CA1093867A - Apparatus and method for the fabrication of internally weld-cladded pipe elbows - Google Patents
Apparatus and method for the fabrication of internally weld-cladded pipe elbowsInfo
- Publication number
- CA1093867A CA1093867A CA353,422A CA353422A CA1093867A CA 1093867 A CA1093867 A CA 1093867A CA 353422 A CA353422 A CA 353422A CA 1093867 A CA1093867 A CA 1093867A
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- Canada
- Prior art keywords
- weld
- toroidal body
- cladding
- shells
- toroidal
- Prior art date
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Abstract
Abstract of the Disclosure A weld-cladding method includes the steps of a method of internally weld-cladding a toroidal body, said method comprising the steps of forming a pair of torus-sector half-shells; machining the edges of each half-shell;
subsequently welding the half-shells together into a toroidal body; straight-ening and heat treating the toroidal body; thereafter applying a weld-clad along tangential generatrix lines on the inside of the toroidal body; and subsequently stress-annealing the weld-cladded toroidal body. As a result of use of the method, the so-called Kardo seam can be omitted.
subsequently welding the half-shells together into a toroidal body; straight-ening and heat treating the toroidal body; thereafter applying a weld-clad along tangential generatrix lines on the inside of the toroidal body; and subsequently stress-annealing the weld-cladded toroidal body. As a result of use of the method, the so-called Kardo seam can be omitted.
Description
'7 This application is a division of copending application Serial No.
294455~ filed January 6th 1978.
This invention relates to a method for the fabrication of internally weld-cladded toroidal bodies such as pipe elbows.
As is known, large pipe elbows generally consist of rela~ively thick ferritic base structures for reasons of strength and economy and are provided on the inside with austenitic weld-cladding for protection against corrosion. In order to produce such elbows, flat sheets are generally hot-pressed in a die to form torus-sector half-shells. These half-shells are then heat treated and machined at the edges. Next, the half-shells are cladded internally and subsequently welded together in two longitudinal seams. The welding operation is usually accomplished from the outside in the ~ollowing manner. ~i~st, the austenitic cladding layers which protrude at the seam location in the outermost material layer,i.e.~ in the innermost layer of the half-shells, beyond the base material are welded tight by means of the TIG (tungsten inert gas) method. Next, the entire thickness of several milli-meters of the cladding layer is filled by means of an austenitic welding material (Arosto 347).
In order to prevent carburization of the austenitic layer during a subsequent welding together of the ferritic base struckures, it has been necessary to lay down a so-called Kardo seam as an insulating layer. Such a seam consists of very low carbon material, the composition of which, for example, reads in percent by weight: C-0.01; Mo-0.05; Si-0.05; Cu-0.0~5;
P-0.01, S-0.08 and the remainder iron ~Fe). This Kardo seam protrudes ~`utward-ly beyond the cladding lay0r by a few millimeters, for example, three milli-meters and thus extends substantially into the base structure at the seam location of the hal~-shells to be welded. This Kardo seam has thereafter been followed by at least one manual seam of ferritic welding ma~erial.
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Thereafter> the seam location is filled up, preferably by a submerged arc welding technique.
However, the Kardo seam which protrudes into the ferritic base material represents a discontinuity in the strength of the pipe elbow and must be taken into consideration in designing the wall thickness.
Further, in the known processes for joining the half-shells, the cross section is generally distorted so heavily that the structure must also be straightened out aterwards. However, during this straightening process, elongations and stresses are introduced. This can lead, in a subsequent annealing operation, to structure chan~es wherein detrimental brittle frac-ture properties can occur due to the formation of a coarse grain.
AccordinglyJ it is an object of the invention to improve the con-struction of large toroidal bodies.
It is another object of the invention to improve the britt~e Fract-ure behavior of a large pipe elbow formed of half-shells which are welded together.
It is another object of the invention to avoid the need for a Kardo seam in welding two half-shells together to form a toroidal body.
Briefly, the invention provides a method for internally weld-cladding toroidal bodies such as pipe elbows.
The method comprises the steps of forming a pair of torus-sector half-shells, machining the edges of each half-shell, subsequently welding the half-shells together into a toroidal body and straightening and heat treating the toroidal body. Thereafter, the invention employs the steps of applying a weld-clad along tangential generatrix lines on the inside of the toroidal body and subsequently stress-ànnealing the weld-cladded toroidal body.
294455~ filed January 6th 1978.
This invention relates to a method for the fabrication of internally weld-cladded toroidal bodies such as pipe elbows.
As is known, large pipe elbows generally consist of rela~ively thick ferritic base structures for reasons of strength and economy and are provided on the inside with austenitic weld-cladding for protection against corrosion. In order to produce such elbows, flat sheets are generally hot-pressed in a die to form torus-sector half-shells. These half-shells are then heat treated and machined at the edges. Next, the half-shells are cladded internally and subsequently welded together in two longitudinal seams. The welding operation is usually accomplished from the outside in the ~ollowing manner. ~i~st, the austenitic cladding layers which protrude at the seam location in the outermost material layer,i.e.~ in the innermost layer of the half-shells, beyond the base material are welded tight by means of the TIG (tungsten inert gas) method. Next, the entire thickness of several milli-meters of the cladding layer is filled by means of an austenitic welding material (Arosto 347).
In order to prevent carburization of the austenitic layer during a subsequent welding together of the ferritic base struckures, it has been necessary to lay down a so-called Kardo seam as an insulating layer. Such a seam consists of very low carbon material, the composition of which, for example, reads in percent by weight: C-0.01; Mo-0.05; Si-0.05; Cu-0.0~5;
P-0.01, S-0.08 and the remainder iron ~Fe). This Kardo seam protrudes ~`utward-ly beyond the cladding lay0r by a few millimeters, for example, three milli-meters and thus extends substantially into the base structure at the seam location of the hal~-shells to be welded. This Kardo seam has thereafter been followed by at least one manual seam of ferritic welding ma~erial.
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Thereafter> the seam location is filled up, preferably by a submerged arc welding technique.
However, the Kardo seam which protrudes into the ferritic base material represents a discontinuity in the strength of the pipe elbow and must be taken into consideration in designing the wall thickness.
Further, in the known processes for joining the half-shells, the cross section is generally distorted so heavily that the structure must also be straightened out aterwards. However, during this straightening process, elongations and stresses are introduced. This can lead, in a subsequent annealing operation, to structure chan~es wherein detrimental brittle frac-ture properties can occur due to the formation of a coarse grain.
AccordinglyJ it is an object of the invention to improve the con-struction of large toroidal bodies.
It is another object of the invention to improve the britt~e Fract-ure behavior of a large pipe elbow formed of half-shells which are welded together.
It is another object of the invention to avoid the need for a Kardo seam in welding two half-shells together to form a toroidal body.
Briefly, the invention provides a method for internally weld-cladding toroidal bodies such as pipe elbows.
The method comprises the steps of forming a pair of torus-sector half-shells, machining the edges of each half-shell, subsequently welding the half-shells together into a toroidal body and straightening and heat treating the toroidal body. Thereafter, the invention employs the steps of applying a weld-clad along tangential generatrix lines on the inside of the toroidal body and subsequently stress-ànnealing the weld-cladded toroidal body.
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The method thus welds the half-shells pr;or to being weld-cladded.
As a result, the Kardo seam described above can be omitted so that the ~is-continuities of strength mentioned above no longer occur. In addition, any coarse grain which may have formed when the welded-together toroidal body is straightened out can be made a fine grain again in the subsequent stress-annealing step. This has not been possible with the previously known!f~bri-cation methods as described abovè since the already clad torus bodies must not be exposed to a high heat treatment temperature because this would lead to detrimental carburization of the austenitic cladding layer.
The heat treatment which may be used includes an annealing of the toroidal body at temperatures of 900C to 950C and a subsequent quenching in water, oil or air. In addition, the step of stress-annealing may include heating of the toroidal body to a temperature of about 600C and a subsequent cooling in air.
For the sake of clarity, the method and apparatus of the afore-mentioned application No. 294445 are described below, along with the iven-tion claimed herein.
These and other objects and advantages of t~e invention wil] be-come more apparent from the following detailed description and accompanying drawings in which:
FIGURE 1 illustrates an elevational view of an apparatus for use in prac~ising the invention; and FIGURE 2 illustrates a view taken on line II-II of FIGURE 1.
Referring to FIGURE 1, ~he apparatus for internally welding a toroidal body such as a pipe elbow 11 has a pair of pillow blocks 2, 3 in which a tilting means 4 is rotatably mounted via bearings 1. As shown, this tilting means 4 has a pair of side plates 5, 5', in which journals 6, 6' are .
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The method thus welds the half-shells pr;or to being weld-cladded.
As a result, the Kardo seam described above can be omitted so that the ~is-continuities of strength mentioned above no longer occur. In addition, any coarse grain which may have formed when the welded-together toroidal body is straightened out can be made a fine grain again in the subsequent stress-annealing step. This has not been possible with the previously known!f~bri-cation methods as described abovè since the already clad torus bodies must not be exposed to a high heat treatment temperature because this would lead to detrimental carburization of the austenitic cladding layer.
The heat treatment which may be used includes an annealing of the toroidal body at temperatures of 900C to 950C and a subsequent quenching in water, oil or air. In addition, the step of stress-annealing may include heating of the toroidal body to a temperature of about 600C and a subsequent cooling in air.
For the sake of clarity, the method and apparatus of the afore-mentioned application No. 294445 are described below, along with the iven-tion claimed herein.
These and other objects and advantages of t~e invention wil] be-come more apparent from the following detailed description and accompanying drawings in which:
FIGURE 1 illustrates an elevational view of an apparatus for use in prac~ising the invention; and FIGURE 2 illustrates a view taken on line II-II of FIGURE 1.
Referring to FIGURE 1, ~he apparatus for internally welding a toroidal body such as a pipe elbow 11 has a pair of pillow blocks 2, 3 in which a tilting means 4 is rotatably mounted via bearings 1. As shown, this tilting means 4 has a pair of side plates 5, 5', in which journals 6, 6' are .
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3~6'7 mounted and journalled in the bearings 1. In addTtion, the. tilting means has a yoke 7 which extends between the side plates 5-, 5'. The center of the yoke 7 is provided with an eye 8 (FIGURF. 2) on an axis parallel to the prin-cipal direction of the side plates 5, 5'.
In addition, ~he apparatus has a turntable 10 which is rotatably mounted via a pivot shaft 9 in the eye 8 of the yoke 7. Further, the pivo~
shaft 9 is stepped at the free end and provided with a thread 12 (FIGuRE~?) which projects beyond the yoke 7. In order to rokate the turntable 10 relative to the yoke 7, a worm gear 1~ is mounted on the reduced end of the pivot shaft 9 iTI abutment with a shoulder ~not shown) of the shaft 9 and is secured against rotation by a key (not shown) and against displacement by a nut 13 threaded onto the thrcad 12. The worm gear 14 whlch is thus rotatable about the axis of the shaft 9 meshes with a worm 26 of a reduction motor 28 mounted on the yoke 7 in suitable manner. This motor 28 is program-contro-lled in a manner (not shown), for example, by a computer.
The height of the pillow blocks 2~ 3 and ~he tilting means 4 are such that the turntable 10, including the super structures secured thereon and on the side plate 5', as described below, can be turned through an angle of 360 about the horizontal axis oF the journals 6, 6'. This hori-zontal axis also passes perpendicularly through the pivot axis of the turn-~table 10 so that during the tilting of the turntable 10, the axis of the pi~ot shaft 9 executes one revolution in a vertical plane 22.
As shown in FIGURE 1, the turntable 10, has a central cutout 20 and a plurality (e.g. 10) of radial mounting slots 21 for clamping of a toroidal body 11 to be weld-cladded thereon.
; As shown, contrary to the journal 6, the journal 6l extends beyond the bearing of the pillow block 2. This extension carries a worm gear 25 ~ , 6'7 which is secured to the journal 6'~ for example by means of a key. In order to rotate the tilting means 4 about the horizontal axis, the worm gear 25 engages a worm 27 of a reduction motor 29. Thls reduction motor 29 is pro-gram-controlled in a manner simllar to the reduction motor 28.
A curved outrigger 35 is detachably secured to the tilting means
In addition, ~he apparatus has a turntable 10 which is rotatably mounted via a pivot shaft 9 in the eye 8 of the yoke 7. Further, the pivo~
shaft 9 is stepped at the free end and provided with a thread 12 (FIGuRE~?) which projects beyond the yoke 7. In order to rokate the turntable 10 relative to the yoke 7, a worm gear 1~ is mounted on the reduced end of the pivot shaft 9 iTI abutment with a shoulder ~not shown) of the shaft 9 and is secured against rotation by a key (not shown) and against displacement by a nut 13 threaded onto the thrcad 12. The worm gear 14 whlch is thus rotatable about the axis of the shaft 9 meshes with a worm 26 of a reduction motor 28 mounted on the yoke 7 in suitable manner. This motor 28 is program-contro-lled in a manner (not shown), for example, by a computer.
The height of the pillow blocks 2~ 3 and ~he tilting means 4 are such that the turntable 10, including the super structures secured thereon and on the side plate 5', as described below, can be turned through an angle of 360 about the horizontal axis oF the journals 6, 6'. This hori-zontal axis also passes perpendicularly through the pivot axis of the turn-~table 10 so that during the tilting of the turntable 10, the axis of the pi~ot shaft 9 executes one revolution in a vertical plane 22.
As shown in FIGURE 1, the turntable 10, has a central cutout 20 and a plurality (e.g. 10) of radial mounting slots 21 for clamping of a toroidal body 11 to be weld-cladded thereon.
; As shown, contrary to the journal 6, the journal 6l extends beyond the bearing of the pillow block 2. This extension carries a worm gear 25 ~ , 6'7 which is secured to the journal 6'~ for example by means of a key. In order to rotate the tilting means 4 about the horizontal axis, the worm gear 25 engages a worm 27 of a reduction motor 29. Thls reduction motor 29 is pro-gram-controlled in a manner simllar to the reduction motor 28.
A curved outrigger 35 is detachably secured to the tilting means
4 about a center of curvature located on the pivot axis of the pivot shaft ~. In addition, a means is provided for ad~usting the outrigger 35 relative to the pivot axis and to the plane of the turntable 10. This means includes a plate 30 provided with a slot 31 through which a screw 24 passes into the side plate 5' to hold the plate 30 on the side plate 5' and a slotted arm 34 of the outrigger 35. The slotted arm 34 is fastened on the plate 30 by means of a screw 32 which threads into a region of the plate 30 outside of the slot 31. In addition, a spacer 33 is provided between the plate 30 and the arm 34. As shown, the outrigger 35 is curved over most oE its length and has a radius of curvature corresponding to the radius of curvature of the toroidal body 11. For bodies 11 of different radii of curvature, differently curved outriggers 35 are provided. Accordingly, the mounting of the outriggers 35 to the tilting means 4 is made detachably to permit ready replacement.
A weld-cladding means 37 is detachably mounted on the outrigger 35 for rotation in a vertical plane relative to the outrigger 35. As shown, the weld-cladding means 37 is disposed at the free end of the ou~-rigger 35 so as to be disposed in common with the pivot axis of the turn-table 10 in the vertical plane 22. The mounting is such that the weld-cladding means 37 is rotatable relative to the turntable 10 and the tilting means 4. The weld-cladding means 37 receives welding material in ribbon form from a roll 40 which is rotatably mounted on the outrigger 35.
': ' 3~^7 ~lternatively, in order to guide the ribbon in a simpler manner, the roll 40 may be disposed on an axis parallel to the pivot shaft 9 rather than in per-pendicular relation as shown so that the surface of the ribbon is perpen-dicular to the turntable 10.
The spacer 33 between the plate 30 and arm 34 may consist of an elctrically non-conductive material and the screw 32 can be surrounded by or underlayed with an insulator so as to provide a means for electrically in-sulating the outrigger 35 from the tilting means 4 and the turntable 10.
In this case, welding current can be fed via the o~ltrigger 35 to the weld-cladding means 37. This can be accomplished in any suitable manner and isnot further described.
The weld-cladding means 37 can be controlled in synchroTIism with the reduction motor 29 in such a manner that the principal axis o~ the weld-cladding means 37 always remains vertical in space. ~lowever, it is also possible to reset the vertical ~osition of the cladding means 37 in the vertical plane 22 prior to each operation thereof. This is always p~eceded by an incremental movement or step of the turntable 10 in the tilting direction.
As shown in ~IGURE 1, the toroldal body forms a 90 angle and is clamped to the turntable 10 by means of three clamps ~2 in such a manner that the axis of curvature of the body 11 is coaxial with the pivot shaft 9.
By shifting the plate 30 and the arm 34 in the ranges permitted by the slots, the outrigger 35 can be set so that the pivot point of the weld-cladding means 37 coincides with the longitudinal axis, i.e., the center of the cir-cle generating the toroidal surface of the shaped body 11. Thus~ when the table 10 rotates, the pivot point of the weld-cladding means 37 is always located on the core axis 23 of the body 11 as the body 11 rotates about the , - . - ,: - ~.:
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,. ;.~ . .. .~: , axis of the pivot shaft 9.
In order to fabricate a toroidal body such as a pipe elbow 11, the following steps are carried out. First, two torus-sector half-shells are fabricated ~rom suitably cut sheets in a known manner by die forging. These half-shells are then machined at the longitudinal edges, i.e., prepared for a subsequent welding operation, for instance, by deburring and cleaning the edges so as to provide the edges with a surface suitable for welding. The surfaces are then welded together to form a toroidal body of the two half-shells. In order to remove any deformation that may have occurred during welding, the toroidal body 11 is then straightened out and subsequently heat treated for tempering or removal o stresses due to the straightening opera-tion, This heat treatment co~sists of amlealing of the toroidal body at temperatures of 900C to 950C and a subsequent quenching in water, oil or air.
Thereafter, the toroidal body is aligned on the turntc~le 10 with the axis of the curvature of the body 11 parallel to the axis of the pivot 9.
The body 11 is then fastened by means of the clamps 42. Unless the outrigger 35 and the weld-cladding means 37 are already mounted and set up with the welding means 37 in the vertical plane 22, as would be the case in the fabri-Z0 cation of a number of elbows with the same shapes and dimensions, the out-rigger 35 is selected according to the curvature of the toroidal body 11 and is mounted and adjusted on the side plate 5' by means of the plates 30, 31.
The adjustment is such that the welding means 37 is located with its center of rotation in the vertical plane 22, and more specifically, in the center of the circle generating the toroida] body 11. During this adjustment, the welding means 37 canad~antageously be removed from the outrigger 35 i~ the center of rotation of the welding means 37 is marked at the outrigger 35.
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The body 11, outrigger 35, and welding means 37 are then mutually aligned so that the pivot point of the weld-cladding means 37 is located on the core axis 23 of the toroidal body 11 when the turntable 10 rotates about the axis of the shaft 9. llowever, it is also possible to arrange the weld-cladding means 37 eccentrically of the axis of the shaft g. This requires the pivot point to be reset after each incremental tilting of the turntable 10 in the tilting direction.
The cladding layer is then applied in incremental steps. To this end, the turntable 10 is rotated about the axis of the shaft 9 by an angle which corresponds at least to the angle defined by the toroidal body 11.
This constitutes a working forward stroke during which material is applied.
The turntable is then rotated in the opposite direction. This constitutes an idle reverse stroke during which ma~erial is not applied. Between each two working strokes, the inc]ination of the turntable 10 is changed in the tilt-ing direction in accordance with the wid~h of the cladding. This is carried out by an incremental tilting of the table 10 about the axis of the journals 6, 6' via the reduction motor 29 and gears 27, 25. During this time, the position of the weld-cladding means 37 is automatically changed relative to the outrigger 35 in the opposite direction or must be readjusted by hand so that the cladding means 37 retains a vertical position for each working stroke.
If required, a welding powder funnel which is provided at the welding means 37 can be refilled between the two working strokes. Alternatively~ an auto-matic feed for the powder may be provided.
After applying the weld-clad along the tangential genera~rix lines on the inside of the toroidal body, the body 11 is stress-annealed. This step can be accomplished by heating the finished pipe elbow or toroidal body 11 to about 600C and subsequently cooling the elbow in air.
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A weld-cladding means 37 is detachably mounted on the outrigger 35 for rotation in a vertical plane relative to the outrigger 35. As shown, the weld-cladding means 37 is disposed at the free end of the ou~-rigger 35 so as to be disposed in common with the pivot axis of the turn-table 10 in the vertical plane 22. The mounting is such that the weld-cladding means 37 is rotatable relative to the turntable 10 and the tilting means 4. The weld-cladding means 37 receives welding material in ribbon form from a roll 40 which is rotatably mounted on the outrigger 35.
': ' 3~^7 ~lternatively, in order to guide the ribbon in a simpler manner, the roll 40 may be disposed on an axis parallel to the pivot shaft 9 rather than in per-pendicular relation as shown so that the surface of the ribbon is perpen-dicular to the turntable 10.
The spacer 33 between the plate 30 and arm 34 may consist of an elctrically non-conductive material and the screw 32 can be surrounded by or underlayed with an insulator so as to provide a means for electrically in-sulating the outrigger 35 from the tilting means 4 and the turntable 10.
In this case, welding current can be fed via the o~ltrigger 35 to the weld-cladding means 37. This can be accomplished in any suitable manner and isnot further described.
The weld-cladding means 37 can be controlled in synchroTIism with the reduction motor 29 in such a manner that the principal axis o~ the weld-cladding means 37 always remains vertical in space. ~lowever, it is also possible to reset the vertical ~osition of the cladding means 37 in the vertical plane 22 prior to each operation thereof. This is always p~eceded by an incremental movement or step of the turntable 10 in the tilting direction.
As shown in ~IGURE 1, the toroldal body forms a 90 angle and is clamped to the turntable 10 by means of three clamps ~2 in such a manner that the axis of curvature of the body 11 is coaxial with the pivot shaft 9.
By shifting the plate 30 and the arm 34 in the ranges permitted by the slots, the outrigger 35 can be set so that the pivot point of the weld-cladding means 37 coincides with the longitudinal axis, i.e., the center of the cir-cle generating the toroidal surface of the shaped body 11. Thus~ when the table 10 rotates, the pivot point of the weld-cladding means 37 is always located on the core axis 23 of the body 11 as the body 11 rotates about the , - . - ,: - ~.:
,, : ~ . .
,,, . .~ -., ~ .. .
:., .. :~,.. . .::i :,:
,. ;.~ . .. .~: , axis of the pivot shaft 9.
In order to fabricate a toroidal body such as a pipe elbow 11, the following steps are carried out. First, two torus-sector half-shells are fabricated ~rom suitably cut sheets in a known manner by die forging. These half-shells are then machined at the longitudinal edges, i.e., prepared for a subsequent welding operation, for instance, by deburring and cleaning the edges so as to provide the edges with a surface suitable for welding. The surfaces are then welded together to form a toroidal body of the two half-shells. In order to remove any deformation that may have occurred during welding, the toroidal body 11 is then straightened out and subsequently heat treated for tempering or removal o stresses due to the straightening opera-tion, This heat treatment co~sists of amlealing of the toroidal body at temperatures of 900C to 950C and a subsequent quenching in water, oil or air.
Thereafter, the toroidal body is aligned on the turntc~le 10 with the axis of the curvature of the body 11 parallel to the axis of the pivot 9.
The body 11 is then fastened by means of the clamps 42. Unless the outrigger 35 and the weld-cladding means 37 are already mounted and set up with the welding means 37 in the vertical plane 22, as would be the case in the fabri-Z0 cation of a number of elbows with the same shapes and dimensions, the out-rigger 35 is selected according to the curvature of the toroidal body 11 and is mounted and adjusted on the side plate 5' by means of the plates 30, 31.
The adjustment is such that the welding means 37 is located with its center of rotation in the vertical plane 22, and more specifically, in the center of the circle generating the toroida] body 11. During this adjustment, the welding means 37 canad~antageously be removed from the outrigger 35 i~ the center of rotation of the welding means 37 is marked at the outrigger 35.
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The body 11, outrigger 35, and welding means 37 are then mutually aligned so that the pivot point of the weld-cladding means 37 is located on the core axis 23 of the toroidal body 11 when the turntable 10 rotates about the axis of the shaft 9. llowever, it is also possible to arrange the weld-cladding means 37 eccentrically of the axis of the shaft g. This requires the pivot point to be reset after each incremental tilting of the turntable 10 in the tilting direction.
The cladding layer is then applied in incremental steps. To this end, the turntable 10 is rotated about the axis of the shaft 9 by an angle which corresponds at least to the angle defined by the toroidal body 11.
This constitutes a working forward stroke during which material is applied.
The turntable is then rotated in the opposite direction. This constitutes an idle reverse stroke during which ma~erial is not applied. Between each two working strokes, the inc]ination of the turntable 10 is changed in the tilt-ing direction in accordance with the wid~h of the cladding. This is carried out by an incremental tilting of the table 10 about the axis of the journals 6, 6' via the reduction motor 29 and gears 27, 25. During this time, the position of the weld-cladding means 37 is automatically changed relative to the outrigger 35 in the opposite direction or must be readjusted by hand so that the cladding means 37 retains a vertical position for each working stroke.
If required, a welding powder funnel which is provided at the welding means 37 can be refilled between the two working strokes. Alternatively~ an auto-matic feed for the powder may be provided.
After applying the weld-clad along the tangential genera~rix lines on the inside of the toroidal body, the body 11 is stress-annealed. This step can be accomplished by heating the finished pipe elbow or toroidal body 11 to about 600C and subsequently cooling the elbow in air.
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Claims (2)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of internally weld-cladding a toroidal body, said method comprising the steps of forming a pair of torus-sector half-shells;
mechining the edges of each half-shell;
subsequently welding the half-shells together into a toroidal body;
straightening and heat treating the toroidal body;
thereafter applying a weld-clad along tangential generatrix lines on the inside of the toroidal body; and subsequently stress-annealing the weld-cladded toroidal body.
mechining the edges of each half-shell;
subsequently welding the half-shells together into a toroidal body;
straightening and heat treating the toroidal body;
thereafter applying a weld-clad along tangential generatrix lines on the inside of the toroidal body; and subsequently stress-annealing the weld-cladded toroidal body.
2. A method as set forth in claim 1 wherein said step of heat treat-ing includes annealing of the toroidal body at temperatures of 900°C to 950°C
and subsequent quenching in one of water, oil and air and said step of stress-annealing includes heating of the toroidal body to a temperature of about 600°C and subsequent cooling in air.
and subsequent quenching in one of water, oil and air and said step of stress-annealing includes heating of the toroidal body to a temperature of about 600°C and subsequent cooling in air.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA353,422A CA1093867A (en) | 1977-01-10 | 1980-06-05 | Apparatus and method for the fabrication of internally weld-cladded pipe elbows |
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH238/77 | 1977-01-10 | ||
| CH23877A CH609268A5 (en) | 1977-01-10 | 1977-01-10 | |
| CA294,455A CA1090172A (en) | 1977-01-10 | 1978-01-06 | Apparatus and method of the fabrication of internally weld-cladded pipe elbows |
| CA353,422A CA1093867A (en) | 1977-01-10 | 1980-06-05 | Apparatus and method for the fabrication of internally weld-cladded pipe elbows |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1093867A true CA1093867A (en) | 1981-01-20 |
Family
ID=27165455
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA353,422A Expired CA1093867A (en) | 1977-01-10 | 1980-06-05 | Apparatus and method for the fabrication of internally weld-cladded pipe elbows |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1093867A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111088419A (en) * | 2019-12-09 | 2020-05-01 | 河北亚都管道装备集团有限公司 | Manufacturing method of large-caliber thick-wall seamless hot-pressing elbow of 630 ℃ ultra-supercritical unit G115 and elbow |
-
1980
- 1980-06-05 CA CA353,422A patent/CA1093867A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111088419A (en) * | 2019-12-09 | 2020-05-01 | 河北亚都管道装备集团有限公司 | Manufacturing method of large-caliber thick-wall seamless hot-pressing elbow of 630 ℃ ultra-supercritical unit G115 and elbow |
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