US3212766A

US3212766A - Apparatus for depth hardening long tubes

Info

Publication number: US3212766A
Application number: US285543A
Authority: US
Inventors: Heinenberg Fritz; Fritsch Werner; Philipp Clemens
Original assignee: Mannesmann AG
Current assignee: Vodafone GmbH
Priority date: 1960-08-15
Filing date: 1963-05-22
Publication date: 1965-10-19
Anticipated expiration: 1982-10-19

Description

Oct. 19, 1965 F. HEINENBERG ETAL 3,212,755

APPARATUS FOR DEPTH HARDENING LONG TUBES Original Filed Aug. 15, 1960 4 Sheets-Sheet 1 :1 fiwenfors Fr/fz Heme/wary l/l emer HY/SC/i C/emens P/I///,0,0 By fhelf a/fomeys Oct. 19, 1965 F. HEINENBERG ETAL 3,212,766

APPARATUS FOR DEPTH HARDENING LONG TUBES 4 Sheets-Sheet 2 Original Filed Aug. 15, 1960 Oct. 19, 1965 F. HEINENBERG ETAL 3,212,766

APPARATUS FOR DEPTH HARDENING LONG TUBES Original Filed Aug. 15, 1960 4 Sheets-Sheet 5 men/0m Fr/fz He/henber Werner Fr y m C/emens l m/40 y fhe/r affamey Oct. 19, 1965 F. HEINENBERG ETAL APPARATUS FOR DEPTH HARDENING LONG TUBES 4 Sheets-Sheet 4 Original Filed Aug. 15, 1960 nxh wwm w United States Patent 9 Claims. (Cl. 2666) This application is a division of my copending application 49,783, filed August 15, 1960, now abandoned.

This invention is for improvements in or relating to apparatus for depth hardening long tubes or other hollow bodies. One field in which the present invention has been found to be especially applicable is that of tubes employed in oil fields. Great difiiculty has been found in depth hardening long tubes in such a way as to obtain rapid warp-free depth hardening of the tubes.

Steel which, because of its chemical composition, has a tendency to form cracks, is not generally hardened by water but preferably is quenched in oil. It has heretofore been known to immerse long tubes in an oil bath on swinging arms or on a roller bed located in an oblique position in an oil bath. In this case, while the tube cools on the outer surface, the oil flows into the interior of the tube from both ends. It would be quite impossible to get a useful process for hardening long tubes in an oil bath by any method heretofore known when the tubes to be hardened have such length. When the tube was heretofore immersed in a bath, both ends were immersed and the oil flowed into the interior of the tube from both ends. The two streams of oil met at about the middle of the tube accompanied by an appreciable production of bubbles. These bubbles interfered with the uniform dissipation of heat and with the obtaining of thorough hard-,

ening. Furthermore, the necessary critical oil cooling speed has not been attained .at all points on the tube by this prior art method. As a result the tube has tended to warp. If the tube was put in the bath perpendicularly an extraordinarily deep oil container was required for the long tubes. This is not practical. If the tubes were immersed in a slanting position, as already mentioned, the oily fluid came into the tube not only from the bottom but also from the top and air bubbles trapped in the middle resulted in places in the tube that were poorly hardened or warped. Practically therefore there was no usable process for hardening long tubes in an oil bath.

It has heretofore been known in the Heinenberg US. Patent 2,888,374 dated May 26, 1959, to harden long tubes by applying a coolant on the inside. This was done by introducing the cooling liquid at an open end of a horizontal tube in a vortical manner and at sufiicient speed and pressure so that the coolant flowed in a vortical manner throughout the entire length of the tube.

According to the present invention, it is possible to depth harden tubes that are positioned substantially horizontal while using oil and still have the hardening occur at the necessary critical cooling speed while cooling a tube from both inside and out using oil as the coolant and doing so uniformly and without warping of the tube.

In the drawings, FIG. 1 is a schematic plan view of hardening apparatus constructed according to the invention.

FIG. 2 is a view in vertical section across the hardening vessel showing the loading and unloading means, taken on the line A-B of FIG. 1.

FIG. 3 is a view in vertical lengthwise section part way across the hardening vessel looking at the turbulence nozzle and taken on the line C-D of FIG. 1.

3,212,766 Patented Oct. 19, 1965 "ice FIG. 4 is a view in elevation across the hardening vessel showing the turbulence nozzle from the side with the adjusting pin in section, taken on the line E-F of FIG. 3.

FIG. 5 is a view in longitudinal section through the turbulence nozzle itself.

In the embodiment shown in the drawings there is a tube 1 coming from a tempering furnace (not shown). The tube is brought on a line of rollers 2 and is lifted therefrom by a series of pivoted levers 3 intercalated with the line of rollers 2 (see FIGS. 1 and 2). The levers 3 lower the tube 1 onto an oblique draining gate consisting of arms 4, 4a, and 4b. These arms extend down into a hardening vessel 5 which is filled with oil up to the dot and dash line 6. These levers 3 when in substantially horizontal position as shown in FIG. 2 hold the tube temporarily above the level 6 of the oil bath but over the bath. A further lowering of the levers allows the tube to slide with low initial speed onto the arms 4a, 4b, etc. and into the oil. In this way splashing is avoided. As shown in FIG. 2 there are end stops 7 at the lower ends of the arms 4a, 4b, etc. These serve to hold the tube in a position completely immersed in the bath and substantially horizontal. The tubes can be, say, 5 to 8 from absolute horizontal because this slightly slanted posit-ion assists the oil in running out of the tube when the tube is lifted out after hardening (see angle in FIG. 4). While this substantially horizontal slanting is preferred for the practical reason indicated, the tube can be exactly horizontal if desired. However, the arms 4a, 4b, etc. are bent diiferently as shown in FIG. 2 in order that in the immersion position the bubbles may not be trapped but driven from the lower end of the tube shown in FIG. 4 to the upper end and out of the tube which bubbles otherwise would prevent proper hardening as already described.

Immersed in the bath is a turbulence nozzle 8 to pro vide the high speed and vertical flow of oil through the interior of the tube. It is so located as to be axially in line, i.e. in front of the tube 1 resting on the stops 7. According to the prior invention the nozzle is attached to the tube end by a clamping and pressing device. It is made pivotally swingable toward the end of the tube. For this purpose the nozzle is screwed by steep thread onto a swinging arm 9 carried by an adjustable pin 10 on a short horizontal shaft 11. This shaft extends outside the bath and has lever 15 fastened thereon. The exact height of the nozzle is regulated by the pin 10 with its nuts 12. The nuts lock the nozzle in position. In this way different diameters of tube can be treated. The lever 15 connects to working or pressure exerting cylinder 14 adapted to force the turbulence nozzle 8 against the end of the tube 1. The nozzle has a cone-shaped outer jacket to facilitate its introduction into the end of the tube even if the latter is not exactly concentric. It is the lower end of the tube which is in front of the nozzle. If the nozzle is to be changed it is lifted out of the bath by a hook 16 on the swinging arm 9. A crane can engage the hook 16. The nozzle has branch bores 17 at the discharge end of the nozzle. These bores 17 empty into an open ring 18 facing toward the pipe. These bores connect with the internal spiral walls which give the oil its vortical movement. With this construction it is possible to deep harden even upset tube ends. The tube ends having a greater walI thickness than the rest of the tube receive an additional flow of oil around them and the dissipation of heat is accelerated at this point. The swinging arm 9 is connected to the oil circulation pump 27 and

pipes

28, 29 by a flexible hose 13.

The oil used for the internal cooling of the tube returns to the hardening vessel. The oil in the vessel is treated and cooled in the usual manner.

A mechanism is provided in the embodiment shown in the drawings to lift the tubes out of the hardening vessel 5.

This lifting-out mechanism comprises endless chain belts 19 arranged at intervals lengthwise of the bath 5. Each is driven by its own sprocket wheel 20 and drive 25 located above the bath and has coupling hooks thereon adapted to engage the tube as it rests in the end stops 7. It is not necessary to provide a second sprocket wheel in the baths for the lower ends of the chains nor to have retightening devices for the chains. These freely hanging chains have another important advantage in that-they are so located as to contact the tube when it enters the bath, the tube forcing the chain to the side. The contact with the chains helps to stop any rolling movement of the in-' coming tube in an elastic manner so that damage to the surface of the tube is avoided. This location of the chains also means that the tube is positively picked up later by the hooks. In FIG. 1 of the drawings three such chain belts are shown. In FIG. 2 a tube 1 already hardened rests above the oil level 6 in the coupling hooks 21 and in this position any oil which remained behind in the tube flows back into the hardening vessel 5. On the next movement of the chain the tube 1 is dropped on the draining gate 22 which slopes downwardly to the discharge rollers 23 whence it is transported to the tempering furnace (not shown).

If desired the cycle of operation of these chains can be controlled by limit switches 26 (FIG. 1) located in the path of the chain and given the following sequence: On the first working stroke, the tube is lifted by the coupling hooks to the position above the bath previously referred to. In this position the tube is in a slightly slanted position as above mentioned. At the next chain movement this tube is dropped to horizontal position on the discharge gate and another coupling hook steps forward and raises the following tube into this slightly slanted position.

It should be noted that while the nozzle may be applied to the end of the tube before the latter is immersed in the oil and the nozzle and tube immersed together as a unit, the important point is that the vortical flow through the interior of the tube starts in less than two seconds after immersion. Otherwise the oil will flow into the interior of the tube in the one open end if the nozzle has been applied and if not applied,,then in both ends, and uniform depth hardening will be impossible. It is therefore preferable to insert the nozzle in the tube immediately after immersion and start the flow in less than about two seconds after the tube has been immersed. In this way oil not traveling interiorly in the high speed and vortical manner can be kept out of both ends of the tube and perfect depth hardening will result by the combination of a simultaneous external cooling bath and high speed interior vortical oil cooling. What is claimed is: 1. Apparatus for warp-free depth hardening of long tubes in liquid comprising a hardening container, a cooling bath therein, and arms adapted to hold a tube immersed in the bathin a position several degrees oblique with reference to the horizontal, in combination with a coolant vortical-flow inducing nozzle in the bath movably mounted to be swung to and from operative relation with the lower end of the tube and force a vortical flow of coolant into the tube,

and a pressure-exerting cylinder adjacent the hardening container and adapted by lever, shaft and pin means to move the vortical flow-inducing nozzle concentrically into relation with the lower tube end.

2. Apparatus for warp-free depth hardening of long tubes in liquid comprising a hardening container,

a cooling bath therein,

and tilting arms adapted to hold a tube immersed in the bath in a position inclined several degrees from the horizontal,

in combination with a turbulence nozzle in the bath movably mounted to be swung to and from operative relation with the lower end of the tube and force a vortical flow of coolant into the tube,

a pressure-exerting cylinder adjacent the hardening container and adapted by lever, shaft and pin means associated with the cylinder and container to force the turbulence nozzle concentrically into relation with the lower tube end,

and a pump and connection providing coolant from the bath to the nozzle at speed and pressure sufficient to ensure that the coolant flows in a vortical manner throughout the entire length of the tube and exits from the higher end of the tube into the bath.

3. Apparatus according to claim 1 including a swinging ar-rn nozzle mount that is adjustable in height,

a pivoted shaft with the pin being adjustable and connecting the swinging arm and the shaft,

andfnuts associated with said pin to regulate the height adjustment of the nozzle for tubes of various dia'meters.

4. Apparatus according to claim 3 in which there is a hook. carried at the upper end of the swinging arm to facilitate removal of the nozzle.

5. Apparatus according to claim 3 in which the nozzle has an outer jacket in the shape of a cone.

6. Apparatus according to claim 3 in which the nozzle is detachable by steep threads.

7. A.turbulence nozzle for an apparatus in accordance with claim 3 in which the nozzle has a jacket around the circumference thereof and there are branch bores which empty into an annular nozzle space pointed toward the end of the tube.

8. Apparatus according to claim 3 in which there are a plurality of chain belts adapted to bring incoming rolling tubes to a gradual, gentle halt .in the bath, a single driven sprocket wheel for each chain belt, end stops on the arms to provide the oblique position of tubes during hardening, and coupling hooks for lifting the hardened tubes out of the vessel.

9. Apparatus according to claim 8 in which there are limit switches controlling the movement of the coupling hooks, said hooks being adapted to be successively immobilized above the oil bath, with a hardened tube in oblique position to facilitate draining and then, to discharge the tube in horizontal position.

References Cited by the Examiner UNITED STATES PATENTS 2,670,746 3/54 Kearney 134166 XR 2,807,272 9/57 McCray 2666 XR 2,888,374 5/59 Heinenberg 148143 WHITMORE A. WILTZ, Primary Examiner.

JAMES H. TAYMAN, JR., Examiner.

Claims

1. APPARATUS FOR WARP-FREE DEPTH HARDENING OF LONG TUBES IN LIQUID COMPRISING A HARDENING CONTAINER, A COOLING BATH THEREIN, AND ARMS ADAPTED TO HOLD A TUBE IMMERSED IN THE BATH IN A POSITION SEVERAL DEGREES OBLIQUE WITH REFERENCE TO THE HORIZONTAL, IN COMBINATION WITH A COOLANT VORTICAL-FLOW-INDUCING NOZZLE IN THE BATH MOVABLY MOUNTED TO BE SWUNG TO AND FROM OPERATIVE RELATION WITH THE LOWER END OF THE TUBE AND FORCE A VORTICAL FLOW OF COOLANT INTO THE TUBE,