DE202008002660U1 - Apparatus for heat treatment of a tubular body for a production pipe - Google Patents

Abstract

contraption for heat treatment of a tubular body (2) of a Delivery tube, comprising a heating device (30) for heating the inner surface (29) of the tubular body (2) with a downstream quenching shower (31) and means for cooling the outer surface (11) of the tubular body (2), characterized in that the tubular body (2) in a receptacle (3) can be fixed, wherein between a jacket body (8) the receptacle (3) and the tubular body (2) an annular space (12) is designed for the passage of a coolant (KM) and in the receptacle (3) form elements (22) are arranged, which the outer surface (29) of the tubular body (2) contact.

Description

The The invention relates to a device for heat treatment a tubular body for a delivery pipe.

Far widespread is the use of delivery pipes in the pipe string the concrete distributor masts of truck-mounted concrete pumps and the like Applications in hydraulic or pneumatic transport of solids by means of pipelines.

The requirements for such delivery pipes are complex. The inside of the delivery pipes should have the highest possible hardness to oppose the usually very abrasive solids high wear resistance, whereas the outside of the delivery pipes should be shock and pressure resistant with low risk of breakage and cracking. In addition, a long service life of the delivery pipes is aimed at the simplest possible construction. By the DE 198 09 529 C2 includes a conveyor pipe for the transport of solids to the prior art. The production pipe has a single-layer hardened tubular body made of a steel material. In order to assemble the delivery pipes to form a pipe string, the pipe bodies are equipped at each pipe end with coupling collars.

An apparatus and method for quench hardening of pipes using a pipe heating inductor is known from US 5,156,055 DE 23 49 913 A1 known. Here, the tube experiences within a quenching device by an externally mounted inductor a continuous heating to hardening temperature and a deterrence from outside and inside by means of quenching.

The from the US-A-2,556,243 Known proposal describes the hardening of the outer and inner surface of a tubular body. For this purpose, an inner and an outer inductor are provided, each with associated Abschreckbrause.

The are tubular body produced by the known methods for use as conveying pipes for solids transport not or only conditionally suitable, but at least in need of improvement, because they are due to their hardness in the field the outer wall to breakage and cracking in practical operation tend.

Especially in thin-walled tubular bodies with a wall thickness of 5 mm or less, the hardening of the inner forms Surface of the pipe body using a Heating device in the form of an inductor as difficult because a controller the hardening process over the wall thickness not or only conditionally possible. The wall of the pipe body is completely annealed and due to the hardened by subsequent cooling. In practice, however, it would be desirable, in particular for reasons of weight, high-performance delivery pipes or tubular body for delivery pipes available to provide with low wall thickness and a precise trained hardening zone on the inner surface of the tubular body and a tough material structure on the outside.

Of the Invention is therefore based on the prior art, the task basically, a device for heat treatment of a tubular body of a Show conveyor pipe, with which a precise Formation of a hardening zone on the inner surface of the tubular body, in particular in thin-walled Tubular bodies, is possible.

These Task is by a device for heat treatment a tubular body according to the features of claim 1 solved.

The Device comprises a receptacle in which the tubular body is determinable. Between a shell body of the recording and the tubular body is an annular space formed for passage a coolant. In the recording are also mold elements arranged, which is the outer surface of the Contact tubular body.

through the shape of the elements can be adjusted, the cross section of the tubular body and be pressed or held around.

advantageous Embodiments and developments of the fundamental Concept of the invention are the subject of the dependent claims 2 to 7.

The radial position of the mold elements relative to the tubular body is adjustable. For this purpose, the form elements in threaded holes be screwed the jacket body of the recording. The setting of the Form elements are made such that the tube body during the heat treatment a round cross-section with the highest possible accuracy has. In the recording, therefore, the cross section of the tubular body is defined or mechanically corrected. As a result, the inductor is uniform spaced from the pipe inner wall, which is advantageous to the hardening process effect. The adjustment of the form elements takes place under consideration the thermal expansion of the tubular body during the heat treatment.

The Recording includes end modules, between which the sheath body is arranged. In the end modules of the tubular body with fixable to its ends.

As mentioned above, preferably an induction coil or an inductor is used as the heating device, which is opposite to the inner surface the tubular body is spaced and positioned over slide shoes.

In one end module is one coolant inlet and the other Endmodul provided a coolant outlet, wherein the coolant inlet and the coolant outlet with the annulus fluid-conducting are connected.

Of the Coolant inlet has an annular distribution chamber on, which arranged distributed over its circumference through openings communicates with the annulus. The coolant outlet points on the other hand, an annular collecting chamber, in which the annulus opens.

According to the invention the tubular body during the heat treatment held in a receptacle, wherein the cross section of the tubular body through in the receptacle and on the outer surface the tubular body acting form elements is adjusted. During the heat treatment, the outer becomes Surface of the tubular body cooled. in this connection the coolant flows through an annulus the jacket body of the receptacle and the tubular body from a coolant inlet to a coolant outlet.

With the device according to the invention and the associated method, even with thin-walled tubular bodies with a wall thickness of 5 mm or less, a very precise hardening depth can be achieved on the inner surface of the tubular body. This is achieved by the shape-fixing support of the tubular body in the receptacle and the qualified cooling, in which the heat dissipation on the outside is so high that the outer boundary layer is not heated above the transformation temperature, ie the A _C3 transformation point of the material. In this way, in the outer surface layer, the transformation of ferrite into austenite is prevented, so that the layer is not cured.

Of the Pipe body is absorbed in the recording by force the outer surface over the mold elements pressed around. Adjusting the cross section of the pipe body contributes significantly to the precise curing process at. Manufacturing technology, the pipe body inevitably a certain ovality. This ovality requires with an inductive heating by an inside in the tubular body arranged inductor stray fields of the magnetic field or a uneven heating of the pipe body and thus leads to an uneven and insufficient curing process. According to the invention the tube is pressed and / or round during the hardening process held in the round shape, allowing precise hardening the inner surface of the tubular body possible is. The high heat dissipation at the outer Surface of the tubular body is achieved by that the coolant in the longitudinal direction of the tubular body on the outer surface along the Coolant inlet at one end of the tubular body to the coolant outlet at the other end of the tubular body flows. Advantageously, the coolant enters axially into the annulus and also leaves the annulus again in the axial direction.

Preferably the tubular body consists of a highly wear-resistant Steel material, especially steel grade C60, with corresponding high carbon content. The heating of the tubular body from the inside is preferably inductive. Accordingly comes as Heating device for heat treatment an inductor for use. By means of the inductor becomes the inner surface of the tubular body and the wall area to be hardened to a temperature above the complete ferrite dissolution heated and the steel material austenitized. Subsequently the tube body is cooled quickly, and indeed by means of a quenching shower connected downstream of the inductor. hereby occurs a transformation of austenite into martensite. Through this Structural change becomes the inner surface hardened the tubular body.

at The heat treatment is the tubular body in the Held recording and arranged relative to the pipe body Induktor moves, both longitudinally and rotationally. The tubular body and the inductor are used in the heat treatment moved in the longitudinal direction relative to each other. For quality improvement contributes further when pipe body and inductor perform a rotational movement relative to each other. hereby is a uniform heating of the Inner layer of the tube body during the heat treatment ensured.

Possibly it may be necessary to cut the ends of the tubular body, because in the end region of the tubular body a qualified Hardening process is not possible.

Around to complete the tube body to a conveyor tube, this is provided at the end with flanges. By means of the flanges The delivery pipes can be coupled together to form a pipe string. Preferably, the flanges become the ends of the tubular body adhesive-technically determined. This can be disadvantageous Structural changes on the pipe body due be avoided by thermal joining operations.

The The invention is based on an embodiment described in more detail. Show it:

1 an end view of a device according to the invention for the heat treatment of a tubular body;

2 a longitudinal section through the representation of 1 along the line AA;

3 a cross section through a tubular body and

4 technically schematized a conveyor pipe with a pipe body according to the invention in a longitudinal section.

In the 1 and 2 is with 1 a device for heat treatment of a tubular body 2 for a conveyor pipe called. The pipe body 2 is single-layered and consists of a highly wear-resistant steel material, in particular steel grade C60. The pipe body 2 has a wall thickness s of less than 5 mm, in particular, the tubular body 2 a wall thickness s of 2-3 mm.

The device 1 includes a recording 3 , in which the tubular body 2 can be fixed in the heat treatment. The recording 3 is divided into two parts and has an upper half 4 and a lower half of the receiver 5 on which are relative to each other from an open position to a closed position and vice versa displaced. Shown in the 1 and 2 the closed position, in which the tubular body 2 in the recording 3 is held. The recording 3 has two end modules 6 . 7 between which a sheath body 8th is arranged. In the end modules 6 . 7 is the pipe body 2 with his ends 9 . 10 clamped.

Between the shell body 8th and the outer surface 11 of the tubular body 2 is an annulus 12 designed for the passage of a coolant KM. The coolant KM passes through a coolant inlet 13 at one end 9 of the tubular body 2 axially into the annulus 12 one. On the other end 10 of the tubular body 2 the coolant KM passes through a coolant outlet 14 axially out of the annulus 12 out.

The coolant inlet 13 includes two radially in the end module 6 extending inlet holes 15 . 16 , which in an annular distribution chamber 17 lead. The distribution chamber 17 is arranged on its circumference distributed through openings 18 with the annulus 12 in fluid-conducting connection. The coolant KM goes through the inlet holes 15 . 16 in the final module 6 the distribution chamber 17 fed, distributed there and passes through the through holes 18 in the annulus 12 , In the annulus 12 the coolant KM flows in the longitudinal direction of the pipe body 2 on the outer surface 11 along. The annulus 12 flows into the final module 7 in an annular collection chamber 19 the coolant outlet 14 , Via two radially aligned outlet holes 20 . 21 in the final module 7 the coolant KM leaves the device 1 and can be fed to a recooling and / or recirculation.

In the recording 3 are in the longitudinal direction at a distance and distributed over the circumference form elements 22 arranged. The form elements 22 stand opposite the inner surface 23 of the jacket body 8th towards the pipe body 2 in front. In the closed position of the device 1 Contact the moldings 22 the outer surface 11 of the tubular body 2 , This allows the cross section of the tubular body 2 by applying force to the outer surface 11 about the form elements 22 be set. In this way, the cross section of the tubular body 2 in the recording 3 pressed around or held round.

The radial position of the mold elements 22 relative to the tubular body 2 is adjustable. This is illustrated by the arrow r. Every form element 22 has a basic body 24 and a printhead 25 on. At the base body 24 is an external thread 26 intended. In the jacket body 8th are blind holes 27 with on the external thread 26 coordinated internal threads 28 arranged. The form elements 22 can do so in the blind holes 27 screwed in and depending on the depth of engagement at a radial distance to the tubular body 2 be positioned.

For heating and hardening of the inner surface 29 of the tubular body 2 includes the device 1 a heater in the form of an inductor 30 with downstream quenching shower 31 on. The inductor 30 is end to a bracket 32 attached and over guide shoes 33 in the tube body 2 positioned. In this way, the winding points 34 of the inductor 30 over the circumference a constant distance to the inner surface 29 of the tubular body 2 on.

To a pipe body 2 To harden, this is in the device 1 inserted. The device 1 is then closed, leaving the tubular body 2 held in the receptacle. About the set to the nominal cross-sectional shape elements 22 becomes the tubular body 2 pressed around and held during the heat treatment. The setting of the form elements 22 in their radial distance from the tubular body 2 is taking into account the thermal expansion of the tubular body 2 made as a result of heating. This allows the tubular body 2 be kept precisely round during the heat treatment. By means of the inductor 30 then becomes the tubular body 2 heated to hardening temperature above the A _C3 point and then by the coolant to the inner surface 29 over the quenching shower 31 cooled quickly and consequently an inner layer 35 hardened (see also 3 ). At the same time, the outer surface becomes 11 of the tubular body 2 cooled. In this case, the coolant KM flows from the coolant inlet 13 through the annulus 12 in Longitudinal direction of the tubular body 2 on the outer surface 11 along to the coolant outlet 14 , In this way, such a large heat dissipation on the outer surface 11 of the tubular body 2 be achieved that the temperature of the tubular body 2 outside the conversion or hardening temperature does not exceed. This retains the outer surface 11 or an outer layer 36 the Wall 37 of the tubular body 2 their ductile material properties and remains impact and pressure resistant.

In the heat treatment, the tube body 2 in the recording 3 held relatively in its longitudinal direction L to the inductor 30 emotional. At the same time the pipe body 2 and the inductor 30 rotated relative to each other, as illustrated by the arrow P.

In the 3 is a tube body hardened according to the invention 2 shown in cross section. You can see the hardened inner layer 35 and the uncured outer layer 36 , Internal tests have shown that a precise adjustment of the hardness curve in the wall 37 of the tubular body 2 is possible. The inner layer 35 can be about two thirds of the wall thickness of the tubular body 2 Precise hardening, whereas the outer layer 36 maintains the desired ductility.

To complete the pipe body 2 to the delivery pipe 38 becomes the tubular body 2 end with flanges 39 . 40 provided, as in the 4 is shown. Preferably, the flanges 39 . 40 adhesive at the ends 9 . 10 of the tubular body 2 established. Each end in front of the tubular body 2 are wear rings 41 . 42 inside the flanges 39 . 40 glued.

1

contraption

2

pipe body

3

admission

4

upper female half

5

lower female half

6

end module

7

end module

8th

covering body

9

End of v. 2

10

End of v. 2

11

outer surface v. 2

12

annulus

13

Coolant inlet

14

coolant outlet

15

inlet bore

16

inlet bore

17

distribution chamber

18

Through opening

19

plenum

20

outlet bore

21

outlet bore

22

forming element

23

inner surface v. 8th

24

body

25

printhead

26

external thread

27

blind hole

28

inner thread

29

inner surface v. 2

30

inductor

31

quench nozzles

32

bracket

33

guide shoe

34

winding

35

inner layer

36

outer layer

37

Wall v. 2

38

delivery pipe

39

flange

40

flange

41

wear ring

42

wear ring

KM

coolant

L

longitudinal direction

r

arrow

s

Wall thickness v. 2

P

arrow

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 19809529 C2 [0003]
• - DE 2349913 A1 [0004]
• - US 2556243 A [0005]

Claims (7)

Device for heat treatment of a tubular body ( 2 ) of a conveyor tube, comprising a heating device ( 30 ) for heating the inner surface ( 29 ) of the tubular body ( 2 ) with a downstream quenching shower ( 31 ) and means for cooling the outer surface ( 11 ) of the tubular body ( 2 ), characterized in that the tubular body ( 2 ) in a recording ( 3 ) can be fixed, wherein between a shell body ( 8th ) of the recording ( 3 ) and the tubular body ( 2 ) an annulus ( 12 ) is designed for the passage of a coolant (KM) and in the receptacle ( 3 ) Form elements ( 22 ) are arranged, which the outer surface ( 29 ) of the tubular body ( 2 ) to contact. Apparatus according to claim 1, characterized in that the radial position of the mold elements ( 22 ) relative to the tubular body ( 2 ) is adjustable. Device according to claim 1 or 2, characterized in that the receptacle ( 3 ) End modules ( 6 . 7 ) between which the shell body ( 8th ), wherein the tubular body ( 2 ) with its ends ( 9 . 10 ) in the end modules ( 6 . 7 ) is determinable. Device according to claim 3, characterized in that in an end module ( 6 ) a coolant inlet ( 13 ) and in the other end module ( 7 ) a coolant outlet ( 14 ), wherein the coolant inlet ( 13 ) and the coolant outlet ( 14 ) with the annulus ( 12 ) are fluidly connected. Device according to claim 4, characterized in that the coolant inlet ( 13 ) an annular distribution chamber ( 17 ), which has distributed over its circumference arranged through openings ( 18 ) with the annulus ( 12 ). Apparatus according to claim 4 or 5, characterized in that the coolant outlet ( 14 ) an annular collecting chamber ( 19 ) into which the annular space ( 12 ) opens. Device according to at least one of claims 1 to 6, characterized in that the heating device ( 30 ) via guide shoes ( 33 ) in the tubular body ( 2 ) is positioned.