JP2013202656A - Mold for continuous casting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold for continuous casting capable of simplifying a mounting structure and capable of improving temperature measurement accuracy of a cooling plate better than before.SOLUTION: A mold for continuous casting having a mold body formed with a space vertically penetrating inside is for manufacturing a cast slab by cooling and solidifying molten steel supplied to the space in the mold body. A rear surface side of a cooling plate 10 composing the mold body is provided with a sheathed thermocouple 14 including a temperature measurement part 11 covered with a metal cap 12 and the metal cap 12 mounted with a lead wire 13. The metal cap 12 is fixed to the rear surface of the cooling plate 10.

Description

  The present invention relates to a continuous casting mold used for producing a slab.

Conventionally, a slab has been cast by using a continuous casting mold having a mold body in which a space portion penetrating in the vertical direction is formed inside, and solidifying the molten steel supplied to the space portion while cooling the mold body. doing.
When producing slabs, it is necessary to ensure that the solidified shell formed in the mold body grows. However, if the solidified shell growth is unstable, the solidified shell is broken and breaks in which unsolidified molten steel flows out. Out may occur, for example, and there may be an accident such as interruption of a casting operation, a long pause, and damage to equipment.
Therefore, as a method for predicting the occurrence of this breakout, for example, as shown in Patent Document 1, a plurality of thermocouples are embedded in a cooling plate constituting a mold body, and a temperature change or the like of these thermocouples is detected. Is disclosed.

However, the thermocouple used in the conventional technology has a structure in which a copper wire or enamel wire is connected to the tip of the copper constantan wire, and this is wound around the thermocouple as a winding. Is complicated and unusable. Moreover, since the thermocouple is rod-shaped (constantan rod), it is difficult to bend it, and there is a possibility that it cannot be installed depending on the location.
Therefore, the present inventors use a sheathed thermocouple having a simple configuration as a thermocouple for measuring the temperature of the cooling plate. The attachment structure of this sheath thermocouple is shown in FIG.
As shown in FIG. 3, on the back surface side of the cooling plate 80, a large number of water guide grooves 81 are provided along the casting direction, and the water supply portion and the drainage portion of the back plate 82 disposed in contact with the back surface of the cooling plate 80. Cooling water is allowed to flow in each water guide groove 81 via (not shown) to cool the cooling plate 80.

The back plate 82 is attached and fixed to the cooling plate 80 by a large number of bolts 83. Specifically, the male screw formed on the front side of the bolt 83 is screwed with the female screw formed on the cooling plate 80, and the male screw formed on the base side of the bolt 83 is disposed on the back side of the back plate 82. The cap nut 84 to be engaged is screwed.
Here, an O-ring 85 is attached to the front side of the bolt 83 that contacts the cooling plate 80, and a packing 86, a seal ring 87, and an O-ring are provided on the base side of the bolt 83 protruding from the back surface of the back plate 82. 88 is attached to prevent leakage of cooling water.

A through hole 89 is formed in the bolt 83 in the axial direction. A thermocouple 90 is inserted into the through hole 89, and a temperature measuring unit 91 provided at the tip of the thermocouple 90 is connected to the cooling plate 80. Pressed against the back. Specifically, the spring member 93, the tubular reduction rod 94, and the pipe 95 are sequentially inserted into the thermocouple 90 provided with the flange portion 92 at the tip, and the cap nut 84 is tightened to The temperature measuring unit 91 inserted into the hole 96 formed on the back surface side of the cooling plate 80 is pressed against the back surface of the cooling plate 80 by the elastic force of the spring member 93 disposed between the reduction rod 94.
Thereby, the temperature of the cooling plate 80 can be measured by the thermocouple 90.

However, since the above-described mold has a structure in which the temperature measuring unit 91 of the thermocouple 90 is pressed against the back surface of the cooling plate 80 by the spring material 93, for example, due to deterioration of the spring material 93 or the like, The pressing force of the temperature measuring unit 91 becomes weak, the responsiveness of the temperature of the cooling plate 80 to the thermocouple deteriorates, and the temperature measurement accuracy may be lowered.
Further, as described above, since the spring material 93 is used, the mounting structure of the thermocouple 90 is complicated. For this reason, since a wider place is needed for attachment of the thermocouple 90, for example, the thermocouple 90 could not be densely arranged and a lot of necessary temperature measurement information could not be obtained. .

Thus, for example, as shown in Patent Document 2, a sheath thermocouple (tip-fixed sheathed thermocouple) is disclosed in which a tip portion is welded and fixed to a metal body to be measured.
This sheath thermocouple is capable of encasing a metal auxiliary tube made of a material that is more conductive than the sheath on the outside of the sheath and energizing the tip of the metal auxiliary tube to the outer surface of the sheath at or near the tip. Since the tip is welded and fixed to the metal body to be measured by flowing a high current for welding through the metal auxiliary pipe, the high current for welding flows through the metal auxiliary pipe outside the sheath. The red heat phenomenon of the inner sheath is avoided.

JP 2006-284503 A Utility Model Registration No. 3150476

  However, since the conventional sheathed thermocouple has a structure in which a metal auxiliary tube is externally provided on the outside of the sheath, the width (outer diameter) of the sheath thermocouple including the metal auxiliary tube becomes wide (large). The sheath thermocouple may not be densely arranged. Further, depending on the thickness of the metal auxiliary pipe, it is difficult to bend the sheath thermocouple, and there is a possibility that it cannot be attached depending on the location. And since it is necessary to arm the metal auxiliary tube outside the sheath, for example, the structure is complicated, and it is necessary to insert the sheath thermocouple into the pore of the metal auxiliary tube before using the sheath thermocouple Therefore, workability is poor, and further, the length of the metal auxiliary pipe is increased, which increases the material cost and is uneconomical. Furthermore, since the metal auxiliary pipe outside the sheath is a highly conductive pipe (copper or copper alloy), the heat at the temperature measuring point is transferred to the metal auxiliary pipe (heat is taken away) at the time of temperature measurement. There is a problem that can not be obtained temperature measurement information.

  The present invention has been made in view of such circumstances. The mounting structure can be simplified, the degree of freedom of the mounting position can be expanded, and the temperature measurement accuracy of the cooling plate is improved compared with the prior art with good workability and economy. An object of the present invention is to provide a continuous casting mold that can be improved.

The continuous casting mold according to the present invention that meets the above object has a mold body in which a space portion penetrating in the vertical direction is formed inside, and solidifies while cooling the molten steel supplied to the space portion by the mold body. In a continuous casting mold for producing a slab,
On the back side of the cooling plate constituting the mold body, a sheath thermocouple is provided in which the temperature measuring part is covered with a metal cap and a lead wire is attached to the metal cap, and the metal cap is provided on the back side of the cooling plate. It is fixed.

In the continuous casting mold according to the present invention, a metal cap that covers the temperature measuring portion of the sheath thermocouple is fixed to the back surface of the cooling plate, so that the response of the cooling plate temperature to the sheath thermocouple is excellent. The temperature measurement accuracy of the cooling plate can be improved as compared with the conventional case.
In addition, since the lead wire is attached to the metal cap, when the metal cap is fixed, for example, the metal cap can be fixed to the back surface of the cooling plate by passing a current through the lead wire using a stud welding method. Therefore, the mounting structure can be simplified.
Furthermore, since the metal cap can be fixed to the back surface of the cooling plate using the lead wire, it is not necessary to externally attach the metal auxiliary tube to the outside of the sheath. As a result, the sheath thermocouple can be easily bent without making the sheath thermocouple wide, so that the degree of freedom of the mounting position can be expanded (for example, the sheath thermocouple can be arranged densely). Good workability and economical. Furthermore, heat at the temperature measuring point is not lost to the metal auxiliary pipe during temperature measurement, and accurate temperature measurement information is easily obtained.

(A) is a partial side sectional view showing a thermocouple mounting structure provided in a continuous casting mold according to an embodiment of the present invention, (B) is a side view showing a state before the thermocouple is mounted, (C) is a partial enlarged side sectional view showing the mounting structure of the thermocouple. (A) is a fragmentary sectional side view which shows the attachment structure of the thermocouple provided in the casting mold for continuous casting which concerns on other embodiment of this invention, (B) is a back view which shows the attachment structure of the thermocouple. . It is a plane sectional view which shows the attachment structure of the thermocouple provided in the casting mold for continuous casting which concerns on a prior art example.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
As shown in FIGS. 1A to 1C, a continuous casting mold (hereinafter also simply referred to as a mold) according to an embodiment of the present invention has a space portion (not shown) penetrating in the vertical direction on the inside. The mold body is formed by solidifying while cooling the molten steel supplied to the space portion with the mold body, and the mold body is formed, and each of the pair is an example of a cooling plate. A sheath thermocouple 14 in which the temperature measuring unit 11 is covered with a metal cap 12 and a lead wire 13 is attached to the metal cap 12 is provided on the short side (not shown) and the back side of the pair of long sides 10. A metal cap 12 is fixed to the back side of the short side and the pair of long sides 10. This will be described in detail below.

As shown in FIG. 1 (A), the mold has a pair of short sides arranged opposite to each other with a gap, and a pair of long sides 10 arranged opposite to each other with the short sides sandwiched from both sides in the width direction. Is a quadruple mold having
In addition, each short side and each long side 10 are comprised with copper or a copper alloy, and the back plate 15 (an example of a support member) which contacts and is fixed to each back surface of this short side and the long side 10 is stainless steel or steel. It consists of Moreover, many water guide grooves are provided in the casting direction (drawing direction) on the back side of each short side and each long side 10 (see FIG. 3).

  The back plate 15 is attached and fixed to the long side 10 by a large number of bolts 16 (the same applies to the short side). Specifically, the male screw formed on the front side of the bolt 16 is screwed with the female screw formed on the back side of the long side 10, and the male screw formed on the base side of the bolt 16 is connected to the back side of the back plate 15. The cap nut arranged in is screwed together. An O-ring 17 is attached to the front side of the bolt 16 that contacts the long side 10, and a packing, a seal ring, and an O-ring are attached to the base side of the bolt 16 that protrudes from the back surface of the back plate 15. The leakage of cooling water is prevented (see FIG. 3).

As shown in FIGS. 1A and 1B, the bolt 16 has a through hole 18 formed in the axial direction thereof, and a sheath thermocouple 14 is inserted into the through hole 18.
The basic structure of the sheath thermocouple 14 is conventionally known, and a pair of different thermoelectric powers are provided via an insulating material 20 (inorganic insulator such as magnesium oxide) in a metal protective tube 19 (for example, made of stainless steel). The thermocouple element wires 21 and 22 (here, copper and constantan) are provided. The pair of thermocouple wires 21 and 22 protrudes from a through hole provided in the axial direction of the cap nut, and in use, one end of two contact points of each thermocouple wire 21 and 22 is used. An electromotive force is generated when a temperature difference is given between the (cold junction) and the other end (thermal junction), and the voltage of this electromotive force is measured and compared with a known electromotive force table. The temperature is measured.

The sheath thermocouple 14 has a wire diameter of, for example, about φ1 mm to φ5 mm, and the temperature measuring unit 11 at the tip is covered with an alumel metal cap (metal cap) 12.
The metal cap 12 is attached to the sheath thermocouple 14 as shown in FIG. 1C, in the recess 23 having a circular cross section formed on the base side of the metal cap 12, the temperature measuring portion of the sheath thermocouple 14. 11 is inserted, and the base end portion of the metal cap 12 is fixed to the metal protective tube 19 of the sheath thermocouple 14 by using a silver solder 24. However, the method is not particularly limited to this method as long as the metal cap does not fall off the sheath thermocouple, and other methods can of course be employed.

Here, as shown in FIG. 1B, the tip portion of the metal cap 12 in an unused state (before fixing) has a tapered shape (conical shape) and is pointed (two points in FIG. 1A). The chain line) is not limited to this.
The material of the metal cap is not limited to alumel, and may be another material having conductivity and appropriate strength, such as copper, copper alloy, or nickel alloy.
And the above-mentioned sheath thermocouple can also be formed, for example, by forming a through hole in the back plate and inserting it into the through hole. In this case, a sealing member is provided on the back side of the back plate to prevent leakage of cooling water from the through hole.

A lead wire 13 is attached to the metal cap 12 as shown in FIG. The surface of the metal protective tube 19 is covered with a heat-shrinkable tube 25 made of PTFE (polytetrafluoroethylene). However, the insulating heat-resistant tape is wound around, the insulating heat-resistant tube is externally mounted, or the insulation protection is performed. A paste can also be applied.
Specifically, a tape made of a PTFE resin film bonded on one side, a tape made of inorganic glass fiber, a tube made of inorganic glass fiber, an insulating heat resistant paste such as an inorganic ceramic adhesive, or the like can be used.

The lead wire 13 is, for example, a wire covered with FEP (a resin mainly composed of a copolymer of tetrafluoroethylene and hexafluoropropylene) over a plurality of thin copper wires (about φ0.2 mm), The metal protective tube 19 at the base of the metal cap 12 is wound a plurality of times (here, three times) via a heat shrinkable tube 25 and fixed with silver solder.
Note that the material of the lead wire is not limited to the above-described configuration as long as it has a low electrical resistance compared to the metal protective tube 19 and a highly conductive material. For example, other materials (for example, copper Of course, an alloy can also be used. Further, the covering material for covering this material (for example, copper wire) is not particularly limited as long as it can prevent welding current from being short-circuited and make welding more reliable. It is also possible to use a material that coats the surface.

The metal cap 12 is fixed to the back surface of the long side 10 according to the following procedure.
First, after the back plate 15 is arranged on the back surface of the long side 10 where the concave portion 26 is formed at the temperature measurement position, and the back plate 15 is attached and fixed with a large number of bolts 16, the sheath thermocouple 14 prepared in advance, that is, The sheath thermocouple 14 in which the temperature measuring unit 11 is covered with the metal cap 12 and the lead wire 13 is attached to the metal cap 12 is inserted into the through hole 18 of each bolt 16.
Thereby, the sheath thermocouple 14 is arranged on the back side of the long side 10.

Next, one electrode of a stud welding machine (not shown) is attached to a portion where the material of the lead wire 13 is exposed (portion not covered with the covering material), and the other electrode is connected to the side wall of the long side 10. The metal cap 12 is disposed in the recess 26 while being energized.
As a result, a high current flows when the bottom position of the recess 26 and the metal cap 12 are sufficiently close to each other, an arc is generated between the tip portion of the metal cap 12 and the bottom of the recess 26, and the metal cap 12 has a long side. 10 is fixed (welded) to the back surface (the same applies to the short side).

Therefore, the heat generated when the metal cap 12 is welded damages the metal protective tube having a very thin thickness (for example, about 0.1 to 0.5 mm) (for example, melting, deterioration, and tearing). The metal cap 12 can be fixed to the back surface of the long side 10.
When the metal cap 12 is fixed to the back surface of the long side 10 in this way, the thermocouple wires 21 and 22 of the sheath thermocouple 14 are directly attached to the back surface of the long side 10 as shown in FIG. Although it is preferable to contact, each thermocouple strand of a sheath thermocouple may contact the back surface of a long side indirectly through the metal of a metal cap.

The metal cap 12 can be fixed to the back surface of the long side 10 before the back plate 15 is attached and fixed to the back surface of the long side 10. In this case, after attaching a large number of bolts 16 to the long side 10, inserting the sheath thermocouple 14 into the through holes 18 of each bolt 16, and fixing the metal cap 12 to the back surface of the long side 10 by the method described above. The back plate 15 is attached and fixed to the back surface of the long side 10.
As described above, by attaching the metal cap 12 to the back surface of the long side 10, the mounting structure of the sheath thermocouple 14 can be simplified, and the response to the sheath thermocouple 14 at the temperature of the long side 10 can be improved. The temperature measurement accuracy of the long side 10 can be improved as compared with the conventional case.

As described above, since the attachment structure of the sheath thermocouple 14 is simple, a plurality of sheath thermocouples 14 can be densely attached to the back surface of the long side 27 as shown in FIGS. It is. A brief description is given below.
First, a plurality of holes 28 are formed at intervals of, for example, 2 to 10 mm (preferably an upper limit of 5 mm) at the temperature measurement position on the back side of the long side 27. Each of the holes 28 is continuous with a small-diameter hole portion 29 (for example, having a diameter of about 1.5 to 6 mm) in which the metal cap 12 is disposed and a base side of the small-diameter hole portion 29, and has a diameter larger than the small-diameter hole portion 29. It is comprised with the large diameter hole part 30 (for example, a diameter is about 3-10 mm).

Each sheath thermocouple 14 to which the bolt 31, the washer 32, the seal rubber 33, and the washer 34 are attached is disposed in the plurality of holes 28. At this time, the temperature measuring unit 11 is disposed in the small-diameter hole 29, and the bolt 31, the washer 32, the seal rubber 33, and the washer 34 are disposed in the large-diameter hole 30. The leakage of the cooling water from the portion 30 side into the small diameter hole portion 29 can be prevented.
Here, the metal cap 12 is fixed to the back surface of the long side 27 in the small-diameter hole 29. This fixing time is before or after fixing the washer 32, the seal rubber 33, and the washer 34 with the bolt 31. Either is acceptable.

As described above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the configuration described in the above embodiment, and the matters described in the scope of claims. Other embodiments and modifications conceivable within the scope are also included. For example, the case where the continuous casting mold of the present invention is configured by combining some or all of the above-described embodiments and modifications is also included in the scope of the right of the present invention.
In the above embodiment, the case where the sheath thermocouple is fixed to the back surfaces of the pair of short sides and the pair of long sides has been described. Further, it may be fixed. Moreover, the attachment structure of a sheath thermocouple can also be used together with the conventional attachment structure (refer FIG. 3).

  Further, in the above-described embodiment, the case where the target for providing the thermocouple is the cooling plate of the mold body of the four-set mold is not particularly limited as long as the mold is provided with the thermocouple, For example, it is of course possible to apply the present invention to a mold for manufacturing a billet or a beam blank (used for H-shaped steel), and further to a block mold in which water conduction holes are drilled in a forged or forged copper block. The mold structure may be, for example, a mold used in a conventionally known vertical bending type continuous casting machine or a mold used in a curved type continuous casting machine.

  In the embodiment, the sheath thermocouple is a thermocouple element made of copper and constantan. However, the present invention is not limited to this, and, for example, JIS C1602 can be used depending on the use environment. -1995 N thermocouple (+ leg (leg to be connected to the + terminal of the instrument for thermoelectromotive force): an alloy mainly composed of nickel, chromium and silicon,-leg (+ leg opposite to the leg) : Alloy mainly composed of nickel and silicon), K thermocouple (+ leg: alloy mainly composed of nickel and chromium,-Leg: alloy mainly composed of nickel), E thermocouple (+ leg: mainly composed of nickel and chromium) Alloy,-leg: alloy mainly composed of copper and nickel), J thermocouple (+ leg: iron,-leg: alloy mainly composed of copper and nickel), T thermocouple (+ leg: copper,-leg) : Alloys mainly composed of copper and nickel).

10: Long side (cooling plate), 11: Temperature measuring part, 12: Metal cap, 13: Lead wire, 14: Sheath thermocouple, 15: Back plate, 16: Bolt, 17: O-ring, 18: Through hole, 19: Metal protective tube, 20: Insulating material, 21, 22: Thermocouple wire, 23: Recess, 24: Silver brazing, 25: Heat shrinkable tube, 26: Recess, 27: Long side, 28: Hole, 29: Small diameter hole, 30: Large diameter hole, 31: Bolt, 32: Washer, 33: Seal rubber, 34: Washer

Claims (1)

In a continuous casting mold for producing a slab by solidifying the molten steel supplied to the space portion while cooling with the mold body, the mold body having a space portion penetrating in the vertical direction formed inside,
On the back side of the cooling plate constituting the mold body, a sheath thermocouple is provided in which the temperature measuring part is covered with a metal cap and a lead wire is attached to the metal cap, and the metal cap is provided on the back side of the cooling plate. A continuous casting mold characterized by being fixed.

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