JPS5912145Y2 - Forge welded pipe manufacturing equipment - Google Patents

Description

[Detailed description of the invention] This invention is an induction heating heater that heats the skelp, which is the material for forge-welded pipes, in a heating furnace, and then uniformly heats the temperature of both edges of the skelp to the forge-welding temperature. The present invention relates to a forge-welded pipe manufacturing apparatus equipped with the following.

In general, forge-welded pipes are made by passing the skelp, which is the raw material, through a heating furnace and heating both edges of the skelp to 1300°C, which is the forge-welding temperature.
After being heated back and forth, it is passed through a certain type of roll to be bent into a roughly O-shaped cross section, and then passed between forge welding rolls and the opposed edges on both sides are butt welded to form a pipe.

However, in this method, the entire skelp is heated in a heating furnace, and while both edges of the skelp are heated to the forge welding temperature, the center of the skelp, which does not need to be heated to the forge welding temperature, is also heated to the forge welding temperature. Since it is heated to a similar temperature, there is a disadvantage that there is an extremely large amount of waste from the viewpoint of thermal economy and yield due to scale loss.

For this reason, conventionally, as shown in Figs. 6 and 7, an inductor IH is placed at a suitable location between the heating furnace F for the skelp S and a certain roll FR, and the skelp S is first passed through the heating furnace F. , After heating the whole to around 1000'C, which is lower than the forge welding temperature,
Through the inductor IH, both side edge parts El of the squelp S,
Only Er is selectively heated to around 1300°C, which is the forge welding temperature, and the Skelp S is sequentially passed through a forge roll FR and a forge weld roll WR to form a pipe, thereby achieving significant energy savings. A method has been proposed (Japanese Patent Publication No. 43-14092).

As shown in FIG. 7, the inductor IH used in this method includes a long copper rod 71 and a skeleton S.
A pair of short copper rods 72, 73 arranged in a straight line parallel to the copper rod 71 with a distance slightly longer than the width of the copper rod 71, and above the front end of the copper rod 71 and the front end of the front copper rod 72, bottom side,
and above the rear end of the copper rod 71 and the rear end of the rear copper rod 73;
A pair of bridge-like thick-walled copper bands 74 each extending on the lower surface side,
74, 74', 74', and a pair of terminal pieces 75 attached to opposite ends of the copper rods 72 and 73. 76 as a whole in a rectangular frame in plan view.

Such an inductor IH has a copper rod 71 on its long side,
72 and 73 are both side edge parts El and Er of the scalp S
The thick copper strip 74, which is one short side, is positioned parallel to and opposite to these side end surfaces.
, 74, between the copper rods 71 and 72, 73, and between the thick copper strips 74', 74' on the other short side. A high frequency current is passed between 76 and the magnetic flux formed around the inductor IH is cut to generate an induced current on the surface of the squelp S passing through, thereby selectively heating the edge parts El and Er on both sides of the squelp S. This is the conflict that led to this.

However, in a method using such an inductor IH, the temperature of the edge portions El and Er on both sides of the skelp S extracted from the heating furnace F depends on the structure of the heating furnace F or the wall thickness of the skelp S itself. For example, in an inductor IH, both edge portions El and E
Even if r is heated uniformly, both edge portions El,
It is unavoidable that a temperature difference of about 5 to 20°C is normally formed in Er, and furthermore, due to the swinging of the skelp during operation, the copper rods 71, 72, 73 and the edge parts El, Er Due to the variation in the separation dimension of the Skelp S, the temperature difference between the edges on both sides of the inductor IH is further exacerbated, and the amount of upset varies widely, resulting in poor product quality. Edges E on both sides of rods 71, 72, 73 and Skelp S
Even if an attempt is made to shorten the distance between the two edge parts El and Er, there is a risk that the edge parts El and Er will deform if they come into contact with the copper rods 71, 72, 73, so there is a limit to the shortening. Efficiency generally has to stay at a low value, there are limits to energy saving, and the range of width dimensions of Skelp S that can be heated using an inductor IH with a certain specification is narrow, so it is difficult to use an inductor with different specifications. In addition, as mentioned above, there is a temperature difference between the edges El and Er on both sides of the Skelp S extracted from the heating furnace F, so correction is often required. With the inductor IH, there were some difficulties in putting it into practical use, such as the fact that this correction was not available.

The present invention has been developed in view of the above circumstances, and its purpose is to provide a skelp on each of the front and back sides of the passage area of the skelp, and to extend one part of the skelp over an appropriate length into the passage area of each of the edge portions on both sides of the skelp. A pair of induction heating coils are provided so as to face each other, and at least one of the coils is configured to change the state of electromagnetic coupling between the coil and each of the edges on both sides of the squelp. By uniformly heating only the edges of both sides of the skelp to the appropriate forge welding temperature, not only can a large amount of thermal energy be saved, but also the product quality of the forge welded tube itself can be significantly improved. We are here to provide you with the equipment.

Hereinafter, the present invention will be specifically explained based on drawings showing embodiments thereof.

Fig. 1 is a schematic diagram showing a forge-welded pipe manufacturing apparatus according to the present invention (hereinafter referred to as the invention apparatus), Fig. 2 is an enlarged perspective view partially cut away showing an induction heating coil constituting a heater, and Fig. 3 The figure is a perspective view showing a coil, its driving means, and its control system;
FIG. 4 is an explanatory diagram of the operation of the coil with respect to the squelp,
In the diagram, S is Skelp, F is Furnace, FR is Kaigata Roll, W
R is a forge-welded roll, which is a forged roll FR from the heating furnace F.
In the movement range of Skelp S, induction heating coils Cu and Cd for controlling the heater are installed using a mounting frame 30 as shown in FIG. The central part is heated to around 1180°C, which does not interfere with bending and drawing by a group of drawing rolls (not shown), and the edge parts El and Er on both sides are heated to around 1200°C and extracted from the heating furnace F. After that, it was introduced between the coils Co and Cd, and the temperature was raised mainly at the edge portions El and Er on both sides to about 1300'C, which is the forge welding temperature.Then, it was passed through a preform roll FR and bent into an approximately O-shaped cross section. and further passed through a forge welding roll WR to form opposing opposite side edge portions E.
L and Er are butt-forge welded together to form a pipe, and then sent as is to subsequent processes such as finishing (not shown).

As shown in FIG. 2, the induction heating coils Cu and Cd have a coil main body 11. which is fitted into the grooves 1a and 2a provided in the cores 1 and 2, the lower surface of the core 1, and the upper surface of the core 2, respectively. It is constructed in 21.

Each of the cores 1 and 2 is a silicon steel plate in the shape of a short fence, and a similar silicon steel plate in the shape of a short fence with recesses formed by punching in the portions corresponding to the shapes and positions of the grooves 1a and 2a. The cores are closely stacked to form a rectangular shape and bound together with a band (not shown), and the lower surface side of the core 1 and the upper surface side of the core 2 are provided with the recesses formed in the silicon steel plate, respectively. The grooves 1a and 2a have a concave cross section and are rectangular in plan view with four sides parallel to the four sides of each core 1 and 2.

The coil bodies 11 and 21 are constructed by winding long strip-shaped copper plates, each of which has a rectangular cross section and a hollow interior to allow cooling water to pass through, along the grooves 1a and 2a, and solidifying them with varnish. has been done.

Both ends 11a, 21a of the coil bodies 11, 21 are grooved 1.
Hole 1 penetrating from the peripheral wall of a, 2a to the outer periphery of core 1, 2
3. 23 to the outside.

The high frequency current output from the frequency converter ■ connected to the commercial power supply E via the transformer T is connected to the power factor correction capacitor C.
From the ends 11 a, 21 a connected to the coil body 11.D, respectively. 21 is energized.

The mounting frame 30 has a U-shape in front view with a vertical beam 31 and an upper arm 32 and a lower arm 33 that are arranged parallel to each other on the upper and lower ends thereof, and the coil Cu is connected to the upper arm 3.
2 with the fixed side of the coil body 11 facing downward, and the coil Cd with the fixed side of the coil body 21 facing upward on the upper surface of the lower arm 33, respectively, and the straight portions 11 1, 11 r of the coil bodies 11 and 21, respectively. , 21 1, 21 r are fixed along both side edge portions El and Er of the scalp S.

The upper arm 32 is horizontally fixed to the upper end of the longitudinal beam 31, and wheels 34. Suspension rods 35, 35 are erected, and the entire mounting frame 30 is suspended on a rail R installed horizontally above the Skelp S in a direction perpendicular to the moving direction of the Skelp S. It is positioned on the side of the edge portion Er of the Skelp S, and is movable in a direction perpendicular to the moving direction of the Skelp S with the upper and lower coils Cu and Cd facing the upper and lower surfaces of the Skelp S.

Further, a motor M1 is disposed on the upper surface of the upper arm 32, and its output shaft is linked via a chain to a sprocket 34' provided coaxially with one of the wheels 34, so that the motor M1 rotates in the forward and reverse directions. The mounting frame 30 is moved in a direction perpendicular to the moving direction of the squelp S, and as shown in FIG.
1, horizontal separation dimensions h1, h2, h from the inner edge of 21r
3, h4 can be changed.

On the other hand, the lower arm 33 has a horizontal shaft 3 fixed to its base end.
3a to the lower end of the vertical beam 31 so as to be pivotable up and down about a horizontal axis 338.

A gear 33b is fixed to the shaft end of the horizontal shaft 33a, and the gear 33b meshes with a gear 33C that meshes with the gear of the output shaft of the motor M2 fixed to the lower end of the vertical beam 31. The lower arm 33 is rotated in the vertical direction around the horizontal axis 33a by the forward and reverse drive of Skelp S, as shown by imaginary lines in FIG.
The vertical separation dimensions v1 and v2 from the straight portions 21 1 and 21 r surfaces of the coil body 21 can be changed.

Reference numeral 40 denotes a control unit that controls the drive of the motors M1 and M2.The control unit 40 has temperature sensors Sl and Sr connected to it via a temperature difference transmitter 41, and temperature sensors Sl' and Sr' connected to a feedback circuit 42. connected via.

The temperature sensors Sl and Sr are arranged to face the edge parts El and Er on both sides of the squelp S on the upstream side of the coils Cu and Cd in the moving direction of the squelp S, and detect the temperature of the edge parts El and Er on both sides. is input to the temperature difference transmitter 41 to detect the temperature difference between the two, and when this temperature difference is input to the control unit 40, the control unit 40 moves the mounting frame 30 to the rail R so as to eliminate the temperature difference between the two. along the width direction of the squelp S, and also rotates the lower arm 33 in the up and down direction around the base end, so that the coil main body 11. in each coil Cu, Cd. 21 straight part 11 1, 11
r, 21 1, 21 Horizontal and vertical separation dimensions h1, h2 between r and both side edge parts El, Er of the scalp S
, h3, h4 and ■1, v2.
, M2.

The temperature sensors Sl' and Sr' are disposed on the downstream side of the coils Cu and Cd in the moving direction of the squelp S, facing the edge parts El and Er on both sides of the squelp S,
Skelp S after being heated by coils Cu and Cd
When the temperatures of both edge portions El and Er are detected and output to the control unit 40 via the feedback circuit 42, the control unit 40 will not issue a signal if the temperature difference between the two is zero; If there is a temperature difference between motors M, M2, each coil C is
Coil body 11,' 21 (7) at u, Cd
A drive signal is issued to the motors M1 and M2 to adjust the horizontal and/or vertical separation dimensions h1 to h4, V1, and v2 between the straight portions 111, 11r, 211, and 21r and the edge portions El and Er on both sides of the squelp S. It's like this.

As mentioned above, the temperature detected by the temperature sensors Sl' and Sr' is used for correcting the position of the coils Cu and Cd, but it is not limited to this. It may also be used to judge whether or not there is a person.

? The adjustment ratio between the movement adjustment amount of the attachment frame 30 and the rotation adjustment amount of the lower arm 33 is not particularly limited. For example, coarse adjustment can be made by moving the attachment frame 30 in the left-right direction, and coarse adjustment can be made by moving the attachment frame 30 in the left-right direction. The temperature sensors Sl', Sr can be finely adjusted by rotating the temperature sensors Sl', Sr, or can be adjusted based on the detected temperatures of the temperature sensors Sl', Sr by moving the mounting frame 30.
The correction adjustment based on the detected temperature ' may be performed by rotating the lower arm 33.

When a high-frequency current is applied to the coil body 11.21, the magnetic flux generated by this energization passes through the squelp S2, especially the edge portions El and Er on both sides.
An induced current flows through and heats the edge portions El and Er on both sides, but when the horizontal or vertical separation between the edge portions El and Er and the coil body 11.21 changes, The amount of magnetic flux passing through the squelp S will also change, and the induced current generated in the squelp S will change accordingly, and the amount of heating for both side edge portions El and Er will also change.

In other words, in the present device, the above-mentioned horizontal separation dimension h1
~h4, by changing the vertical separation dimensions v1 and v2, the electromagnetic coupling state between the coils Cu, Cd and the squelp S is changed to make the temperature of the edge portion El and the edge portion Er uniform.

In the above embodiment, the coils Cu and Cd are both movable in the horizontal direction, and the coil Cd is movable in the vertical direction, but one of the coils Cu and Cd is fixed and the other is moved horizontally. Alternatively, it goes without saying that it may be configured to be movable in the vertical direction.

In the device of the present invention, if there is a temperature difference between the edge portions El and Er of the squelp S before reaching the coils Cu and Cd, in other words, immediately after being extracted from the heating furnace F, for example, When the temperature is lower than that of the edge portion Er, the temperature difference transmitter 41 detects the temperature difference between the edge portions El and Er based on the temperature from the temperature sensors Sl and Sr that have detected the temperature of the edge portions El and Er. A signal corresponding to
Based on this input signal, a drive signal is issued to the motors M1 and M2 at an appropriate ratio, and the mounting frame 30 is moved to the right in FIG. 4, and the coil body 11. The horizontal separation dimensions h and h3 between the straight parts 11 1 and 21 1 of 21 and the edge part El are small, and conversely, the straight parts 11 r and 21 r
The horizontal separation dimensions h2 and h4 between the coil body 21 and the edge portion Er are set large, while the lower arm 33 is rotated upward from the horizontal position, and the straight portion 211 of the coil body 21 and the edge portion E1 are rotated upward.
Vertical separation dimension ■1 is the straight part 21 r and the edge part Er
is set relatively smaller than the vertical separation dimension V2,
The edge portion E1 is heated more strongly than the edge portion Er.

On the other hand, if the temperature of the edge portion Er is lower than the temperature of the edge portion E1, the mounting frame 30 is moved to the left in FIG. 4, and the coil body 11. 21 straight part 11 r, 21
The horizontal distance h2, ht between r and the edge portion Er is small, the horizontal distance between the straight portion 11 1, 21 1 and the edge portion El is set large, and the lower arm 3
3 is rotated below the horizontal position so that the vertical separation dimension ■2 between the straight portion 21r and the edge portion Er of the coil body 21 is relative to the vertical separation dimension ■1 between the straight portion 211 and the edge portion E1. is set to be small, and the edge portion Er is set to be smaller than the edge portion E.
It will be heated more strongly than 1.

FIG. 5 is a schematic diagram showing another example of the coil used in the present device together with the drive means and its control system, and in the figure CI, C
r is a coil for induction heating, and is disposed facing the movement area of the squelp S between the heating furnace F and the preform roll FR.

Each coil CI, Cr is a core 51 that is U-shaped when viewed from the front.
1,51r and coil bodies 521, 52r made of hollow strip-shaped copper plates wound around the coil bodies 521, 52r. At the end of each coil body 521, 52r, the current from the power source E is passed through a frequency converter. The frequency is set by (2), the power factor is corrected by the capacitor CD, and then the power is applied individually.

Each coil CI and Cr are supported by support rods 531 and 53r.
A support beam 6 is installed horizontally in a direction perpendicular to the moving direction of the Skelp S above the passage area of the Skelp S.
It is suspended at 0.

At the upper end of each support rod 531, 53r, a sliding body 541,
54r is provided, and these sliding bodies 541, 54r are slidably fitted into the support groove 60a of the support beam 60, and are movable along the support beam 60 in a direction perpendicular to the moving direction of the squelp S. ing.

The operating rods of air cylinders 551, 55r fixed to the lower surface of the support beam 60 are connected to each sliding body 541, 54r, and the coil bodies 521, 521 of each coil CI, Cr are activated by the operation of the air cylinders 551, 55r. Horizontal separation dimensions hl, hr between 52r and both side edge parts El, Er of Sgelp S (both side edge parts El,
Dimensions between Er and the opposing circumferential surfaces of the coil bodies 521, 52r)
It is possible to change the .

Reference numeral 61 denotes a control unit that controls the current flowing to the coil bodies 521, 52r and drives the air cylinders 551, 55r, and is located upstream of the coils CI, Cr in the moving direction of the squelp S. It is connected to the width direction temperature sensor So arranged in the width direction of the
The width direction temperature sensor S.

Skelp S detected by
The temperature difference between the coil bodies 521 and 521 is calculated based on the temperature distribution in the width direction of the coil body 521, especially the temperature of the edge portions El and Er on both sides, and a control signal is issued to the frequency converter 2 to eliminate the temperature difference. The frequency of the current applied to 52r is changed.

If the frequency of the current to be applied to both coil bodies 52 1 , 52 r exceeds the controllable range of the frequency converter, first a drive signal is issued to both air cylinders 55 1 , 55 r. The coil bodies 521 and 52 in the coils CI and Cr are activated.
The separation dimensions hl and hr between r and the edge portions El and Er on both sides of the squelp S are set so as to eliminate the temperature difference between the edge portions El and Er on both sides, and then both coil bodies 521, 5
Finely adjust the frequency of the energizing current with respect to 2r,
Both edge portions El and Er are uniformly heated to a preset optimum temperature within the forge welding temperature range.

As described above, the device of the present invention is provided with a pair of induction heating coils that are constructed so that a portion thereof faces over an appropriate length into the passage area of each of the edge portions on both sides of the squelp, and at least one of the coils is Since the structure is configured such that the electromagnetic coupling state between the coil and the edge portions on both sides of the scalp can be changed, the temperature of the edge portions on both sides of the scalp can be made uniform.

In addition, in the device of the present invention shown in Figures 1 to 4, the coils are arranged above and below the passage area of the squelp, so the distance between the coil and the squelp can be narrowed and the heating efficiency for the squelp is high. When used, the method of Japanese Patent Publication No. 43-14092, which could not be put to practical use due to the various problems mentioned above, can be realized, and the present invention contributes to energy saving and quality improvement in forge welded pipe manufacturing. is huge.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the proposed device, Fig. 2 is an enlarged perspective view showing the coil with a part cut away, Fig. 3 is a perspective view showing the coil, its driving means, and its control system, and Fig. 4 is a diagram showing the structure of the squelp. 5 is a perspective view showing another example of the coil used in the present device together with its driving means and its control system; FIG. 6 is a schematic diagram showing a conventional forge-welded pipe manufacturing device; FIG. The figure is also an enlarged perspective view of an inductor used in a conventional forge-welded tube manufacturing apparatus. S...Skelp, F...Heating furnace, FR
..... Certain shape roll, WR ..... forge welding roll, Cu, Cd, CI, Cr ..... coil,
1, 2... Core, 11... Coil body, 111, llr... Straight part, 21...
・Coil body, 21l, 21r... straight part,
521, 52r... Coil body.

Claims (1)

[Scope of utility model registration request] Power through a heating furnace. In a forge-welded pipe manufacturing apparatus that further induction-heats both side edges of a sun-heated skelp and then bends it into a cylindrical shape and forge-welds the opposite edge parts to each other, A pair of induction heating coils are arranged and configured so that a portion thereof faces over an appropriate length into the passage area of each edge portion on both sides of the skelp, and at least one of the coils is connected to the coil and the skelp. 1. A forge-welded pipe manufacturing apparatus, characterized in that the forge-welded pipe manufacturing apparatus is configured to be able to change the state of electromagnetic coupling between the respective edge portions on both sides.