JPS5855217B2 - Hardening equipment for metal tubes - Google Patents

Description

Detailed Description of the Invention The present invention relates to a device for quenching metal pipes such as steel pipes, and more specifically to a quenching device for cooling metal pipes such as steel pipes by applying a cooling water flow along the axial direction to both the inner and outer surfaces of the heated metal pipes. It is related to the device.

Conventionally, so-called ring quenching equipment for metal pipes such as steel pipes has been used, in which a large number of high-pressure injection nozzles are arranged in a ring around the outer circumference of the steel pipe, and high-pressure cooling liquid, such as cooling water, is sprayed onto the outer surface of the steel pipe. A so-called immersion quenching apparatus is known in which a steel pipe is immersed in a cooling liquid, such as cooling water, in a cooling tank.

However, the former type of ring hardening equipment has a lower cooling capacity than the latter type of immersion hardening equipment, and also has the problem that the cooling rate of the inner surface of thick inner pipes is low, so conventional ring hardening equipment has a lower cooling capacity than the latter type of immersion hardening equipment. A method has been put into practical use in which a header equipped with an injection nozzle is inserted into the steel pipe in order to supplementally cool the inner surface of the steel pipe in addition to cooling the outer surface using an injection device, but this method is not applicable to small diameter pipes. However, when processing a large number of steel pipes continuously, the header must be inserted into and removed from the steel pipes one by one, making it impossible to increase the processing capacity beyond a certain level.

On the other hand, in the case of the latter type of immersion hardening equipment, if the heated steel pipe is simply placed in and immersed in cooling water, the surface of the steel pipe will be covered with a vapor film produced by the boiling of the cooling water, and the cooling rate of the pipe will be reduced. is slower than the critical cooling rate for martensitic transformation required for normal quenching, making it impossible to obtain the quenching effect.

Therefore, in the past, a plurality of injection nozzles were arranged at intervals in the circumferential direction on the outer periphery of the steel pipe to be quenched in the cooling tank, and high-pressure water was ejected in the tangential direction of the steel pipe in a circle along the outer periphery of the steel pipe. An annular stirring flow is generated, and in addition to this, an appropriate axial jet nozzle is used to apply an axial water flow to the inner surface of the steel pipe.

However, in this kind of immersion hardening equipment, in order to generate an agitation flow on the outer surface of the tube, stationary cooling water that does not directly contribute to cooling the tube is also moved, resulting in low energy efficiency. death,
Moreover, there is the problem of having to increase the amount of water ejected.
In addition, in order to cool the steel pipe uniformly along its length,
Since a large number of injection nozzles must be arranged at small intervals along the length of the steel pipe, the equipment becomes multiple and expensive, and furthermore, one of the injection nozzles may become clogged.
Alternatively, the cooling water injected from each injection nozzle may interfere with each other, resulting in uneven heating.

Therefore, the inventors of the present invention have already proposed a so-called axial flow type hardening device as a device that can effectively solve the above-mentioned problems.

To roughly explain the quenching equipment, Fig. 1 is a schematic diagram showing the overall structure, and Fig. 2 is a schematic diagram of the quenching device shown in Fig. 1.
This is a sectional view taken along a line, and a hollow cylindrical body 3 having an inner diameter larger than the outer diameter of a steel pipe 2 to be quenched is arranged almost horizontally in a cooling tank 1.

This cylindrical body 3 receives the steel pipe 2 to be hardened, and as shown in FIG. The supports, which can be opened and closed by moving up and down against the case 3a, and which are arranged at predetermined intervals in the longitudinal direction on the inner surface of the case 3a, hold the steel pipe 2 on the stand 4 between its central axis and the cylindrical body. 3. Make sure that the center axis is parallel to the
Preferably, they are supported so that they are substantially aligned.

Therefore, a space (tube outer surface side flow path) 5 is formed between the outer peripheral surface of the steel pipe 2 and the inner peripheral surface of the cylindrical body 3.

A large-diameter pipe-shaped outer nozzle 6 is disposed on one end of the cylindrical body for applying a water flow parallel to the axial force direction of the cylindrical body 3 to the tube outer surface side flow path 5, and An inner nozzle 7 in the form of a small diameter pipe is disposed inside the outer nozzle 6 for applying a water flow to the inner side of the steel pipe 2 housed in the cylindrical body 3 along its axial direction.

The outer nozzle 6 is made such that the inner diameter of its open end substantially matches the inner diameter of the cylindrical body 3, and at least the center axis of the open end of the outer nozzle 6 is made to match the inner diameter of the cylindrical body 3. 3 and so that the open end is in contact with or very close to the end surface of the cylindrical body 3.

On the other hand, the inner nozzle 7 is made so that the inner diameter and outer diameter of the open end almost match the inner diameter and outer diameter of the steel pipe 2 to be hardened. The outer nozzle 6 is inserted into the outer nozzle 6 by penetrating the outer wall of the curved portion thereof.

The inner nozzle 7 is positioned such that the central axis of its open end coincides with the central axis of the cylindrical body 3.

Further, the inner nozzle 7 is configured to move forward and backward along its axial direction, in other words, to move toward and away from the open end of the steel pipe 2 housed in the cylindrical body 3.

The end of the cylindrical body 3 opposite to each nozzle 6.7 is open, and the cooling tank 1 is extended in the direction in which the cylindrical body 3 extends, and the side edge of the cooling tank extension 1a is open. A drainage channel 8 is provided outside the cooling water flooding portion 1b.

According to the apparatus shown in FIGS. 1 and 2, the cooling tank 1
By injecting cooling water from the respective nozzles 6.7, a cooling water flow is applied to both the inner and outer circumferential sides of the steel pipe 2 along the direction of the axle. Therefore, the cooling water that has removed heat from the steel pipe 2 instantly flows away toward the rear end, so that a stable cooling rate can always be obtained, and as a result, the entire steel pipe 2 is uniformly heated without uneven heating. Can be cooled.

By the way, in order to be able to harden various steel pipes with different outer diameters from small diameter pipes to large diameter pipes in the above-mentioned hardening apparatus, the inner diameter of the cylindrical body 3 must be set to the maximum diameter of the steel pipes to be hardened. Although it is necessary to set the inner diameter of the cylindrical body 3 larger than the outer diameter of the steel pipe, if the inner diameter of the cylindrical body 3 is set large in this way, it is possible to accommodate steel pipes of various diameters, but on the other hand, when a small diameter pipe is accommodated, The cross-sectional area of the tube outer surface side flow path 5 formed between the outer peripheral surface of the small diameter tube and the inner peripheral surface of the cylindrical body 3 becomes considerably large, and the amount of cooling water flowing through the tube outer surface side flow path 5 becomes larger than necessary. It becomes a large amount.

In such a case, if the amount of cooling water spouted from the outer nozzle 6 is set to the minimum amount required to cool the outer surface of the tube, then
If the flow rate of the cooling water becomes slow or if a space is created in the cylindrical body 3 and the cooling water becomes wavy, the steel pipe 2 may be exposed on the surface of the cooling water and uneven heating may occur. Even when quenching a tube, it is necessary to flow the cooling water with the tube outer surface side flow path 5 filled with the cooling water. The power required to flow the cooling water through the passage 5 is larger than necessary, which not only increases operating costs but also consumes energy unnecessarily, so there is still room for improvement.

This invention was made in view of the above circumstances, and it is possible to form a cylindrical housing part that matches the outer diameter of the metal tube to be hardened, thereby controlling the amount of cooling water, especially the amount of cooling water on the outer circumference side of the metal tube, to an appropriate level. The object of the present invention is to provide a metal tube hardening device that can harden metal tubes.

Embodiments of the present invention will be described below with reference to FIGS. 3 to 12. FIG. 3 is a plan view of the main parts of an embodiment of the quenching apparatus of the present invention, and FIG. It is a cross-sectional view taken along the line, and a rotating shaft 11 passing through the cooling tank 10 along its longitudinal direction is provided horizontally,
The end of the rotating shaft 11 protruding from the cooling tank 10 is connected to a rod 1 of a hydraulic cylinder 12 erected outside the cooling tank 10.
2a via a lever 13, and a plurality of case arms 1 are connected to the portion of the rotating shaft 11 located in the cooling tank 10.
4 are attached at predetermined intervals, and these case arms 14
A case 16 having a semicircular cross section and forming a part of the cylindrical body 15 is attached to the upper tip of the cylinder 15. Therefore, when the hydraulic cylinder 12 is not in operation, the case 16 is held approximately horizontally in the cooling water. By rotating the case 16 counterclockwise in FIG. 4 with the hydraulic cylinder 12, the case 16 is rotated counterclockwise together with the case arm 14.

An inner case 17 is attached to the inner surface of the case 16, as shown in an enlarged view in FIG. The inner case 17 forms the lower half of a cylindrical housing portion 19 for housing a steel pipe 18 to be hardened.

The inner case 17 is configured to be attachable to and detachable from the case 16. To explain the mounting structure and the device for attaching and detaching the two, the inner case 17 is attached at multiple locations in the longitudinal direction of the case 16 in the width direction (in the vertical direction in FIG. 3). ) is formed with a swollen protrusion 20, and a locking piece 21 is disposed within the protrusion 20 with its tip raised above the bottom surface of the protrusion 20, as shown in FIGS. 6 and 7. In addition, an engagement piece 22 that protrudes in the width direction (vertical direction in FIGS. 3 and 6) is provided at a predetermined location in the longitudinal direction of the inner case 17.
7 in the longitudinal direction and inserting the engaging piece 22 under the locking piece 21, the inner case 17 is fixed to the inner surface of the case 16, and the inner case 17 is moved in the opposite direction. The inner case 17 can be removed from the case 16 by sliding the engaging piece 22 out of the locking piece 21.

Also, the device for sliding the inner case 17 is the third one.
It is constructed as shown in FIG. 8 and FIG.

That is, a pin 25 is attached to the longitudinal end of the inner case 17 via an end plate 23 and a bracket 24 in a direction perpendicular to the sliding direction of the inner case 17, and is engaged with the pin 25. A swing lever 26 is arranged within the cooling tank 10.

The swing lever 26 has a notch 26a formed in the vertical direction with a width larger than the diameter of the pin 25, and the pin 25 is inserted into the cutout 26a. The inner case 17 is slid in its longitudinal direction by rotating in the left-right force direction in FIG. It is configured so that it does not come into contact with the inner surface.

Further, a connecting rod 28 is attached to the swinging lever 26 and extends through the rear end wall of the cooling tank 10 via a sealing portion 27. It is connected to the.

Next, on the inner surface of the inner case 17, a plurality of supports 30 each having a substantially square cross section are arranged at intervals in the longitudinal direction of the inner case 17, and these supports should be hardened at the supports 30. Line contact with the steel pipe 18 and the steel pipe 1
8 is held horizontally so that its central axis is substantially coincident with or parallel to the central axis of the case 16, that is, the central axis of the cylindrical body 15.

In order to prevent turbulence from occurring in the cooling water flow along the axial direction of the steel pipe 18, the support is designed so that both front and rear ends in the streamline direction of the cooling water flow are streamlined. It is preferable that a large number of holes be provided on the surface in contact with the steel pipe 18 so that the surface in contact with the steel pipe 18 can be quickly cooled by contacting the steel pipe 18 with more holes.

The cooling tank 10 is horizontally provided with second rotating shafts 32 that extend through the cooling tank 10 along its longitudinal direction and are supported by hanging arms 31 at regular intervals. The end protruding from the lever 3 is attached to a rod 33a of a second hydraulic cylinder 33 installed outside the cooling tank 10.
4, and a plurality of cover arms 35 are attached at regular intervals to the portion of the rotating shaft 32 located inside the cooling tank 10, and at the bottom of the tip of these cover arms 35,
A cover 36 having a semicircular cross section and forming the cylindrical body 15 together with the case 16 is attached.

That is, the cylindrical body 15 is configured so that it can be opened and closed by operating the second hydraulic cylinder 33 to rotate the second rotating shaft 32, thereby rotating the cover 36 together with the cover arm 35. ing.

An inner cover 37 is attached to the inner surface of the cover 36, as shown in an enlarged view in FIG. The inner cover 37 and the inner case 17 form a cylindrical accommodating portion 19 for accommodating the steel pipe 18 to be hardened.

The inner cover 37 is configured to be attachable to and detachable from the cover 36, and the configuration for attaching and detaching both is as follows.

As shown in FIG. 9, a locking pin 38 having a through hole 38a in its upper end is bored upward at a predetermined location in the longitudinal direction of the inner cover 37, and the locking pin 38 of the cover 36 An insertion hole 39 is formed at a location corresponding to the cover 36, and a lock 40 is arranged on the upper surface of the cover 36 to be inserted into a through hole 38a at the upper end of the locking pin 38 protruding from the cover 36 so as to be movable back and forth. has been done.

A lever 42 rotatably attached to a mounting base 41 is disposed on the upper surface of the cover 36 near the cockpit 40,
The lower end of the lever 42 is rotatably connected to the cockpit 40, and the upper end of the lever 42 is attached to a rod 43 of a cylinder 43 attached to the upper surface of the mounting base 41.
Therefore, by operating the cylinder 43 and rotating the lever 42 in the clockwise direction as shown in FIG. The inner cover 37 is fixed to the inner surface of the cover 36, and the lever 42 is rotated counterclockwise using the cylinder 43, so that the locking pin 40 is inserted into the through hole 38 of the locking pin 38.
The inner cover 37 is configured to be detachable from the cover 36 by pulling it out from a.

A flange portion 1 protruding in the radial direction of the cylindrical body 15 is provided at each abutting portion between the case 16 and the cover 36, that is, at each left and right side edge of the case 16 and the cover 36.
6a and 36a are formed, and a backing 44 is attached to the flange portion 36a of the cover 36 for sealing between the flange portion 16a of the case 16, and when the case 16 and the cover 36 are combined, a cylindrical body is formed. The backing 44 is configured to prevent cooling water from leaking to the outside of the cylindrical body 15 from between the case 16 and the cover 36 when the cylindrical body 15 is closed.

Further, on the outer surface of the cover 36, a plurality of pairs of brackets 45 protruding in the left-right direction are provided at regular intervals in the axial direction of the cover 36, and each of the brackets 45
A clamp arm 46 for clamping the cover 36 to the case 16 by engaging the lower surface of the flange portion 16a of the case 16 with its tip end is rotatably attached to the intermediate portion of the clamp arm 46. A clamp cylinder 47 for rotating the clamp arm 46 is provided on the upper surface of the cover 36.

Furthermore, as shown in FIG. 10, on the upper surface of one end of the cover 36, a tube holding cylinder 48 is erected downward, and the tip of the rod 48a is attached to the cover 36.
A presser rod 49 is attached to the support rod 49 that passes through the inner case 17 and presses the steel pipe 18 against the stand 30 to fix it.

On the outside of the cooling tank 10, transport rollers 50 for transporting the steel pipes 18 to be hardened are arranged along the longitudinal direction of the cooling tank 10, and on the transport rollers 50 side of the cooling tank 10. A third rotating shaft 51 extending along the longitudinal direction of the cooling tank 10 is attached to the upper part of the outer wall surface, and a plurality of carry-in arms 52 whose tips extend between the respective transport rollers 50 are attached to the rotating shaft 51 at predetermined intervals. Furthermore, a plurality of skids 53 are provided at predetermined intervals on the upper part of the outer wall where the rotation shaft 51 of the cooling tank 10 is provided, and are inclined slightly downward toward the cylindrical body 15. Ori,
By rotating the carry-in arm 52 together with the rotating shaft 51 in the counterclockwise direction in FIG. It has been stolen so as to roll on 53.

Further, at the bottom of the cooling tank 10, an unloading guide plate 54 for receiving the steel pipe 18 dropped from the case 16 is arranged with a slight downward slope to the left in FIG. A chain 56 is wound around a sprocket 55a placed near the end of the guide plate 54 and a sprocket 55b placed above the cooling tank 10.
A plurality of chain dogs 57 are attached to this chain 56 for carrying out the steel pipes 18 on the carrying out guide plate 54 from inside the cooling tank 10.

Furthermore, at one end in the longitudinal direction of the cooling tank 10, there is provided an outer nozzle 58a in the form of a large diameter pipe, the inner diameter of which is approximately the same as the inner diameter of the cylindrical accommodating portion 19. The outer nozzle 5 is provided so that its central axis substantially coincides with the central axis of the cylindrical body 15, and its open end is in contact with or very close to the end surface of the cylindrical body 15.
Inside 8a, an inner nozzle 58h shaped like a small diameter pipe is arranged coaxially with the outer nozzle 58a.

This inner nozzle 58b is made so that the inner diameter and outer diameter of its open end almost match the inner diameter and outer diameter of the steel pipe 18 to be hardened. is inserted into the inside of the outer nozzle 58a through a sealing sleeve 59 provided through the outer wall of the curved portion of the steel pipe 18
is positioned to coincide with the central axis of the

The inner nozzle 58b has a U-shape as a whole as shown in FIG. 10, and its rear end is connected to a sealing sleeve 60.
The inner nozzle 58b is slidably inserted into the water supply main pipe 61 through the inner nozzle 58b, and the open end of the inner nozzle 58b is housed in the cylindrical body 15 by a cylinder 62 for advancing and retreating horizontally arranged near the middle part of the inner nozzle 58b. It is intercepted so that it can move toward and away from the open end of the steel pipe 18.

In order to quench the steel pipe 18 using the quenching device stolen as described above, first the second hydraulic cylinder 33 is
, the cover 36 is raised to open the cylindrical body 15, and in this state, the heated steel pipe 18 on the conveyance roller 50 is moved onto the carry-in skid 53 by rotating the carry-in arm 52. The steel pipe 18 is rolled on the skid 53 and dropped into the cooling tank 10,
By doing so, the steel pipe 18 is placed on the support 30 inside the inner case 17.

Thereafter, by returning the second hydraulic cylinder 33, the cover 36 is placed over the case 16 to close the cylindrical body 15, and the clamping cylinder 47 is operated to move the clamp arm 46 onto the case 16. The case 16 and the cover 36 are integrated by engaging with the flange portion 16a.

As a result, the steel pipe 18 is housed substantially horizontally inside the cylindrical housing portion 19 formed by the inner case 17 and the inner cover 37.

After the steel pipe 18 is accommodated in the cylindrical housing part 19 in this manner, the pipe holding cylinder 48 is operated to press the steel pipe 18 against the support holder 30 using the holding rod 49.
is fixed, and the inner nozzle 58b is moved forward with the advancing/retracting cylinder 62 to bring its open end into contact with or very close to the open end of the steel pipe 18, and in this state, each nozzle 58a, ssb When a preset flow rate of cooling water is ejected from the pipe, the cooling water flows along the axial direction of the steel pipe 18 on the outer circumferential side and the inner circumferential side thereof, and as a result, the entire steel pipe 18 is cooled almost uniformly, eliminating uneven heating. arise.

Hardening is performed without any hardening.

When quenching the steel pipe 18 as described above, the inner diameter of the cylindrical housing part 19 is adjusted so that the amount of cooling water flowing around the outer circumference of the steel pipe 18 does not increase unnecessarily.
In other words, it is necessary to make the inner diameter of the cylindrical accommodating part 19 large for large diameter steel pipes, and to make the inner diameter of the cylindrical accommodating part 19 small for small diameter steel pipes. For this purpose, multiple types of inner cases 17 and inner covers 37 with different inner curvature radii are prepared, and the outer diameter of the steel pipe 18 to be hardened is determined from among the inner cases 17 and inner covers 37. It is only necessary to select a suitable one and attach it to the case 16 and cover 36.

In the above-mentioned quenching apparatus, the operation of replacing the inner case 17 and the inner cover 37, that is, the operation of attaching and detaching them to and from the case 16 and the cover 36 can be performed as described below.

First, the case where the inner case 17 and the inner cover 37 are removed from the case 16 and the cover 36 will be explained. As shown in FIG. 11A, the case 16 is held horizontally in the cooling tank 10, and the cover 3
6 are placed one on top of the other, and in this state, by operating the cylinder 43 for the cotter, the cotter 40 is moved backward and removed from the through hole 38a of the locking pin 38, and the inner cover 37 is removed from the cover 36. The second hydraulic cylinder 33 as shown in Figure B
When the cover 36 is rotated together with the second rotating shaft 32 and the cover arm 35, only the inner cover 37 is left on the inner case 17.

Next, the inner case 17 is moved together with the inner cover 37 by operating the two-stage cylinder 29 disposed on the rear end side of the cooling tank 10 and rotating the swinging lever 26 clockwise in FIG. 8. A locking piece 21 is provided inside the protruding part 20 of the case 16 with an engaging piece 22 that is slid slightly to the right and projects on both sides of the inner case 17.
Let them come out.

In this way, the engagement between the inner case 17 and the case 16 is disengaged, and therefore the inner case 17 and the inner cover 3 are disengaged.
7 can be carried out from the case 16 while being integrated.

In addition, when carrying out the inner case 17 and the inner cover 37, they are lifted by a crane (not shown) and carried out. In this case, the cover 36 is further rotated to lift the inner case 17 and the inner cover 37. the pin 25 and the swing lever 26, and release the contact between the pin 25 and the swing lever 26 by slightly returning the swing lever 26.
Make settings so that the two do not interfere with each other.

Moreover, in order to attach the inner case 17 and the inner cover 37 to the case 16 and the cover 36, it is enough to perform the operation in reverse to the above-mentioned operation, and first open the cylindrical body 15 as shown in FIG. 11B. Case 16
The inner case 17 and inner cover 37 that are stacked on top of each other are carried into the interior, and then the swing lever 26 is moved to the eighth position.
Rotate the inner case 17 counterclockwise in the figure.
8 along with the inner cover 37.

Then, the engaging pieces 2 protruding from both sides of the inner case 17
2 enters the lower side of the locking piece 21 provided in the protrusion 20 of the case 16, and the inner case 17 is first fixed to the case 16.

Next, when the cover 36 is rotated and overlapped with the case 16, the locking pin 38 protruding from the upper part of the inner cover 37 enters the insertion hole 39 formed in the cover 36 and protrudes above the cover 36. Here, operate the cylinder 43 for the Kottor and lock the Kottor 40 with the locking pin 3.
If the inner cover 37 is inserted into the through hole 38a of
is fixed to the inner surface of the cover 36.

In addition, since the case 16 rotates around the first rotating shaft 11 as described later, in order to prevent the pin 25 and the swing lever 26 from interfering with each other when the case 16 rotates, , after the above-mentioned installation operation is completed, the swing lever 26
is rotated slightly clockwise in FIG. 8 to release the contact between the pin 25 and the swing lever 26.

Therefore, as described above, by replacing the inner case 17 and the inner cover 37 and making the inner diameter of the cylindrical housing part 19 match the outer diameter of the steel pipe 18 to be hardened, the cooling that flows on the outer circumferential side of the steel pipe 18 can be prevented. The amount of water does not increase unnecessarily, so it is possible to optimize the power required to jet the cooling water or to reduce operating costs.

After quenching the steel pipe 18 for a predetermined time (several tens of seconds) as described above, the amount of cooling water injected from each nozzle 58a, 58b is reduced, and at the same time, the clamping cylinder 47 is returned to its original position, and the cover 30 is removed by the clamp arm 46. At the same time, by operating the second hydraulic cylinder 33, the cover 36 is raised to open the cylindrical body 15, and by operating the first hydraulic cylinder 12, the case 16 is moved to the case arm 14. At the same time, it is rotated counterclockwise in FIG.

Then, the steel pipe 18 after quenching falls from the support stand 30 onto the unloading guide plate 54, rolls over the unloading force guide plate 54, reaches its end, and from there is transferred to the chain dog 57. It is then lifted up from the cooling tank 10 and moved to an appropriate location such as an outlet (not shown).

On the other hand, while the steel pipe 18 is being pulled up by the chain dock 57, the case 16 is returned to the original position shown in FIG. 4 by the hydraulic cylinder 12 and stands by to receive the subsequent steel pipe 18. The hardening process for the steel pipe 18 is completed, and the hardening work can be performed continuously by repeating the above-described operation.

Although not specifically explained in the above embodiment, when the inner diameter of the cylindrical housing part 19 is changed by replacing the inner case 17 and the inner cover 37, the end of the inner case 17 and the inner cover 37 on the outer nozzle 58a side As shown in FIG. 12, the opening end of the outer nozzle 58aθ) and the end of the cylindrical housing 19 coincide, but the central axis of the opening end of the inner nozzle 58b and the steel pipe 1
Therefore, if the cooling water is jetted from the inner nozzle 58b as it is, turbulence will occur in the cooling water flow, making it difficult to apply a cooling water flow along the axial direction to the inner peripheral side of the steel pipe 18. Therefore, the hardening effect may be inhibited.

Therefore, in order to solve this problem, when the inner case 17 and the inner cover 37 are replaced, the tip of the inner nozzle 58b is replaced accordingly.
It is preferable that the opening end of the inner nozzle 58b is always aligned with the steel pipe 18.

As is clear from the above description, according to the hardening apparatus of the present invention, on the inner surface of the case and cover that constitute the cylindrical body,
An inner case and an inner cover that constitute a cylindrical accommodating portion for accommodating a steel pipe are provided, and the inner case and inner cover are configured to be attachable to and detachable from the case and cover, so that the radius of curvature or dimension of the inner surface is If you prepare multiple types of inner cases and inner covers with different diameters, select the inner case and inner cover according to the outer diameter of the steel pipe to be hardened, and attach them to the case and cover, the steel pipe will be heated inside the tubular interior. The cross-sectional area of the flow path formed on the outer circumferential side of the steel pipe can be set to an appropriate area and will not become unnecessarily wide. Since it is possible to prevent the flow of cooling water, it is possible to reduce the power required to flow the amount of cooling water or reduce the operating cost.
Furthermore, it can also contribute to energy saving.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the quenching apparatus already proposed, Fig. 2 is a sectional view taken along the line II-I in Fig. 1, and Fig. 3 is a partial plan view showing the main parts of an embodiment of the present invention. , Figure 4 is I of Figure 3.
5 is an enlarged sectional view showing the cylindrical body, FIG. 6 is an enlarged sectional view of the part ■ in FIG. 3, and FIG. 7 is a sectional view taken along the line ■-■ in FIG. 8 is a cross-sectional view taken along the line ■-■ in FIG. 3, FIG. 9 is an enlarged view taken along the line IX-IX in FIG. 3, and FIG. 10 is an outside nozzle, an inside nozzle, and a presser foot. A partially sectional front view mainly showing the rod, FIG. 11 is a cross-sectional view showing the process of attaching and removing the inner case and inner cover, and FIG. 12 is a schematic diagram showing the relative positions of the tip of each nozzle and the inner case and inner cover. It is. 15...Cylindrical body, 16...Case, 1
7... Inner case, 18... Steel pipe, 19... Cylindrical housing part, 21... Locking piece, 22... Engagement Joining piece, 36...Cover 37...Inner cover 38...Lock pin, 38a...Through hole, 40...
・Cock, 58a...Outer nozzle, 58b...
...inner nozzle.

Claims (1)

[Scope of Claims] 1. A cylindrical body that accommodates a metal tube to be hardened so that its central axes are parallel to each other, and a cooling water flow is applied along the axial direction to both the inner and outer circumferential sides of the metal tube inside the cylindrical body. A metal tube hardening apparatus is provided with a nozzle disposed at one end of a cylindrical body, and the cylindrical body is configured to be openable and closable by a case and a cover having a semicircular cross section that approach and separate from each other in the radial direction. and an inner case having a semicircular cross section smaller in diameter than the case is removably attached to the inner surface of the case so that their center axes are parallel to each other, and an inner cover having a semicircular cross section smaller in diameter than the cover. is removably attached to the inner surface of the cover so that their central axes are parallel, and the inner case and inner cover form a cylindrical accommodating portion for accommodating the metal tube. Hardening equipment for metal tubes. 2. The cylindrical body is configured to open and close when the cover moves in the vertical direction with respect to the case, and retaining pieces projecting left and right are formed at predetermined locations in the longitudinal direction of the inner case. The case is provided with a locking piece for inserting and locking the engaging piece by sliding the inner case in its longitudinal direction, and the outer surface of the inner cover has a tip end. A locking pin with a through hole formed therein is protrudingly provided in the cover, and an insertion hole for inserting the locking pin is formed in the cover, and a through hole for the locking pin is formed in the outer surface of the cover. 2. The metal tube hardening apparatus according to claim 1, further comprising a rotor that is movable back and forth for inserting into the inner cover and fixing the inner cover to the inner surface of the cover.