DE102008009009B3 - Procedure for heat treatment of a tube body of a feed pipe to transport highly abrasive solids, comprises heating and hardening the internal surface of a tube body while subjecting the external surface of the tube body with a coolant - Google Patents

Abstract

The procedure for heat treatment of a tube body (2) of a feed pipe for hydraulic or pneumatic transport of highly abrasive solids, comprises heating and hardening the internal surface of a tube body while subjecting the external surface of the tube body with a coolant. The tube body is held in a reception (3) during the heat treatment. The cross-section of the tube body is arranged in the reception and is set to a mold element influenced on the outer surface of the tube body. The coolant flows through a ring area (12) from a coolant inlet to coolant outlet. The procedure for heat treatment of a tube body (2) of a feed pipe for hydraulic or pneumatic transport of highly abrasive solids, comprises heating and hardening the internal surface of a tube body while subjecting the external surface of the tube body with a coolant. The tube body is held in a reception (3) during the heat treatment. The cross-section of the tube body is arranged in the reception and is set to a mold element influenced on the outer surface of the tube body. The coolant flows through a ring area (12) between a sleeve body (8) of the reception and the tube body from a coolant inlet to coolant outlet. The tube body is pressed in the reception through power effect on the outer surface over the mold element. The coolant is led in longitudinal direction of the body at the outer surface along from the coolant inlet at an end of the tube body to the coolant outlet at the other end of the tube body. The coolant enters and emerges axially in the ring area. The internal surface of the tube body heats by inductors and is subsequently hardened through a coolant application over a quenching shower. The tube body held in the reception is moved relative to the inductor arranged in the tube body. Independent claims are included for: (1) procedure for the fabrication of a feed pipe with a tube body; and (2) a device for heat treatment of a tube body of a feed pipe.

Description

The The invention relates to a method and a device for heat treatment a tubular body for a delivery pipe and a method of manufacturing a production pipe.

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

The requirements for such delivery pipes are complex. On the inside, 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 produced by the known method tubular body are for use as delivery pipes for Sediment transport not or only partially suitable, but at least improvement, because they are due to their hardness in the field the outer wall tend to breakage and cracking in practical operation.

Especially in thin-walled tubular bodies with a wall thickness of 5 mm or less, the hardening of the inner surface of the tubular body is under Using a heater in the form of an inductor as difficult because a control of the hardening process over the Wall thickness not or only conditionally possible is. The wall of the pipe body will be complete durchgeglüht and as a result of the ensuing Cooling hardened. For the Practice would be However, it is desirable, in particular for weight reasons, high-performance conveying pipes or tubular body for delivery pipes for disposal to provide with low wall thickness and one precise trained hardness 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 based, a method and apparatus for heat treatment of a tubular body a conveyor pipe show with which a precise Formation of a hardening zone on the inner surface of the tubular body, especially in thin-walled Tubular bodies, is possible and further a method of manufacturing a production pipe from such a tubular body show.

The inventive method for heat treatment a tubular body for a Delivery pipe is characterized in claim 1.

According to the invention pipe body while the heat treatment held in a receptacle, wherein the cross section of the tubular body by in the recording arranged and acting on the outer surface of the tubular body Form elements is set. While the heat treatment will be the outer surface of the tubular body cooled. Hereby flows the coolant through an annular space between the jacket body of the receptacle and the tubular body of a coolant inlet to a coolant outlet.

With the method according to the invention, 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.

advantageous Further developments of the method according to the invention are the subject the dependent claims 2 to 6.

The tubular body is pressed in the receptacle by force on the outer surface of the mold elements around. The setting of the cross section of the tubular body contributes significantly to precise curing process at. Manufacturing technology, the pipe body inevitably on a certain ovality. This ovality causes inductive heating by an inductor arranged inside the tubular body stray fields of the magnetic field or uneven heating of the tubular body and thus leads to an uneven and insufficient curing process. According to the invention, the tube is pressed round during the curing process and / or held in the round shape, so that a precise hardening of the inner surface of the tubular body is possible. The high heat dissipation on the outer surface of the tubular body is achieved by flowing 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. Advantageously, the coolant enters the annular space axially and also leaves the annular space in the axial direction.

Preferably consists of the tubular body from a highly wear-resistant Steel material, especially steel grade C60, with corresponding high carbon content. The warming of the tubular body from the inside is preferably inductive. Accordingly comes as Heating device for the heat treatment an inductor is used. By means of the inductor, the inner surface of the tubular body and the one to be hardened Wall area heated to a temperature above the complete ferrite dissolution and the steel material austenitizes. Subsequently, the tube body is fast cooled, by means of a quenching shower downstream of the inductor. This results in a transformation of austenite into martensite. Through this structural change becomes the inner surface of the tubular body hardened.

at the heat treatment becomes the tubular body held in the receptacle and arranged relative to the pipe body Induktor moves, both longitudinally and rotationally. The pipe body and the inductor become longitudinally heat-treated moved relative to each other. To increase quality continues to contribute at, when tubular body and inducer rotate relative to each other. hereby is a uniform heating of the Inner layer of the tubular body in the heat treatment ensured.

Possibly It may be necessary to cap the ends of the tubular body, as in the end Area of the tubular body a qualified hardening process not possible is.

Around the tubular body to a conveyor pipe To complete, this end is provided with flanges (claim 7). By means of the flanges can the delivery pipes be coupled together to form a pipe string. Preferably the flanges at the ends of the tubular body adhesively determined. This allows adverse microstructural changes on the pipe body as a result of thermal joining operations be avoided.

Of the representational Part of the task is performed by a device for heat treatment a tubular body according to the characteristics of claim 9 solved.

The Device comprises a receptacle in which the tubular body can be fixed is. Between a shell body the receptacle and the tubular body is an annular space formed for the passage of a coolant. In the recording mold elements are further arranged, which the outer surface of the tubular body to contact.

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

The radial position of the mold elements relative to the tubular body adjustable. You can do this the mold elements screwed into threaded holes of the jacket body of the recording be. The adjustment of the mold elements is carried out so that the tubular body at the heat treatment a round cross section with as possible has high accuracy. In the recording, therefore, the cross section defined the tubular body or mechanically corrected. As a result, the inductor is uniform to Pipe inner wall spaced, which is beneficial to the curing process effect. The adjustment of the form elements takes place under consideration the thermal expansion of the tubular body in the heat treatment.

The The receptacle comprises end modules between which the jacket body is arranged is. In the end modules, the pipe body can be fixed with its ends.

When Heater comes - like mentioned - preferably an induction coil or an inductor used, in relation to the inner surface of the Tubular body via sliding shoes spaced and positioned.

In an end module is a coolant inlet and a coolant outlet is provided in the other end module, the coolant inlet and the coolant outlet are fluidly connected to the annular space.

The coolant inlet has an annular distribution chamber which communicates with the annulus via distributed through openings arranged on its circumference. The coolant outlet In contrast, has an annular collection chamber into which the annulus opens.

The Invention is described below with reference to an embodiment. 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 in the Heat treatment to be kept precisely round. 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 the 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 profile 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

Forderrohr

39

flange

40

flange

41

wear ring

42

wear ring

KM

coolant

L

longitudinal direction

r

arrow

s

Wall thickness v. 2

P

arrow

Claims (15)

Method for heat treatment of a tubular body ( 2 ) of a conveyor tube, wherein the inner surface ( 29 ) of the tubular body ( 2 ) is heated and hardened while the outer surface ( 11 ) of the tubular body ( 2 ) is acted upon by a coolant (KM), characterized in that the tubular body ( 2 ) during the heat treatment in a receptacle ( 3 ), wherein the cross section of the tubular body ( 2 ) in the recording ( 3 ) and on the outer surface ( 11 ) of the tubular body ( 2 ) acting form elements ( 22 ) and the coolant (KM) through an annulus ( 12 ) between a jacket body ( 8th ) of the recording ( 3 ) and the tubular body ( 2 ) from a coolant inlet ( 13 ) to a coolant outlet ( 14 ) flows. Method according to claim 1, characterized in that the tubular body ( 2 ) in the recording ( 3 ) by applying force to the outer surface ( 11 ) over the form elements ( 22 ) is pressed around. A method according to claim 1 or 2, characterized in that the coolant (KM) in the longitudinal direction of the tubular body ( 2 ) on the outer surface ( 11 ) along the coolant inlet ( 13 ) at one end ( 9 ) of the tubular body ( 2 ) to the coolant outlet ( 14 ) on the other end ( 10 ) of the tubular body ( 2 ). Method according to at least one of claims 1 to 3, characterized in that the coolant (KM) axially into the annulus ( 12 ) enters and leaves. Method according to at least one of claims 1 to 4, characterized in that the inner surface ( 29 ) of the tubular body ( 2 ) by means of an inductor ( 30 ) and then by a coolant application on a Abschreckbrause ( 31 ) is hardened. Method according to claim 5, characterized in that the tubular body ( 2 ) in the recording ( 3 ) held relative to the tubular body ( 2 ) arranged inductor ( 30 ) is moved. Method for manufacturing a conveyor tube ( 38 ) with a tubular body ( 2 ) manufactured according to at least one of claims 1 to 6, characterized in that the tubular body ( 2 ) at the end with flanges ( 39 . 40 ). Method according to claim 7, characterized in that the flanges ( 39 . 40 ) at the ends ( 9 . 10 ) of the tubular body ( 2 ) are determined by adhesive technology. 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 9, characterized in that the radial position of the mold elements ( 22 ) relative to the tubular body ( 2 ) is adjustable. Apparatus according to claim 9 or 10, 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 11, 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 12, 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 12 or 13, 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 9 to 14, characterized in that the heating device ( 30 ) via guide shoes ( 33 ) in the tubular body ( 2 ) is positioned.