JPS628149Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a vertical induction heating device suitable for use in heating cylindrical steel billets and the like in a production line for steel pipes and the like.

As is well known, an induction heating device is constructed using a cylindrical induction heating coil, and an object to be heated is inserted into a hollow part of the induction heating coil and heated. In particular, as an induction heating device used to heat a cylindrical steel billet to be supplied to a steel pipe extruder in a steel pipe production line, a vertical induction heating device in which the axis of an induction heating coil is arranged vertically is used. equipment is used. In addition, due to the principle of induction heating, the frequency of the AC power supply used when heating small diameter billets (approximately 180 mmφ or less) with this type of induction heating device is
In terms of heating efficiency, it is preferable to use a frequency higher than that of the commercial AC power supply (50Hz or 60Hz). Such an induction heating device is particularly called a medium frequency vertical induction heating device.

By the way, in the medium-frequency vertical induction heating device described above, for example, if the center axis of the billet is eccentric or inclined with respect to the center axis of the induction heating coil, the magnetic flux of the induction heating coil will not pass through the billet evenly, and the billet will become uneven. Heat is generated. In addition, if the length of the induction heating coil is not appropriate for the length of the billet, the so-called end effect of magnetic flux will be noticeable, and the magnetic flux will pass through the ends and center of the billet equally. There will be a temperature difference between them. Therefore, a problem arises in that the billet is heated unevenly, which not only causes problems during heat processing by the steel pipe extruder, but also adversely affects the quality of the finished steel pipe. occurs.

Conventionally, therefore, a method has been adopted in which a magnetic adjustment member called a dummy billet or the like is placed at the end of the billet. However, although this method of using a dummy billet is effective for reducing the edge effect of the magnetic flux, the central axis of the billet is eccentric,
Also, it was not possible to prevent uneven heat caused by the tilting, and it was not possible to solve all of the above-mentioned problems.

In view of the above-mentioned circumstances, this invention provides a vertical induction heating device that can uniformly heat the billet and therefore solve all the above-mentioned problems. a guide member attached to the guide member; a column supported by the guide member and vertically slidable along the central axis of the induction heating coil; It comes into contact with the center of the upper end surface of the billet inserted into the hollow part,
It is characterized by comprising a plug for positioning the center thereof, and an annular magnetic adjustment member attached to the pillar body so as to be slidable in the vertical direction.

Hereinafter, embodiments of this invention will be described with reference to the drawings. FIG. 1 is a front sectional view showing the structure of a vertical induction heating device according to an embodiment of the invention.
In this figure, 1 is a base, and this base 1 has an opening 1a formed therein. Further, an annular fixing plate 2 is attached to the opening 1a of the base 1 via an annular plate 3. Further, a cylindrical induction heating coil 4 is vertically disposed on the upper surface of the fixing plate 2, and an annular fixing plate 5 is attached to the upper end of the induction heating coil 4. In addition, the fixed plate 2,
Annular plate body 3, induction heating coil 4, and fixed plate 5
are attached to each other with a common axis, and a cylindrical fireproof heat insulating member 6 is inserted along the inner peripheral surfaces thereof. Further, a disc-shaped upper plate 7 is attached to the upper surface of the fixed plate 5, and a round hole 7a is formed in the center of the upper plate 7, and an inner peripheral edge along the round hole 7a of the upper plate 7 is formed. A cylindrical guide member 8 is attached. Further, round holes 7b and 7c are formed at positions slightly apart from the round hole 7a of the upper plate 7, and cylindrical guide members 9a and 9 are formed around the round holes 7b and 7c.
b are attached to each. A centering pipe 10 made of non-magnetic steel is inserted into the above-mentioned guide member 8 so as to be slidable in the vertical direction. A disk-shaped lid 11 is attached to the upper end of this centering pipe 10, and is designed to prevent movement of the centering pipe 10 when it has descended to the lower limit position as shown in the figure. Moreover, a cooling pipe is arranged inside this centering pipe 10, and both ends of this cooling pipe are connected to cooling water supply pipes 12 attached to the lid body 11.
and a cooling water discharge pipe 13, respectively.
Further, as shown in FIG. 2, a conical centering plug 14 made of non-magnetic steel is removably attached to the lower end of the centering pipe 10. Further, an annular sliding member 15 made of non-magnetic steel is attached to the lower end of the centering pipe 10 so as to be slidable in the vertical direction. In this case, the sliding member 15 is prevented from moving downward by the plug 14, so that it does not fall off from the centering pipe 10. Further, the upper ends of support arms 16a to 16d made of non-magnetic steel are attached to the lower surface of the sliding member 15 by welding, and the lower ends of these support arms 16a to 16d are attached with an annular shape made of iron. A magnetic adjustment dummy billet 17 is attached by welding. A cooling water passage 17a is formed inside this dummy billet 17 for magnetic adjustment, and an inlet and a drainage port of this cooling water passage 17a are connected to a cooling water supply pipe 18 and a cooling water outlet attached to the upper surface of the dummy billet 17. They are each connected to a pipe 19. The cooling water supply pipe 18 and the cooling water discharge pipe 19 are supported by guide members 9a and 9b attached to the above-mentioned upper plate 7 so as to be slidable in the vertical direction. (See FIG. 1) The vertical induction heating device 20 is configured as described above.

On the other hand, below the vertical induction heating device 20, there is a push rod 22 that supports the cylindrical billet 21, a drive section (not shown) that moves the push rod 22 in the vertical direction, and a drive section (not shown) that moves the billet 21 vertically and An insertion/removal mechanism 25 is provided which includes guide plates 23 and 24 each having a V-shaped cross section and which maintains its axis aligned with the axis of the induction heating coil 4 . This insertion/removal mechanism 25 allows the induction heating coil 4 of the billet 21 to
Insertion and removal are performed. Note that this insertion/removal mechanism 25
is similar to that used in conventional vertical induction heating devices.

Vertical induction heating device 20 configured as above
The operation of heating the cylindrical billet 21 using the heating device will be explained with reference to FIGS. 1 and 3. First, when inserting the billet 21 into the vertical induction heating device 20 from the state shown in FIG.
The push rod 22 is pushed upward by the drive section. As a result, the billet 21 is pushed up while being guided in the axial direction of the induction heating coil 4 by the guide plates 23 and 24. Next, billet 21
When the upper end surface comes into contact with the lower end surface of the dummy billet 17, the dummy billet 17 is guided by the sliding member 15 in the axial direction of the centering pipe 10 and pushed up. Further, when the inner peripheral edge of the upper end surface of the billet 21 comes into contact with the circumferential surface of the centering plug 14, the centering plug 14 and the centering pipe 10 are guided in the axial direction of the induction heating coil 4 by the guide member 8. While being pushed up, it is pushed up. When the billet 21 is inserted into the hollow part of the induction heating coil 4 as shown in FIG. 3, the movement of the push rod 22 is stopped. As a result, billet 2
1 is held in this position. In this case, the billet 21 is prevented from moving in the vertical direction by the centering plug 14 and the push rod 22, and is also prevented from moving in the lateral direction by the centering plug 14. This prevents the center axis of the billet 21 from being eccentric or inclined with respect to the center axis of the induction heating coil 4.

Next, when heating the billet 21, as shown in FIG. 3, an AC power source 26 is connected to the induction heating coil 4, and the billet 21 is heated by induction. in this case,
Cooling water is supplied from the outside to the cooling pipe in the centering pipe 10 and the cooling water passage in the dummy billet 17 to prevent the centering pipe 10 and the dummy billet 17 from overheating. Further, the lower end surface of the dummy billet 17 is in contact with the upper end surface of the billet 21 to prevent overheating caused by the edge effect of the magnetic flux occurring at the upper end surface of the billet 21.

Next, when the billet 21 is to be pulled out from the vertical induction heating device 20, the billet 21 is pulled out by an operation completely opposite to the operation at the time of insertion described above.

In this manner, according to the embodiment described above, eccentricity and inclination of the billet 21 are prevented when inserting and removing the billet 21 and during heating, so that the billet 21 can be heated uniformly, and
It is possible to prevent the billet 21 from damaging the inner peripheral surfaces of the induction heating coil 4 and the heat insulating member 6. Further, although the inner diameter of the hollow portion of the billet 21 usually changes depending on the type, in the above-mentioned embodiment, since the conical centering plug 14 is used, the inner diameter of the hollow portion of the billet 21 changes depending on the type. ,
There is no need to replace the centering plug 14 each time, and workability is very good. Furthermore, since the centering plug 14 is in contact with the billet 21 which is heated to a high temperature, its peripheral surface will wear out after a certain period of time and it will be necessary to replace it with a new one. can easily perform the replacement work.

In the embodiment described above, the centering pipe 10 is hollow, but it may be solid, or the centering pipe 10 and the centering plug 14 may be integrated. Further, although the plug 14 is shown as having a conical shape, a hemispherical or bowl-shaped plug may also be used.

As explained above, according to this invention, the guide member attached to the upper end surface of the induction heating coil;
a column supported by the guide member and slidable in the vertical direction along the central axis of the induction heating coil; and a column attached to the lower end of the column and inserted into the hollow part of the induction heating coil. A plug that contacts the center of the upper end surface of the billet to determine its center position and an annular magnetic adjustment member that is slidably attached to the columnar body in the vertical direction are provided, so that the billet can be heated uniformly. Therefore, it is possible to obtain the advantage of being able to solve all problems during thermal processing and adverse effects on quality that occur when the billet is heated non-uniformly.

[Brief explanation of the drawing]

FIG. 1 is a front cross-sectional view showing the configuration of a vertical induction heating device according to an embodiment of the invention, FIG. 2 is a perspective view showing the configuration of the main part of the same embodiment, and FIG. FIG. 3 is a front cross-sectional view showing a state in which a billet 21 is heated by a vertical induction heating device. 4... Induction heating coil, 7... Plate, 8... Guide member, 10... Centering pipe (column), 14...
...Centering plug (plug), 17...Dummy billet (magnetic adjustment member).

Claims (1)

[Scope of utility model registration request] In a vertical induction heating device in which a cylindrical induction heating coil is arranged vertically, a guide member attached to an upper end surface of the induction heating coil and a central axis of the induction heating coil supported by the guide member are provided. a column that is slidable in the vertical direction along the column; and a column that is attached to the lower end of the column and that comes into contact with the center of the upper end surface of the object to be heated that is inserted into the hollow part of the induction heating coil to determine its center position. a plug that performs
A vertical induction heating device comprising: an annular magnetic adjustment member attached to the columnar member so as to be slidable in the vertical direction.