EP0089019B1

EP0089019B1 - Method and apparatus for sequentially quenching steel pipes

Info

Publication number: EP0089019B1
Application number: EP19830102368
Authority: EP
Inventors: Frederick William Kruppert
Original assignee: Kruppert Enterprises Inc
Current assignee: Kruppert Enterprises Inc
Priority date: 1982-03-17
Filing date: 1983-03-10
Publication date: 1986-12-30
Also published as: DE3368686D1; EP0089019A3; JPS58171528A; CA1205730A; EP0089019A2

Description

The present invention relates to an apparatus and method for hardening steel and more particularly to a method and apparatus for sequentially quenching steel pipes of substantial and varying thicknesses.
The production of steel tubular products may be accomplished by a variety of methods. For example, in the Fretz-Moon process, which is based on the principle of forge welding, an endless strip of steel is heated to about 2552°F (1400°C) and then fed through a series of shaping and welding rolls. In the Mannesmann piercing process, which relies on the principle of helical rolling, the steel is rolled to a minimum width and then pierced by a mandrel, which forms a cavity in the steel bar. The thick-walled tube produced by this process can subsequently be reduced to thin-walled tubing by passing it through special rolls, which vary in cross-sectional shape around their circumference. Other processes include the use of hot extrusion and rotary forging among other techniques.
After completion of these processes for producing tubular products, the steel must be subsequently hardened by heat treating. Quenching is one of the oldest and most common methods of hardening steel by heat treatment. It consists of heating the steel above its critical transformation temperature at which a component known as austenite begins to form, and then cooling it fast enough, usually by quenching into a liquid such as water or oil, to avoid any transformation of the austenite until it reaches the relatively low temperature range within which it transforms to a hard martensite. The steel is subsequently reheated or tempered to remove the internal stresses caused by the inherent expansion of the martensite.
Traditional heat treating processes and apparatus are generally limited in the number of tubular pieces of steel which can be handled regardless of the size of each piece. Thus, if the same facilities are employed where smaller tubular products are treated, the cost per weight of steel processed increases. For example, a typical quenching unit may only handle up to 160 pipes per hour regardless of size, although the rate of pipe production is a function of the weight of steel in the pipes. Thus, if a heat treating line, including an austenizing furnace, a quenching unit, and a tempering furnace, is to be profitable it must be built or adapted to produce a given range of pipe, such as 4.76 cm to 14 cm outside diameter.
The traditional methods and apparatus are not only limited in the number of tubular products that can be quenched, due to an inability to maintain throughput based on the weight of steel, but the thickness of the steel is also a limiting factor. The quenching of steel from its critical transformation temperature to the martensitic transformation temperature requires a rather severe cooling rate if the formation of pearlite is to be avoided. Given the importance of the cooling rate in producing the desired properties, the production of large pieces of steel has always presented particular difficulties, since the temperature drop at the center of a given piece of steel lags the temperature drop at the surface.
A number of processes have been developed in an attempt to address these problems. As to thickness or size, metal alloys, such as manganese, silicon, nickel or chromium have been added to retard the formation of pearlite to allow for an initial lower quench and to enhance in other ways the final properties of the steel. However, the use of alloys adds considerably to the expense of the steel.
GB-A-1 097 029 discloses an installation for cooling of slab blooms or similar products. The installation includes a plurality of wheels fixed to a horizontal shaft and provided with apertures having a closed contour and angularly spaced one from another about the wheel axis. The apertures in one wheel are horizontally aligned with the apertures of the other wheels. The slab blooms or similar products to be cooled are plunged into a vessel containing a liquid coolant as the wheels rotate. A roller conveyor is provided for introducing the products to be cooled into the apertures and for extracting same therefrom.
U.S. Patent No. 3,877,685 discloses an apparatus for quenching a steel pipe with a cooling medium including an isolator which is in fluid communication with a retractable nozzle. The isolator and retractable nozzle cooperate so that the relative proportion of cooling liquid passing into the pipe and around the pipe may be varied. The flow of cooling medium is directed along the longitudinal axis of the steel pipe.
U.S. Patent No. 4,165,246 discloses a process for heat treating steel pipes with a wall thickness ranging from 16 to 36 mm. After the steel pipe is heated, it is passed on rollers to a cooling zone while water directed from nozzles encircling the pipe quenches the surface below the martensitic transformation temperature.
U.S. Patent No. 4,116,716 discloses an immersion cooling apparatus including a cooling tank containing cooling liquid, a mechanism for locking the immersed pipe in position, and a nozzle extending toward the interior of the pipe in the direction of the pipe axis.
U.S. Patent No. 3,650,282 discloses the use of a circumferential support equipped with a closely spaced array of jet structures which apparently establish a water curtain or solid sheet of water to penetrate a steam film.
These and other devices and methods, which employ a variety of quenching mechanisms using cooling baths and the like, as well as varying assembly line techniques, suffer from one or more of several limitations. For example, these devices and methods often fail to provide a sufficiently severe quench, so that the thickness of steel pipe which may be successfully treated is limited. Likewise, the strength and other properties attainable for a given thickness of pipe are limited. Also, many devices and methods do not provide uniform cooling or cannot accommodate a steel piece of varying thickness such as upset pipe. Additionally, some devices cannot vary the character of the quench from segment to segment or along the length of a pipe. Furthermore, these devices and methods generally fail to provide a process which can sequentially quench a number of tubular products at a steady processing rate based on the weight of steel processed. Moreover, such methods and devices are limited in the number of tubular pieces of steel which may be processed. This, in turn, often necessitates additional process steps, such as reheating prior to quenching.
These and other limitations of prior processes and methods are substantially minimized if not eliminated by the present invention.
The apparatus of the present invention is defined in claim 1. The apparatus includes a rotatable magazine having a plurality of receptacles for detachably holding the steel pieces and a cooling medium source for supplying a cooling medium to each receptacle. In one embodiment the cooling medium source includes a means for separately directing a cooling medium in a substantially circumferential flow pattern around the exterior surface of the steel piece as it is held in a receptacle. In another embodiment each receptacle has a primary opening along its length for accepting the steel piece. Each receptacle may also be equipped with a secondary opening for discharging the cooling medium. Closing means may be provided for selectively closing off the primary and secondary openings. Each receptacle may have at least one sliding clamp for selectively securing the steel piece in the receptacle.
Each barrel may be divided into compartments to facilitate a rate of cooling variable among exterior segments of the steel piece. Additionally, each barrel may be adapted to receive a steel pipe of varying diameter or, through use of a blank, of varying length. The blank may comprise a hollow-bodied steel piece with an opening at each end thereof. Each barrel may be equipped with a plurality of openings for channeling the cooling medium in substantially circumferential flow around exterior segments of the piece of steel. At least a portion of the openings may be equipped with nozzles.
The steel piece preferably rests on partitions mounted along the interior of the barrel. The partitions are preferably contoured to fit the exterior surface of the steel piece.
Internal quenching means may be provided for supplying a cooling medium to the interior of the hollow bodied steel piece while it is held in a barrel. In one embodiment the internal quenching means includes a means for passing a cooling medium through the interior of the steel piece and a means for injecting a gas into the cooling medium to insure sufficient turbulence in the cooling medium as it passes through the interior of the piece to facilitate heat transfer from the interior surface of the piece to the cooling medium.
In another embodiment the interior quenching means may include a cooling medium conduit located along the axis of the pipe and having a tapered outlet adapted to direct the cooling medium into the interior of a pipe. A gas conduit is telescopically mated in the cooling medium conduit and has a gas conduit outlet near the tapered outlet of the cooling medium conduit. The gas conduit outlet is adapted to inject the gas from the gas conduit into the cooling medium. Additionally, a series of helical vanes are mounted in the interior of the cooling medium conduit for imparting a helical flow pattern to the cooling medium leaving the tapered outlet. The helical vanes may be mounted at an angle of about 35 degrees with the horizontal axis of the pipe.
In another embodiment, the cooling medium source is adapted to increase the pressure of the cooling medium on the exterior of a hollow bodied steel piece upon the supplying of the cooling medium to the interior of the piece. For example, the cooling medium source may include a primary cooling medium conduit, exterior and interior cooling medium conduits for respectively delivering a cooling medium to the interior and exterior of the hollow bodied steel piece in each barrel, and a feeder conduit for selectively placing the exterior and interior cooling medium conduit in communication with each other. The feeder conduit may be equipped with a one-way valve.
In another embodiment the apparatus of the present invention may include a motor driven rotatable magazine having interior quenching means and an exterior quenching means mounted on the magazine, a primary cooling medium source for supplying cooling medium to the interior quenching means and exterior quenching means, a motor for rotating the magazine, a feeder for placing each pipe in a barrel, and a receiver for sequentially receiving each pipe from a barrel. The rotatable magazine includes two circular plates rotatably mounted in spaced relation to each other. The plates have a plurality of openings spaced around and at a distance from the center of each plate. The plates are connected by a plurality of barrels mounted to the inside face of each plate such that the barrels are in communication with the openings in the plates. Each barrel is of a sufficient length to receive a pipe and includes: a primary opening along its length for accepting a pipe, a secondary opening for discharging water from the barrel, a closing means for selectively closing off the primary and secondary openings, a plurality of partitions for cradling a pipe and separating the barrel into a plurality of compartments along its length and a plurality of openings in the surface of each barrel for circulating a cooling medium. The interior quenching means may include a plurality of cooling medium conduits tapered outlets for directing water into the interior of the pipe. One end of the conduit is connected to the openings and located along the axis of a pipe as it rests in a barrel. Each exterior quenching conduit may include a series of secondary conduits for supplying a cooling medium to each compartment of each barrel. The primary cooling medium source supplies the cooling medium to both the interior quenching means and the exterior quenching means. To this end the primary cooling medium source includes a conduit rotatable in relation to the base.
There is also provided a method of sequentially heat treating a steel pipe including the steps of: (1) heating each pipe to a temperature above its austenizing temperature; (2) moving a plurality of.barrels along a cyclical path from an inlet station to an outlet station while concurrently: (a) filling each barrel with a sufficient amount of a cooling medium to cushion a pipe as it is placed in the barrel; (b) placing a pipe in each barrel as it passes the inlet station; (c) circulating the cooling medium around the exterior of the pipe while directing a cooling medium through the interior of the pipe as the receptacle travels from the inlet to the outlet station; and (d) removing the pipe from the barrel at the outlet station.
In accordance with one aspect of the present invention the weight of the steel pieces or pipes heated above their austenizing temperature is at least equal to the weight of the steel pipes quenched in a given period of time. In accordance with another aspect of the present invention a portion of the cooling medium initially directed to the interior of each pipe is selectively routed to the exterior of the pipe in order to affect the pressure of the cooling medium circulating around the pipe.
If water is used forthe cooling medium, the water used for both interior and exterior quenching should be maintained at a temperature of 27°C or less. Further, the water passing through the system should be generally at a pressure in the range of 56,300 to 91,500 kg/m2.
Examples of the more important features of this invention have thus been summarized rather broadly in order that the detailed description thereof that follows may be better understood, and in order that the contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter, and which will also form the subject of claims appended hereto.

Figure 1 is an elevation view of a preferred embodiment of the present invention taken along line 1-1 of Figure 2;
Figure 2 is a cross-sectional view of a preferred embodiment of the present invention;
Figure 3 is a closeup view of a portion of the embodiment shown in Figure 2;
Figure 4 is another view of a portion of the embodiment shown in Figure 2 and taken along line 4-4 of Figure 3;
Figure 5 is another view of the portion of the embodiment shown in Figure 3;
Figure 6 is a cross-sectional view of a portion of the embodiment shown in Figure 2;
Figure 7 is a vertical cross-sectional view of a portion of an internal quenching means;
Figure 8 is a partial cross-sectional frontal view taken along line 8-8 from Figure 7; and
Figure 9 is a closeup view of a gas conduit outlet of the internal quenching means shown in Figure 7.
Reference to these drawings will further explain the invention when taken in conjunction with the description of the preferred embodiments.

Referring generally to Figures 1-9, there will now be described a preferred device and method of sequentially quenching steel pipe in accordance with the present invention. Generally, the apparatus may include a means for imparting rotation 10, a magazine 30, a gas supply system 40, barrels or receptacles 50, clamping means 70, feed mechanism 110, receiver 130, interior quenching means or internal quencher 140, cooling medium source 180, and exterior cooling or quenching means 190. The magazine, which is rotated by means for imparting rotation 10, includes plates 31 and 32 between which are mounted barrels or receptacles 50. Feed mechanism-110 is adapted to place a pipe into each barrel as it rotates in magazine 30. The pipes are held in the barrels 50 by clamping means 70 and are quenched by interior quenching means 140 and exterior cooling means 190 as each barrel rotates in the magazine and moves toward receiver 130. Each quenched pipe is subsequently released onto receiver 130 from which it may be forwarded for further processing. Cooling medium source 180 supplies cooling medium to the interior quenching means 140 and the exterior cooling means 190 throughout the process.
As shall hereinafter be more fully described, interior quenching means and exterior cooling means useful in this invention as well as other matters related to this invention are described in part in the applicant's copending European patent application, Publication No. 0086988 and entitled "Method and Apparatus for Quenching Steel Pipes", which is hereby incorporated by reference.
Referring now to Figures 1 and 2 means for imparting rotation shown generally at 10 include a variable speed motor 11 which is mounted on a motor base 12. Plate gear yokes 15 and 16 are respectively mounted on bases 13 and 14. Shafts 19 and 20 are journaled at one end into and through plate gear yokes 15 and 16, respectively, and are operatively connected at the other end to the variable speed motor 11. Plate gears 16 and 17 are integrally mounted on shafts 19 and 20, respectively, such that they are located within yokes 15 and 16. As the plate gears are integrally mounted on shafts 19 and 20, rotation of those shafts by variable speed motor 11 causes the rotation of the plate gears in plate gear yokes 15 and 16.
A magazine shown generally at 30 includes two circular plates 31 and 32. A portion of each plate is provided with teeth around its circumference which are adapted to mesh with the teeth of plate gears 17 and 18, respectively. Additionally, a circumferential segment of each plate is adapted to engage grooved rolls 21, which are mounted on bases 24 by means of pins 22 and flanges 23. Thus, each of the plates 31 and 32 are rotatably supported at grooved rolls 21 and plate gears 17 or 18. Additionally, as the teeth of plate gears 17 and 18 mesh with the teeth of plates 31 and 32, respectively, rotation of shafts 19 and 20 by variable speed motor 11 causes the rotation of plates 31 and 32.
As shown in Figure 1 plates 31 and 32 are connected by means of barrels or receptacles 50. Access to each barrel 50 through plates 31 and 32 is provided by means of openings 33, which are spaced around and at a distance from the center of each plate. As each barrel 50 is integrally mounted at either end to plates 31 and 32, each circumferentially spaced barrel 50 rotates with plates 31 and 32.
Plates 31 and 32 are also provided with central openings 34, while plate 32 is equipped with auxiliary plate openings 35. Gas or air reservoir 44 is integrally mounted through central plate openings 34, while exterior feed conduits 191 of exterior quenching means 190 pass through auxiliary openings 35 in plate 32 and are attached at one end to plate 31. As with the barrels or receptacles 50, air or gas reservoir 44 and exterior feed conduits 191 are integrally mounted to plates 31 and 32 and so rotate along with plates 31 and 32 and barrels 50.
Gas or air reservoir 44 is supplied by a gas supply system shown generally at 40. Gas reservoir 44 is essentially a hollow cylinder which is supplied with gas at one end by conduit 43 and sealed at the other end by means of gas reservoir wall 45. The gas supply system includes a gas supply pipe 41 which is fixed in relation to magazine 30. Inlet conduit 43 is in communication at one end with gas reservoir 44 and at the other end with gas supply pipe 41 through means of swivel coupling 42. Thus, conduit 43 places air reservoir 44 in communication with gas supply pipe 41, while still allowing inlet conduit 43 to rotate in relation to gas supply conduit 41, which is stationary.
Referring now to Figures 1 through 6, barrels or receptacles 50 are provided with primary openings 51 and secondary openings 52. Primary openings 51 are of sufficient size to accept each pipe 90 as it is fed to each barrel 50 from feeding mechanism 110 as shall hereinafter be more fully described. The secondary openings indicated at 52 allow the discharge of cooling medium from each barrel. The secondary openings 52 may be selectively closed by an appropriate closing means such as shutter 79.
Each barrel 50 is divided into compartments along its length by means of partitions 53. Each partition 53 is detachably mounted on the surface of each barrel by means of flanges 57 and bolts 54. Flanges 57 are integrally mounted to the interior surface of each barrel 50 such that each partition 53 is securely yet detachably mounted in each barrel 50 by means of bolts 54.
The surface of each barrel 50 is also provided with a plurality of openings 55 which place the interior of each barrel 50 in communication with a cooling medium passing from branch pipes 193 through flow chambers 195 of exterior cooling means 190. The openings 55 are adapted to direct a cooling medium from each flow chamber 195 in a circumferential flow pattern around the exterior surface of a pipe or other object resting in the barrel. By way of example, the openings 55 may be placed at varying angles depending upon their location around the interior surface of each barrel 50.
Openings 55 may also be threaded. Nozzles 56 may then be inserted in the threaded holes to direct the cooling medium from each flow chamber 195 in a substantially circumferential flow pattern around the exterior surface of the pipe resting in each barrel. As the holes may be filled with plugs, the number, as well the type of nozzles, may be varied depending on the specific flow pattern desired. Alternately, the flow chambers 195 may be equipped with deflector plates as described in applicant's co-pending application, serial number 346,755, filed February 8, 1982, which is hereby incorporated by reference.
Each barrel 50 is provided with a plurality of clamping means 70 which serves to hold each pipe 90 in place as the barrel rotates in magazine 30 from feed mechanism 110 to receiver 130. As best shown in Figures 3-6 the clamping means includes a contoured clamping rib 83 which may be detachably mounted to clamp rib flanges 82 by means of clamping bolts 81. The clamp rib flanges 82 are in turn integrally attached at one end to clamping arm 71. Consequently, the movement of clamping arm 71 causes the movement of clamp rib flanges 82 and hence contoured clamping rib 83. Clamping rib flanges 82_; contoured clamping rib 83 and bolts 81 thus form a movable clamping member 80 which slides circumferentially in each receptacle.
The clamping means 70 is also equipped with a closing means in the form of a deflection plate cover or shutter 79. The shutter is integrally attached at one end to clamping arm 71 and is slidably mounted on the outside surface of barrel 50. Thus, as shown in Figures 3 and 5, as clamping arm 71 moves along clamping arm slot 84, deflector plate cover or shroud 79 moves over primary barrel opening 51. As indicated in Figure 5, an end segment of shutter 79 overlaps a segment of the exterior barrel wall on the opposite side of primary opening 51. Deflection plate cover or shutter 79 runs a sufficient distance along the length of the barrel to close off an appropriate segment of primary opening or slot 51 as shall hereinafter be more fully described.
Shutter 79 may be mounted such that a portion of shutter 79 as indicated at 85 may act as a closing means to selectively close secondary opening 52. Thus, when shutter 79 covers primary opening 51, secondary opening 52 is open. However, when shutter 79 is withdrawn from primary opening 51, secondary opening 52 is covered. Although openings 51 and 52 are preferably alternately opened and closed, primary opening 51, secondary opening 52, and shutter 79 may also be arranged such that openings 51, 52, or both may be partially uncovered depending upon the pressure of the cooling medium and the particular quenching pattern desired.
At the opposite end from movable clamping member 80, clamping arm 71 is attached to flange 73 by means of clamp arm pin 72. As best shown in Figures 2 and 6, flange 73 is integrally attached to clamp cylinder shaft or piston 76. Movement of clamp cylinder piston 76 by clamp cylinder 74 thus causes movement of clamping arm 71 and so movement of shutter 79 as well as movable clamping member 80.
Each clamping cylinder 74 is pivotally mounted on exterior feed conduit 191 by means of flange 75, clamp cylinder bracket 77 and clamp cylinder pins 78. Flange 75 is integrally mounted to the exterior of exterior feed conduit 191, while clamp cylinder 74 is free to rotate about pins 78 which are integrally attached to clamp cylinder 74 at one end and rotatably mounted into clamp cylinder brackets 77 at the other end.
In accordance with one aspect of the present invention, the arrangement of the shutter 79, and the openings 55 or nozzles 56 should be such as to provide a circumferential flow pattern of the cooling medium around the exterior of the pipe 90. The cooling medium is preferably directed so as not to impinge upon the pipe surface in order to facilitate uniform cooling of the pipe. As indicated in Figure 5 the closing of shutter 79 aids in the completion of the circumferential flow pattern about the upper portion of each pipe 90. Depending upon the exact nature of the circumferential flow desired, the shutters 79 should extend substantially along the length of each barrel 50.
As also shown in Figure 5 partitions 53 and contoured clamping ribs 83 are preferably adapted to closely conform to the circumference of the pipe 90 as it rests in each barrel 50. However, depending upon the type of pipe and the type of cooling sequence, it may be unnecessary to have the partitions or clamping ribs or both contoured to the surface of the pipe. Additionally, each of the upper segments of the partitions 53 and the contoured clamping ribs 83 are adapted to facilitate movement of a pipe 90 in and out of each barrel or receptacle 50. As the type of partition 53 or contoured clamping rib 83 may differ along the length of the barrel 50, pipes of varying sizes and diameters may be accommodated. Additionally, any given clamping rib 83 or quenching support or partition 53 may be readily detached by removal of bolts or pins 81 or 54, respectively, and replaced with a different rib or partition. Thus, each barrel may be adapted to handle varying sizes of pipe with variable circumferences along their length.
By way of example, the partitions and clamping ribs closer to the center of a barrel may accommodate a pipe with an outside diameter of five inches (12.7 cm) while partitions or ribs able to accommodate a pipe with an outside diameter of 5.875 inches (14.9 cm) may be inserted at each end of the barrel or receptacle. Thus, five-inch (12.7 cm) pipe with external upset of 5.875 inches (14.9 cm) may be secured along its length within the barrel 50.
Referring now to Figure 2, feed mechanism 110 includes feed ramp 111 which is supported by means of feed ramp support 112. Feed cylinder 118 is pivotally mounted on feed cylinder base 121 by means of feed cylinder pin 119 and feed cylinder flange 120. Shaft or piston 117 is pivotally mounted to feed arm flange 115 by means of feed arm pin 116. The other side of feed arm flange 115 is integrally attached to feed arm shaft 114 which is in turn integrally mounted to L-shaped feed arm 113. Feed arm shaft 114 is rotatably supported by feed base 122. Thus, the retraction of piston 117 by feed cylinder 118 causes the clockwise movement of feed arm flange 115 which in turn causes the rotation of shaft 114 and hence the movement of L-shaped feed arm 113. As shown in Figure 2 a shorter segment 123 of L-shaped feed arm 113 is adapted to receive a pipe from feed ramp 111 when the L-shaped feed arm 113 is in a vertical position, while the longer portion 124 of L-shaped feed arm 113 is adapted to facilitate the movement of a pipe 90 into a receptacle 50 when L-shaped feed arm 113 is in a horizontal position.
Although not shown, feed mechanism 110 generally comprises a plurality of feed ramps 111 and L-shaped feed arms 113. In such a case feed arm shaft 114 may run substantially parallel to the pipe as it rests in the feed arms 113 and so serve to move the feed arms in a coordinated fashion. Additionally, any suitable number of feed cylinders 118 may be used.
Feed mechanism 110 may be located or adapted to feed a pipe at varying locations. By way of example, feed ramp 111 may be adjusted in both height and slope to vary the position along the cyclical path of each barrel at which it receives a pipe. However, feed mechanism 110 should be located so as to allow each barrel 50 to have a sufficient amount of cooling medium to cushion a pipe as it enters a barrel. Additionally, feed mechanism 110 and receiver 130 should be located to provide a proper input and output of pipe for the desired quenching sequence or cycle.
As also shown in Figure 2 receiving ramp 131 of receiver 130 is mounted on receiving ramp base 132 and is adapted to receive a pipe 90 which is released from a barrel 50 as it comes close to ramp 131. Ramp 131 is slightly inclined in order to facilitate the movement of pipes 90 away from magazine 30.
Referring now to Figures 1, and 7-9, in accordance with another aspect of the present invention there is also provided an interior quenching means or internal quencher 140, which comprises a cooling medium feed conduit 141 and a gas feed conduit 142. The gas feed conduit 142 is mounted in a cylindrical rod 143. Cooling medium feed conduit 141 is integrally attached at one end to plate 32 and is equipped with an internal fixed sleeve 144, which is integrally mated along its length to the interior wall of conduit 141.
Movable sleeve or sliding tube 145, which has a tapered end portion 146, is telescopically mated with the internal fixed sleeve 144. The tapered end portion 146 is adapted to sealingly engage the inlet of a pipe 90 as it rests in a barrel 50.
Cylindrical rod 143 is integrally mounted in movable sleeve 145 by means of helical vanes 147, which are integrally attached along the interior surface of movable sleeve 145. As shown in Figure 7 cylindrical rod 143 is also supported by arms or support rods 148 which are mated on the interior surface of sliding tube 145.
It is preferable that vanes 147 remain essentially stationary. For example, when the vanes are integrally mounted in movable sleeve 145, the sleeve should be mounted to avoid substantial rotation of the vanes by the swirling cooling medium passing through the sleeve. By way of example, the sleeve 144 could be fitted with grooves to accept flanges extending from movable sleeve 145.
The outlet of gas feed conduit 142 is equipped with a plug or nozzle 156 which is shown in more detail in Figure 9. The plug 156 is threaded into cylindrical rod 143 by means of threads shown at 157. As the end of feed conduit 142 is equipped with apertures 158 the flow of gas through gas feed conduit 142 occurs around the tapered end portion of plug 156 as shown by the arrows in Figure 9.
In accordance with another aspect of the present invention, the spiral vanes are preferably at an angle of approximately 35° with the horizontal, particularly when water is used as a cooling medium. This angle will impart a relatively long spiral to the flowing water and so reduce the time the water travels the length of the pipe and is discharged through interior discharge outlet 61. Additionally, multiple vanes are preferred in order to aid in imparting sufficient turbulence to the cooling medium. However, the arrangement of the vanes may be varied depending upon the exact nature of the helical motion desired in the cooling medium. For example, variations in the type and amount of cooling medium, the type of pipe being quenched, the severity of the quench desired and the amount of gas to be injected may all affect the exact configuration chosen for the vanes.
The gas feed conduit 142 is connected to conduit 149 such that the flow of gas through gas feed conduit 142 may be controlled by shutoff valve 159. Gas feed conduit 142 is supported by cylindrical rod 143 along its length. As cylindrical rod 143 is telescopically mated-into sealed housing or stuffing box 152 which is attached at one end to piston 153, movement of piston 153 causes the movement of rod 143 and hence conduit 142 and sleeve 145. Conduit 149 is attached to a flexible hose 151 by means of swivel coupling 150 to accommodate both the movement of the gas feed conduit 142 with cylindrical rod 143 and, depending on the source of air supply to flexible conduit 151, the rotation of the interior quenching means 140 with plate 32.
Internal quench cylinder 154 is attached to cooling medium feed conduit 141 and hence to magazine 30 by means of support or flange 155.
Cooling medium source 180 includes a stationary feed pipe 181 which is placed in communication with primary feed pipe 182 by means of connecting sleeve 183. Stationary feed pipe 181 is attached to connecting sleeve 183 by means of swivel joint 184. As primary feed pipe 182 is integrally mounted to magazine 30 and so rotates with the magazine swivel joint 184 allows a cooling medium, such as water, from stationary feed pipe 181 to be fed to the magazine 30 in much the same fashion that gas supply pipe 41 supplies a gas, such as air, to gas reservoir 44.
Sleeve 183 is mounted in a steady bearing 185, which is in turn mounted on a bearing support or base 186. Although not always required, the use of steady bearing 185 may be preferable in order to limit the effect of vibrations caused by the rotation of magazine 30. For example, steady bearing 185 may serve to reduce shock and vibration to swivel joint 184.
Primary feed pipe 182 supplies cooling medium to the interior cooling means 140 through cooling medium feed conduit 141 and valve 169 and to the exterior cooling means 190 through exterior feed conduit 191 and exterior feed conduit valve 192.
The exterior cooling means 190 includes exterior feed conduits 191 which run parallel to barrel 50. Branch pipes 193 place each exterior feed conduit 191 in communication with flow chamber 195 and hence the interior of barrels 50. The flow of cooling medium through each of the branch pipes 193 is controlled by means of valves 194.
Valves 169, 192 and 193 may thus control the pressure and flow rate of the cooling medium to the interior and exterior cooling means. However, valves 192 and 193 preferably remain at least partially open throughout the process in order to ensure that each barrel 50 has a sufficient amount of cooling medium to cushion the pipe before it enters the barrel.
As shown in Figure 1 the branch pipes 193 are located between partitions 53 such that the flow of cooling medium may be varied in between the partitions. Thus, the flow of cooling medium to any given segment of the exterior surface of a pipe 90 resting in a barrel 50 may be varied, since the flow rate and pressure of the cooling medium to each compartment formed by the partitions may be varied by means of valves 194. Alternately, a greater number of branch pipes may be provided to vary flow of the quenching medium within any compartment. However, in accordance with the present invention, it is preferable to at least provide partitions between regions of varying flow rate where the controlling characteristic, such as thickness of a pipe wall, changes abruptly. By way of example, when quenching upset pipe a partition is preferably located at each boundary of the upset to insure a relatively clear line of demarcation in the cooling regimes between the upset and the segment of the pipe adjacent thereto.
The pressure of the cooling medium in any compartment may also be varied by means of shutters 79. For example, shutters 79 may extend along the length of each barrel from one clamping means to the next, thus allowing the discharge of water substantially only through secondary openings 52. Alternately, discharge of cooling medium from each barrel may be partially or completely regulated by the discharge of the cooling medium through those portions of primary openings 51 and secondary openings 52 not covered by shutters 79. In this regard the shutters may be varied in length or other appropriate dimension and, depending upon the configuration of the clamping means 70, may only be partially closed over the opening 51. Additional discharge conduits or openings (not shown) may also be provided to control the pressure and flow rate of the cooling medium passing around the pipe or other object being quenched.
Referring again to Figure 1, valve 169 may be employed to further control the pressure of the cooling medium both to the interior and exterior of a pipe 90. Cooling medium conduit 141 supplies cooling medium to the interior of each pipe 90 as it rests in a barrel 50. Feeder conduit 170 places cooling medium feed conduit 141 in communication with exterior feed conduit 191, which provides the flow of cooling medium to the exterior of each pipe 90. Thus, the flow of cooling medium to the interior and exterior of a pipe 90 and, hence, the internal and external pressures, may be interrelated.
In accordance with one aspect of the present invention, feeder conduit 170 is equipped with a check or one-way valve 171 which is mounted in check valve housing 172, such that cooling medium may only flow from cooling medium feed conduit 141 to exterior feed conduit 191. The flow of cooling medium through feeder conduit 170 insures that the cooling medium circulating around a pipe 90 will have sufficiently high pressure to ensure proper cooling of the pipe.
As previously indicated the flow of cooling medium through cooling medium feed conduit 141 is controlled by valve 169. The operation of valve 169 is in turn controlled by the operation of the interior quenching means 140 through means of internal quench linkage 160. As shown in Figure 1, link arm 161 is mounted at one end on cylindrical rod 143 by means of link arm pin 162 and at the other end to valve stem 166 by means of link arm pin 163. Link arm 161 is pivotally mounted to center pivot arm 165 by means of link arm pivot pin 164. Consequently, cylindrical rod 143 and valve stem 166 respond to each other's movements by moving in opposite directions to each other. Thus, when piston 153 is extended and cylindrical rod 143 has inserted tapered end portion 146 into a pipe 90, valve stem 166 has moved valve disc or plug 167 to the right as shown in Figure 1, thus allowing the flow of the cooling medium from primary feed pipe 182 to the cooling medium feed conduit 141 and hence into the interior of pipe 90. Similarly, when piston 153 is retracted into internal quench cylinder 154 such that tapered end portion 146 is not in communication with the interior of a pipe 90, the flow of cooling medium from primary feed pipe 182 is blocked, since valve stem 166 has pushed valve disc or plug 167 into the path of the cooling medium.
The number of barrels mounted in magazine 30 may be varied depending upon the rate at which pipes or other steel pieces must be quenched and the particular quenching sequence desired. However, in accordance with the present invention, it is preferable that the number and capacity of the barrels is such that the steel pipes may be processed in sufficiently high numbers to avoid additional process steps, such as the reheating of steel pipes prior to quenching as shall hereinafter be more fully described.
Referring now to Figures 1-9, in operation a series of pipes are sequentially fed onto feed ramp 111. L-shaped feed arm 113 is initially in a vertical position with piston 117 of cylinder 118 retracted such that the first pipe 90 rolls onto the shorter portion 123 of L-shaped feed arm 113. Cylinder 118 is then activated to extend piston 117 which in turn causes flange 115 to rotate shaft 114 thus causing L-shaped arm 113 to rotate such that longer portion 124 of feed arm 113 comes into alignment with the upper segment of partitions 53 and movable clamping members 80. As portion 124 is slightly inclined, the pipe 90 rolls through opening 51 into barrel or receptacle 50. As shown in Figure 2 the lower portion of L-shaped feed arm 113 is curved thus allowing it to slide along surface of the next pipe as it waits to be fed into the next barrel.
Just before the barrel 50 comes into alignment with the portion 124 of L-shaped feed arm 113 and thus accepts pipe 90, valves 192 and 194 allow a sufficient flow of cooling medium from primary feed pipe 182 through exterior feed pipe 191 and branch pipes 193 such that barrel 50 has a sufficient amount of water therein to cushion the entrance of pipe 90 into barrel 50.
Almost as soon as pipe 90 has entered barrel 50 cylinder 74 retracts clamp cylinder piston 76 thus causing clamping arm 71 to move through clamp arm slot 84. As movable clamping member 80 and shutter 79 are integrally attached to clamping arm 71 both movable clamping member 80 and shutter 79 move across opening 51. Thus, pipe 90 is held in barrel 50 as the barrel continues to rotate in a counterclockwise direction as shown by the arrows in Figure 2.
Almost simultaneously with the movement of the clamping means, piston 153 is extended by cylinder 154. This in turn opens valve 169 due to the movement of valve stem 166 and hence valve disc or plug 167 through means of internal quench linkage 160. Cylindrical rod 143 also moves forward. This forward movement of the cylindrical rod through the sealed housing or stuffing box 152 in turn causes the forward movement of movable sleeve or sliding tube 145. As movable sleeve 145 travels forward toward the inlet of pipe 90 it slides through fixed sleeve 144 until the tapered end segment 146 sealingly engages the inlet of pipe 90.
Once the pipe is held in position by means of clamping means 70 and brought into contact with the internal quenching means 140, water flows through feed conduit 141. Concurrently therewith valves 194 open to deliver the water through openings 55 or appropriately placed nozzles 56 and hence in a circumferential flow pattern around the exterior of pipe 90, while shut off valve 149 opens to allow gas from flexible conduit 151 to pass through conduit 149 and gas feed conduit 142 and hence into the water passing through the tapered end portion 146 of sleeve 145. As the water must pass through helical vanes 147, the water enters the inlet of pipe 90 in a helical flow pattern. Additionally, the water is injected with sufficient amount of gas, such as air, to aerate the water and insure sufficient turbulence to avoid the creation of steam and vapor pockets and so prevent non-uniform cooling and otherwise facilitate heat transfer from the pipe wall into the water.
In accordance with one aspect of the present invention, the internal and external quenching preferably begin almost simultaneously in order to promote a more uniform cooling sequence across the thickness of a pipe wall as the pipe rests in a barrel 50. Thus, the full circumferential flow of water from flow chamber 195 and tapered end portion 146 preferably begins within a few tenths of a second or less after the pipe 90 is rolled into the barrel or receptacle 50. Additionally, the flow of water from the flow chambers preferably begins before the pipe leaves feed arm 113 such that the entrance of the pipe into the barrel is appropriately cushioned. In this regard it is noted that the continual removal of water through secondary openings 52 or gaps in the coverage of primary opening 51 by shutters 79 serves to remove impurities and maintain the water temperature and pressure at desired levels.
In accordance with one aspect of the present invention, it is important to maintain the flow of water into each of the exterior quenching compartments formed by partition 53 in a substantially circumferential pattern such that the flow of water moves along the exterior surface of each pipe 90. The water should generally not directly impinge on the pipe if uniform cooling is to be achieved.
The pressure of the water entering from valves 194 should be sufficient to create sufficient turbulence so the pockets of steam or vapor are removed as the water flows circumferentially along the pipe surface. Additionally, the flow rate should be such as to provide a fairly rapid turnover of the water in each compartment in order to prevent the circumferentially flowing turbulent water within each compartment from rising above a specified temperature. More particularly, the flow rate is preferably such as to keep the water at an overall temperature of about 80°F (27°C) and preferably 70°F (21°C) or less, since the cooling power of water increases rapidly as the water temperature increases beyond about 75°F (24°C). In fact, this loss of cooling power is almost expotential such that water at a temperature of 120°F (49°C) has only about 20% of the cooling power of water at 70°F (21°C). However, use of water at a higher temperature can still prove advantageous when compared to prior processes using water of similar temperature due to the favorable circumferential flow pattern created, the high turnover of the water in each compartment, and the use of a plurality of barrels or receptacles in a rotating magazine.
The water flowing into the interior of the pipe 90 is preferably at a pressure of about 70,370 kg/m² and should be within the range of about 42,222 to 77,407 kg/m² prior to injection of the gas. This is believed to be a high enough pressure to provide needed turbulence and allow the gas to force the water to adhere more closely to the interior pipe wall as it passes through the pipe. To this end the pressure of water in feed pipe 181 should be at a sufficiently higher pressure, such as 94,955 kg/m².
The internal and external quenches are continued for a predetermined amount of time during which the barrel continues its rotation in magazine 30. The time of the quench, the speed of rotation of the magazine, the extent to which primary and secondary openings 51 and 52 are closed off, the rate of flow of the cooling medium through flow chambers 195 and cooling medium feed conduit 141, as well as the flow of gas through gas feed conduit 142 and other variables may all be regulated during the quenching operation to provide a proper cooling sequence for the pipe 90. To this end thermocouples and other sensors (not shown) may be employed along with appropriate process controls to control the flow of the cooling medium and gas in order to control the cooling sequence undergone by each pipe as well as the rate at which the pipes are passed through the magazine.
As the barrel 50 continues to rotate in the magazine and approach receiver 130, the cooling sequence is completed and cylinder 154 retracts the piston 153 thus causing the retraction of cylindrical rod 143. This in turn causes the movement of plug 167 due to the action of internal quench linkage 160 and the withdrawal of movable sleeve 145 such that the tapered end portion 146 of the movable sleeve disengages the pipe 90 as the flow of water to the cooling medium feed conduit 141 is cut off by valve 169. Additionally, the flow of water to flow chambers 195 is cut off or reduced by means of valves 194 and cylinder 74 retracts piston 76 thus causing shutter 79 and movable clamping member 80 to withdraw from primary opening 51. Given the orientation of the barrel 51 as it approaches the receiver 130, the withdrawal of the clamping mechanism from opening 51 allows barrel 90 to slide out onto ramp 131 of receiver 130.
The barrel then continues to rotate in the magazine toward feeding mechanism 110 and begins filling with water in order to repeat the sequence. The position in the magazine 30 where each barrel 50 receives a pipe 90 from L-shaped feed arm 113 may be thought of as an inlet position or station. Similarly, the position in the magazine 30 where each barrel 50 releases a pipe 90 onto receiving ramp 131 may be thought of as an outlet position or station. Thus, as each barrel rotates in the magazine it makes a cyclical path between the inlet and outlet stations. As best shown in Figures 2 and 6, the orientation of the barrels as they approach the outlet station is such that any excess water supplied to the barrel flows through the primary opening over the lip of the barrel. Thus, the amount of water in the barrel as it passes the inlet station is already being replenished.
In operation, valve 169 is preferably closed when the pipe rolls out onto receiving ramp 131. However, valve 192 preferably remains at least partially open such that the barrel is continually supplied with water through exterior conduit 191 and branch pipes 193. Consequently, a pipe 90 entering the barrel 50 from feed mechanism 110 rolls into a cushion of water. Thereafter, as previously described valve 169 is opened and water flows through the cooling medium feed conduit 141 and into the interior of pipe 90. Water also flows through feeder conduit 170, since check valve 171 permits fluid flow into exterior feed conduit 191. Due to this additional flow from conduit 170, the water on the exterior surface of the pipe is more easily maintained at sufficiently high pressures to promote proper heat transfer from the exterior surface of the pipe to the water. However, feeder conduit 170 may not be required depending upon the water pressure in stationary feed pipe 181 and the control of valve 192. Additionally, a two-way valve may be substituted for check valve 171 to provide greater control over the flow of water through feed conduit 170.
As will be appreciated by one skilled in the art having the benefit of this disclosure, given the variable flow rates, pressures, and other conditions attainable in each compartment, the present invention is particularly suitable for quenching internal and external upset pipe, casing or tapered steel pieces. Of course, in the case of pipe with uniform thickness the flow rates do not necessarily have to be varied. Additionally, steel pipe with walls of greater thickness or lower alloy content may now be successfully heat treated.
The process and apparatus of the present invention may also be used to treat tool joints after they are welded to a tubular member such as drill pipe. Thus, the tool joint and pipe may be of similar composition and the tool joint need not have a higher alloy content to withstand the temperature changes caused by welding. For example, a tool joint, which may be thought of as a sleeve of additional thickness added to the end of the pipe, may first be welded to a piece of pipe. Thereafter, the pipe-tool joint combination may be heated above its critical austenizing temperature and quenched in accordance with the present invention.
As will also be appreciated by one skilled in the art having the benefit of this disclosure, the quenching of steel pipe in accordance with the present invention provides a process which can sequentially quench a number of tubular products at a sufficiently high rate such that a steady production rate may be maintained based on the weight of steel processed. This may be illustrated by the following examples.
The capacity of a typical pipe mill system, such as a Mannesman system, is generally measured in terms of the tons of steel pipe rolled every hour. Examples of quenching times for various sizes of tubing or casing are shown in Table 1. The estimated minimum quenching time is calculated assuming that each pipe is quenched from 871°C to ambient temperature using water at 27°C. The water supplied to each barrel would have a flow rate of approximately 5,320 I/min and a pressure in the range of 56,300 to 91,500 kg/m².
Table 2 illustrates the number and tonnage of pieces of steel quenched if the tubing or casing set forth in Table 1 were quenched in line with a rolling mill of the designated capacity. As indicated, it is generally preferable to increase the number of barrels in the rotating magazine as the capacity of the rolling mill increases. A loading and unloading time of ten seconds is assumed for the traditional inside-outside quench unit.
These calculations demonstrate the increased processing capacity that will result through use of the present invention. Since most prior processes can only separately quench a percentage of the pipes produced, additional quenching units must be built, production rates reduced, or additional furnaces provided to reheat the pipes which have cooled prior to quenching. In contrast, the magazine of the present invention can separately quench a varying number of pipes at varying rates, thus more closely matching or exceeding the capacity of the production units to the extent desired, and, alternately, also provide more quenching time for each pipe.
In regard to this last alternative all of the total available quench time need not be used. The flow rate or pressure of the water flowing to each barrel can be separately controlled, such that the quench may be varied or cut-off depending upon the weight of the pipe and the type of quench desired.
It may be preferable in some instances to provide different size receptacles or barrels 50 to accommodate varying sizes of pipe or other tubular products. Additionally, different units could be provided. By way of example one unit might have receptacles adaptable to accept pipe with outside diameters of 4.5 to 10 inches (11.4 to 25.4 cm) while another unit might have barrels adaptable to accept pipe ranging from 1.5 to 4.5 inches (3.8 to 11.4 cm) in outside diameter.
The various cylinders such as clamp cylinder 74, feed cylinders 118, quench cylinders 154 may be operated by air or other gas from reservoir 44. Alternately, the cylinders may be hydraulic.
The apparatus of the present invention may be equipped with appropriate process controls to insure proper timing sequence for the various valves and other devices. Based on the foregoing disclosure the nature of such controls should be apparent to one skilled in the art. However, pneumatic controls will generally be preferred to electrical ones in view of the extensive use of water or similar cooling mediums. Additionally, a cam system may be employed to aid in the control and sequencing of the quenching operation. For example, a cam system push rod device similar to one used on automated screw making lathes may be employed. The cam system could be operatively connected to the pneumatic or hydraulic control system and so used to ultimately control the flow of a cooling medium such as water to each barrel depending upon the location of the barrel as it rotates in the magazine.
As will be appreciated by one skilled in the art having the benefit of this disclosure a number of modifications may be made to the foregoing apparatus and method within the scope of the present invention. For example, each receptacle 50 may be varied in shape and the number of flow chambers may be varied depending on the source of the cooling medium, the maximum and minimum thickness of pipe or other object to be quenched by a given barrel and other variables. A blank may also be supplied such that a barrel of a given length may accommodate pipes of differing lengths. Additionally, although the cooling medium is preferably water and the gas is preferably air, any variety of cooling media or gases may be employed or interchanged within the spirit of the present invention. Furthermore, the interior quenching means may be used with conventional quenching techniques. Similarly, the exterior circumferential quenching means may be used to quench the exterior of the pipe while conventional quenching techniques are used on the interior. However, it is preferable in most cases to use both the internal gas-injected quench and the circumferential exterior quench in order to facilitate uniform and rapid heat transfer from the pipe to the cooling medium and otherwise take full advantage of the present invention. Also the nature and extent of the partitions, the number of compartments, or the number of barrels in the magazine may be varied depending upon the cooling sequence or other effects desired. Furthermore, provision may be made to cool and recycle the cooling medium for repeated use in the magazine. Also hydraulic rather than air cylinders may be employed, though the former is preferable.
Further modifications and alternative embodiments of the apparatus and method of this invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the manner of carrying out the invention. It is to be understood that the forms of the invention herewith shown and described will be taken as the presently preferred embodiments. Various changes may be made in size, shape and arrangement of parts. For example, equivalent elements or materials may be substituted for those illustrated and described herein, parts may be reversed, and certain features of the invention may be utilized independent of the use of other features, all of which would be apparent to one skilled in the art after having the benefit of this description of the invention.

Claims

1. An apparatus for sequentially quenching a plurality of steel pipes comprising a rotatable magazine having a plurality of receptacles for detachably holding the steel pipes, characterized in that each receptacle (50) has an inlet to accept a cooling medium and an outlet to discharge the cooling medium from the receptacle, each receptacle also being configured to form an annular space in conjunction with the pipe located in the receptacle, said inlet, outlet and annular space being configured to facilitate a circumferential flow of cooling medium around separate longitudinal exterior segments of the steel pipe to remove heat from the steel, while replenishing at least a portion of the cooling medium which has removed heat from the steel, said exterior segments being at least partially immersed in the cooling medium which flows substantially circumferentially and generally independently around each longitudinal exterior segment in a flow pattern sufficiently directed and turbulent to effect general uniform transformation of each segment of the steel pipe; and further characterized in that there is provided a cooling medium source for supplying a cooling medium to each receptacle.

2. The apparatus of claim 1 further characterized in that the receptacle is divided into compartments to facilitate a rate of cooling variable among exterior segments of the steel pipe.

3. The apparatus of claim 1 further characterized in that each receptacle is adapted to receive a steel pipe of varying diameter.

4. The apparatus of claim 1 further characterized in that there is provided a blank for filling in a portion of each receptacle not occupied by the steel pipe.

5. The apparatus of claim 1 further characterized in that the steel pipe rests on partitions mounted along the interior of each receptacle.

6. The apparatus of claim 5 further characterized in that the partitions are contoured to fit the exterior surface of the steel pipe.

7. The apparatus of claim 1 further characterized in that there is provided an internal quenching means for supplying a cooling medium to the interior of each steel pipe while it is held in a receptacle.

8. The apparatus of claim 7 further characterized in that the internal quenching means comprises:

a cooling medium conduit located along the axis of the pipe and having a tapered outlet adapted to direct a cooling medium into the interior of the pipe;

a gas conduit telescopically mated in the cooling medium conduit and having a gas conduit outlet near the tapered outlet of the cooling medium conduit, the gas conduit outlet being adapted to inject a gas from the gas conduit into the cooling medium; and

a series of helical vanes mounted in the interior of the cooling medium conduit and adapted to impart a helical flow pattern to the cooling medium leaving the tapered outlet.

9. The apparatus of claim 8 further characterized in that the vanes are mounted at an angle of about 35 degrees with the horizontal axis of the pipe.

10. The apparatus of claim 7 further characterized in that the cooling medium source is adapted to increase the pressure of the cooling medium on the exterior of the steel pipe upon the supplying of the cooling medium to the interior of the steel pipe.

11. The apparatus of claim 10 further characterized in that the cooling medium source comprises a primary cooling medium conduit, and exterior and interior cooling medium conduits for respectively delivering a cooling medium to the interior and exterior of the steel pipe in each receptacle, and a feeder conduit for selectively placing the exterior and interior cooling medium conduits in communication with each other.

12. The apparatus of claim 11 wherein the feeder conduit is equipped with a one-way valve.

13. The apparatus of claim 1 further characterized in that

(a) the magazine is a motor-driven rotatable magazine formed by two circular plates rotatably mounted in spaced relation to each other, the plates having a plurality of openings spaced around and at a distance from the center of each plate and connected by the plurality of receptacles mounted to the inside face of each plate in communication with an opening, each receptacle being of sufficient length to receive a pipe and including -

an opening along its length for accepting a pipe and discharging water;

an inlet for receiving water into the receptacle,

a plurality of partitions for cradling a pipe and separating the receptacle into a plurality of compartments along the length of the receptacle, and

a plurality of openings in the surface of each receptacle for circulating a water cooling medium in a substantially circumferentially flow pattern around a pipe resting in the receptacle;

(b) an interior quenching means including

a cooling medium conduit located along the axis of a pipe and having a tapered outlet adapted to direct a cooling medium into the interior of the pipe,

a gas conduit telescopically mated in the cooling medium conduit and having a gas conduit outlet near the tapered outlet of the cooling medium conduit, the gas conduit outlet being adapted to inject a gas from the gas conduit into the cooling medium, and

a series of helical vanes mounted in the interior of the cooling medium conduit and adapted to impart a helical flow pattern to the cooling medium leaving the tapered outlet;

(c) a feeder for sequentially placing each pipe in a receptacle, and

(d) a receiver for sequentially receiving each pipe from a receptacle.

14. A method of sequentially heat treating a plurality of steel pipes including the steps of heating each pipe to a temperature above its austenizing temperature and moving a plurality of receptacles along a substantially circular path from inlet to outlet station, said method characterized in that while moving the plurality of receptacles from inlet to outlet there are accomplished the steps of:

(a) filling each receptacle with a sufficient amount of a cooling medium comprising water to at least partially cushion a pipe as it is placed in the receptacle;

(b) placing a pipe in each receptacle as it passes the inlet station while forming a generally annular space around the exterior surface of a portion of the pipe;

(c) circulating at least a portion of the cooling medium substantially circumferentially around the longitudinal exterior segments of the pipe while replenishing at least a portion of the cooling medium, the flow of the cooling medium being sufficient in conjunction with the size of the generally annular space such that replenishment of the cooling medium results in replenishment of at least a portion of the cooling medium directed substantially circumferentially around the pipe once said cooling medium has removed heat from steel in the pipe, said cooling medium being further sufficiently directed and turbulent to effect generally uniform transformation of each segment of the pipe; and concurrently therewith, directing a cooling medium through the interior of the pipe as a receptacle travels from the inlet to the outlet station; and

(d) removing the pipe from the receptacle at the outlet station after another pipe has been placed in a following receptacle.

15. The method of claim 14 characterized in that the weight of the steel pipes heated above their austenizing temperature is at least equal to the weight of the steel pipes quenched in a given period of time.

16. The method of claim 14 characterized in that a portion of the cooling medium initially directed to the interior of the pipe is selectively-routed to the exterior of the pipe in order to affect the pressure of the cooling medium flowing circumferentially around the pipe.

17. The method of claim 14 further characterized in that the cooling medium is water and wherein the water is maintained at a temperature of 27°C or less.

18. The method of claim 14 characterized in that the cooling medium is water and wherein the water is at a pressure in the range of approximately 56,300 to 92,500 kg/m².

19. A method according to claim 14 further characterized in that the step of quenching the interior surface of the steel pipe comprises the step of directing a cooling medium through the interior of the steel pipe at a flow rate which may be independently varied from the flow rate of the cooling medium around one or more exterior finite longitudinal segments of the pipe.

20. The method of claim 14 characterized in that a gas is directed with the cooling medium through the interior of the pipe, said gas being under sufficient pressure to facilitate heat transfer between the cooling medium and the interior surface of the pipe.