WO2009072216A1 - Immersion nozzle and method of continuous casting - Google Patents

Immersion nozzle and method of continuous casting Download PDF

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Publication number
WO2009072216A1
WO2009072216A1 PCT/JP2007/073899 JP2007073899W WO2009072216A1 WO 2009072216 A1 WO2009072216 A1 WO 2009072216A1 JP 2007073899 W JP2007073899 W JP 2007073899W WO 2009072216 A1 WO2009072216 A1 WO 2009072216A1
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WO
WIPO (PCT)
Prior art keywords
immersion nozzle
mass
preheating
nozzle
mold
Prior art date
Application number
PCT/JP2007/073899
Other languages
French (fr)
Japanese (ja)
Inventor
Satoru Ito
Shinichi Fukunaga
Masaharu Sato
Taijiro Matsui
Mineo Niitsuma
Tomohide Takeuchi
Original Assignee
Nippon Steel Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nippon Steel Corporation filed Critical Nippon Steel Corporation
Priority to CN200780101795.3A priority Critical patent/CN101883647B/en
Priority to KR1020107011538A priority patent/KR20100080938A/en
Priority to PCT/JP2007/073899 priority patent/WO2009072216A1/en
Priority to BRPI0722253-0A2A priority patent/BRPI0722253A2/en
Publication of WO2009072216A1 publication Critical patent/WO2009072216A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/10—Supplying or treating molten metal
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
    • B22D41/50—Pouring-nozzles
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/48—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on zirconium or hafnium oxides, zirconates, zircon or hafnates

Definitions

  • the present invention relates to an immersion nozzle used in a continuous production method for molten metal, and a continuous production method including a preheating step for preheating the immersion nozzle.
  • the immersion nozzle is attached to the bottom of the tundish and is configured to discharge the molten metal in the evening dish into the mold from the discharge port at the lower end of the nozzle.
  • This immersion nozzle is used in a state where the lower end side is immersed in the molten metal in the mold, thereby preventing the injected molten metal from scattering and preventing the injected molten metal from contacting the atmosphere. Oxidation is suppressed.
  • the immersion nozzle can be injected in a rectified state, impurities such as slag and non-metallic inclusions floating in the molten metal are prevented from being caught in the molten metal. As a result, the quality of the chips can be improved and the stability of the operation can be secured.
  • Such an immersion nozzle is generally formed of Al 2 O 3 —SiO 2 to C (carbon) refractory or Al 2 O 3 C refractory.
  • a 1 2 O 3 - C refractories containing steel immersion nozzle, A 1 2 O 3 is superior in corrosion resistance to the refractory and the molten metal, C inclusions (slag It is currently most widely used in continuous casting of molten metal because it is difficult to wet with the component), has low expansion, and has good thermal conductivity.
  • mold powder floats on the surface of the molten steel in the mold.
  • This mold powder generally contains C a 0, S i 0 2 , C a F 2 , N a 2 0, C, and its basicity is about 1, so Al 2 O 3 and S i Refractories containing O 2 will be severely damaged.
  • the conventional refractory containing Al 2 03 1 C has a large melting loss in the outer periphery of the immersion nozzle that contacts the mold powder (hereinafter referred to as the powder line part) and cannot be used for a long time. There was a problem.
  • Z r O 2 C-quality refractory has a combination of excellent corrosion resistance against mold powder of Z r 0 2 and the thermal shock resistance of C.
  • This Z r 0 2 Use of C-quality refractories in the powder line can improve the durability of the immersion nozzle.
  • increasing the Z r ⁇ 2 causes a decrease in thermal shock resistance, cracking and breakage problems during use occurs.
  • to improve the thermal shock resistance it is effective to increase the amount of C and reduce the amount of ZrO 2 , but the corrosion resistance is reduced.
  • Z r 0 2 It is necessary to optimize the amount of C and C. Above JP 1 1 one 3 0 2 0 7 No. 3 described in Japanese configuration, Z r O 2 in the amount 7 0-9 5 mass%, and 5-3 0% by weight the amount of C This optimization is aimed at.
  • a combustion gas is blown by a burner 100 as shown in FIG.
  • Japanese Laid-Open Patent Publication No. 10-1118876 proposes a method in which the outer periphery of the immersion nozzle is surrounded by an electric heater and heated by heat transfer / radiation.
  • the time required for preheating is long.
  • the C component in the refractory of Zr ⁇ 2 _C quality disappears as C ⁇ gas or CO 2 gas due to oxidation.
  • a large-diameter pore is formed in the Zr 0 2 -C refractory, making it easier for the mold powder to erode in the pore and promoting the melting damage due to the mold powder.
  • the present invention provides an immersion nozzle capable of improving durability
  • the present invention has been devised based on the knowledge that high-frequency induction heating is preferably used to uniformly heat the immersion nozzle.
  • the gist of the present invention is as follows. It is.
  • An immersion nozzle according to the present invention is an immersion nozzle used in a method for continuously producing molten metal, and at least a portion in contact with the slag on the outer periphery is Zr 0 2 : 70% by mass or more And refractory material including FC (free carbon) 30 mass% or less, and preheated by high frequency induction heating
  • Z r 0 2 is 80 mass% or more, and the FC is 20 mass% or less.
  • FC usually includes, for example, carbon remaining after the binder is baked in addition to additive graphite such as scale graphite, electrode scrap, anthracite, and earth graphite.
  • the FC can be selectively heated by high-frequency induction heating, as shown in FIG. 5 and the above-mentioned Japanese Patent Application Laid-Open No. 10 1 1 8 7 46.
  • the immersion nozzle can be preheated uniformly.
  • preheating can be completed in a short time without using combustion gas as in the past, so there is little disappearance of FC in the refractory and the rate of slag erosion can be reduced. Accordingly, the durability of the immersion nozzle can be improved.
  • the immersion nozzle according to the present invention can be realized as the following configuration in addition to the immersion nozzle described in (1) above. That is, the immersion nozzle according to the present invention is an immersion nozzle that is used in a method for continuously forming molten metal, and at least the portion that contacts the slag in the outer peripheral portion is Zr 0 2 : 70 mass% or more. , FC (free carbon): 20% by mass It is formed of a refractory material including the following, and the remaining 10% by mass or less including the stabilizing material of Zr 0 2 and is preheated by high frequency induction heating.
  • the same effect as the invention of the above (1) can be obtained.
  • the Z r ⁇ 2 can be fixed to the refractory in tissue in a stable state by the addition of the stabilizing material, it is possible to prevent the Z R_ ⁇ 2 grains from falling off in the slag. Thereby, it can suppress that the part which contacts slag melts
  • stabilizing Kazai includes C A_ ⁇ , M G_ ⁇ and Y 2 O least for either one also of 3 It is preferable.
  • the continuous forging method according to the present invention includes a preheating step of preheating the immersion nozzle according to any one of the above (1) to (3) by high-frequency induction heating, and the immersion immersed in the preheating step. And a forging step of injecting molten metal from the tundish into the mold through a nozzle.
  • FIG. 1 shows a schematic configuration of a continuous forging machine according to an embodiment of the present invention.
  • 2 is a side sectional view showing the immersion nozzle according to the embodiment of FIG. 1.
  • FIG. 3 is a combination of ZrO 2 and FC of refractory used in the powder line portion of the immersion nozzle in the embodiment of FIG. It is the figure which showed quantity.
  • FIG. 4 is a side sectional view showing the preheating device with the immersion nozzle in the embodiment of FIG.
  • FIG. 5 is a side sectional view showing a state in which the immersion nozzle is preheated by a heating method using a conventional burner.
  • FIG. 1 shows the schematic configuration of the continuous forging machine in this embodiment.
  • 1 is a continuous forging machine, and this continuous forging machine 1 continuously cools and solidifies molten steel to form a steel ingot of a predetermined shape.
  • Such a continuous forging machine 1 includes a ladle 2, a long nozzle 3, a tundish 4, a plurality of immersion nozzles 5, and a plurality of molds 6.
  • FIG. 1 only one immersion nozzle 5 and one mold 6 are shown.
  • the ladle 2 is a heat-resistant container into which molten steel is first introduced in continuous forging, and has an inlet 21 at the bottom.
  • the long nozzle 3 is attached to the inlet 2 1 of the ladle 2 and is configured to discharge the molten steel stored in the ladle 2 into the tundish 4 from the nozzle lower end opening 3 1. .
  • the tundish 4 is a heat-resistant container that is disposed below the long nozzle 3 and stores molten steel injected from the ladle 2 through the long nozzle 3. This tundish 4 is compatible with each mold 6 on the bottom. A plurality of inlets 41 are formed, and a flow rate adjuster (not shown) for adjusting the flow rate of the molten steel flowing out from the inlet 41 is provided inside the inlet 41.
  • a flow rate adjuster (not shown) for adjusting the flow rate of the molten steel flowing out from the inlet 41 is provided inside the inlet 41.
  • the immersion nozzle 5 is specifically described later, and is attached to the lower part of the injection port 41 in the tundish 4, and the molten steel in the tundish 4 is injected into the mold 6 through this nozzle.
  • the mold 6 is a water-cooled vertical mold provided below the immersion nozzle 5.
  • the mold 6 has a predetermined cross-sectional shape, and molten steel from the tundish 4 is continuously injected into the mold 6 through the immersion nozzle 5. With such a mold 6, the molten steel in the mold 6 is cooled, and a solidified shell is formed and grown from the inner peripheral surface side in the mold 6 to form solidified steel.
  • a roller apron and a drawing roll for continuously drawing the steel formed in the mold 6 downward from the lower opening in the mold 6.
  • the steel that has been continuously drawn from the inside of the mold 6 by being drawn by the drawing roll is cut into a predetermined length dimension (not shown) ) Is provided.
  • a steel ingot having a predetermined shape such as a plate shape or a rod shape is formed.
  • FIG. 2 is a side sectional view showing the immersion nozzle according to the present embodiment.
  • Fig. 3 shows the blending amounts of refractory Zr 0 2 and FC used in the powder line part of the immersion nozzle.
  • the immersion nozzle 5 includes a nozzle body 5 1 and a holder 5 2 that is attached to the lower part of the inlet 4 1 and holds the upper end of the nozzle body 5 1.
  • the immersion nozzle 5 is used after being preheated by high frequency induction heating in a preheating process described later.
  • the nozzle body 51 is formed in a substantially cylindrical shape, and is provided with a bottom surface 51 11 that closes its lower end. In the vicinity of the bottom surface portion 5 11 of the side surface portion of the nozzle body 51, a pair of discharge ports 5 1 2 are provided so as to face each other. With such a nozzle body 51, the molten steel flowing from the upper end opening of the nozzle body 51 is discharged into the mold 6 through the pair of discharge ports 5 12.
  • the nozzle body 5 1 is used with its lower end side immersed in molten steel in the mold 6.
  • the two-dot chain line in Fig. 2 shows the slag line S.
  • the nozzle body 51 When the nozzle body 51 is immersed in the molten steel, it contacts the mold powder below the slag line S on the outer peripheral surface of the nozzle body 51 (powder thickness is about 10 mm). Furthermore, the lower side of the mold powder is immersed in the molten steel. In the case of preheating failure, cracks may occur on the upper side of the powder line S.
  • Such a nozzle body 51 has a powder line part 5 1 3 above the discharge port 5 1 2 on the outer peripheral part.
  • the other parts have a two-layer structure made of different refractories.
  • the refractory that forms the powder line part 5 1 3, as shown in area A and area B in Fig. 3, is Zr 0 2 : 70 mass% or more, and FC (free carbon): 30 mass % Or less.
  • the refractory forming the powder line part 5 1 3 is composed of Zr 0 2 : 70 mass% or more, graphite containing FC: 20 mass% or less, as shown by region A in FIG. r ⁇ 10% by mass of balance including stabilizing material that stabilizes 2
  • the following may be comprised.
  • Z R_ ⁇ 2 upper limit of the content is not particularly defined, 1 0 0 is less than mass% may also FC (free carbon> lower limit of the content is also not particularly defined, 0 mass Further, the lower limit of the balance including the stabilizing material is not particularly specified, and may be more than 0 mass%.
  • Parts other than the powder line part 5 1 3 in the nozzle body 5 1 are formed of a refractory material such as A 1 2 0 3 S i O 2 1 C or A 1 2 O 3 1 C, for example.
  • the refractory material used in parts other than the powder line section 5 1 3 is not limited to this, and is a material that can provide excellent fire resistance and low melt wettability to the molten steel flowing through the nozzle body 5 1. Any of them can be adopted.
  • FIG. 4 is a side sectional view showing the preheating device with the immersion nozzle attached.
  • 7 is a preheating device, and this preheating device 7 preheats the immersion nozzle 5 by high frequency induction heating.
  • a preheating device 7 includes a heat-resistant container 7 1, an outer coil 7 2, an inner coil 7 3, and an induced current applying device (not shown).
  • the outer coil 72 is an induction heating coil confiscated inside the heat-resistant container 71, and is configured to be able to accommodate from the lower end of the nozzle body 51 to the upper part of the middle part on the inner peripheral side of the coil. .
  • the inner coil 7 3 is an induction heating coil similar to the outer coil 7 2, and is configured to be inserted inside from the upper opening of the nozzle body 5 1.
  • the induction current application device includes the outer coil 7 2 and the inner coil 7 2. 7 3 each This is a device that applies a high-frequency induced current.
  • the continuous forging method according to this embodiment will be described using an example in which the continuous forging machine 1 and the preheating device 7 configured as described above are used.
  • the continuous forging method of the present embodiment includes a preheating step, a forging step, a drawing step, and a steel ingot forming step.
  • a preheating device 7 shown in FIG. 4 is used to preheat the immersion nozzle 5 by high frequency induction. Specifically, first, the preheating device 7 is set with respect to the immersion nozzle 5 removed from the tundish 4. In this set state, the nozzle body 51 is accommodated in the outer coil 72, and the inner coil 73 is inserted into the inside from the upper opening of the nozzle body 51. Then, an induced current is applied to the outer coil 72 and the inner coil 73 by an induced current application device. As a result, a high-density eddy current is generated in the vicinity of FC included in the nozzle body 51, generating large Joule heat, and the entire nozzle body 51 is heated uniformly.
  • the temperature of the nozzle body 5 1 reaches 100 ° C. or more in a heating time of about 0.5 to 2 hours, for example.
  • a heating time of about 0.5 to 2 hours, for example.
  • the nozzle body 5 1 is heated to 1 100 ° C or higher, and when heated with a burner 1 0 0 (see Fig. 5) as in the past, a maximum of 5 0 0 ° ( ⁇ 6
  • high-frequency induction heating can only produce a maximum temperature difference of about 300 ° C between each part.
  • molten steel is forged using the continuous forging machine 1 shown in Fig. 1.
  • dip the immersion nozzle 5 preheated in the preheating process After installing in the inlet 4 1 of the 4th, introduce molten steel into the ladle 2. This molten steel flows from the ladle 2 into the tundish 4 through the long nozzle 3 and is rectified in the tundish 4. After that, the rectified molten steel is injected into the mold 6 through the immersion nozzle 5 while adjusting the outflow amount with a flow rate adjuster (illustrated), and a constant molten metal level is maintained in the mold 6. .
  • a flow rate adjuster illustrated
  • the nozzle body 5 1 is uniformly preheated in the preheating process, so the thermal shock received by the immersion nozzle 5 from the molten steel is alleviated, and there is no problem such as cracking. Occurrence can be prevented. And since the powder line part 5 1 3 is formed of a refractory material containing Z r 0 2 and FC in the above range, it has high corrosion resistance against the mold powder, and according to the mold powder. Melting damage can be suppressed.
  • the mold powder erodes inside the pores and prevents crystal grains in the refractory from falling into the mold powder. it can. Therefore, the durability of the immersion nozzle 5 can be improved.
  • the steel that has been cooled and solidified in the mold 6 is continuously drawn downward by means of a roller apron (not shown) and a drawing port.
  • the steel drawn by the drawing roll is cut into a predetermined length by a cutting machine to continuously form pieces having a predetermined shape.
  • the long nozzle 3 and the tundish 4 are preheated in addition to the immersion nozzle 5.
  • preheating was performed without the immersion nozzle 5 being attached to the tundish 4, but preheating was performed with the immersion nozzle 5 being attached to the tundish 4. May be.
  • Immersion nozzles A plurality of immersion nozzles similar to the immersion nozzle 5 of the above embodiment shown in FIG. 2 were prepared.
  • the nozzle body 51 has a maximum outer diameter of ⁇ 140 mm, an inner diameter of ⁇ 80 mm, and a length of 700 mm.
  • Refractory composition The composition of the refractory forming each powder line part 5 1 3 includes the composition shown in each plot in Fig. 3, including those shown in Table 1 below.
  • Forming method After kneading refractory aggregate and scaly graphite together with a binder, pour the kneaded material (yes earth) into a nozzle-shaped rubber mold. If different materials are to be poured, insert a rubber mold so that it does not get mixed. Then, it is hardened by applying a high pressure (50 to 10 OMPa) with a wet CIP molding method. After taking out the molded product from the frame, firing is performed at a high temperature of 100 0 ⁇ or more in a reducing atmosphere. After cooling, it is processed to the required dimensions, applied with antioxidants, and then used in actual equipment.
  • a high pressure 50 to 10 OMPa
  • 'Preheater Same as preheater 7 shown in Fig.4. Use an outer coil 7 2 with a diameter of 200 mm and a length of 500 mm, and an inner coil 7 3 with a diameter of 70 mm and a length of 300 mm. did.
  • the outer coil 7 2 was applied with an induction current having a frequency of 30 kHz, a current of 20 A, and a power of 15 kW.
  • An inductive current having a frequency of 37 kHz, a current of 200 A, and a power of 12 kW was applied to the inner coil 73.
  • 'Preheater Preheated using the burner 1 0 0 shown in Fig. 5.
  • a burner 1 0 0 is inserted into the inside from the upper end opening of the immersion nozzle 5 and sprayed with combustion gas.
  • Forging method Same as the forging process in the above embodiment. Specifically, after each submerged nozzle 5 is preheated alone, it is attached to each tundish 4, and forging starts 5 minutes after the end of preheating. It was.
  • Table 1 also shows the results of the forging experiment (melting rate index, trouble occurrence index) for the immersion nozzles 5 of Examples 1 to 6 and Comparative Examples 1 and 2.
  • Example 1 when the rate of erosion of Comparative Example 1 (the amount of erosion of the powder line part 5 1 3 due to forging was divided by the operating time) was 1 0 0 The melting rate for ⁇ 6 and Comparative Example 2 is indexed.
  • Trouble occurrence index Trouble occurrence for Example 1 when the trouble occurrence rate for Comparative Example 1 (ratio between the number of times of forging and the number of occurrences of defects such as breakage or cracking) is 100 The rate is an index.
  • Examples 1 and 2 differ in that the preheating method is high frequency induction heating (IH), and comparative examples 1 and 2 are heating by a burner.
  • IH high frequency induction heating
  • Example 1 when the erosion rate index is compared, Example 1 is 10% lower than Comparative Example 1, and Example 2 is about 9.5 compared to Comparative Example. % Is low. This is different from the case of preheating with a high frequency induction heating, unlike the case of preheating with a burner. This is presumably because the preheating is completed in a short time without using the soot, and the loss of C in the powder line part 5 1 3 is prevented.
  • Example 1 is 85% lower than Comparative Example 1. This is presumably because each part of the nozzle body 51 was preheated more uniformly when preheated by high frequency induction heating than when preheated by a burner. As a result, it was found that it was difficult for the mold powder to melt and the frequency of occurrence of defects such as cracks at the start of fabrication could be significantly reduced. In other words, it was found that the durability of the immersion nozzle 5 can be improved.
  • the powder line part 5 1 3 contains about 5% of CaO, and Z r
  • the blending amount of O 2 is 75% by mass (Example 1), 82% by mass (Example 2).
  • Example 3 88% by mass (Example 3) and 70% by mass (Example 6), with Example 3 being the highest ⁇ and Example 6 being the lowest.
  • the blending amount of F C is 20% by mass (Example 1), 13% by mass (Example 2),
  • Example 3 8 mass% (Example 3) and 26 mass% (Example 6).
  • Example 3 is the lowest and Example 6 is the highest.
  • Example 1 when comparing the erosion rate index, Example 1 is about 5% lower than Example 6, Example 2 is about 9% lower than Example 6, and Example 3 is The value is about 13% lower than Example 6. This is thought to be due to an increase in the corrosion resistance of the powder line portion 5 1 3 to the mold powder due to an increase in the proportion of Zr 0 2 with excellent corrosion resistance.
  • the high thermal shock resistance of the powder line portion 5 13 can be obtained by setting the blending amount of FC to 30% by mass or less. Furthermore, it was found that the good thermal shock resistance of the powder line portion 5 13 can be maintained even when the blending amount of FC is 20% by mass or less.
  • Example 3 As shown in Table 1, when Examples 3 and 4 and Example 5 are compared, the amount of Z r 0 2 contained in the powder line part 5 1 3 is 8 8 mass% (Example 3), 86 mass% (Example 4) and 85 mass% (Example 5). In addition, Examples 3 and 4 contain 4% Ca 0 and Mg O as stabilizers, respectively, and Example 5 does not contain any stabilizer.
  • Example 3 is about 5% lower than Example 5, and Example 4 is about 7% lower than Example 5.
  • the balance containing the stabilizing material is more than 10% by mass, the effect is exerted, but the proportion of ZrO 2 is relatively small and sufficient corrosion resistance to the mold powder is obtained. Since it becomes difficult to obtain, it is preferably 10% by mass or less.
  • the present invention is not limited to the above-described embodiments, and modifications, improvements and the like within the scope that can achieve the object of the present invention are included in the present invention.
  • the composition of the powder line portion 5 13 is not limited to the composition of Examples 1 to 6, and any composition that falls within the region A in FIG. 3 and the basket is included in the present invention.
  • the FC when FC is present in the refractory, the FC can be selectively heated by high-frequency induction heating, and the immersion nozzle can be preheated uniformly. For this reason, after preheating, it is possible to prevent the occurrence of defects such as cracks in the submerged nozzle at the start of forging, and it is possible to suppress melting damage due to slag in the portion that contacts the slag during the forging process. Therefore, the durability of the immersion nozzle can be improved.

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Abstract

An immersion nozzle that attains an enhancement of durability; and a method of continuous casting including the step of preheating the immersion nozzle. The immersion nozzle is one for use in a method of continuous casting for molten metal, characterized in that the immersion nozzle at at least its area of outer circumferential part brought into contact with slag consists of a refractory containing 70 mass% or more ZrO2 and 30 mass% or less FC (free carbon), or a refractory composed of 70 mass% or more ZrO2, 20 mass% or less FC (free carbon) and 10 mass% or less the balance containing a ZrO2 stabilizer, and that the immersion nozzle is preheated by high-frequency induction heating.

Description

明 細 書 浸漬ノズルおよび連続铸造方法 技術分野  Description Immersion nozzle and continuous fabrication method Technical Field
本発明は、 溶融金属の連続铸造方法に使用される浸漬ノズル、 お よび、 この浸漬ノズルを予熱する予熱工程を含む連続铸造方法に関 する。 背景技術  The present invention relates to an immersion nozzle used in a continuous production method for molten metal, and a continuous production method including a preheating step for preheating the immersion nozzle. Background art
従来、 溶融金厲を連続的に冷却凝固させて所定形状の铸片を形成 する連続铸造方法が知られており、 この連続铸造方法では、 浸漬ノ ズルを介してタンディ ッシュからモ一ルド (水冷铸型) 内に溶融金 属を注入する铸造工程が実施される。  Conventionally, there has been known a continuous forging method in which molten metal is continuously cooled and solidified to form pieces of a predetermined shape. In this continuous forging method, a mold (water-cooled) is formed from a tundish through an immersion nozzle. A forging process is performed in which molten metal is injected into the mold.
浸漬ノズルは、 タンディ ッシュの底部に取り付けられて、 夕ンデ ィ ッシュ内の溶融金属をノズル下端の吐出口よりモールド内に吐出 するように構成されている。 この浸漬ノズルは、 下端側をモールド 内の溶融金属中に浸漬させた状態で使用され、 これにより、 注入溶 融金属の飛散を防止すると共に、 注入溶融金属の大気との接触を防 止して酸化を抑制している。 また、 浸漬ノズルは、 整流化した状態 で注入可能であるため、 溶融金属に浮遊するスラグゃ非金属介在物 などの不純物が溶融金属中へ巻き込まれることを防止している。 結 果、 铸片品質を改善できると共に、 操業の安定性を確保できる。  The immersion nozzle is attached to the bottom of the tundish and is configured to discharge the molten metal in the evening dish into the mold from the discharge port at the lower end of the nozzle. This immersion nozzle is used in a state where the lower end side is immersed in the molten metal in the mold, thereby preventing the injected molten metal from scattering and preventing the injected molten metal from contacting the atmosphere. Oxidation is suppressed. Moreover, since the immersion nozzle can be injected in a rectified state, impurities such as slag and non-metallic inclusions floating in the molten metal are prevented from being caught in the molten metal. As a result, the quality of the chips can be improved and the stability of the operation can be secured.
このような浸漬ノズルは、 一般的に、 A l 2 O 3 — S i O 2 〜 C (カーボン） 耐火物や A l 2 O 3 一 C耐火物にて形成されている。 これら A 1 2 O 3 — C含有耐火物製の浸漬ノズルは、 A 1 2 O 3 が 耐火性および溶融金属に対する耐食性に優れ、 Cが介在物 （スラグ 成分） に対して濡れ難く、 膨張量が低く、 かつ、 熱伝導性が良好な ことから、 現在、 溶融金属の連続铸造において最も広く用いられて いる。 Such an immersion nozzle is generally formed of Al 2 O 3 —SiO 2 to C (carbon) refractory or Al 2 O 3 C refractory. These A 1 2 O 3 - C refractories containing steel immersion nozzle, A 1 2 O 3 is superior in corrosion resistance to the refractory and the molten metal, C inclusions (slag It is currently most widely used in continuous casting of molten metal because it is difficult to wet with the component), has low expansion, and has good thermal conductivity.
ここで、 溶融金属の連続铸造の際、 モールド内の溶鋼湯面上には モールドパウダーと呼ばれる低塩基度で侵食性の強いスラグが浮遊 している。 このモールドパウダーは一般的に C a 0、 S i 〇 2 、 C a F 2 , N a 2 〇、 Cを含有しており、 その塩基度は 1程度である ため、 A l 2 O 3 や S i O 2 を含む耐火物を著しく溶損させてしま う。 このため、 従来の A l 2 03 一 C含有耐火物では、 浸漬ノズル の外周部におけるモールドパウダーに接する部位 （以下、 パウダー ライン部と称す） の溶損が大きく、 長期の使用に耐えられないとい う問題があった。 Here, during the continuous casting of molten metal, slag, which has a low basicity and is highly erodible, called mold powder floats on the surface of the molten steel in the mold. This mold powder generally contains C a 0, S i 0 2 , C a F 2 , N a 2 0, C, and its basicity is about 1, so Al 2 O 3 and S i Refractories containing O 2 will be severely damaged. For this reason, the conventional refractory containing Al 2 03 1 C has a large melting loss in the outer periphery of the immersion nozzle that contacts the mold powder (hereinafter referred to as the powder line part) and cannot be used for a long time. There was a problem.
この問題に対して、 従来、 浸漬ノズルのパウダーライン部に Z r O 2 — C質の耐火物を使用したものが、 例えば、 特開平 1 1 — 3 0 2 0 7 3号公報で知られている。 In order to deal with this problem, conventionally, a powder line part of a submerged nozzle using a ZrO 2 —C quality refractory is known, for example, in Japanese Laid-Open Patent Publication No. 1 1-3 0 2 0 7 3 Yes.
Z r O 2 — C質の耐火物は、 Z r 〇 2 のモ一ルドパウダーに対す る優れた耐食性と、 Cの耐熱衝撃性とを組み合わせた特徴を有して おり、 この Z r〇 2 — C質の耐火物をパウダ一ライン部に使用する ことで、 浸漬ノズルの耐用性を向上できる。 Z r O 2 — C-quality refractory has a combination of excellent corrosion resistance against mold powder of Z r 0 2 and the thermal shock resistance of C. This Z r 0 2 — Use of C-quality refractories in the powder line can improve the durability of the immersion nozzle.
このような Z r 〇 2 — C質の耐火物において、 耐食性をより向上 させるためには、 Cの配合量を少なく して、 Z r〇 2 の配合量を増 加させることが効果的である。 しかし、 Z r 〇 2 の増量は耐熱衝撃 性の低下を引き起こし、 使用時の割れや折れの問題が発生する。 一 方、 耐熱衝撃性を向上させるためには、 Cの配合量を増加させて、 Z r O 2 の配合量を少なくすることが効果的であるが、 耐食性は低 下する。 Such Z r 〇 2 - In C refractories in, in order to improve the corrosion resistance, by reducing the amount of C, it is effective to increase the amount of Z R_〇 2 . However, increasing the Z r 〇 2 causes a decrease in thermal shock resistance, cracking and breakage problems during use occurs. On the other hand, to improve the thermal shock resistance, it is effective to increase the amount of C and reduce the amount of ZrO 2 , but the corrosion resistance is reduced.
このように、 耐食性および髙耐用性を高めるためには Z r 02 お よび Cの配合量を最適化する必要がある。 上記特開平 1 1 一 3 0 2 0 7 3号公報に記載の構成では、 Z r O 2 の配合量を 7 0〜 9 5質 量％、 Cの配合量を 5〜 3 0質量％とすることで当該最適化を図つ ている。 In this way, Z r 0 2 It is necessary to optimize the amount of C and C. Above JP 1 1 one 3 0 2 0 7 No. 3 described in Japanese configuration, Z r O 2 in the amount 7 0-9 5 mass%, and 5-3 0% by weight the amount of C This optimization is aimed at.
ところで、 上記铸造工程では、 浸漬ノズルの温度が低い場合、 溶 融金属の注入を開始する際に浸漬ノズルの割れや閉塞が起こったり 、 溶融金属上にスラグが十分に浮上せずに铸片の品質が低下してし まう等の不具合が発生することがある。 このため、 浸漬ノズルを予 熱しておく ことで、 溶融金属の注入を開始した際に浸漬ノズルに生 じる温度差を減少させて、 上記不具合の発生を防止することが考え られる。  By the way, in the forging process, when the temperature of the immersion nozzle is low, the immersion nozzle is cracked or clogged when starting the injection of the molten metal, or the slag does not float sufficiently on the molten metal. Problems such as quality deterioration may occur. Therefore, by preheating the immersion nozzle, it is conceivable to reduce the temperature difference that occurs in the immersion nozzle when the injection of molten metal is started, thereby preventing the occurrence of the above problems.
このような予熱法としては、 例えば図 5に示すようにバーナー 1 0 0により燃焼ガスを吹き付けるものが考えられる。  As such a preheating method, for example, a combustion gas is blown by a burner 100 as shown in FIG.
また、 浸漬ノズルの外周を電熱器で囲み伝熱 · 輻射により加熱す る方法も例えば、 特開平 1 0 — 1 1 8 7 4 6号公報で提案されてい る。  In addition, for example, Japanese Laid-Open Patent Publication No. 10-1118876 proposes a method in which the outer periphery of the immersion nozzle is surrounded by an electric heater and heated by heat transfer / radiation.
しかしながら、 上記特開平 1 1 一 3 0 2 0 7 3号公報に記載され たような Z r O 2 — C質の耐火物をパウダーライン部に使用した浸 漬ノズルを予熱した後、 铸造工程を実施する場合、 Z r 0 2 — C質 の耐火物は高熱膨張材であるため、 次の （A ) 、 ( B ) のような問 題がある。 However, after preheating a soaking nozzle using a ZrO 2 —C quality refractory material in the powder line part as described in the above-mentioned Japanese Patent Application Laid-Open No. 11 1300 073, the forging process is performed. When implemented, Zr 0 2 — C quality refractory is a high thermal expansion material, so there are the following problems (A) and (B).
( A ) 図 5に示すようなバ一ナ一 1 0 0を用いて予熱する場合、 ノ ズルの上端からバーナー 1 0 0 を挿入して、 内部に燃焼ガスを吹き 付け下端側の吐出孔より排気する。 このため、 ノズル全体を均一に 加熱することが困難であり、 この温度差に伴う Z r 0 2 の熱膨張差 に起因して応力割れなどが発生してしまう。 (A) When preheating is performed using a burner 1 100 as shown in Fig. 5, a burner 1 0 0 is inserted from the upper end of the nozzle, and combustion gas is blown into the inside from the discharge hole on the lower end side. Exhaust. For this reason, it is difficult to uniformly heat the entire nozzle, and stress cracking or the like occurs due to the difference in thermal expansion of Z r 0 2 due to this temperature difference.
また、 バーナーによる予熱の場合、 予熱に要する時間が長く、 か つ、 燃焼ガスより生じる酸化性雰囲気により、 Z r 〇 2 _ C質の耐 火物における C成分が酸化により C〇ガスあるいは C O 2 ガスとな つて消失してしま ン 。 しのため、 Z r 〇 2 ― C質の耐火物中に大径 の気孔が形成されて当該気孔内にモールドパウダ一が侵食し易くな り、 モールドパウダ一による溶損が助長されてしまう問題がある。Also, in the case of preheating with a burner, the time required for preheating is long. In addition, due to the oxidizing atmosphere generated from the combustion gas, the C component in the refractory of Zr ○ 2 _C quality disappears as C ○ gas or CO 2 gas due to oxidation. For this reason, a large-diameter pore is formed in the Zr 0 2 -C refractory, making it easier for the mold powder to erode in the pore and promoting the melting damage due to the mold powder. There is.
( B ) 上記特開平 1 0 — 1 1 8 7 4 6号公報に d載の電熱器を用い て予熱する場合、 c成分の消失は防止できるものの 、 伝熱 · 輻射に よりノズルを加熱しているので、 部分的には 1 4 0 0 °cに達するが 全体を均一に加熱することはやはり難しい o (B) In the case of preheating using the d-heater described in Japanese Patent Application Laid-Open No. 10-1 1 8 7 46, the loss of the c component can be prevented, but the nozzle is heated by heat transfer / radiation. Partly reaches 1400 ° C, but it is still difficult to heat the whole evenly o
本発明は、 耐用性を向上できる浸漬ノズル、 および、  The present invention provides an immersion nozzle capable of improving durability, and
ズルを予熱する予熱工程を含む連続铸造方法を提供する To provide a continuous forging method including a preheating process for preheating the sludge
発明の開示 Disclosure of the invention
本発明は、 浸漬ノズルを均一に加熱するためには 、 高周波誘導加 熱を用いるのが良いとの知見に基づいて案出されたものであり、 本 発明の要旨とすることころは以下の通りである。  The present invention has been devised based on the knowledge that high-frequency induction heating is preferably used to uniformly heat the immersion nozzle. The gist of the present invention is as follows. It is.
( 1 ) 本発明に係る浸漬ノズルは、 溶融金属の連続鍀造方法に使用 される浸漬ノズルであって、 少なく とも外周部のスラグと接触する 部分が、 Z r 〇 2 ： 7 0質量％以上と、 F C (フリ—カーボン） 3 0質量％以下とを含んで構成された耐火物にて形成されており、 高 周波誘導加熱によって予熱されることを特徴とする (1) An immersion nozzle according to the present invention is an immersion nozzle used in a method for continuously producing molten metal, and at least a portion in contact with the slag on the outer periphery is Zr 0 2 : 70% by mass or more And refractory material including FC (free carbon) 30 mass% or less, and preheated by high frequency induction heating
より好ましくは、 Z r 〇 2 は 8 0質量％以上であり、 前記 F Cは 2 0質量％以下であることを特徴とする。 More preferably, Z r 0 2 is 80 mass% or more, and the FC is 20 mass% or less.
ここで、 Z r O 2 の配合量が 7 0質量％より も低い場合、 および 、 F Cの配合量が 3 0質量％よりも高い場合は、 モ一ルドパウダ一 に対する十分な耐食性が得られない。 このような浸漬ノズルは、 例えば、 各種無機物の微粉と、 フエノ ール樹脂などのバインダとを混練したものを、 C I P法などにて所 定の形状に成形し、 これを還元焼成することにより形成される。 Z r O 2 は、 結晶粒サイズが数 ^ mから 2 m m程度のものが使用され る。 また、 F Cは、 例えば、 通常、 鱗状黒鉛、 電極屑、 無煙炭、 土 状黒鉛等の添加黒鉛の他、 バインダが焼成した際に残留した炭素分 をも含む。 Here, if the amount of Z r O 2 is 7 less than 0 wt%, and, when the amount of FC is 3 greater than 0% by mass, no sufficient corrosion resistance can not be obtained for mode one Rudopauda scratch. Such an immersion nozzle is formed, for example, by kneading various inorganic fine powders with a binder such as phenol resin into a predetermined shape by the CIP method, etc., and then reducing and firing this. Is done. ZrO 2 having a crystal grain size of about several m to 2 mm is used. In addition, FC usually includes, for example, carbon remaining after the binder is baked in addition to additive graphite such as scale graphite, electrode scrap, anthracite, and earth graphite.
本発明によれば、 耐火物中に F Cが存在することにより、 高周波 誘導加熱にて当該 F Cを選択的に加熱でき、 図 5や上記特開平 1 0 一 1 1 8 7 4 6号公報に示すような従来の加熱法にて浸漬ノズルを 予熱する場合に比べて、 浸漬ノズルを均一に予熱できる。  According to the present invention, since FC exists in the refractory, the FC can be selectively heated by high-frequency induction heating, as shown in FIG. 5 and the above-mentioned Japanese Patent Application Laid-Open No. 10 1 1 8 7 46. Compared to the case where the immersion nozzle is preheated by such a conventional heating method, the immersion nozzle can be preheated uniformly.
このため、 鍩造工程にて溶融金属の注入を開始する際、 溶融金属 により浸漬ノズルが受ける熱衝撃を緩和でき、 割れ等の不具合が発 生することを防止できる。 特に、 ノズルを均一に予熱できるので、 耐熱衝撃性にも優れた F Cの配合量を 2 0質量％以下に下げたとし ても、 割れ等の不具合が発生することがない。 これにより、 Z r O For this reason, when the injection of molten metal is started in the forging process, the thermal shock received by the immersion nozzle by the molten metal can be mitigated, and problems such as cracking can be prevented. In particular, since the nozzle can be preheated uniformly, even if the blending amount of FC with excellent thermal shock resistance is reduced to 20% by mass or less, problems such as cracks do not occur. This makes Z r O
2 の配合割合をさらに増大させることが可能となるので、 スラグに よる溶損速度を低減できる。 Since the blending ratio of 2 can be further increased, the rate of erosion caused by slag can be reduced.
また、 高周波誘導加熱によれば、 従来のように燃焼ガスを使用せ ずに短時間で予熱を完了できるので、 耐火物中の F Cの消失が少な く、 スラグによる溶損速度を低減できる。 従って、 浸漬ノズルの耐 用性を向上させることができる。  Also, with high frequency induction heating, preheating can be completed in a short time without using combustion gas as in the past, so there is little disappearance of FC in the refractory and the rate of slag erosion can be reduced. Accordingly, the durability of the immersion nozzle can be improved.
( 2 ) 本発明に係る浸漬ノズルは、 上記 （ 1 ) に記載の浸漬ノズル の他に、 以下の構成としても成立するものである。 すなわち、 本発 明に係る浸漬ノズルは、 溶融金属の連続铸造方法に使用される浸漬 ノズルであって、 少なく とも外周部のスラグと接触する部分が、 Z r 0 2 ： 7 0質量％以上と、 F C (フリーカーボン） ： 2 0質量％ 以下と、 Z r 02 の安定化材を含む残部 1 0質量％以下とを含んで 構成された耐火物にて形成されており、 高周波誘導加熱によつて予 熱されることを特徴とする。 (2) The immersion nozzle according to the present invention can be realized as the following configuration in addition to the immersion nozzle described in (1) above. That is, the immersion nozzle according to the present invention is an immersion nozzle that is used in a method for continuously forming molten metal, and at least the portion that contacts the slag in the outer peripheral portion is Zr 0 2 : 70 mass% or more. , FC (free carbon): 20% by mass It is formed of a refractory material including the following, and the remaining 10% by mass or less including the stabilizing material of Zr 0 2 and is preheated by high frequency induction heating.
この （ 2 ) の発明によれば、 上記 （ 1 ) の本発明と同様の効果を 奏することができる。 これに加えて、 安定化材の添加により Z r 〇 2 を安定した状態で耐火物組織内に固定でき、 スラグ中に Z r〇 2 結晶粒が脱落することを防ぐことができる。 これにより、 スラグと 接触する部分がスラグにより溶損してしまう ことを抑制できる。 従 つて、 浸漬ノズルの耐用性をさらに向上させることができる。 According to the invention of (2), the same effect as the invention of the above (1) can be obtained. In addition, the Z r 〇 2 can be fixed to the refractory in tissue in a stable state by the addition of the stabilizing material, it is possible to prevent the Z R_〇 2 grains from falling off in the slag. Thereby, it can suppress that the part which contacts slag melts | dissolves by slag. Therefore, the durability of the immersion nozzle can be further improved.
( 3 ) 本発明に係る浸漬ノズルは、 上記 （ 2 ) に記載の浸漬ノズル において、 安定化材は、 C a〇、 M g〇および Y 2 O 3 のうち少な く ともいずれか 1種を含むことが好ましい。 (3) immersion nozzle according to the present invention, in the immersion nozzle according to the above (2), stabilizing Kazai includes C A_〇, M G_〇 and Y 2 O least for either one also of 3 It is preferable.
ここで、 Z r〇 2 の配合量が 7 0質量％よりも低い場合、 F Cお よび残部の配合量を合計したものが 3 0質量％よりも高い場合は、 モールドパウダ一に対する十分な耐食性が得られない。 Here, if the amount of Z R_〇 2 7 lower than 0 wt%, if the sum of the amount of FC Contact and balance 3 higher than 0 mass%, sufficient corrosion resistance to mold powder one I can't get it.
( 4 ) 本発明に係る連続铸造方法は、 上記 （ 1 ) 〜 （ 3 ) のいずれ かに記載の浸漬ノズルを、 高周波誘導加熱により予熱する予熱工程 と、 前記予熱工程にて予熱された前記浸漬ノズルを介してタンディ ッシュからモールドに溶融金属を注入する铸造工程と、 を備えるこ とを特徴とする。  (4) The continuous forging method according to the present invention includes a preheating step of preheating the immersion nozzle according to any one of the above (1) to (3) by high-frequency induction heating, and the immersion immersed in the preheating step. And a forging step of injecting molten metal from the tundish into the mold through a nozzle.
この （ 4 ) の発明によれば、 上記 （ 1 ) 〜 （ 3 ) のいずれかに記 載の効果を奏することができる。 従って、 浸漬ノズルの耐用性を向 上させることができる。 図面の簡単な説明  According to the invention of (4), the effects described in any of (1) to (3) above can be achieved. Therefore, the durability of the immersion nozzle can be improved. Brief Description of Drawings
図 1 は、 本発明の一実施形態における連続铸造機の概略構成を示 す。 図 2は、 図 1の実施形態に係る浸漬ノズルを示す側断面図である 図 3は、 図 1の実施形態における浸漬ノズルのパウダーライン部 に使用する耐火物の Z r O 2 と F Cの配合量を示した図である。 図 4は、 図 1の実施形態における浸漬ノズルが装着された状態の 予熱装置を示す側断面図である。 FIG. 1 shows a schematic configuration of a continuous forging machine according to an embodiment of the present invention. 2 is a side sectional view showing the immersion nozzle according to the embodiment of FIG. 1. FIG. 3 is a combination of ZrO 2 and FC of refractory used in the powder line portion of the immersion nozzle in the embodiment of FIG. It is the figure which showed quantity. FIG. 4 is a side sectional view showing the preheating device with the immersion nozzle in the embodiment of FIG.
図 5は、 従来のバーナーを用いた加熱法により浸漬ノズルを予熱 している状態を示す側断面図である。 発明を実施するための最良の形態  FIG. 5 is a side sectional view showing a state in which the immersion nozzle is preheated by a heating method using a conventional burner. BEST MODE FOR CARRYING OUT THE INVENTION
以下、 本発明の一実施形態を図面に基づいて説明する。  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
〔連続铸造機の概略構成〕  [Schematic configuration of continuous forging machine]
図 1 に本実施形態における連続铸造機の概略構成を示す。 図 1 に おいて、 1は連続铸造機であって、 この連続铸造機 1は、 溶鋼を連 続的に冷却凝固させて、 所定形状の鋼塊を形成するものである。 こ のような連続鍀造機 1 は、 取鍋 2 と、 ロングノズル 3 と、 タンディ ッシュ 4と、 複数の浸漬ノズル 5 と、 複数のモールド 6 とを備えて いる。 なお、 図 1では、 浸漬ノズル 5およびモールド 6 をそれぞれ 1つだけ図示している。  Figure 1 shows the schematic configuration of the continuous forging machine in this embodiment. In FIG. 1, 1 is a continuous forging machine, and this continuous forging machine 1 continuously cools and solidifies molten steel to form a steel ingot of a predetermined shape. Such a continuous forging machine 1 includes a ladle 2, a long nozzle 3, a tundish 4, a plurality of immersion nozzles 5, and a plurality of molds 6. In FIG. 1, only one immersion nozzle 5 and one mold 6 are shown.
取鍋 2は、 連続踌造において最初に溶鋼が導入される耐熱容器で あり、 底面部には注入口 2 1が設けられている。  The ladle 2 is a heat-resistant container into which molten steel is first introduced in continuous forging, and has an inlet 21 at the bottom.
ロングノズル 3は、 取鍋 2の注入口 2 1 に取り付けられて、 取鍋 2内部に貯留された溶鋼をノズル下端開口部 3 1 よりタンディ ッシ ュ 4内に吐出するように構成されている。  The long nozzle 3 is attached to the inlet 2 1 of the ladle 2 and is configured to discharge the molten steel stored in the ladle 2 into the tundish 4 from the nozzle lower end opening 3 1. .
タンディ ッシュ 4は、 ロングノズル 3の下方に配設されて、 取鍋 2からロングノズル 3 を介して注入された溶鋼を貯留する耐熱容器 である。 このタンディ ヅシュ 4は、 底面部には各モールド 6に対応 した複数の注入口 4 1が形成されており、 この注入口 4 1 の内部に は注入口 4 1より流出する溶鋼の流量を調整する流量調整機 （図示 省略） が設けられている。 このようなタンディ ッシュ 4により、 取 鍋 2からの溶鋼が整流化され、 当該溶鋼が各モールド 6に所定量ず つ分配されるようになっている。 The tundish 4 is a heat-resistant container that is disposed below the long nozzle 3 and stores molten steel injected from the ladle 2 through the long nozzle 3. This tundish 4 is compatible with each mold 6 on the bottom. A plurality of inlets 41 are formed, and a flow rate adjuster (not shown) for adjusting the flow rate of the molten steel flowing out from the inlet 41 is provided inside the inlet 41. By such a tundish 4, the molten steel from the ladle 2 is rectified, and the molten steel is distributed to each mold 6 by a predetermined amount.
浸漬ノズル 5は、 具体的には後述するが、 タンディ ッシュ 4にお ける注入口 4 1の下部に取り付けられており、 このノズルを介して タンディ ッシュ 4内の溶鋼がモールド 6 に注入される。  The immersion nozzle 5 is specifically described later, and is attached to the lower part of the injection port 41 in the tundish 4, and the molten steel in the tundish 4 is injected into the mold 6 through this nozzle.
モールド 6は、 浸漬ノズル 5の下方に設けられた水冷式の铸型で ある。 モールド 6内は所定の断面形状を有しており、 このモールド 6内に浸漬ノズル 5を介してタンディ ッシュ 4からの溶鋼が連続的 に注入される。 このようなモールド 6 により、 モールド 6内の溶鋼 は冷却されて、 モールド 6内の内周面側から凝固シェルが形成 · 成 長して、 凝固した鋼が形成されるようになっている。  The mold 6 is a water-cooled vertical mold provided below the immersion nozzle 5. The mold 6 has a predetermined cross-sectional shape, and molten steel from the tundish 4 is continuously injected into the mold 6 through the immersion nozzle 5. With such a mold 6, the molten steel in the mold 6 is cooled, and a solidified shell is formed and grown from the inner peripheral surface side in the mold 6 to form solidified steel.
また、 モールド 6の下方には、 モールド 6内にて形成された鋼を 、 モールド 6内の下方開口部から下方に連続的に引き抜く ローラー エプロンおよび引抜ロールが設けられている。 （図示省略） さらに 、 引抜ロールの下流側には、 引抜ロールにて引き抜かれて、 モール ド 6内から連続して延びた状態の鋼を、 所定の長さ寸法に切断する 切断機 （図示省略） が設けられている。 この切断機にて鋼が切断さ れることにより、 例えば板状や棒状など所定形状の鋼塊が形成され るようになっている。  Further, below the mold 6, there are provided a roller apron and a drawing roll for continuously drawing the steel formed in the mold 6 downward from the lower opening in the mold 6. (Not shown) Further, on the downstream side of the drawing roll, the steel that has been continuously drawn from the inside of the mold 6 by being drawn by the drawing roll is cut into a predetermined length dimension (not shown) ) Is provided. By cutting the steel with this cutting machine, a steel ingot having a predetermined shape such as a plate shape or a rod shape is formed.
〔浸漬ノズルの構成〕  [Structure of immersion nozzle]
次に、 浸漬ノズル 5の構成について、 図 2 、 3に基づいて説明す る。 図 2は、 本実施形態に係る浸漬ノズルを示す側断面図である。 図 3は、 浸漬ノズルのパウダーライン部に使用する耐火物の Z r 〇 2 と F Cの配合量を示した図である。 図 2において、 浸漬ノズル 5は、 ノズル本体 5 1 と、 注入口 4 1 の下部に取り付けられてノズル本体 5 1の上端部を保持するホルダ 一 5 2 とを備えている。 この浸漬ノズル 5は、 後述する予熱工程に おいて高周波誘導加熱により予熱されてから使用される。 Next, the configuration of the immersion nozzle 5 will be described with reference to FIGS. FIG. 2 is a side sectional view showing the immersion nozzle according to the present embodiment. Fig. 3 shows the blending amounts of refractory Zr 0 2 and FC used in the powder line part of the immersion nozzle. In FIG. 2, the immersion nozzle 5 includes a nozzle body 5 1 and a holder 5 2 that is attached to the lower part of the inlet 4 1 and holds the upper end of the nozzle body 5 1. The immersion nozzle 5 is used after being preheated by high frequency induction heating in a preheating process described later.
ノズル本体 5 1 は、 略円筒状に形成されて、 その下端を閉塞する 底面部 5 1 1が設けられている。 このノズル本体 5 1 における側面 部の底面部 5 1 1近傍には、 一対の吐出口 5 1 2カ^ 互いに対向す る状態で設けられている。 このようなノズル本体 5 1 により、 ノズ ル本体 5 1の上端開口より流入した溶鋼が、 一対の吐出口 5 1 2を 介してモールド 6内へと吐出されるようになっている。  The nozzle body 51 is formed in a substantially cylindrical shape, and is provided with a bottom surface 51 11 that closes its lower end. In the vicinity of the bottom surface portion 5 11 of the side surface portion of the nozzle body 51, a pair of discharge ports 5 1 2 are provided so as to face each other. With such a nozzle body 51, the molten steel flowing from the upper end opening of the nozzle body 51 is discharged into the mold 6 through the pair of discharge ports 5 12.
また、 ノズル本体 5 1 は、 その下端側がモールド 6内の溶鋼に浸 漬された状態で使用される。 ここで、 図 2中二点鎖線はスラグライ ン Sを示す。 ノズル本体 5 1が当該溶鋼中に浸潰された状態では、 ノズル本体 5 1の外周面におけるスラグライン Sよりも下側にてモ 一ルドパウダーに接触 （パウダー厚みは 1 0 m m程度） し、 さらに モールドパウダ一よりも下側が溶鋼中に浸漬している。 予熱不良の 場合、 パウダ一ライン Sよりも上側にて割れが発生する場合がある このようなノズル本体 5 1は、 外周面部のうち吐出口 5 1 2より も上側のパウダーライン部 5 1 3 と、 それ以外の部位とが、 それぞ れ異なる耐火物で形成された 2層構造となっている。  The nozzle body 5 1 is used with its lower end side immersed in molten steel in the mold 6. Here, the two-dot chain line in Fig. 2 shows the slag line S. When the nozzle body 51 is immersed in the molten steel, it contacts the mold powder below the slag line S on the outer peripheral surface of the nozzle body 51 (powder thickness is about 10 mm). Furthermore, the lower side of the mold powder is immersed in the molten steel. In the case of preheating failure, cracks may occur on the upper side of the powder line S. Such a nozzle body 51 has a powder line part 5 1 3 above the discharge port 5 1 2 on the outer peripheral part. The other parts have a two-layer structure made of different refractories.
パウダーライン部 5 1 3 を形成する耐火物は、 図 3中領域 Aおよ び領域 Bに示すように、 Z r 〇 2 ： 7 0質量％以上と、 F C (フリ —カーボン） ： 3 0質量％以下とを含んで構成されている。 また、 パウダーライン部 5 1 3を形成する耐火物は、 図 3中領域 Aで示す ように、 Z r 〇 2 ： 7 0質量％以上と、 黒鉛を含む F C ： 2 0質量 %以下と、 Z r〇 2 を安定化させる安定化材を含む残部 1 0質量％ 以下とを含んで構成されていてもよい。 The refractory that forms the powder line part 5 1 3, as shown in area A and area B in Fig. 3, is Zr 0 2 : 70 mass% or more, and FC (free carbon): 30 mass % Or less. Also, the refractory forming the powder line part 5 1 3 is composed of Zr 0 2 : 70 mass% or more, graphite containing FC: 20 mass% or less, as shown by region A in FIG. r〇 10% by mass of balance including stabilizing material that stabilizes 2 The following may be comprised.
Z r〇 2 含有量の上限値は特に規定するものではなく、 1 0 0質 量％未満であれば良く、 また F C (フリーカーボン〉 含有量の下限 値も特に規定するものではなく、 0質量％超であれば良い。 さらに 、 安定化材を含む残部の下限値も特に規定するものではなく、 0質 量％超であれば良い。 Z R_〇 2 upper limit of the content is not particularly defined, 1 0 0 is less than mass% may also FC (free carbon> lower limit of the content is also not particularly defined, 0 mass Further, the lower limit of the balance including the stabilizing material is not particularly specified, and may be more than 0 mass%.
ノズル本体 5 1 におけるパウダーライン部 5 1 3以外の部位は、 例えば A l 2 0 3 一 S i O 2 一 Cや A l 2 O 3 一 C等の耐火物にて 形成されている。 なお、 パウダーライン部 5 1 3以外の部位に使用 する耐火物はこれに限定されず、 ノズル本体 5 1 内部を流通する溶 鋼に対して優れた耐火性および低い溶融濡れ性が得られる材料であ れば、 いずれをも採用できる。 Parts other than the powder line part 5 1 3 in the nozzle body 5 1 are formed of a refractory material such as A 1 2 0 3 S i O 2 1 C or A 1 2 O 3 1 C, for example. Note that the refractory material used in parts other than the powder line section 5 1 3 is not limited to this, and is a material that can provide excellent fire resistance and low melt wettability to the molten steel flowing through the nozzle body 5 1. Any of them can be adopted.
〔予熱装置の構成〕  [Configuration of preheating device]
次に、 上記した構成の浸漬ノズル 5を予熱する予熱装置について 、 図 4に基づいて説明する。 図 4は、 浸漬ノズルが装着された状態 の予熱装置を示す側断面図である。  Next, a preheating device for preheating the immersion nozzle 5 having the above-described configuration will be described with reference to FIG. FIG. 4 is a side sectional view showing the preheating device with the immersion nozzle attached.
図 4において、 7は予熱装置であって、 この予熱装置 7は浸漬ノ ズル 5を高周波誘導加熱により予熱する。 このような予熱装置 7は 、 耐熱容器 7 1 と、 外コイル 7 2 と、 内コイル 7 3 と、 誘導電流印 加装置 （図示せず） とを備えて構成されている。  In FIG. 4, 7 is a preheating device, and this preheating device 7 preheats the immersion nozzle 5 by high frequency induction heating. Such a preheating device 7 includes a heat-resistant container 7 1, an outer coil 7 2, an inner coil 7 3, and an induced current applying device (not shown).
外コイル 7 2は、 耐熱容器 7 1 の内部に収用された誘導加熱コィ ルであって、 コイル内周側にノズル本体 5 1の下端部から中間部上 方までを収容可能に構成されている。  The outer coil 72 is an induction heating coil confiscated inside the heat-resistant container 71, and is configured to be able to accommodate from the lower end of the nozzle body 51 to the upper part of the middle part on the inner peripheral side of the coil. .
内コイル 7 3は、 外コイル 7 2 と同様の誘導加熱コイルであって 、 ノズル本体 5 1 の上部開口より内部に挿入可能に構成されている 誘導電流印加装置は、 外コイル 7 2および内コイル 7 3のそれぞ れに高周波の誘導電流を印加する装置である。 The inner coil 7 3 is an induction heating coil similar to the outer coil 7 2, and is configured to be inserted inside from the upper opening of the nozzle body 5 1. The induction current application device includes the outer coil 7 2 and the inner coil 7 2. 7 3 each This is a device that applies a high-frequency induced current.
〔連続铸造方法〕  [Continuous fabrication method]
本実施形態に係る連続铸造方法について、 上記のような構成の連 続铸造機 1および予熱装置 7 を使用した例で説明する。  The continuous forging method according to this embodiment will be described using an example in which the continuous forging machine 1 and the preheating device 7 configured as described above are used.
本実施形態の連続踌造方法は、 予熱工程と、 錡造工程と、 引抜ェ 程と、 鋼塊形成工程とを備えて構成されている。  The continuous forging method of the present embodiment includes a preheating step, a forging step, a drawing step, and a steel ingot forming step.
予熱工程では、 図 4に示す予熱装置 7を用いて、 浸漬ノズル 5を 高周波誘導により予熱する。 具体的には、 まず、 タンディ ッシュ 4 から外された状態の浸漬ノズル 5に対して予熱装置 7 をセッ 卜する 。 このセッ トされた状態では、 ノズル本体 5 1 は、 外コイル 7 2内 に収容され、 ノズル本体 5 1 の上部開口より内部に内コィル 7 3が 挿入された状態となっている。 そして、 誘導電流印加装置により、 外コイル 7 2および内コイル 7 3に誘導電流を印加する。 これによ り、 ノズル本体 5 1 に含まれる F C近傍に高密度のうず電流が発生 して大きなジュール熱が発生し、 ノズル本体 5 1全体が均一に加熱 される。  In the preheating process, a preheating device 7 shown in FIG. 4 is used to preheat the immersion nozzle 5 by high frequency induction. Specifically, first, the preheating device 7 is set with respect to the immersion nozzle 5 removed from the tundish 4. In this set state, the nozzle body 51 is accommodated in the outer coil 72, and the inner coil 73 is inserted into the inside from the upper opening of the nozzle body 51. Then, an induced current is applied to the outer coil 72 and the inner coil 73 by an induced current application device. As a result, a high-density eddy current is generated in the vicinity of FC included in the nozzle body 51, generating large Joule heat, and the entire nozzle body 51 is heated uniformly.
この高周波誘導加熱により、 例えば 0 . 5〜 2時間程度の加熱時 間で、 ノズル本体 5 1 の温度は 1 0 0 0 °C以上に達する。 また、 例 えばノズル本体 5 1 を 1 1 0 0 °C以上に加熱する場合、 従来の如く バーナー 1 0 0 (図 5参照） で加熱する場合には各部間で最大 5 0 0 ° ( 〜 6 0 0 °Cの温度差が生じるが、 高周波誘導加熱によれば各部 間で最大 3 0 0 °C程度の温度差しか生じない。  By this high frequency induction heating, the temperature of the nozzle body 5 1 reaches 100 ° C. or more in a heating time of about 0.5 to 2 hours, for example. For example, when the nozzle body 5 1 is heated to 1 100 ° C or higher, and when heated with a burner 1 0 0 (see Fig. 5) as in the past, a maximum of 5 0 0 ° (~ 6 Although a temperature difference of 0 ° C occurs, high-frequency induction heating can only produce a maximum temperature difference of about 300 ° C between each part.
そして、 高周波誘導加熱によれば、 従来のように燃焼ガスを使用 せずに短時間で予熱が完了するので、 パウダーライン部 5 1 3中の Cが消失し難く、 当該耐火物中における気孔の拡大が防止される。 铸造工程では、 図 1 に示した連続铸造機 1 を用いて溶鋼の铸造を 行う。 まず、 予熱工程にて予熱された浸漬ノズル 5をタンディ ッシ ュ 4の注入口 4 1 に取り付けた後、 取鍋 2の内部に溶鋼を導入する 。 この溶鋼は、 ロングノズル 3を介して取鍋 2からタンディ ッシュ 4内部へと流動し、 タンディ ッシュ 4の内部にて整流化される。 こ の後、 整流化された溶鋼を、 流量調整機 （図示） にて流出量を調整 しながら、 浸漬ノズル 5を介してモールド 6内に注入し、 モールド 6において一定の湯面レベルを維持する。 In addition, according to high frequency induction heating, preheating is completed in a short time without using combustion gas as in the conventional case, so that C in the powder line portion 5 1 3 is not easily lost, and pores in the refractory are not easily lost. Expansion is prevented. In the forging process, molten steel is forged using the continuous forging machine 1 shown in Fig. 1. First, dip the immersion nozzle 5 preheated in the preheating process. After installing in the inlet 4 1 of the 4th, introduce molten steel into the ladle 2. This molten steel flows from the ladle 2 into the tundish 4 through the long nozzle 3 and is rectified in the tundish 4. After that, the rectified molten steel is injected into the mold 6 through the immersion nozzle 5 while adjusting the outflow amount with a flow rate adjuster (illustrated), and a constant molten metal level is maintained in the mold 6. .
この铸造工程において、 溶鋼の注入を開始する際、 予熱工程にて ノズル本体 5 1 を均一に予熱してあるので、 浸漬ノズル 5が溶鋼に より受ける熱衝撃が緩和されて、 割れ等の不具合の発生を防止でき る。 そして、 パウダーライン部 5 1 3は、 Z r 〇 2 および F C等を 上記範囲で含有した耐火物にて形成されているので、 モ一ルドパゥ ダーに対する高い耐食性を有しており、 モールドパウダ一による溶 損を抑制できる。 また、 予熱工程での予熱によりパウダーライン部 5 1 3中の気孔が拡大されていないので、 当該気孔内部にモールド パウダーが侵食して耐火物中の結晶粒がモールドパウダー中に脱落 することを防止できる。 したがって、 浸漬ノズル 5の耐用性を向上 できる。 In this forging process, when the injection of molten steel is started, the nozzle body 5 1 is uniformly preheated in the preheating process, so the thermal shock received by the immersion nozzle 5 from the molten steel is alleviated, and there is no problem such as cracking. Occurrence can be prevented. And since the powder line part 5 1 3 is formed of a refractory material containing Z r 0 2 and FC in the above range, it has high corrosion resistance against the mold powder, and according to the mold powder. Melting damage can be suppressed. Also, since the pores in the powder line part 5 1 3 are not enlarged due to preheating in the preheating process, the mold powder erodes inside the pores and prevents crystal grains in the refractory from falling into the mold powder. it can. Therefore, the durability of the immersion nozzle 5 can be improved.
引抜工程では、 モールド 6内において冷却 ' 固化された鋼を、 図 示しないローラーエプロンおよび引抜口一ルにより下方に連続的に 引き出す。  In the drawing process, the steel that has been cooled and solidified in the mold 6 is continuously drawn downward by means of a roller apron (not shown) and a drawing port.
鋼塊形成工程では、 当該引抜ロールにて引き抜かれた鋼を切断機 により所定の長さ寸法で切断して、 所定形状の铸片を連続的に形成 する。  In the steel ingot forming step, the steel drawn by the drawing roll is cut into a predetermined length by a cutting machine to continuously form pieces having a predetermined shape.
なお、 予熱工程では、 浸漬ノズル 5の他にも、 ロングノズル 3お よびタンディ ッシュ 4をも予熱する。 また、 予熱工程において浸漬 ノズル 5 をタンディ ッシュ 4に組み付けない状態で予熱するとした が、 浸漬ノズル 5をタンディ ッシュ 4に組み付けた状態で予熱を施 してもよい。 In the preheating process, the long nozzle 3 and the tundish 4 are preheated in addition to the immersion nozzle 5. In the preheating process, preheating was performed without the immersion nozzle 5 being attached to the tundish 4, but preheating was performed with the immersion nozzle 5 being attached to the tundish 4. May be.
実施例 Example
上述した本実施形態の効果を確認するための実施例について説明 する。  An example for confirming the effect of the above-described embodiment will be described.
〔実験試料〕  [Experimental sample]
• 浸漬ノズル ： 図 2に示す上記実施形態の浸漬ノズル 5 と同様のも のを複数準備した。  • Immersion nozzles: A plurality of immersion nozzles similar to the immersion nozzle 5 of the above embodiment shown in FIG. 2 were prepared.
• ノズル寸法 ： ノズル本体 5 1 の最大外径寸法は φ 1 4 0 mm、 内 径寸法は φ 8 0 mm, 長さ寸法は 7 0 0 mmとした。  • Nozzle dimensions: The nozzle body 51 has a maximum outer diameter of φ140 mm, an inner diameter of φ80 mm, and a length of 700 mm.
， 耐火物組成 ： 各パウダーライン部 5 1 3を形成する耐火物の組成 は、 以下の表 1 に示すものを含め、 図 3中各プロッ トに示した組 成のものも含まれている。  , Refractory composition: The composition of the refractory forming each powder line part 5 1 3 includes the composition shown in each plot in Fig. 3, including those shown in Table 1 below.
• 形成法 ： 耐火骨材、 鱗状黒鉛をバインダーと共に混練した後、 ノ ズル形状のゴム型に混練物 （はい土） を流し込む。 異材質を流し 込む場合には、 ゴム型に仕切りを入れて混入しないように流し込 む。 その後、 湿式の C I P成形法にて高圧 （ 5 0〜 1 0 O M P a ) の水圧をかけて固める。 枠から成形品を取り出した後は、 還元 雰囲気で 1 0 0 0 ^以上の高温で焼成を行う。 冷却後は、 必要な 寸法に加工し、 酸化防止材を塗布した後、 実機での使用となる。 • Forming method: After kneading refractory aggregate and scaly graphite together with a binder, pour the kneaded material (yes earth) into a nozzle-shaped rubber mold. If different materials are to be poured, insert a rubber mold so that it does not get mixed. Then, it is hardened by applying a high pressure (50 to 10 OMPa) with a wet CIP molding method. After taking out the molded product from the frame, firing is performed at a high temperature of 100 0 ^ or more in a reducing atmosphere. After cooling, it is processed to the required dimensions, applied with antioxidants, and then used in actual equipment.
表 1 table 1
Figure imgf000016_0001
Figure imgf000016_0001
〔高周波誘導加熱による予熱〕 [Preheating by high frequency induction heating]
• 予熱対象 ： 実施例 1〜 6  • Preheating target: Examples 1 to 6
' 予熱装置 ： 図 4に示す予熱装置 7 と同様である。 外コイル 7 2に は径寸法 2 0 0 mm、 長さ寸法 5 0 0 mmのものを使用し、 内 コイル 7 3には径寸法 φ 7 0 mm、 長さ寸法 3 0 0 mmのものを 使用した。  'Preheater: Same as preheater 7 shown in Fig.4. Use an outer coil 7 2 with a diameter of 200 mm and a length of 500 mm, and an inner coil 7 3 with a diameter of 70 mm and a length of 300 mm. did.
' 誘導電流 ： 外コイル 7 2には周波数 3 0 k H z、 電流 2 0 0 A、 電力量 1 5 kWの誘導電流を印加した。 内コイル 7 3には、 周波 数 3 7 k H z , 電流 2 0 0 A、 電力量 1 2 kWの誘導電流を印加 した。  'Inductive current: The outer coil 7 2 was applied with an induction current having a frequency of 30 kHz, a current of 20 A, and a power of 15 kW. An inductive current having a frequency of 37 kHz, a current of 200 A, and a power of 12 kW was applied to the inner coil 73.
• 予熱時間 ： 4 0分  • Preheating time: 40 minutes
〔バーナー加熱による予熱〕  [Preheating by burner heating]
• 予熱対象 ： 比較例 1 , 2  • Preheating target: Comparative examples 1 and 2
' 予熱装置 ： 図 5に示すバーナー 1 0 0を用いて予熱した。 図 5に おいて、 浸漬ノズル 5を耐熱容器 1 0 1 中に収容した状態で、 浸 漬ノズル 5の上端開口部より内部にバーナー 1 0 0 を挿入して燃 焼ガスを吹き付けている。  'Preheater: Preheated using the burner 1 0 0 shown in Fig. 5. In FIG. 5, with the immersion nozzle 5 housed in the heat-resistant container 10 1, a burner 1 0 0 is inserted into the inside from the upper end opening of the immersion nozzle 5 and sprayed with combustion gas.
• 燃焼ガス ： C O G (Coke-oven Gas ： コ一クス炉ガス）  • Combustion gas: C O G (Coke-oven Gas)
• 空気比 ： 1. 2  • Air ratio: 1.2
• 予熱時間 ： 9 0分  • Preheating time: 90 minutes
〔铸造実験〕  [Forging experiment]
• 実験対象 ： 実施例 1〜 6および比較例 1， 2  • Experiment subjects: Examples 1 to 6 and Comparative Examples 1 and 2
• 連続鍀造機 ： 図 1 に示す上記実施形態の連続铸造機 1 と同様のも のを使用した （ 8チャージ） 。  • Continuous forging machine: The same one as the continuous forging machine 1 of the above embodiment shown in Fig. 1 was used (8 charges).
• 铸造'方法 ： 上記実施形態における铸造工程と同様である。 具体的 には、 各浸漬ノズル 5を単体で予熱した後、 それぞれタンディ ッ シュ 4に取り付けて、 予熱終了の時点から 5分後に錡造を開始し た。 • Forging method: Same as the forging process in the above embodiment. Specifically, after each submerged nozzle 5 is preheated alone, it is attached to each tundish 4, and forging starts 5 minutes after the end of preheating. It was.
• 鋼種 ： 低炭素鋼 （炭素濃度 0. 0 6質量％)  • Steel type: Low carbon steel (carbon concentration 0.06 mass%)
• モールドパウダーの塩基度 ： 1 . 0  • Mold powder basicity: 1.0
• 操業時間 ： 合計 3 6 0分  • Operating hours: Total 3 60 minutes
〔実験結果〕  〔Experimental result〕
実施例 1〜 6、 比較例 1 , 2の浸漬ノズル 5について、 上記铸造 実験の結果 （溶損速度指数、 トラブル発生指数） を表 1 に併せて 示す。  Table 1 also shows the results of the forging experiment (melting rate index, trouble occurrence index) for the immersion nozzles 5 of Examples 1 to 6 and Comparative Examples 1 and 2.
• 溶損速度指数 ： 比較例 1 についての溶損速度 （铸造によってパゥ ダ一ライン部 5 1 3が溶損した量を操業時間で除算したもの） を 1 0 0 とした場合における、 実施例 1〜 6および比較例 2につい ての当該溶損速度を指数化したものである。  • Melting rate index: Example 1 when the rate of erosion of Comparative Example 1 (the amount of erosion of the powder line part 5 1 3 due to forging was divided by the operating time) was 1 0 0 The melting rate for ˜6 and Comparative Example 2 is indexed.
• トラブル発生指数 ： 比較例 1 についてのトラブル発生率 （铸造し た回数と、 折損や割れなどの不具合が発生した回数との比） を 1 0 0 とした場合における、 実施例 1 についてのトラブル発生率を 指数化したものである。  • Trouble occurrence index: Trouble occurrence for Example 1 when the trouble occurrence rate for Comparative Example 1 (ratio between the number of times of forging and the number of occurrences of defects such as breakage or cracking) is 100 The rate is an index.
〔知見 1 ： 高周波誘導加熱の効果について〕  [Knowledge 1: About the effect of high frequency induction heating]
表 1 に示すように、 実施例 1 と比較例 1 とはパウダーライン部 5 1 3 の組成が同一であり （ Z r 〇 2 ： F C ： C a O = 7 5 ： 2 0 ： 5 ) 、 実施例 2 と比較例 2 とはパウダーライン部 5 1 3 の組成が同 一である （ Z r 〇 2 ： F C : C a〇 = 8 2 ： 1 3 ： 5 ) 。 また、 実 施例 1， 2は予熱方法が高周波誘導加熱 （ I H) であり、 比較例 1 , 2はバーナーによる加熱であるという点で異なっている。 As shown in Table 1, the composition of Example 1 and Comparative Example 1 are the same in the powder line part 5 1 3 (Zr 0 2 : FC: C a O = 75: 20: 5). Example 2 and Comparative Example 2 have the same composition of the powder line part 5 1 3 (Zr 0 2 : FC: C a 0 = 8 2: 1 3: 5). Examples 1 and 2 differ in that the preheating method is high frequency induction heating (IH), and comparative examples 1 and 2 are heating by a burner.
表 1の結果において、 溶損速度指数を比較すると、 実施例 1は比 較例 1 に対して 1 0 %低い値となっており、 また、 実施例 2は比較 例に対して約 9. 5 %低い値となっている。 これは、 高周波誘導加 熱により予熱した場合、 バーナーで予熱した場合と異なって燃焼ガ スを使用せずに短時間で予熱が終了するので、 パウダーライン部 5 1 3 における Cの消失が防止されためと考えられる。 In the results shown in Table 1, when the erosion rate index is compared, Example 1 is 10% lower than Comparative Example 1, and Example 2 is about 9.5 compared to Comparative Example. % Is low. This is different from the case of preheating with a high frequency induction heating, unlike the case of preheating with a burner. This is presumably because the preheating is completed in a short time without using the soot, and the loss of C in the powder line part 5 1 3 is prevented.
また、 表 1の結果において、 トラブル発生指数を比較すると、 実 施例 1は比較例 1 に対して 8 5 %低い値となっている。 これは、 高 周波誘導加熱により予熱した場合、 バーナーにより予熱した場合よ り も、 ノズル本体 5 1 の各部が均一に予熱されたためと考えられる 以上より、 高周波誘導加熱にて浸漬ノズル 5を予熱することで、 モールドパゥダ一に溶損し難くなり、 かつ 、 铸造開始時における割 れなどの不具合の発生頻度を著しく低減できることが分かった。 つ まり、 浸漬ノズル 5の耐用性を向上できることが分かった。  In addition, in the results of Table 1, when the trouble occurrence index is compared, Example 1 is 85% lower than Comparative Example 1. This is presumably because each part of the nozzle body 51 was preheated more uniformly when preheated by high frequency induction heating than when preheated by a burner. As a result, it was found that it was difficult for the mold powder to melt and the frequency of occurrence of defects such as cracks at the start of fabrication could be significantly reduced. In other words, it was found that the durability of the immersion nozzle 5 can be improved.
〔知見 2 ： Z r O 2 と F Cとの配合割合について〕  [Knowledge 2: Mixing ratio of ZrO2 and FC]
表 1 に示すように 、 実施例 1〜《3 , 6 とを比較すると、 いずれも パウダ一ライン部 5 1 3に C a Oが 5質 %程含まれており、 Z r As shown in Table 1, when Examples 1 to << 3, 6 are compared with each other, the powder line part 5 1 3 contains about 5% of CaO, and Z r
O 2 の配合量は 、 7 5質量 % (実施例 1 ) 、 8 2質量％ (実施例 2The blending amount of O 2 is 75% by mass (Example 1), 82% by mass (Example 2).
) 、 8 8質量％ (実施例 3 ) 、 7 0質量 % (実施例 6 ) であり、 実 施例 3が最も高 < 、 実施例 6が最も低くなつている。 この分、 F C の配合量は、 2 0質量％ (実施例 1 ) 、 1 3質量％ (実施例 2 ) 、), 88% by mass (Example 3) and 70% by mass (Example 6), with Example 3 being the highest <and Example 6 being the lowest. For this, the blending amount of F C is 20% by mass (Example 1), 13% by mass (Example 2),
8質量％ (実施例 3 ) 、 2 6質量％ (実施例 6 ) であり、 実施例 3 が最も低く、 実施例 6が最も高くなつている。 8 mass% (Example 3) and 26 mass% (Example 6). Example 3 is the lowest and Example 6 is the highest.
そして、 表 1の結果において、 溶損速度指数を比較すると、 実施 例 1 は実施例 6に対して約 5 %低く、 実施例 2は実施例 6に対して 約 9 %低く、 実施例 3は実施例 6に対して約 1 3 %低い値となって いる。 これは、 耐食性に優れた Z r 〇 2 の配合割合が増大したため 、 パウダーライン部 5 1 3のモールドパウダーに対する耐食性が向 上したことによるものと考えられる。 And in the results of Table 1, when comparing the erosion rate index, Example 1 is about 5% lower than Example 6, Example 2 is about 9% lower than Example 6, and Example 3 is The value is about 13% lower than Example 6. This is thought to be due to an increase in the corrosion resistance of the powder line portion 5 1 3 to the mold powder due to an increase in the proportion of Zr 0 2 with excellent corrosion resistance.
これら実施例 1〜 3， 6 においては、 溶鋼の注入開始時において 殆ど割れ等が発生しておらず、 いずれも良好な耐熱衝撃性を示して いた。 これは、 耐熱衝撃性に優れた F Cの配合量が十分であったこ とと、 高周波誘導加熱によりノズル本体 5 1が均一に加熱されたた めによるものと考えられる。 In these Examples 1 to 3 and 6, at the start of molten steel injection Almost no cracks occurred, and all of them exhibited good thermal shock resistance. This is thought to be due to the fact that the blending amount of FC having excellent thermal shock resistance was sufficient and the nozzle body 51 was heated uniformly by high frequency induction heating.
なお、 表 1 には示さなかったが、 Z r 〇 2 の配合量が 7 0質量％ よりも低い場合や、 F Cの配合量が 3 0質量％よりも高い場合は、 Z r O 2 の配合量が十分でなく、 モールドパウダーに対する十分な 耐食性が得られなかった。 Although not shown in Table 1, and if the amount of Z r 〇 2 7 lower than 0 wt%, if the amount of FC is 3 greater than 0% by mass, compounding of Z r O 2 The amount was not sufficient and sufficient corrosion resistance to the mold powder could not be obtained.
以上より、 Z r〇 2 の配合量を 7 0質量％以上とすることで、 モ 一ルドパウダーに対する十分な耐食性が得られ、 さらに、 Z r 〇 2 の配合量を 8 0質量％以上とすることで、 当該耐食性をより向上で きることが分かつた。 From the above, by the amount of Z R_〇 2 and 7 0 wt% or more, to obtain a sufficient corrosion resistance to model one field powder, further, to the 8 0 wt% or more amount of Z r 〇 2 It has been found that the corrosion resistance can be further improved.
また、 F Cの配合量を 3 0質量％以下とすることで、 パウダ一ラ イン部 5 1 3の高度な耐熱衝撃性が得られることが分かった。 さら に、 F Cの配合量を 2 0質量％以下としても、 パウダ一ライン部 5 1 3の良好な耐熱衝撃性を維持できることが分かった。  Further, it was found that the high thermal shock resistance of the powder line portion 5 13 can be obtained by setting the blending amount of FC to 30% by mass or less. Furthermore, it was found that the good thermal shock resistance of the powder line portion 5 13 can be maintained even when the blending amount of FC is 20% by mass or less.
〔知見 3 ： 安定化材の添加による効果について〕  [Knowledge 3: Effect of adding stabilizers]
表 1 に示すように、 実施例 3 , 4と実施例 5 とを比較すると、 い ずれもパウダ一ライン部 5 1 3に含まれる Z r 〇 2 の量が、 8 8質 量％ (実施例 3 ) 、 8 6質量％ (実施例 4 ) 、 8 5質量％ (実施例 5 ) と同程度となっている。 また、 実施例 3， 4にはそれぞれ安定 化材として C a〇、 M g Oが 4 %含まれており、 実施例 5には安定 化材が添加されていない。 As shown in Table 1, when Examples 3 and 4 and Example 5 are compared, the amount of Z r 0 2 contained in the powder line part 5 1 3 is 8 8 mass% (Example 3), 86 mass% (Example 4) and 85 mass% (Example 5). In addition, Examples 3 and 4 contain 4% Ca 0 and Mg O as stabilizers, respectively, and Example 5 does not contain any stabilizer.
そして、 表 1の結果において、 溶損速度指数を比較すると、 実施 例 3は実施例 5に対して約 5 %低い値となっており、 さらに、 実施 例 4は実施例 5に対して約 7 %低い値となっている。 これは、 安定 化材の添加により耐火物組織内から Z r O , 結晶粒が脱落し難くな P T/JP2007/073899 つたためと考えられる。 And in the results of Table 1, when the erosion rate index is compared, Example 3 is about 5% lower than Example 5, and Example 4 is about 7% lower than Example 5. % Is low. This is because the addition of the stabilizer makes it difficult for ZrO and crystal grains to fall out of the refractory structure. PT / JP2007 / 073899 This is probably because of the problem.
また、 安定化材を含んだ残部が 1 0質量％よりも多い場合でも、 その効果は発揮されるものの、 相対的に Z r O 2 の配合割合が少な く、 モールドパウダ一に対する十分な耐食性が得られ難くなるため 、 1 0質量％以下とすることが好ましい。 In addition, even when the balance containing the stabilizing material is more than 10% by mass, the effect is exerted, but the proportion of ZrO 2 is relatively small and sufficient corrosion resistance to the mold powder is obtained. Since it becomes difficult to obtain, it is preferably 10% by mass or less.
なお、 表 1 には示さなかったが、 安定化材として Υ 2 Ο 3 を添加 した場合も同様の結果が得られた。 Although not shown in Table 1, the same result was obtained when Υ 2 Ο 3 was added as a stabilizer.
以上より、 安定化材を 1 0質量％以下添加することにより、 パゥ ダ一ライン部 5 1 3の溶損速度を低減できることが分かった。  From the above, it was found that by adding 10% by mass or less of the stabilizing material, the melting rate of the powder line portion 5 13 can be reduced.
なお、 本発明は上述の実施例に限定されず、 本発明の目的を達成 できる範囲での変形、 改良等は本発明に含まれる。 例えば、 パウダ 一ライン部 5 1 3の組成は、 実施例 1〜6の組成に限定されず、 図 3の領域 A , Β内に収まる組成であれば、 本発明に含まれるもので ある。 産業上の利用可能性  It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements and the like within the scope that can achieve the object of the present invention are included in the present invention. For example, the composition of the powder line portion 5 13 is not limited to the composition of Examples 1 to 6, and any composition that falls within the region A in FIG. 3 and the basket is included in the present invention. Industrial applicability
本発明によれば、 耐火物中に F Cが存在することにより、 高周波 誘導加熱にて当該 F Cを選択的に加熱でき、 浸漬ノズルを均一に予 熱できる。 このため、 予熱後、 铸造開始時において浸漬ノズルに割 れ等の不具合が発生することを防止でき、 铸造工程時におけるスラ グと接触する部分のスラグによる溶損を抑制できる。 したがって、 浸漬ノズルの耐用性を向上させることができる。  According to the present invention, when FC is present in the refractory, the FC can be selectively heated by high-frequency induction heating, and the immersion nozzle can be preheated uniformly. For this reason, after preheating, it is possible to prevent the occurrence of defects such as cracks in the submerged nozzle at the start of forging, and it is possible to suppress melting damage due to slag in the portion that contacts the slag during the forging process. Therefore, the durability of the immersion nozzle can be improved.

Claims

1. 溶融金属の連続錡造方法に使用される浸漬ノズルであって、 少なく とも外周部のスラグと接触する部分が、 Z r〇 2 : 7 0質量 %以上と、 F C (フリー力一ボン） ： 3 0質量％以下とを含んで構 成された耐火物にて形成請されており、 高周波誘導加熱によって予熱 されることを特徴とする浸漬ノズル。 1. An immersion nozzle used in the continuous metal casting method, where at least the part in contact with the slag on the outer periphery is Zr 0 2 : 70% by mass or more, FC (free force one bond) A submerged nozzle characterized in that it is formed of a refractory composed of 30% by mass or less and is preheated by high frequency induction heating.
2. 溶融金属の連続铸造方法に使用される浸漬ノズルであって、 少なく とも外周部のスラグと接触する部分が、 Z r〇 2 : 7 0質量 %以上と、 F C (フリー力一ボン） ： 2 0質量％以下と、 Z r 〇 2 囲 2. It is an immersion nozzle used in the continuous casting method of molten metal, and at least the part in contact with the slag on the outer circumference is Zr 0 2 : 70% by mass or more, FC (free force one bond): 20 mass% or less, Z r 0 2
の安定化材を含む残部 1 0質量％以下とを含んで構成された耐火物 にて形成されており、 高周波誘導加熱によって予熱されることを特 徴とする浸漬ノズル。 An immersion nozzle, characterized in that it is formed of a refractory material including the remaining 10% by mass or less including a stabilizing material, and is preheated by high-frequency induction heating.
3. 請求項 2 に記載の浸漬ノズルにおいて、 前記安定化材は、 C a O、 M g Oおよび Y 2 Ο 3 のうち少なく ともいずれか 1種を含む ことを特徴とする浸漬ノズル。 3. In the immersion nozzle according to claim 2, wherein the stabilizing Kazai the immersion nozzle, characterized in that it comprises a C a O, least any one also of M g O and Y 2 Omicron 3.
4. 請求項 1〜 3のいずれかに記載の浸漬ノズルを、 高周波誘導 加熱により予熱する予熱工程と、 前記予熱工程にて予熱された前記 浸漬ノズルを介して夕ンディ ッシュからモールドに溶融金属を注入 する铸造工程と、 を備えることを特徴とする連続铸造方法。  4. A preheating step of preheating the immersion nozzle according to any one of claims 1 to 3 by high frequency induction heating, and a molten metal from the evening dish to the mold via the immersion nozzle preheated in the preheating step. A continuous forging method, comprising: a forging step for pouring.
PCT/JP2007/073899 2007-12-05 2007-12-05 Immersion nozzle and method of continuous casting WO2009072216A1 (en)

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JP2007185682A (en) * 2006-01-12 2007-07-26 Nippon Steel Corp Method and device for preheating immersing nozzle for continuous casting

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US20230001472A1 (en) * 2019-11-26 2023-01-05 Refractory Intellectual Property Gmbh & Co. Kg An exchangeable nozzle for a nozzle changer system, a method for manufacturing such a nozzle, a nozzle changer system comprising such a nozzle and a tundish comprising such a nozzle changer system
JP7071605B1 (en) 2022-03-02 2022-05-19 黒崎播磨株式会社 Refractory and refractory members for continuous casting
WO2023167008A1 (en) * 2022-03-02 2023-09-07 黒崎播磨株式会社 Refractory product for use in continuous casting, and refractory product member
JP2023128028A (en) * 2022-03-02 2023-09-14 黒崎播磨株式会社 Refractory for continuous casting and refractory member

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KR20100080938A (en) 2010-07-13

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