoulder defining a stop positioned to limit axial movement of the second main body portion of the push bullet into the cylindrically shaped bore of the second die part during the compression-metal extrusion process.
So that the manner in which the features and advantages of the invention, as well as others which will become apparent, may be understood in more detail, a more particular description of the invention briefly summarized above may be had by reference to the embodiments thereof which are illustrated in the appended drawings, which form a part of this specification. It is to be noted, however, that the drawings illustrate only various embodiments of the invention and are therefore not to be considered limiting of the invention's scope as it may include other effective embodiments as well.
The present invention will now be described more fully hereinafter with reference to the accompanying drawings, which illustrate embodiments of the invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the illustrated embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
Tubular Member Formation.
The table below provides a high-level summary of one example of a process for forming a tubular member 41 (see, e.g.,
Preform Stub End Formation
As noted above, according to an embodiment of the present invention, a tube/tubular member 41 (see, e.g.,
As provided in the example and table above and as perhaps best shown in
As perhaps best shown in
As perhaps best shown in
Stub End Enhancement
As noted above, according to an embodiment of the present invention, a BTS tube with flange/stub end fitting 31 at least substantially oriented normal to the main axis of the stub end fitting 31 (a.k.a. an upset preform) shown in
As provided in the example and table above and as perhaps best shown in
As perhaps best shown in
Referring again to
As perhaps best shown in
As perhaps best shown in
Still referring to
According to an embodiment of the present invention, the gap between portions of the annular shoulder 146 of the second die part 130 and portions of the stub end fitting 31 between an outer surface of the main body 153 of the stub end fitting 31 and the proximal facing surface 157 of the flange 33 of the stub end fitting 31 defining an annular shaped fillet 158, are not tilled or are not completely filled during the extrusion process and will be completed with an external weld, described later. According to another embodiment of the present invention, the extrusion process results in metal flow in both gaps, which together, collectively form a die cavity 190 between the first and the second die parts 110, 130.
Referring again to
As perhaps best shown in
According to the embodiment of the present invention, described above, the radius of the fillet is adjusted to that shown at indicator 205 through the addition of welding material. That is, weld material is added to the fillet having the radius shown at indicator 158 (
According to an exemplary configuration, the welding process includes application of single pass gas metal arc welding (MIG) and two passes gas tungsten arc welding (GTAW), although others are within the scope of the present invention. If to be completed to the specifications of the end-user as part of the manufacturing process, after welding is completed, the fillet 205 can be rough machined, and a technician can then examine the fillet 205 and, if necessary, apply a bending force to straighten the flange 203. That is, the flange 203 can be straightened so that all portions of the distal facing surface 207 of the stub end fitting 203 lie in the same plane being normal to the main axis of the stub end fitting 201 if not already lying in the same plane. The stub end fitting 201, in its final form, is then heat treated, for example, at a solution anneal temp of approximately 1900° F. or other appropriate temperature depending upon the type of material used. Upon completion of the annealing process, both the inner and outer diameter of the main body 209 and flange 203 are given the full machining.
Beneficially, as perhaps best shown in
Embodiments of the present invention provide several advantages. For example, various embodiments of the present invention provide methods and a new multi-part die design which provides a commercially efficient manufacturing process for forming a stub end without the need for welding a flange to a tubular member, without the need for adding welding or buildup material to the inner radius of the flange that could be subjected to direct contact with a corrosive service, and which provides an enhanced microstructure. Advantageously, without a need for applying weld material to build up the inner diameter adjacent the flange inspection complexity and costs can be significantly reduced. Stub ends manufactured according to various embodiments of the present invention can also advantageously enhance fluid flow characteristics of fluid within the pipe when operationally employed, particularly at the point of interface between the main body of the tubular member and the flange, and between adjacent stub ends. Advantageously, as described with respect to the exemplary configuration, the enhancements formed through metal extrusion can be conducted in accordance with a cold forging process without the utilization of an external heat source.
In the drawings and specification, there have been disclosed a typical preferred embodiment of the invention, and although specific terms are employed, the terms are used in a descriptive sense only and not for purposes of limitation. The invention has been described in considerable detail with specific reference to these illustrated embodiments. It will be apparent, however, that various modifications and changes can be made within the spirit and scope of the invention as described in the foregoing specification. For example, it should be understood that the featured multi-part die can have different sizes to precisely accommodate different sized tubular members and flanges.
Claims
1. A method of forming a metal stub end fitting for a pipe, comprising:
- (a) bending a distal end of a tubular member to create a flange, the flange and the tubular member defining a junction with an interior radius; and
- (b) placing the flange within a cavity of a die and applying a distally directed force to a proximal end of tubular member while restraining inward deformation of the tubular member, causing the flange to conform to dimensions of the cavity and decreasing the interior radius.
2. The method as defined in claim 1, wherein the cavity has a distal face that is frusto-conical, causing a distally facing surface of the flange to become frusto-conical.
3. The method as defined in claim 2, further comprising the step of machining the distally facing surface of the flange to a flat surface.
4. The method as defined in claim 1, wherein during step (b) the cavity restrains expansion of an outer diameter of the flange.
5. The method as defined in claim 1, further comprising the step of applying a weld bead around an exterior fillet joining the flange with the tubular member.
6. The method as defined in claim 5, further comprising the step of machining the weld bead to a desired external radius for the exterior fillet.
7. The method as defined in claim 1, wherein step (a) comprises deforming the distal end of the tubular member with a conically shaped punch to create a conical flange, then deforming the conical flange with a flat punch to flatten the flange.
8. The method as defined in claim 1, wherein step (b) creates a sharp interior corner at the junction.
9. A method of forming a metal stub end fitting for a pipe, comprising:
- (a) forming a circumferentially extending flange on a distal end of a tubular member, the flange and the tubular member defining a junction with an interior radius;
- (b) providing a die having a cylindrical chamber with proximal and distal ends, the distal end being surrounded by a distally facing surface;
- (c) inserting the tubular member into the distal end of the chamber with the flange in contact with the distally facing surface;
- (d) securing a closure plate to a distal side of the die, trapping the flange within a cavity between the distally facing surface and a face on the closure plate;
- (e) providing a plunger having a cylindrical portion and an external annular shoulder, the cylindrical portion of the plunger having an outer diameter substantially equal to an inner diameter of the tubular member; and
- (f) inserting the cylindrical portion of the plunger into the tubular member and past the flange, engaging a proximal end of the tubular member with the external shoulder and applying a force that shortens a length of the tubular member and causes metal at the junction to flow, decreasing the interior radius.
10. The method as defined in claim 9, wherein the face of the closure plate is frusto-conical, causing the distally facing surface of the flange to become frusto-conical.
11. The method as defined in claim 10, wherein the conical area of the face of the closure plate has a slope in the range from 8 to 15 degrees.
12. The method as defined in claim 10, further comprising the step of machining the distally facing surface of the flange to a flat surface.
13. The method as defined in claim 9, wherein the distal end surrounded by the distal facing surface is located within an annular chamber having a cylindrical inner diameter substantially equal to an outer diameter of the flange.
14. The method as defined in claim 9, further comprising the step of applying a weld bead around an exterior fillet joining the flange with the tubular member.
15. The method as defined in claim 14, further comprising the step of machining the weld bead to a desired radius for the exterior fillet.
16. The method as defined in claim 9, wherein step (a) comprises deforming the distal end of the tubular member with a conically shaped punch to create a conical shape to create conical flange, then deforming the conical flange with a flat punch to create the a flat shape for the flange.
17. The method as defined in claim 9, wherein step (f) creates a sharp interior corner at the junction.
18. A method of forming a metal stub end fitting for a pipe, comprising:
- (a) forming a circumferentially extending flange on a distal end of a tubular member, the flange and the tubular member defining a junction with an interior radius;
- (b) providing a die having a cylindrical chamber with proximal and distal ends, the distal end being surrounded by a distally facing surface, the distally facing surface surrounding the distal end being located within an annular chamber having a cylindrical inner diameter substantially equal to an outer diameter of the flange;
- (c) inserting the tubular member into the distal end of the chamber with the flange in contact with the distally facing surface;
- (d) securing a closure plate to a distal side of the die, trapping the flange within a cavity between the distally facing surface and a face on the closure plate, the face of the closure plate being frusto-conical;
- (e) providing a plunger having a cylindrical portion and an external annular shoulder, the cylindrical portion of the plunger having an outer diameter substantially equal to an inner diameter of the tubular member;
- (f) inserting the cylindrical portion of the plunger into the tubular member and past the flange, engaging a proximal end of the tubular member with the external shoulder and applying a force that shortens a length of the tubular member and causes metal at the junction to flow, decreasing the interior radius and causing the distally facing surface of the flange to become frusto-conical;
- (g) machining the distally facing surface of the flange to a flat surface;
- (h) applying a weld bead around an exterior fillet joining the flange with the tubular member; and
- (i) machining the weld bead to a desired radius for the exterior fillet.
19. The method as defined in claim 18, wherein step (f) creates a sharp interior corner at the junction.
20. The method as defined in claim 19, wherein the conical area of the face of the closure plate has a slope in the range from 8 to 15 degrees.
Type: Application
Filed: Nov 29, 2010
Publication Date: May 31, 2012
Applicant: Mach IP LLC (Houston, TX)
Inventor: Thomas J. Mach (Houston, TX)
Application Number: 12/955,145
International Classification: B21J 5/02 (20060101); B21D 53/00 (20060101);