WO2020158465A1 - Method for controlling sliding nozzle device, and method for manufacturing slab - Google Patents
Method for controlling sliding nozzle device, and method for manufacturing slab Download PDFInfo
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- WO2020158465A1 WO2020158465A1 PCT/JP2020/001590 JP2020001590W WO2020158465A1 WO 2020158465 A1 WO2020158465 A1 WO 2020158465A1 JP 2020001590 W JP2020001590 W JP 2020001590W WO 2020158465 A1 WO2020158465 A1 WO 2020158465A1
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- molten steel
- nozzle
- sliding
- ladle
- nozzle hole
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- 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
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- 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
- B22D11/16—Controlling or regulating processes or operations
- B22D11/18—Controlling or regulating processes or operations for pouring
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- 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
- B22D41/14—Closures
- B22D41/22—Closures sliding-gate type, i.e. having a fixed plate and a movable plate in sliding contact with each other for selective registry of their openings
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- 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
- B22D41/14—Closures
- B22D41/22—Closures sliding-gate type, i.e. having a fixed plate and a movable plate in sliding contact with each other for selective registry of their openings
- B22D41/42—Features relating to gas injection
Definitions
- the present invention relates to a method for controlling a sliding nozzle device and a method for manufacturing a slab.
- Some molten steel (molten metal) holding containers, such as tundish and ladle, used in the steelmaking process of steelworks have a sliding nozzle device installed at the bottom.
- the sliding nozzle device installed at the bottom of the ladle is generally used to prevent the molten steel from entering and solidifying into the nozzle hole until the start of pouring, etc. Is filled. Since this clogging sand causes a decrease in cleanliness in casting of high cleanliness steel, there is a case where an operating method is performed in which the clogging sand is once discharged and then casting is performed.
- the sliding nozzle device is opened in a state where the ladle is placed at the sand discharging position, and the sand and a part of the molten steel are taken out from the ladle. Then, the sliding nozzle device is closed to stop the pouring of the molten steel. Further, the ladle is placed at the casting position where casting is performed, and the sliding nozzle device is opened to take out the molten steel from the ladle and transfer the molten steel to the tundish or the mold. Then, the cast molten steel is solidified to produce a slab having a predetermined cross-sectional shape.
- a plate is intermittently operated at the initial opening in a sliding nozzle device of a tundish, and gas is blown from the plate into the nozzle holes. (Hereinafter, also referred to as “gas bubbling”) is disclosed.
- Patent Document 1 is a technique for initial opening in a tundish sliding nozzle device, and not for re-pouring of a ladle sliding nozzle device. Further, in Patent Document 1, it is preferable that the gas bubbling time is short, but even if the gas bubbling is performed in the ladle at this time, non-open holes are unavoidably generated at a constant frequency. ..
- the present invention has been made by paying attention to the above-mentioned problems, and it is possible to suppress the generation of non-open holes at the time of re-pouring of molten steel in a ladle, a control method for a sliding nozzle device, and a casting method. It is intended to provide a method for manufacturing a piece.
- a sliding nozzle device control method for pouring the molten steel from a ladle containing molten steel through a sliding nozzle device provided in the ladle, wherein the sliding nozzle is provided.
- the device comprises an upper plate provided on the lower surface of an upper nozzle fixed to the bottom of the ladle and having a first nozzle hole, and a sliding plate provided on the lower surface of the upper plate and having a second nozzle hole.
- the sliding plate has the second nozzle hole that does not overlap the first nozzle hole from the open position in which at least a part of the second nozzle hole overlaps the first nozzle hole.
- the plate is configured to be movable up to a closed position where the first nozzle hole is closed by sliding on the lower surface of the upper plate, and an inert gas is blown to the first nozzle hole at the closed position.
- the sliding plate In the state in which the molten steel is stored in the ladle, the sliding plate is set to the open position, and the gas is introduced through the first nozzle hole and the second nozzle hole.
- a pouring step of pouring out a part of the molten steel from the pan and after the pouring step, the sliding plate is moved to the closed position, and the gas is injected from the gas injection hole through the first nozzle hole.
- a method for controlling a sliding nozzle device is provided, in which the flow rate of the above-mentioned inert gas blown in is 3.9 Nm 3 /(min ⁇ m 2 ) or more and 26.0 Nm 3 /(min ⁇ m 2 ) or less. It
- the molten steel is poured out through a sliding nozzle device provided in the ladle, and the poured molten steel is cast.
- a method for manufacturing a slab which comprises casting the molten steel poured in the re-pouring step by using the method for controlling the sliding nozzle device described above.
- the above-mentioned problems are taken into consideration, and it is possible to suppress the generation of non-open holes when re-pouring molten steel in a ladle, the control of a sliding nozzle device.
- Methods and methods of making slabs are provided.
- the slab manufacturing method according to the present embodiment is intended for a manufacturing method in a continuous casting facility which is a casting facility for continuously casting the molten steel 4 contained in the ladle 1 shown in FIGS. 1 and 2.
- the ladle 1 is a molten steel holding container that contains the molten steel 4 and the slag 5.
- the molten steel 4 contained in the ladle 1 has been subjected to refining treatment with predetermined components and temperatures in advance. Further, in the present embodiment, it is preferable that the steel type of the molten steel 4 is a high cleanliness steel such as a bearing steel.
- the ladle 1 is provided with an upper nozzle 2 and a sliding nozzle device 3.
- the upper nozzle 2 is a refractory nozzle fixed to the bottom of the ladle 1.
- the sliding nozzle device 3 is a nozzle mechanism provided on the lower surface of the upper nozzle 2, and has an upper plate 31, a sliding plate 32, and a lower nozzle 33.
- the upper plate 31 is a plate made of refractory material, and has a circular first nozzle hole 311 that is opened in the vertical direction (vertical direction in FIGS. 1 to 4) which is the vertical direction in the plate surface.
- the upper plate 31 is fixedly provided on the lower surface of the bottom of the ladle 1, and the circular hole of the upper nozzle 2 and the first nozzle hole 311 are provided so as to be concentric with each other when viewed from above and below.
- the hole diameter of the upper nozzle 2 is substantially the same as the hole diameter of the first nozzle hole 311, and also the hole diameters of the second nozzle hole 321 and the lower nozzle 33, which will be described later.
- the sliding plate 32 is a refractory plate, and has a circular second nozzle hole 321 opened vertically in the plate surface and a gas blowing hole 322.
- the sliding plate 32 is provided on the lower surface of the upper plate 31, and is configured to be movable in the horizontal direction (the horizontal direction in FIGS. 1 to 4) by sliding on the lower surface of the upper plate 31.
- the sliding operation of the sliding plate 32 is performed by a sliding mechanism (not shown) such as a cylinder.
- the gas blowing hole 322 is provided at a position separated from the second nozzle hole 321 by a predetermined distance in the sliding direction of the sliding plate 32.
- One end of the gas blowing hole 322 opens on the upper surface of the sliding plate 32, and the other end is connected to a gas supply device (not shown).
- a gas blowing hole 322 when Ar gas is supplied from the gas supply device, the gas is injected from the upper surface of the sliding plate 32 where one end of the gas blowing hole 322 is formed.
- the gas injection hole 322 is not particularly limited in shape as long as the molten steel 4 is unlikely to enter the inside and the Ar gas can be injected.
- the gas blowing hole 322 may have a slit shape, a porous shape, or the like.
- the gas injection hole 322 overlaps with the first nozzle hole 311 when viewed from above and below, and the sliding plate 32 closes the first nozzle hole 311.
- the position of the moving plate 32 is set to the closed position.
- the position of the sliding plate 32 in which at least a part of the second nozzle hole 321 overlaps with the first nozzle hole 311 when viewed from above and below is defined as an open position.
- the sliding nozzle device 3 is in the closed state when the sliding plate 32 is in the closed position, and the sliding nozzle device 3 is in the open state when the sliding plate 32 is in the open position. That is, the sliding plate 32 is configured to move at least from the open position to the closed position by sliding on the lower surface of the upper plate 31.
- the sliding plate 32 can be moved in the sliding direction at the open position to adjust the overlapping margin, which is the region where the second nozzle hole 321 and the first nozzle hole 311 overlap.
- the overlapping margin is the region where the second nozzle hole 321 and the first nozzle hole 311 overlap.
- the lower nozzle 33 is a refractory nozzle.
- the lower nozzle 33 is a lower surface of the sliding plate 32, and is fixedly provided at a position where the circular hole of the lower nozzle 33 and the second nozzle hole 321 concentrically overlap each other when viewed from the up and down direction.
- the sliding nozzle device 3 is closed, and as shown in FIG. 1, the upper nozzle 2 and the first nozzle hole of the ladle 1 are connected.
- the inside of 311 is in a state where the filling sand 6 is contained.
- the plugging sand 6 is for preventing opening failure at the time of initial opening of the ladle 1, and prevents solidification of the molten steel 4 in the upper nozzle 2 and the first nozzle hole 311.
- a pouring process for discharging the filling sand 6 is performed before starting casting.
- the sliding plate 32 is moved to the open position to open the sliding nozzle device 3 to open the sand 6 Is exhausted.
- a part of the molten steel 4 is poured out together with the filling sand 6.
- all of the filling sand 6 is discharged from the ladle 1, and the sliding nozzle device 3 may be warmed by the sensible heat of the poured molten steel.
- the pouring time which is the time for pouring a part of the molten steel from the ladle 1, is preferably 5 seconds or more and 13 seconds or less.
- the pouring time is 5 seconds or more, the sliding nozzle device 3 is warmed to the extent that molten steel does not solidify in the sliding nozzle device 3 in the re-pouring process.
- the pouring time exceeds 13 seconds, the amount of molten steel that is poured out will be too large, and the yield reduction cannot be ignored, for example, the yield of cast slabs relative to molten steel will be less than 99%.
- the sliding plate 32 is moved to the closed position to close the sliding nozzle device 3, and Ar gas is blown from the gas blowing hole 322 (gas bubbling is performed) to perform the gas blowing process. Be seen.
- Ar gas is blown into the molten steel 4 in the ladle 1 through the gas blowing hole 322 for a predetermined time or longer.
- the time for blowing the Ar gas is also referred to as the blowing time or the bubbling time.
- the Ar gas blown from the gas blowing hole 322 moves upward into the ladle 1 through the first nozzle hole 311 and the upper nozzle 2, and stirs the molten steel 4 contained in the ladle 1.
- blowing flow rate is the volume blown in per unit of Ar gas time, 3.9 nm per nozzle Anadan area of the upper nozzle 3 / (min ⁇ m 2) or more 26.0Nm 3 / (min ⁇ m 2 ) below.
- the nozzle diameter of the upper nozzle 2 is 70 mm
- the nozzle hole cross-sectional area of the upper nozzle 2 is 3.8 ⁇ 10 ⁇ 3 m 2
- the flow rate of Ar gas blown from the upper nozzle 2 per unit time is , 15 NL/min or more and 100 NL/min or less.
- the molten steel 4 When the blowing flow rate of Ar gas is less than 3.9 Nm 3 /(min ⁇ m 2 ), the molten steel 4 easily flows into the sliding nozzle device 3 after the clogging sand is discharged and solidifies.
- the flow rate of the Ar gas blown exceeds 26.0 Nm 3 /(min ⁇ m 2 )
- the flow velocity of the Ar gas blown into the sliding nozzle device 3 becomes high, so that the sliding that accompanies the Ar gas occurs.
- the molten steel flow in the vicinity of the nozzle device 3 is accompanied by turbulent vortices. In this case, a stagnation part of the molten steel flow is formed in a region adjacent to the turbulent vortex, and the molten steel 4 in this part easily solidifies.
- the flow rate of Ar gas per nozzle hole cross-sectional area of the upper nozzle is set within a suitable range, and the flow rate of Ar gas per unit time is set regardless of the nozzle hole cross-sectional area of the upper nozzle. It is preferably 15 NL/min or more and 100 NL/min or less, and more preferably 15 NL/min or more and 50 NL/min or less.
- the flow rate of Ar gas is less than 15 NL/min, the stirring force is too small, so that the blowing time must be lengthened, which may lead to a decrease in productivity and an increase in manufacturing cost to compensate the molten steel temperature. There is a nature.
- the flow rate of Ar gas is more than 50 NL/min
- the temperatures of the first nozzle hole 311 and the upper nozzle 2 are lowered by cooling the first nozzle hole 311 and the upper nozzle 2, and the first nozzle hole 311 is cooled.
- the molten steel 4 may solidify and adhere in the upper nozzle 2.
- the flow rate of Ar gas is more than 100 NL/min
- the swing of the bath surface becomes large, and the work of moving the ladle 1 from the packed sand discharge position to the casting position where continuous casting is performed is accompanied with the blowing of Ar gas. Become dangerous. Further, there is a concern that the cleanliness of the molten steel 4 may be deteriorated due to slag inclusion.
- the molten nozzle 4 is temporarily closed to stop the pouring of the molten steel 4 and then opened to restart the pouring of the molten steel 4. Doing is also called re-pouring.
- Blowing time in the gas blowing step is 1/4 or more uniform mixing time of the molten steel 4 in the ladle 1 by stirring the Ar gas t m (s).
- Uniformly mixing time t m is an agitation by Ar gas powered ⁇ (W / T), is a calculated value obtained from a bath shape of the molten steel 4 in the ladle 1.
- the value obtained by the following equation (1) is used as the stirring power ⁇ .
- ⁇ is the stirring power (W/T)
- V g is the flow rate of the Ar gas blown (Nm 3 /min)
- T 1 is the temperature (K) of the molten steel 4
- W is the molten steel 4.
- weight (t) h v denotes blowing depth (Yokufuka of) (m)
- P a is atmospheric pressure (Pa)
- T 0 is the standard state temperature (K), respectively.
- h v is Yokufuka of (m)
- d v denotes the bath diameter (m) to each.
- (2) homogeneously mixing time t m required by the formula are those calculated by simulating the ladle 1 shown in FIGS. 1 and 2 as a bottomed cylindrical shape. That is, the bath depth h v indicates the vertical depth of the molten steel 4 contained in the ladle 1, and the bath diameter d v is the average of the inner diameters of the truncated cone ladle 1 in the region containing the molten steel 4. Indicates a value.
- Patent Document 1 describes that in a tundish sliding nozzle device, increasing the gas bubbling time leads to solidification of molten steel.
- the sliding nozzle device 3 of the ladle 1 the results of investigating the relationship between blowing time and not opening, less than 1/4 of the blowing time is uniform mixing time t m and shorter It was found that the probability of denudation increases in. It is estimated that this is due to the following phenomenon. In gas bubbling in the ladle 1, as shown in FIG. 3, when the blowing time is short, the molten steel 4 is not sufficiently stirred, and a large temperature gradient is generated in the molten steel 4 between the top and bottom of the ladle 1.
- the temperature inside the upper nozzle 2 and the inside of the first nozzle hole 311 decreases, and the possibility that the solidification of the molten steel 4 progresses increases, so that the probability that a non-open hole will occur increases.
- the molten steel 4 is sufficiently stirred, so that the temperature of the molten steel 4 is made uniform at the top and bottom of the ladle 1. For this reason, the temperature inside the upper nozzle 2 and the inside of the first nozzle hole 311 increases, and the solidification of the molten steel 4 is suppressed, so that the generation of non-open holes is suppressed.
- the upper limit of the blowing time is preferably set to 2/5 or less of the uniform mixing time.
- the blowing of Ar gas blowing time it is sufficient that 1/4 or more uniform ⁇ between t m as results.
- the ladle 1 is moved from the packed sand discharging position to the casting position where continuous casting is performed together with the blowing of Ar gas.
- a re-pouring step of pouring the molten steel 4 from the ladle 1 is performed.
- the sliding plate 32 is moved to the open position to open the sliding nozzle device 3, thereby opening the upper nozzle 2, the first nozzle hole 311, and the like.
- Molten steel 4 is poured from the ladle 1 through the second nozzle hole 321 and the lower nozzle 33. Then, the poured molten steel 4 is continuously cast.
- a general method can be used. For example, a long nozzle is connected to the lower nozzle 33, the molten steel 4 poured out through this long nozzle is transferred to a tundish, and further poured from the tundish into a mold (mold), whereby casting is performed. Done.
- the sliding nozzle device 3 is subjected to the control described in the above-described pouring step, blowing step, and re-pouring step. Then, by controlling the sliding nozzle device 3 by this control method to perform continuous casting, a slab having a predetermined cross-sectional shape according to the mold is manufactured.
- the sliding nozzle device 3 is a two-layer type having two plates, the upper plate 31 and the sliding plate 32, but the present invention is not limited to this example.
- the sliding nozzle device 3 may be of the three-layer type shown in FIGS. 5 and 6.
- the sliding nozzle device 3 shown in FIGS. 5 and 6 has an upper plate 31, a sliding plate 32, a lower plate 34, and a lower nozzle 33.
- the upper plate 31, the sliding plate 32, and the lower nozzle 33 are the same as those in the above embodiment.
- the lower plate 34 is a refractory plate, and has a circular third nozzle hole 341 that is vertically opened in the plate surface.
- the lower plate 34 is provided on the lower surface of the sliding plate 32 so as to be fixed to the upper plate 31 so that the first nozzle hole 311 and the third nozzle hole 341 are concentric with each other when viewed from above and below. It is provided so as to overlap. That is, in the sliding nozzle device 3 shown in FIGS. 5 and 6, the sliding plate 32 is provided so as to be sandwiched between the upper plate 31 and the lower plate 34, and slides between the upper plate 31 and the lower plate 34. ..
- the lower nozzle 33 is the lower surface of the lower plate 34, and is fixedly provided at a position where the circular hole of the lower nozzle 33 and the third nozzle hole 341 are concentrically overlapped with each other when viewed from above and below. Further, as shown in FIG.
- the sliding nozzle device 3 is in a closed state when the gas blowing hole 322 is arranged between the first nozzle hole 311 and the third nozzle hole 341.
- the state in which the second nozzle holes 321 are arranged between the first nozzle holes 311 and the third nozzle holes 341 is the state in which the sliding nozzle device 3 is in the open state.
- the sliding nozzle device 3 is not limited to the above-described modified example, and is not particularly limited as long as it is the sliding nozzle device 3 provided in the ladle 1 and is capable of gas bubbling in the closed state.
- the slab production facility may be an ingot casting facility for casting an ingot instead of the continuous casting facility.
- the re-pouring operation is not the pouring for the purpose of discharging the plugged sand 6 in the pouring process, but the pouring of the molten steel 4 for the purpose of normal casting. It may be served.
- molten steel 4 may be transferred to a plurality of injection pipes, and therefore a re-pouring operation may be performed when changing the injection pipe to which molten steel 4 is transferred. ..
- casting may be temporarily interrupted due to equipment troubles, and in this case re-pouring operation may be performed.
- re-pouring operation may be performed similarly to the above-described embodiment, by performing the blowing step when re-pouring, it is possible to suppress the occurrence of non-open holes in the re-pouring step.
- the steel type of the molten steel 4 is not limited to the high cleanliness steel, and is suitably used in the molten steel 4 of any steel type. be able to.
- (1) and equation (2) was used time calculated from the equation, the present invention is not limited to such an example.
- Uniformly mixing time t m is the time required for the component concentration of the molten steel 4 is asymptotic to within a certain range around the final value, it may be those generally defined in refining art. Therefore, (1) and (2) time calculated from the calculation formula other than the formula, may be used as a uniform mixing time t m.
- a uniform mixing time calculation equation for a model closer to the actual shape of the ladle 1 may be used.
- the gas blown in the blowing step was Ar gas, but the present invention is not limited to this example.
- the gas blown in the blowing step may be an inert gas, and a gas other than Ar gas may be used.
- the molten steel 4 is poured from the ladle 1 containing the molten steel 4 through the sliding nozzle device 3 provided in the ladle 1.
- a method for controlling the sliding nozzle device 3 wherein the sliding nozzle device 3 is provided on the lower surface of the upper nozzle 2 fixed to the bottom of the ladle 1 and has an upper plate 31 having a first nozzle hole 311 and an upper plate 31.
- a slide plate 32 having a second nozzle hole 321 provided on the lower surface of the second plate, and the slide plate 32 has an opening position where at least a part of the second nozzle hole 321 overlaps with the first nozzle hole 311.
- the second nozzle hole 321 does not overlap the first nozzle hole 311, and can be moved by sliding the lower surface of the upper plate 31 up to the closed position where the first nozzle hole 311 is closed by the sliding plate 32.
- the sliding plate 32 is further provided with a gas blowing hole 322 for blowing an inert gas into the first nozzle hole 311 and the molten steel 4 is accommodated in the ladle 1.
- the pouring step of pouring a part of the molten steel 4 from the ladle 1 through the first nozzle hole 311 and the second nozzle hole 321, and after the pouring step, the sliding plate 32 is moved to the closed position.
- the blowing time which is the time for blowing the inert gas
- the temperature of the molten steel 4 in the ladle 1 can be made uniform by stirring the inert gas, and the solidification of the molten steel 4 in the sliding nozzle device 3 can be suppressed. ..
- the blowing time is a uniform mixing time t m obtained from the equation (2) using the stirring power ⁇ (W/T) of the equation (1). It is 1/4 or more of (s).
- the uniform mixing time can be calculated with a simple and highly accurate calculation model, and the blowing time can be calculated with a simple calculation method.
- the pouring time which is the time for pouring a part of the molten steel 2 from the ladle 2 is 5 seconds or more and 13 seconds or less.
- the sensible heat of the molten steel 4 that is poured out provides the amount of molten steel 4 that is needed to warm the sliding nozzle device 3 and solidifies the molten steel 4 in the sliding nozzle device 3. Can be suppressed. As a result, the occurrence of non-open holes can be further suppressed during re-pouring of the molten steel 4 in the ladle 1 (re-pouring process) without significantly lowering the molten steel yield.
- the molten steel 4 is poured out from the ladle 1 containing the molten steel 4 through the sliding nozzle device 3 provided in the ladle 1.
- a method for controlling the sliding nozzle device 3 according to any one of (1) to (4) above is used to cast the molten steel 4 poured in a re-pouring step.
- the same effects as those of the configurations of (1) to (4) above can be obtained.
- the quality of the cast product and the casting yield can be improved.
- Example 1 performed by the present inventors will be described.
- casting was performed using the method for producing a slab according to the above-described embodiment, and the reopening hole success rate, which is the success rate of opening in the re-pouring process, was investigated.
- the investigation was conducted using a ladle 1 having a filling amount of the molten steel 4 of 190 t and a nozzle diameter of the upper nozzle 2 of 70 mm (nozzle cross-sectional area 3.8 ⁇ 10 ⁇ 3 m 2 ).
- Example 1 in the pouring process, the sliding plate 32 was placed in the open position for 7 seconds, and the filling sand and the molten steel were poured out. Then, the sliding plate 32 was returned to the closed position, and Ar gas was blown into the molten steel 4 in the ladle 1 from the gas blowing hole 322 through the first nozzle hole 311. The flow rate of Ar gas was 30.0 NL/min (7.8 Nm 3 /(min ⁇ m 2 )). On the other hand, as a comparison, in the pouring process, after the sliding plate 32 is opened for 3 seconds to pour the sand and molten steel, the sliding plate 32 is returned to the closed position, and the first nozzle hole 311 is used.
- the sliding plate 32 is left in the open position for 14 seconds to pour out the clogging sand and the molten steel, then the sliding plate 32 is returned to the closed position, and gas is blown through the first nozzle hole 311.
- Ar gas of 30.0 NL/min was blown into the molten steel 4 in the ladle 1 through the hole 322 (Comparative Example 1-3).
- Example 2 prior to the investigation, the uniform mixing time under the conditions of the actual machine was calculated.
- the temperature T 1 of the molten steel 4 was 1827 (K)
- the weight W of the molten steel 4 was 190 t
- the blowing depth (bath depth) h v was 2.29 m
- the atmospheric pressure P a was 0.1 MPa.
- the standard temperature T 0 was 300 K
- the bath diameter d v was 3.375 m.
- the calculation result is shown in FIG. As shown in FIG. 7, it was confirmed that 1/4 of the uniform mixing time was 61.0 s when the Ar gas blowing flow rate of 30.0 NL/min, which is the condition of the actual machine.
- Example 2 From the above results, continuous casting of molten steel was performed with 1/4 of the uniform mixing time set to 61.0 s, and the reopening hole success rate was investigated.
- continuous casting of molten steel 4 was performed under the same conditions as those for calculating 1/4 of the uniform mixing time, and Ar gas was blown at a blowing flow rate of 30.0 NL/min in the blowing process. went.
- continuous casting was performed under the condition of less than 61.0 s, which is less than 1 ⁇ 4 of the uniform mixing time, and the success rate of reopening hole was investigated (Comparative Example 2).
- FIG. 8 shows the results of the reopening hole success rate in Example 2 and Comparative Example 2.
- the re-opening hole ratio was 75.0% (12 successful opening operations/16 casting operations), which was low.
- the re-opening hole ratio was 93.8% (30 successful opening operations/32 casting operations), and the re-opening hole rate was significantly improved. I was able to confirm that
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Abstract
Provided are a method for controlling a sliding nozzle device and a method for manufacturing a slab, with which it is possible to suppress the occurrence of a non-opening hole when molten steel in a ladle is to be re-poured. The method includes a gas blowing step in which, in a state in which molten steel (4) is accommodated in a ladle (1), a sliding plate (32) is set to an open position, and a portion of the molten steel (4) is poured out from the ladle (1) through a first nozzle hole (311) and a second nozzle hole (321), after which the sliding plate (32) is moved to a closed position and an inert gas is blown from a gas blowing hole (322) into the molten steel (4) in the ladle (1) through the first nozzle hole (311), and, after the gas blowing step, a re-pouring step in which the sliding plate (32) is set to the open position, and molten steel (4) is poured out from the ladle (1) through the first nozzle hole (311) and the second nozzle hole (321), wherein the amount of inert gas blown in in the gas blowing step is at least equal to 3.9 Nm3/(min∙m2) and at most equal to 26.0 Nm3/(min∙m2).
Description
本発明は、スライディングノズル装置の制御方法及び鋳片の製造方法に関する。
The present invention relates to a method for controlling a sliding nozzle device and a method for manufacturing a slab.
製鉄所の製鋼工程において用いられる、タンディッシュや取鍋等の溶鋼(溶湯)保持容器には、その底部にスライディングノズル装置を設置しているものがある。取鍋の底部に設けられるスライディングノズル装置は、鋳込み等の溶鋼の注出開始までの間、一般に、ノズル孔内に溶鋼が侵入・凝固して不開孔状態になるのを防ぐための詰砂が充填されている。この詰砂は、高清浄度鋼の鋳造において清浄度低下の原因となるため、詰砂を一度排出してから鋳造を行う操業方法が行われる場合がある。このような操業方法では、取鍋を詰砂排出位置に配した状態で、スライディングノズル装置を開いて、詰砂と溶鋼の一部とを取鍋から注出する。次いで、スライディングノズル装置を閉じて、溶鋼の注出を停止させる。さらに、取鍋を鋳造が行われる鋳造位置に配して、スライディングノズル装置を開くことで、溶鋼を取鍋から注出して、タンディッシュや鋳型へと溶鋼を移注する。そして、移注された溶鋼が凝固することで、所定の断面形状の鋳片が製造される。
Some molten steel (molten metal) holding containers, such as tundish and ladle, used in the steelmaking process of steelworks have a sliding nozzle device installed at the bottom. The sliding nozzle device installed at the bottom of the ladle is generally used to prevent the molten steel from entering and solidifying into the nozzle hole until the start of pouring, etc. Is filled. Since this clogging sand causes a decrease in cleanliness in casting of high cleanliness steel, there is a case where an operating method is performed in which the clogging sand is once discharged and then casting is performed. In such an operating method, the sliding nozzle device is opened in a state where the ladle is placed at the sand discharging position, and the sand and a part of the molten steel are taken out from the ladle. Then, the sliding nozzle device is closed to stop the pouring of the molten steel. Further, the ladle is placed at the casting position where casting is performed, and the sliding nozzle device is opened to take out the molten steel from the ladle and transfer the molten steel to the tundish or the mold. Then, the cast molten steel is solidified to produce a slab having a predetermined cross-sectional shape.
このような鋳片の製造方法では、一度溶鋼を注出した後にスライディングノズル装置を閉めると、詰砂が充填されていない状態で、ノズル孔に溶鋼が残留することとなる。そして、再びスライディングノズル装置を開く場合には、時としてスライディングノズル装置のノズル孔に残った溶鋼の少なくとも一部が凝固するために、スライディングノズル装置を開いても、溶鋼が注出されない(自然開孔しない)ことがある。なお、このように自然開孔しない現象のことを、不開孔ともいう。不開孔が発生した場合には、酸素ガスの吹付けにより強制開孔処理を実施する酸素洗浄が必要となる。しかし、酸素洗浄を行うと、溶鋼中の金属の酸化反応により介在物生成の問題が発生することがある。また、酸素洗浄を行っても開孔せずに、鋳造中止となることもある。
In such a slab manufacturing method, if the sliding nozzle device is closed after pouring the molten steel once, the molten steel will remain in the nozzle holes without being filled with the filling sand. Then, when the sliding nozzle device is opened again, at least a part of the molten steel left in the nozzle hole of the sliding nozzle device is sometimes solidified, so that the molten steel is not poured out even if the sliding nozzle device is opened (natural opening). May not be punctured). It should be noted that such a phenomenon that spontaneous opening does not occur is also called non-opening. When unopened holes are generated, it is necessary to perform oxygen opening cleaning in which forced opening processing is performed by blowing oxygen gas. However, the oxygen cleaning may cause a problem of inclusion formation due to the oxidation reaction of the metal in the molten steel. Further, even if oxygen cleaning is performed, the casting may not be performed and the casting may be stopped.
スライディングノズル装置における不開孔を防止する技術として、例えば、特許文献1には、タンディッシュのスライディングノズル装置での初期開孔において、プレートを間欠動作させ、さらにこのプレートからノズル孔内にガス吹込み(以下、「ガスバブリング」ともいう。)を行うことが開示されている。
As a technique for preventing non-opening holes in a sliding nozzle device, for example, in Patent Document 1, a plate is intermittently operated at the initial opening in a sliding nozzle device of a tundish, and gas is blown from the plate into the nozzle holes. (Hereinafter, also referred to as “gas bubbling”) is disclosed.
ところで、特許文献1に記載の技術は、タンディッシュのスライディングノズル装置での初期開孔における技術であり、取鍋のスライディングノズル装置の再注出時におけるものではない。また、特許文献1では、ガスバブリングの時間が短いことが好ましいとされているが、取鍋においてこの時間でガスバブリングを行っても、不開孔が一定の頻度で不可避的に発生していた。
By the way, the technique described in Patent Document 1 is a technique for initial opening in a tundish sliding nozzle device, and not for re-pouring of a ladle sliding nozzle device. Further, in Patent Document 1, it is preferable that the gas bubbling time is short, but even if the gas bubbling is performed in the ladle at this time, non-open holes are unavoidably generated at a constant frequency. ..
そこで、本発明は、上記の課題に着目してなされたものであり、取鍋での溶鋼の再注出時において不開孔の発生を抑制することができる、スライディングノズル装置の制御方法及び鋳片の製造方法を提供することを目的としている。
Therefore, the present invention has been made by paying attention to the above-mentioned problems, and it is possible to suppress the generation of non-open holes at the time of re-pouring of molten steel in a ladle, a control method for a sliding nozzle device, and a casting method. It is intended to provide a method for manufacturing a piece.
本発明の一態様によれば、溶鋼を収容した取鍋から、上記取鍋に設けられたスライディングノズル装置を介して上記溶鋼を注出する、スライディングノズル装置の制御方法であって、上記スライディングノズル装置は、上記取鍋の底部に固定された上ノズルの下面に設けられ、第1ノズル孔を有する上プレートと、上記上プレートの下面に設けられ、第2ノズル孔を有する摺動プレートとを有し、上記摺動プレートは、上記第2ノズル孔の少なくとも一部が上記第1ノズル孔に重畳する開位置から、上記第2ノズル孔が上記第1ノズル孔に重畳せず、上記摺動プレートによって上記第1ノズル孔が塞がれた閉位置までを、上記上プレートの下面を摺動することで移動可能に構成され、上記閉位置において、上記第1ノズル孔に不活性ガスを吹込む、ガス吹込み孔をさらに有し、上記取鍋に上記溶鋼が収容された状態において、上記摺動プレートを上記開位置にし、上記第1ノズル孔及び上記第2ノズル孔を介して上記取鍋から上記溶鋼の一部を注出する注出工程と、上記注出工程の後、上記摺動プレートを上記閉位置に移動させ、上記第1ノズル孔を介して上記ガス吹込み孔から上記不活性ガスを上記取鍋内の上記溶鋼に吹込む、ガス吹込み工程と、上記ガス吹込み工程の後、上記摺動プレートを上記開位置にし、上記第1ノズル孔及び上記第2ノズル孔を介して上記取鍋から上記溶鋼を注出する、再注出工程と、を備え、上記ガス吹込み工程では、上記不活性ガスを上記上ノズルのノズル孔断面積あたり及び単位時間あたりに吹込む体積である、上記不活性ガスの吹込み流量を3.9Nm3/(min・m2)以上26.0Nm3/(min・m2)以下とする、スライディングノズル装置の制御方法が提供される。
According to one aspect of the present invention, there is provided a sliding nozzle device control method for pouring the molten steel from a ladle containing molten steel through a sliding nozzle device provided in the ladle, wherein the sliding nozzle is provided. The device comprises an upper plate provided on the lower surface of an upper nozzle fixed to the bottom of the ladle and having a first nozzle hole, and a sliding plate provided on the lower surface of the upper plate and having a second nozzle hole. The sliding plate has the second nozzle hole that does not overlap the first nozzle hole from the open position in which at least a part of the second nozzle hole overlaps the first nozzle hole. The plate is configured to be movable up to a closed position where the first nozzle hole is closed by sliding on the lower surface of the upper plate, and an inert gas is blown to the first nozzle hole at the closed position. In the state in which the molten steel is stored in the ladle, the sliding plate is set to the open position, and the gas is introduced through the first nozzle hole and the second nozzle hole. A pouring step of pouring out a part of the molten steel from the pan, and after the pouring step, the sliding plate is moved to the closed position, and the gas is injected from the gas injection hole through the first nozzle hole. A gas blowing step of blowing an inert gas into the molten steel in the ladle, and after the gas blowing step, the sliding plate is set to the open position, and the first nozzle hole and the second nozzle hole are provided. Re-pouring step of pouring the molten steel from the ladle through the ladle, and in the gas blowing step, the inert gas is blown per nozzle hole cross-sectional area of the upper nozzle and per unit time. A method for controlling a sliding nozzle device is provided, in which the flow rate of the above-mentioned inert gas blown in is 3.9 Nm 3 /(min·m 2 ) or more and 26.0 Nm 3 /(min·m 2 ) or less. It
本発明の一態様によれば、溶鋼を収容した取鍋から、上記取鍋に設けられたスライディングノズル装置を介して上記溶鋼を注出し、注出した上記溶鋼を鋳造する、鋳片の製造方法において、上記に記載のスライディングノズル装置の制御方法を用い、上記再注出工程で注出された上記溶鋼を鋳造する、鋳片の製造方法が提供される。
According to one aspect of the present invention, from a ladle containing molten steel, the molten steel is poured out through a sliding nozzle device provided in the ladle, and the poured molten steel is cast. In the above, there is provided a method for manufacturing a slab, which comprises casting the molten steel poured in the re-pouring step by using the method for controlling the sliding nozzle device described above.
本発明の一態様によれば、上記の課題に着目してなされたものであり、取鍋での溶鋼の再注出時において不開孔の発生を抑制することができる、スライディングノズル装置の制御方法及び鋳片の製造方法が提供される。
According to an aspect of the present invention, the above-mentioned problems are taken into consideration, and it is possible to suppress the generation of non-open holes when re-pouring molten steel in a ladle, the control of a sliding nozzle device. Methods and methods of making slabs are provided.
以下の詳細な説明では、本発明の完全な理解を提供するように、本発明の実施形態を例示して多くの特定の細部について説明する。しかしながら、かかる特定の細部の説明がなくても1つ以上の実施態様が実施できることは明らかである。また、図面は、簡潔にするために、周知の構造及び装置が略図で示されている。
In the following detailed description, many specific details are set forth to illustrate embodiments of the invention to provide a thorough understanding of the invention. However, it will be apparent that one or more implementations may be practiced without the details of such specific details. Also, the drawings schematically show known structures and devices for the sake of brevity.
図1~図4を参照して、本発明の一実施形態に係るスライディングノズル装置3の制御方法及び鋳片の製造方法について説明する。本実施形態に係る鋳片の製造方法では、図1及び図2に示す取鍋1に収容された溶鋼4を連続鋳造する鋳造設備である連続鋳造設備における製造方法が対象となる。
取鍋1は、溶鋼4及びスラグ5を収容する溶鋼保持容器である。取鍋1に収容される溶鋼4は、予め所定の成分及び温度に精錬処理されたものである。また、本実施形態においては、溶鋼4の鋼種として、軸受鋼等の高清浄度鋼を対象とすることが好ましい。取鍋1には、上ノズル2と、スライディングノズル装置3とが設けられる。 With reference to FIGS. 1 to 4, a method for controlling the slidingnozzle device 3 and a method for manufacturing a slab according to an embodiment of the present invention will be described. The slab manufacturing method according to the present embodiment is intended for a manufacturing method in a continuous casting facility which is a casting facility for continuously casting the molten steel 4 contained in the ladle 1 shown in FIGS. 1 and 2.
Theladle 1 is a molten steel holding container that contains the molten steel 4 and the slag 5. The molten steel 4 contained in the ladle 1 has been subjected to refining treatment with predetermined components and temperatures in advance. Further, in the present embodiment, it is preferable that the steel type of the molten steel 4 is a high cleanliness steel such as a bearing steel. The ladle 1 is provided with an upper nozzle 2 and a sliding nozzle device 3.
取鍋1は、溶鋼4及びスラグ5を収容する溶鋼保持容器である。取鍋1に収容される溶鋼4は、予め所定の成分及び温度に精錬処理されたものである。また、本実施形態においては、溶鋼4の鋼種として、軸受鋼等の高清浄度鋼を対象とすることが好ましい。取鍋1には、上ノズル2と、スライディングノズル装置3とが設けられる。 With reference to FIGS. 1 to 4, a method for controlling the sliding
The
上ノズル2は、取鍋1の底部に固定される耐火物製のノズルである。
スライディングノズル装置3は、上ノズル2の下面に設けられるノズル機構であり、上プレート31と、摺動プレート32と、下部ノズル33とを有する。
上プレート31は、耐火物製のプレートであり、プレート面内で鉛直方向である上下方向(図1~図4の上下方向)に開孔する円形の第1ノズル孔311を有する。上プレート31は、取鍋1の底部下面に固定されて設けられ、上下方向から視て、上ノズル2の円形の孔と第1ノズル孔311とが、同心状となるように重畳して設けられる。なお、上ノズル2の孔径は、第1ノズル孔311の孔径と略同じ大きさであり、後述する第2ノズル孔321及び下部ノズル33の孔径とも略同じ大きさである。 Theupper nozzle 2 is a refractory nozzle fixed to the bottom of the ladle 1.
Thesliding nozzle device 3 is a nozzle mechanism provided on the lower surface of the upper nozzle 2, and has an upper plate 31, a sliding plate 32, and a lower nozzle 33.
Theupper plate 31 is a plate made of refractory material, and has a circular first nozzle hole 311 that is opened in the vertical direction (vertical direction in FIGS. 1 to 4) which is the vertical direction in the plate surface. The upper plate 31 is fixedly provided on the lower surface of the bottom of the ladle 1, and the circular hole of the upper nozzle 2 and the first nozzle hole 311 are provided so as to be concentric with each other when viewed from above and below. To be The hole diameter of the upper nozzle 2 is substantially the same as the hole diameter of the first nozzle hole 311, and also the hole diameters of the second nozzle hole 321 and the lower nozzle 33, which will be described later.
スライディングノズル装置3は、上ノズル2の下面に設けられるノズル機構であり、上プレート31と、摺動プレート32と、下部ノズル33とを有する。
上プレート31は、耐火物製のプレートであり、プレート面内で鉛直方向である上下方向(図1~図4の上下方向)に開孔する円形の第1ノズル孔311を有する。上プレート31は、取鍋1の底部下面に固定されて設けられ、上下方向から視て、上ノズル2の円形の孔と第1ノズル孔311とが、同心状となるように重畳して設けられる。なお、上ノズル2の孔径は、第1ノズル孔311の孔径と略同じ大きさであり、後述する第2ノズル孔321及び下部ノズル33の孔径とも略同じ大きさである。 The
The
The
摺動プレート32は、耐火物製のプレートであり、プレート面内で上下方向に開孔する円形の第2ノズル孔321と、ガス吹込み孔322とを有する。摺動プレート32は、上プレート31の下面に設けられ、上プレート31の下面を摺動することで水平方向である左右方向(図1~図4の左右方向)に移動可能に構成される。なお、摺動プレート32の摺動動作は、シリンダー等の不図示の摺動機構によって行われる。
The sliding plate 32 is a refractory plate, and has a circular second nozzle hole 321 opened vertically in the plate surface and a gas blowing hole 322. The sliding plate 32 is provided on the lower surface of the upper plate 31, and is configured to be movable in the horizontal direction (the horizontal direction in FIGS. 1 to 4) by sliding on the lower surface of the upper plate 31. The sliding operation of the sliding plate 32 is performed by a sliding mechanism (not shown) such as a cylinder.
ガス吹込み孔322は、第2ノズル孔321から摺動プレート32の摺動方向に所定の距離だけ離間した位置に設けられる。ガス吹込み孔322は、一端が摺動プレート32の上面に開口し、他端が不図示のガス供給装置に接続される。このようなガス吹込み孔322では、ガス供給装置からArガスが供給されることで、ガス吹込み孔322の一端が形成された摺動プレート32の上面から噴射される。なお、ガス吹込み孔322は、溶鋼4が内部に侵入しにくく、Arガスを噴射可能なものであればよく、形状は特に限定されない。例えば、ガス吹込み孔322は、スリット状やポーラス状等の形状であってもよい。
The gas blowing hole 322 is provided at a position separated from the second nozzle hole 321 by a predetermined distance in the sliding direction of the sliding plate 32. One end of the gas blowing hole 322 opens on the upper surface of the sliding plate 32, and the other end is connected to a gas supply device (not shown). In such a gas blowing hole 322, when Ar gas is supplied from the gas supply device, the gas is injected from the upper surface of the sliding plate 32 where one end of the gas blowing hole 322 is formed. The gas injection hole 322 is not particularly limited in shape as long as the molten steel 4 is unlikely to enter the inside and the Ar gas can be injected. For example, the gas blowing hole 322 may have a slit shape, a porous shape, or the like.
さらに、本実施形態では、図1に示すように、上下方向から視てガス吹込み孔322が第1ノズル孔311に重畳し、摺動プレート32によって第1ノズル孔311が塞がされる摺動プレート32の位置を閉位置とする。また、図2に示すように、上下方向から視て第2ノズル孔321の少なくとも一部が第1ノズル孔311に重畳する摺動プレート32の位置を開位置とする。なお、摺動プレート32が閉位置となる状態をスライディングノズル装置3が閉状態であるとし、摺動プレート32が開位置となる状態をスライディングノズル装置3が開状態であるとする。つまり、摺動プレート32は、上プレート31の下面を摺動することで、少なくとも開位置から閉位置までを移動可能に構成される。
Further, in the present embodiment, as shown in FIG. 1, the gas injection hole 322 overlaps with the first nozzle hole 311 when viewed from above and below, and the sliding plate 32 closes the first nozzle hole 311. The position of the moving plate 32 is set to the closed position. Further, as shown in FIG. 2, the position of the sliding plate 32 in which at least a part of the second nozzle hole 321 overlaps with the first nozzle hole 311 when viewed from above and below is defined as an open position. The sliding nozzle device 3 is in the closed state when the sliding plate 32 is in the closed position, and the sliding nozzle device 3 is in the open state when the sliding plate 32 is in the open position. That is, the sliding plate 32 is configured to move at least from the open position to the closed position by sliding on the lower surface of the upper plate 31.
さらに、摺動プレート32は、開位置において摺動方向に移動することで、第2ノズル孔321と第1ノズル孔311とが重畳する領域である重ね代を調整することができる。このように重ね代を調整することで、溶鋼4をスライディングノズル装置3から注出する際の時間当たりの注出量を調整することができる。このとき、摺動プレート32を閉位置から開位置の方へと移動させていき、第2ノズル孔321と第1ノズル孔311とが重畳し始める位置から完全に重畳する(同心状となる)位置までの位置が開位置の範囲となり、この範囲内で注出量の調整が行われる。
Further, the sliding plate 32 can be moved in the sliding direction at the open position to adjust the overlapping margin, which is the region where the second nozzle hole 321 and the first nozzle hole 311 overlap. By adjusting the overlap margin in this way, the amount of spouting per hour when pouring the molten steel 4 from the sliding nozzle device 3 can be adjusted. At this time, the sliding plate 32 is moved from the closed position toward the open position, and the second nozzle hole 321 and the first nozzle hole 311 are completely overlapped (concentric) with each other. The position up to the position becomes the range of the open position, and the amount of dispensing is adjusted within this range.
下部ノズル33は、耐火物製のノズルである。下部ノズル33は、摺動プレート32の下面であり、上下方向から視て、下部ノズル33の円形の孔と第2ノズル孔321とが同心状に重畳する位置に固定されて設けられる。
なお、鋳造が開始される前の、精錬処理が終了した段階においては、スライディングノズル装置3は閉状態となっており、図1に示すように、取鍋1の上ノズル2及び第1ノズル孔311の内部には詰砂6が入った状態となる。詰砂6は、取鍋1の初期の開口時における、開口不良を防止するためのものであり、上ノズル2及び第1ノズル孔311内での溶鋼4の凝固を防止する。 Thelower nozzle 33 is a refractory nozzle. The lower nozzle 33 is a lower surface of the sliding plate 32, and is fixedly provided at a position where the circular hole of the lower nozzle 33 and the second nozzle hole 321 concentrically overlap each other when viewed from the up and down direction.
At the stage where the refining process is completed before the casting is started, the slidingnozzle device 3 is closed, and as shown in FIG. 1, the upper nozzle 2 and the first nozzle hole of the ladle 1 are connected. The inside of 311 is in a state where the filling sand 6 is contained. The plugging sand 6 is for preventing opening failure at the time of initial opening of the ladle 1, and prevents solidification of the molten steel 4 in the upper nozzle 2 and the first nozzle hole 311.
なお、鋳造が開始される前の、精錬処理が終了した段階においては、スライディングノズル装置3は閉状態となっており、図1に示すように、取鍋1の上ノズル2及び第1ノズル孔311の内部には詰砂6が入った状態となる。詰砂6は、取鍋1の初期の開口時における、開口不良を防止するためのものであり、上ノズル2及び第1ノズル孔311内での溶鋼4の凝固を防止する。 The
At the stage where the refining process is completed before the casting is started, the sliding
本実施形態では、鋳造を開始する前に、詰砂6を排出する注出工程を行う。注出工程では、精錬処理が終了した取鍋1を詰砂排出位置に配した状態で、摺動プレート32を開位置に移動させてスライディングノズル装置3を開状態とすることで、詰砂6を全て排出する。この際、詰砂6と共に溶鋼4の一部も注出される。注出工程では、詰砂6が取鍋1から全て排出され、かつ注出された溶鋼の顕熱でスライディングノズル装置3が温められばよい。スライディングノズル装置3を温めることにより、後述する再注出工程においてスライディングノズル装置3内で溶鋼が凝固することを抑えられる。一方、これらの条件を満たす限りであれば、歩留まりの観点から、溶鋼4の注出量はできるだけ少なくすることが好ましい。従って、取鍋1から溶鋼の一部を注出する時間である注出時間は、5秒以上13秒以内とすることが望ましい。注出時間を5秒以上とすると、再注出工程においてスライディングノズル装置3内で溶鋼が凝固しない程度にスライディングノズル装置3が温められる。一方、注出時間が13秒を超えると、注出される溶鋼が多くなり過ぎ、例えば溶鋼に対する鋳片の歩留まりが99%未満になるなど、歩留まりの低下が無視できなくなる。
In this embodiment, a pouring process for discharging the filling sand 6 is performed before starting casting. In the pouring process, with the ladle 1 that has been subjected to the refining process placed in the sand discharging position, the sliding plate 32 is moved to the open position to open the sliding nozzle device 3 to open the sand 6 Is exhausted. At this time, a part of the molten steel 4 is poured out together with the filling sand 6. In the pouring process, all of the filling sand 6 is discharged from the ladle 1, and the sliding nozzle device 3 may be warmed by the sensible heat of the poured molten steel. By warming the sliding nozzle device 3, it is possible to prevent the molten steel from solidifying in the sliding nozzle device 3 in the re-pouring process described later. On the other hand, as long as these conditions are satisfied, from the viewpoint of yield, it is preferable that the amount of molten steel 4 poured out be as small as possible. Therefore, the pouring time, which is the time for pouring a part of the molten steel from the ladle 1, is preferably 5 seconds or more and 13 seconds or less. When the pouring time is 5 seconds or more, the sliding nozzle device 3 is warmed to the extent that molten steel does not solidify in the sliding nozzle device 3 in the re-pouring process. On the other hand, if the pouring time exceeds 13 seconds, the amount of molten steel that is poured out will be too large, and the yield reduction cannot be ignored, for example, the yield of cast slabs relative to molten steel will be less than 99%.
注出工程の後、摺動プレート32を閉位置に移動させてスライディングノズル装置3を閉状態とし、ガス吹込み孔322からArガスを吹込む(ガスバブリングを行う)、ガス吹込み工程が行われる。ガス吹込み工程では、ガス吹込み孔322から取鍋1内の溶鋼4にArガスを所定時間以上吹込む。なお、Arガスを吹込む時間を吹込み時間またはバブリング時間ともいう。ガス吹込み孔322から吹込まれたArガスは、第1ノズル孔311及び上ノズル2を介して取鍋1の内部へと上昇移動し、取鍋1に収容される溶鋼4を攪拌する。
After the pouring process, the sliding plate 32 is moved to the closed position to close the sliding nozzle device 3, and Ar gas is blown from the gas blowing hole 322 (gas bubbling is performed) to perform the gas blowing process. Be seen. In the gas blowing step, Ar gas is blown into the molten steel 4 in the ladle 1 through the gas blowing hole 322 for a predetermined time or longer. The time for blowing the Ar gas is also referred to as the blowing time or the bubbling time. The Ar gas blown from the gas blowing hole 322 moves upward into the ladle 1 through the first nozzle hole 311 and the upper nozzle 2, and stirs the molten steel 4 contained in the ladle 1.
このとき、Arガスの単位時間あたりに吹き込まれる体積である吹込み流量は、上ノズルのノズル孔断面積あたり3.9Nm3/(min・m2)以上26.0Nm3/(min・m2)以下とする。例えば、上ノズル2のノズル径が70mmの場合、上ノズル2のノズル孔断面積は3.8×10-3m2となるので、上ノズル2から吹き込まれる単位時間あたりのArガスの流量は、15NL/min以上100NL/min以下の範囲となる。Arガスの吹込み流量が3.9Nm3/(min・m2)未満の場合、詰砂が排出された後のスライディングノズル装置3内に溶鋼4が流入して凝固しやすくなる。一方、Arガスの吹込み流量が、26.0Nm3/(min・m2)を超える場合、スライディングノズル装置3内に吹き込まれるArガスの流速が速くなるため、Arガスに随伴して生じるスライディングノズル装置3近傍の溶鋼流動が乱流渦を伴うものとなる。この場合、乱流渦に隣接した領域に溶鋼流動のよどみ部が形成され、この部分の溶鋼4が凝固しやすくなる。
At this time, blowing flow rate is the volume blown in per unit of Ar gas time, 3.9 nm per nozzle Anadan area of the upper nozzle 3 / (min · m 2) or more 26.0Nm 3 / (min · m 2 ) Below. For example, when the nozzle diameter of the upper nozzle 2 is 70 mm, the nozzle hole cross-sectional area of the upper nozzle 2 is 3.8×10 −3 m 2 , so the flow rate of Ar gas blown from the upper nozzle 2 per unit time is , 15 NL/min or more and 100 NL/min or less. When the blowing flow rate of Ar gas is less than 3.9 Nm 3 /(min·m 2 ), the molten steel 4 easily flows into the sliding nozzle device 3 after the clogging sand is discharged and solidifies. On the other hand, when the flow rate of the Ar gas blown exceeds 26.0 Nm 3 /(min·m 2 ), the flow velocity of the Ar gas blown into the sliding nozzle device 3 becomes high, so that the sliding that accompanies the Ar gas occurs. The molten steel flow in the vicinity of the nozzle device 3 is accompanied by turbulent vortices. In this case, a stagnation part of the molten steel flow is formed in a region adjacent to the turbulent vortex, and the molten steel 4 in this part easily solidifies.
なお、上述したように、上ノズルのノズル孔断面積あたりのArガスの吹込み流量を好適範囲内とした上で、上ノズルのノズル孔断面積によらず単位時間あたりのArガスの流量を15NL/min以上100NL/min以下とすることが好ましく、15NL/min以上50NL/min以下の範囲とすることがさらに好ましい。Arガスの流量が15NL/min未満の場合、攪拌力が小さすぎるために、吹込み時間を長くしなければならず、生産性の低下や溶鋼温度を補償するために製造コストの増加を招く可能性がある。一方、Arガスの流量が50NL/min超の場合、第1ノズル孔311及び上ノズル2が冷却されることで、第1ノズル孔311及び上ノズル2の温度が低下し、第1ノズル孔311及び上ノズル2内で溶鋼4が凝固して付着してしまう可能性がある。さらに、Arガスの流量が100NL/min超の場合、浴面の搖動が大きくなり、Arガスの吹込みと共に、取鍋1を詰砂排出位置から連続鋳造が行われる鋳造位置まで移動する作業が危険になる。また、スラグの巻き込みなどにより溶鋼4の清浄性を悪化させる懸念もある。なお、以下では、スライディングノズル装置3を開状態にして溶鋼4を注出した後に、一時的に閉状態にして溶鋼4の注出を停止し、さらに開状態にして溶鋼4の注出を再開することを、再注出ともいう。
In addition, as described above, the flow rate of Ar gas per nozzle hole cross-sectional area of the upper nozzle is set within a suitable range, and the flow rate of Ar gas per unit time is set regardless of the nozzle hole cross-sectional area of the upper nozzle. It is preferably 15 NL/min or more and 100 NL/min or less, and more preferably 15 NL/min or more and 50 NL/min or less. When the flow rate of Ar gas is less than 15 NL/min, the stirring force is too small, so that the blowing time must be lengthened, which may lead to a decrease in productivity and an increase in manufacturing cost to compensate the molten steel temperature. There is a nature. On the other hand, when the flow rate of Ar gas is more than 50 NL/min, the temperatures of the first nozzle hole 311 and the upper nozzle 2 are lowered by cooling the first nozzle hole 311 and the upper nozzle 2, and the first nozzle hole 311 is cooled. Also, the molten steel 4 may solidify and adhere in the upper nozzle 2. Further, when the flow rate of Ar gas is more than 100 NL/min, the swing of the bath surface becomes large, and the work of moving the ladle 1 from the packed sand discharge position to the casting position where continuous casting is performed is accompanied with the blowing of Ar gas. Become dangerous. Further, there is a concern that the cleanliness of the molten steel 4 may be deteriorated due to slag inclusion. In the following, after the sliding nozzle device 3 is opened and the molten steel 4 is poured out, the molten nozzle 4 is temporarily closed to stop the pouring of the molten steel 4 and then opened to restart the pouring of the molten steel 4. Doing is also called re-pouring.
ガス吹込み工程において吹込み時間は、Arガスの攪拌による取鍋1内の溶鋼4の均一混合時間tm(s)の1/4以上とする。均一混合時間tmは、Arガスによる攪拌動力ε(W/T)と、取鍋1内の溶鋼4についての浴形状とから求められる計算値である。本実施形態では、一例として、攪拌動力εとして、下記(1)式で求められる値を用いる。なお、(1)式において、εは攪拌動力(W/T)、VgはArガスの吹込み流量(Nm3/min)、T1は溶鋼4の温度(K)、Wは溶鋼4の重量(t)、hvは吹込み深さ(浴深さ)(m)、Paは雰囲気圧力(Pa)、T0は標準状態温度(K)をそれぞれ示す。
Blowing time in the gas blowing step is 1/4 or more uniform mixing time of the molten steel 4 in the ladle 1 by stirring the Ar gas t m (s). Uniformly mixing time t m is an agitation by Ar gas powered ε (W / T), is a calculated value obtained from a bath shape of the molten steel 4 in the ladle 1. In the present embodiment, as an example, the value obtained by the following equation (1) is used as the stirring power ε. In the formula (1), ε is the stirring power (W/T), V g is the flow rate of the Ar gas blown (Nm 3 /min), T 1 is the temperature (K) of the molten steel 4, and W is the molten steel 4. weight (t), h v denotes blowing depth (Yokufuka of) (m), P a is atmospheric pressure (Pa), T 0 is the standard state temperature (K), respectively.
また、本実施形態では、一例として、均一混合時間tmとして、下記(2)式で求められる計算値を用いる。なお、(2)式において、hvは浴深さ(m)、dvは浴直径(m)をそれぞれ示す。(2)式で求められる均一混合時間tmは、図1及び図2に示す取鍋1を有底円筒状の形状として模して算出するものである。つまり、浴深さhvは取鍋1に収容された溶鋼4の鉛直方向の深さを示し、浴直径dvは溶鋼4が収容された領域における円錐台状の取鍋1の内径の平均値を示す。
Further, in the present embodiment, as an example, as a homogeneous mixing time t m, using a calculated value obtained by the following equation (2). Note that in equation (2), h v is Yokufuka of (m), d v denotes the bath diameter (m) to each. (2) homogeneously mixing time t m required by the formula are those calculated by simulating the ladle 1 shown in FIGS. 1 and 2 as a bottomed cylindrical shape. That is, the bath depth h v indicates the vertical depth of the molten steel 4 contained in the ladle 1, and the bath diameter d v is the average of the inner diameters of the truncated cone ladle 1 in the region containing the molten steel 4. Indicates a value.
ここで、一般的には、スライディングノズル装置3を有する取鍋1で再注出を行う際に、スライディングノズル装置3を閉状態として注入を中断した状態でガスバブリングを行う場合、吹込み時間が短い方が溶鋼の凝固量を抑えられ、不開孔が防止できると考えられてきた。例えば、引用文献1には、タンディッシュのスライディングノズル装置において、ガスバブリング時間を長くすると溶鋼凝固につながることが記載されている。
Here, in general, when re-pouring is performed with the ladle 1 having the sliding nozzle device 3, when gas bubbling is performed with the sliding nozzle device 3 closed and the injection is interrupted, the blowing time is It has been considered that the shorter the length, the more the solidification amount of the molten steel can be suppressed and the non-opening can be prevented. For example, Patent Document 1 describes that in a tundish sliding nozzle device, increasing the gas bubbling time leads to solidification of molten steel.
しかし、本発明者らが、取鍋1のスライディングノズル装置3について、吹込み時間と不開孔との関係を調査した結果、吹込み時間が均一混合時間tmの1/4未満と短い場合において不開孔が発生する確率が上昇することが知見された。これは、以下の現象が原因であると推定される。取鍋1でのガスバブリングでは、図3に示すように、吹込み時間が短いと溶鋼4の攪拌が十分に行われず、取鍋1の上部と底部とで溶鋼4に大きな温度勾配が生じる。このため、上ノズル2内や第1ノズル孔311内の温度が低くなり、溶鋼4の凝固が進行する可能性が高くなることから、不開孔が発生する確率が高くなる。一方、図4に示すように、吹込み時間が長いと溶鋼4の攪拌が十分に行われるため、取鍋1の上部と底部で溶鋼4の温度が均一化される。このため、上ノズル2内や第1ノズル孔311内の温度が高くなり、溶鋼4の凝固が抑制されることから、不開孔の発生が抑制される。このような不開孔の発生抑制の効果を得るためには、吹込み時間を均一混合時間tm以上とすることが重要となる。一方、吹込み時間は、過剰に長すぎると溶鋼4の全体の温度が低下するため好ましくない。このため、吹込み時間の上限は、均一混合時間の2/5以下とすることが好ましい。なお、本実施形態では、ガス吹込み工程にて(1)式及び(2)式を用いて均一混合時間tmを算出することを必須とするものではなく、Arガスの吹込みをする際に結果として吹込み時間が均一混時間tmの1/4以上となっていればよい。
However, when the present inventors, the sliding nozzle device 3 of the ladle 1, the results of investigating the relationship between blowing time and not opening, less than 1/4 of the blowing time is uniform mixing time t m and shorter It was found that the probability of denudation increases in. It is estimated that this is due to the following phenomenon. In gas bubbling in the ladle 1, as shown in FIG. 3, when the blowing time is short, the molten steel 4 is not sufficiently stirred, and a large temperature gradient is generated in the molten steel 4 between the top and bottom of the ladle 1. For this reason, the temperature inside the upper nozzle 2 and the inside of the first nozzle hole 311 decreases, and the possibility that the solidification of the molten steel 4 progresses increases, so that the probability that a non-open hole will occur increases. On the other hand, as shown in FIG. 4, when the blowing time is long, the molten steel 4 is sufficiently stirred, so that the temperature of the molten steel 4 is made uniform at the top and bottom of the ladle 1. For this reason, the temperature inside the upper nozzle 2 and the inside of the first nozzle hole 311 increases, and the solidification of the molten steel 4 is suppressed, so that the generation of non-open holes is suppressed. In order to obtain such an effect, not aperture the generation suppression, it is important to the blowing time homogeneously mixing time t m or more. On the other hand, if the blowing time is excessively long, the temperature of the entire molten steel 4 decreases, which is not preferable. Therefore, the upper limit of the blowing time is preferably set to 2/5 or less of the uniform mixing time. In the present embodiment, and not as an essential calculating a uniform mixing time t m by using a gas in blow step (1) and (2), when the blowing of Ar gas blowing time it is sufficient that 1/4 or more uniform混時between t m as results.
また、ガス吹込み工程では、Arガスの吹込みと共に、取鍋1を詰砂排出位置から連続鋳造が行われる鋳造位置まで移動する。
ガス吹込み工程の後、取鍋1から溶鋼4を注出する、再注出工程を行う。再注出工程では、取鍋1を鋳造位置とした状態で、摺動プレート32を開位置に移動させてスライディングノズル装置3を開状態とすることで、上ノズル2、第1ノズル孔311、第2ノズル孔321及び下部ノズル33を介して取鍋1から溶鋼4を注出する。そして、注出された溶鋼4を連続鋳造する。注出された溶鋼4の連続鋳造方法は、一般的な方法を用いることができる。例えば、下部ノズル33にロングノズルを接続して、このロングノズルを介して注出された溶鋼4をタンディッシュに移注し、さらに、タンディッシュから鋳型(モールド)へと注入することで鋳造が行われる。以上のように、本実施形態では、スライディングノズル装置3について、上述の注出工程、吹込み工程及び再注出工程で説明した制御を行う。そして、この制御方法にてスライディングノズル装置3を制御して連続鋳造を行うことで、鋳型に応じた所定の断面形状の鋳片が製造される。 In addition, in the gas blowing process, theladle 1 is moved from the packed sand discharging position to the casting position where continuous casting is performed together with the blowing of Ar gas.
After the gas blowing step, a re-pouring step of pouring themolten steel 4 from the ladle 1 is performed. In the re-pouring process, with the ladle 1 in the casting position, the sliding plate 32 is moved to the open position to open the sliding nozzle device 3, thereby opening the upper nozzle 2, the first nozzle hole 311, and the like. Molten steel 4 is poured from the ladle 1 through the second nozzle hole 321 and the lower nozzle 33. Then, the poured molten steel 4 is continuously cast. As a continuous casting method of the poured molten steel 4, a general method can be used. For example, a long nozzle is connected to the lower nozzle 33, the molten steel 4 poured out through this long nozzle is transferred to a tundish, and further poured from the tundish into a mold (mold), whereby casting is performed. Done. As described above, in the present embodiment, the sliding nozzle device 3 is subjected to the control described in the above-described pouring step, blowing step, and re-pouring step. Then, by controlling the sliding nozzle device 3 by this control method to perform continuous casting, a slab having a predetermined cross-sectional shape according to the mold is manufactured.
ガス吹込み工程の後、取鍋1から溶鋼4を注出する、再注出工程を行う。再注出工程では、取鍋1を鋳造位置とした状態で、摺動プレート32を開位置に移動させてスライディングノズル装置3を開状態とすることで、上ノズル2、第1ノズル孔311、第2ノズル孔321及び下部ノズル33を介して取鍋1から溶鋼4を注出する。そして、注出された溶鋼4を連続鋳造する。注出された溶鋼4の連続鋳造方法は、一般的な方法を用いることができる。例えば、下部ノズル33にロングノズルを接続して、このロングノズルを介して注出された溶鋼4をタンディッシュに移注し、さらに、タンディッシュから鋳型(モールド)へと注入することで鋳造が行われる。以上のように、本実施形態では、スライディングノズル装置3について、上述の注出工程、吹込み工程及び再注出工程で説明した制御を行う。そして、この制御方法にてスライディングノズル装置3を制御して連続鋳造を行うことで、鋳型に応じた所定の断面形状の鋳片が製造される。 In addition, in the gas blowing process, the
After the gas blowing step, a re-pouring step of pouring the
<変形例>
以上で、特定の実施形態を参照して本発明を説明したが、これら説明によって発明を限定することを意図するものではない。本発明の説明を参照することにより、当業者には、開示された実施形態とともに種々の変形例を含む本発明の別の実施形態も明らかである。従って、特許請求の範囲に記載された発明の実施形態には、本明細書に記載したこれらの変形例を単独または組み合わせて含む実施形態も網羅すると解すべきである。 <Modification>
Although the present invention has been described above with reference to particular embodiments, it is not intended to limit the invention by these descriptions. Other embodiments of the invention, including various modifications to the disclosed embodiments, will be apparent to persons skilled in the art upon reference to the description of the invention. Therefore, it should be understood that the embodiments of the invention described in the claims include the embodiments including these modifications described in this specification alone or in combination.
以上で、特定の実施形態を参照して本発明を説明したが、これら説明によって発明を限定することを意図するものではない。本発明の説明を参照することにより、当業者には、開示された実施形態とともに種々の変形例を含む本発明の別の実施形態も明らかである。従って、特許請求の範囲に記載された発明の実施形態には、本明細書に記載したこれらの変形例を単独または組み合わせて含む実施形態も網羅すると解すべきである。 <Modification>
Although the present invention has been described above with reference to particular embodiments, it is not intended to limit the invention by these descriptions. Other embodiments of the invention, including various modifications to the disclosed embodiments, will be apparent to persons skilled in the art upon reference to the description of the invention. Therefore, it should be understood that the embodiments of the invention described in the claims include the embodiments including these modifications described in this specification alone or in combination.
例えば、上記実施形態では、スライディングノズル装置3が上プレート31及び摺動プレート32の2枚のプレートを有する2層式のものであるとしたが、本発明はかかる例に限定されない。例えば、スライディングノズル装置3を図5及び図6に示す3層式のものにしてもよい。図5及び図6に示すスライディングノズル装置3は、上プレート31と、摺動プレート32と、下プレート34と、下部ノズル33とを有する。上プレート31、摺動プレート32及び下部ノズル33は、上記実施形態のものと同様である。下プレート34は、耐火物製のプレートであり、プレート面内で上下方向に開孔する円形の第3ノズル孔341を有する。下プレート34は、摺動プレート32の下面に、上プレート31に対して固定されて設けられ、上下方向から視て第1ノズル孔311と第3ノズル孔341とが、同心状となるように重畳して設けられる。つまり、図5及び図6に示すスライディングノズル装置3において、摺動プレート32は、上プレート31と下プレート34とに挟まれて設けられ、上プレート31と下プレート34との間を摺動する。なお、下部ノズル33は、下プレート34の下面であり、上下方向から視て、下部ノズル33の円形の孔と第3ノズル孔341とが同心状に重畳する位置に固定されて設けられる。また、図5に示すように、第1ノズル孔311と第3ノズル孔341との間にガス吹込み孔322が配した状態が、スライディングノズル装置3が閉状態となるものであり、図6に示すように、第1ノズル孔311と第3ノズル孔341との間に第2ノズル孔321が配した状態が、スライディングノズル装置3が開状態となるものである。さらに、スライディングノズル装置3は、上記の変形例だけでなく、取鍋1に設けられるスライディングノズル装置3であり、閉状態においてガスバブリングが可能なものであれば、特に限定されない。
For example, in the above embodiment, the sliding nozzle device 3 is a two-layer type having two plates, the upper plate 31 and the sliding plate 32, but the present invention is not limited to this example. For example, the sliding nozzle device 3 may be of the three-layer type shown in FIGS. 5 and 6. The sliding nozzle device 3 shown in FIGS. 5 and 6 has an upper plate 31, a sliding plate 32, a lower plate 34, and a lower nozzle 33. The upper plate 31, the sliding plate 32, and the lower nozzle 33 are the same as those in the above embodiment. The lower plate 34 is a refractory plate, and has a circular third nozzle hole 341 that is vertically opened in the plate surface. The lower plate 34 is provided on the lower surface of the sliding plate 32 so as to be fixed to the upper plate 31 so that the first nozzle hole 311 and the third nozzle hole 341 are concentric with each other when viewed from above and below. It is provided so as to overlap. That is, in the sliding nozzle device 3 shown in FIGS. 5 and 6, the sliding plate 32 is provided so as to be sandwiched between the upper plate 31 and the lower plate 34, and slides between the upper plate 31 and the lower plate 34. .. The lower nozzle 33 is the lower surface of the lower plate 34, and is fixedly provided at a position where the circular hole of the lower nozzle 33 and the third nozzle hole 341 are concentrically overlapped with each other when viewed from above and below. Further, as shown in FIG. 5, the sliding nozzle device 3 is in a closed state when the gas blowing hole 322 is arranged between the first nozzle hole 311 and the third nozzle hole 341. As shown in, the state in which the second nozzle holes 321 are arranged between the first nozzle holes 311 and the third nozzle holes 341 is the state in which the sliding nozzle device 3 is in the open state. Further, the sliding nozzle device 3 is not limited to the above-described modified example, and is not particularly limited as long as it is the sliding nozzle device 3 provided in the ladle 1 and is capable of gas bubbling in the closed state.
また、上記実施形態では、連続鋳造設備において再注出を行う際について説明をしたが、本発明はかかる例に限定されない。例えば、鋳片の製造設備は、連続鋳造設備ではなく、インゴットを鋳造する造塊鋳造設備であってもよい。また、鋳片の製造設備の違いに関わらず、再注出の動作として、注出工程において詰砂6を排出することを目的とした注出ではなく、通常の鋳造を目的として溶鋼4の注出が行われてもよい。例えば、造塊鋳造設備においては、複数の注入管に溶鋼4を移注することがあるため、溶鋼4を移注する注入管を変更する際に、再注出の動作が行われることがある。また、連続鋳造設備においても、設備等のトラブルから一時的に鋳造を中断することがあり、この場合に再注出の動作が行われることがある。これらの場合においても、上記実施形態と同様に、再注出をする際に、吹込み工程を行うことで、再注出工程での不開孔の発生を抑制することができる。さらに、このような鋳造の中断時における不開孔の発生を抑制する目的の場合には、溶鋼4の鋼種は高清浄度鋼に限定されず、どのような鋼種の溶鋼4においても好適に用いることができる。
In addition, in the above embodiment, the case of performing re-pouring in the continuous casting facility has been described, but the present invention is not limited to such an example. For example, the slab production facility may be an ingot casting facility for casting an ingot instead of the continuous casting facility. Further, regardless of the difference in the slab production equipment, the re-pouring operation is not the pouring for the purpose of discharging the plugged sand 6 in the pouring process, but the pouring of the molten steel 4 for the purpose of normal casting. It may be served. For example, in an ingot casting facility, molten steel 4 may be transferred to a plurality of injection pipes, and therefore a re-pouring operation may be performed when changing the injection pipe to which molten steel 4 is transferred. .. Also in continuous casting equipment, casting may be temporarily interrupted due to equipment troubles, and in this case re-pouring operation may be performed. Also in these cases, similarly to the above-described embodiment, by performing the blowing step when re-pouring, it is possible to suppress the occurrence of non-open holes in the re-pouring step. Further, for the purpose of suppressing the generation of non-open holes when the casting is interrupted, the steel type of the molten steel 4 is not limited to the high cleanliness steel, and is suitably used in the molten steel 4 of any steel type. be able to.
さらに、上記実施形態では、均一混合時間tmとして、(1)式及び(2)式から算出される時間を用いるとしたが、本発明はかかる例に限定されない。均一混合時間tmは、溶鋼4の成分濃度が最終値のまわりのある範囲内に漸近するのに要する時間であり、精錬分野において一般的に定義されるものでよい。このため、(1)式及び(2)式以外の算出式から算出される時間が、均一混合時間tmとして用いられてもよい。例えば、(2)式の代わりに、実際の取鍋1の形状により近いモデルを対象とした均一混合時間の算出式が用いられてもよい。
さらに、上記実施形態では、吹込み工程において吹込むガスをArガスとしたが、本発明はかかる例に限定されない。吹込み工程において吹込まれるガスは、不活性ガスであればよく、Arガス以外のガスが用いられてもよい。 Furthermore, in the above embodiment, as a homogeneous mixing time t m, (1) and equation (2) was used time calculated from the equation, the present invention is not limited to such an example. Uniformly mixing time t m is the time required for the component concentration of themolten steel 4 is asymptotic to within a certain range around the final value, it may be those generally defined in refining art. Therefore, (1) and (2) time calculated from the calculation formula other than the formula, may be used as a uniform mixing time t m. For example, instead of the equation (2), a uniform mixing time calculation equation for a model closer to the actual shape of the ladle 1 may be used.
Furthermore, in the above embodiment, the gas blown in the blowing step was Ar gas, but the present invention is not limited to this example. The gas blown in the blowing step may be an inert gas, and a gas other than Ar gas may be used.
さらに、上記実施形態では、吹込み工程において吹込むガスをArガスとしたが、本発明はかかる例に限定されない。吹込み工程において吹込まれるガスは、不活性ガスであればよく、Arガス以外のガスが用いられてもよい。 Furthermore, in the above embodiment, as a homogeneous mixing time t m, (1) and equation (2) was used time calculated from the equation, the present invention is not limited to such an example. Uniformly mixing time t m is the time required for the component concentration of the
Furthermore, in the above embodiment, the gas blown in the blowing step was Ar gas, but the present invention is not limited to this example. The gas blown in the blowing step may be an inert gas, and a gas other than Ar gas may be used.
<実施形態の効果>
(1)本発明の一態様に係るスライディングノズル装置3の制御方法は、溶鋼4を収容した取鍋1から、取鍋1に設けられたスライディングノズル装置3を介して溶鋼4を注出する、スライディングノズル装置3の制御方法であって、スライディングノズル装置3は、取鍋1の底部に固定された上ノズル2の下面に設けられ、第1ノズル孔311を有する上プレート31と、上プレート31の下面に設けられ、第2ノズル孔321を有する摺動プレート32とを有し、摺動プレート32は、第2ノズル孔321の少なくとも一部が第1ノズル孔311に重畳する開位置から、第2ノズル孔321が第1ノズル孔311に重畳せず、摺動プレート32によって第1ノズル孔311が塞がれた閉位置までを、上プレート31の下面を摺動することで移動可能に構成され、閉位置において、第1ノズル孔311に不活性ガスを吹込む、ガス吹込み孔322をさらに有し、取鍋1に溶鋼4が収容された状態において、摺動プレート32を開位置にし、第1ノズル孔311及び第2ノズル孔321を介して取鍋1から溶鋼4の一部を注出する注出工程と、注出工程の後、摺動プレート32を閉位置に移動させ、第1ノズル孔311を介してガス吹込み孔322から不活性ガスを取鍋1内の溶鋼4に吹込む、ガス吹込み工程と、ガス吹込み工程の後、摺動プレート32を開位置にし、第1ノズル孔311及び第2ノズル孔321を介して取鍋1から溶鋼4を注出する、再注出工程と、を備え、ガス吹込み工程では、不活性ガスを上ノズル2のノズル孔断面積あたり及び単位時間あたりに吹込む体積である、前記不活性ガスの吹込み流量を3.9Nm3/(min・m2)以上26.0Nm3/(min・m2)以下とする。
上記(1)の構成によれば、不活性ガスの吹込みによってスライディングノズル装置3内への溶鋼4の流入およびスライディングノズル装置3内近傍の溶鋼流動のよどみを抑制することができ、スライディングノズル装置3内での溶鋼4の凝固を抑制することができる。これにより、取鍋1での溶鋼4の再注出時(再注出工程)において、不開孔の発生を抑制することができる。 <Effects of the embodiment>
(1) In the method for controlling the slidingnozzle device 3 according to one aspect of the present invention, the molten steel 4 is poured from the ladle 1 containing the molten steel 4 through the sliding nozzle device 3 provided in the ladle 1. A method for controlling the sliding nozzle device 3, wherein the sliding nozzle device 3 is provided on the lower surface of the upper nozzle 2 fixed to the bottom of the ladle 1 and has an upper plate 31 having a first nozzle hole 311 and an upper plate 31. And a slide plate 32 having a second nozzle hole 321 provided on the lower surface of the second plate, and the slide plate 32 has an opening position where at least a part of the second nozzle hole 321 overlaps with the first nozzle hole 311. The second nozzle hole 321 does not overlap the first nozzle hole 311, and can be moved by sliding the lower surface of the upper plate 31 up to the closed position where the first nozzle hole 311 is closed by the sliding plate 32. In the closed position, the sliding plate 32 is further provided with a gas blowing hole 322 for blowing an inert gas into the first nozzle hole 311 and the molten steel 4 is accommodated in the ladle 1. The pouring step of pouring a part of the molten steel 4 from the ladle 1 through the first nozzle hole 311 and the second nozzle hole 321, and after the pouring step, the sliding plate 32 is moved to the closed position. , Injecting an inert gas from the gas injection hole 322 into the molten steel 4 in the ladle 1 through the first nozzle hole 311. After the gas injection step, the sliding plate 32 is in the open position. And a re-pouring step of pouring the molten steel 4 from the ladle 1 via the first nozzle hole 311 and the second nozzle hole 321. In the gas blowing step, the inert gas is supplied to the upper nozzle 2. The flow rate of the inert gas blown, which is the volume blown per nozzle hole cross-sectional area and per unit time, is 3.9 Nm 3 /(min·m 2 ) or more and 26.0 Nm 3 /(min·m 2 ) or less. To do.
According to the above configuration (1), it is possible to suppress the inflow of themolten steel 4 into the sliding nozzle device 3 and the stagnation of the molten steel flow in the vicinity of the sliding nozzle device 3 due to the blowing of the inert gas. It is possible to suppress the solidification of the molten steel 4 within 3. As a result, when the molten steel 4 is re-poured in the ladle 1 (re-pouring process), it is possible to suppress the generation of non-open holes.
(1)本発明の一態様に係るスライディングノズル装置3の制御方法は、溶鋼4を収容した取鍋1から、取鍋1に設けられたスライディングノズル装置3を介して溶鋼4を注出する、スライディングノズル装置3の制御方法であって、スライディングノズル装置3は、取鍋1の底部に固定された上ノズル2の下面に設けられ、第1ノズル孔311を有する上プレート31と、上プレート31の下面に設けられ、第2ノズル孔321を有する摺動プレート32とを有し、摺動プレート32は、第2ノズル孔321の少なくとも一部が第1ノズル孔311に重畳する開位置から、第2ノズル孔321が第1ノズル孔311に重畳せず、摺動プレート32によって第1ノズル孔311が塞がれた閉位置までを、上プレート31の下面を摺動することで移動可能に構成され、閉位置において、第1ノズル孔311に不活性ガスを吹込む、ガス吹込み孔322をさらに有し、取鍋1に溶鋼4が収容された状態において、摺動プレート32を開位置にし、第1ノズル孔311及び第2ノズル孔321を介して取鍋1から溶鋼4の一部を注出する注出工程と、注出工程の後、摺動プレート32を閉位置に移動させ、第1ノズル孔311を介してガス吹込み孔322から不活性ガスを取鍋1内の溶鋼4に吹込む、ガス吹込み工程と、ガス吹込み工程の後、摺動プレート32を開位置にし、第1ノズル孔311及び第2ノズル孔321を介して取鍋1から溶鋼4を注出する、再注出工程と、を備え、ガス吹込み工程では、不活性ガスを上ノズル2のノズル孔断面積あたり及び単位時間あたりに吹込む体積である、前記不活性ガスの吹込み流量を3.9Nm3/(min・m2)以上26.0Nm3/(min・m2)以下とする。
上記(1)の構成によれば、不活性ガスの吹込みによってスライディングノズル装置3内への溶鋼4の流入およびスライディングノズル装置3内近傍の溶鋼流動のよどみを抑制することができ、スライディングノズル装置3内での溶鋼4の凝固を抑制することができる。これにより、取鍋1での溶鋼4の再注出時(再注出工程)において、不開孔の発生を抑制することができる。 <Effects of the embodiment>
(1) In the method for controlling the sliding
According to the above configuration (1), it is possible to suppress the inflow of the
(2)上記(1)の構成において、ガス吹込み工程では、不可性ガスを吹込む時間である吹込み時間を、不活性ガスの攪拌による取鍋1内の溶鋼4の均一混合時間の1/4以上とする。
上記(2)の構成によれば、不活性ガスの攪拌によって取鍋1内の溶鋼4の温度を均一にすることができ、スライディングノズル装置3内での溶鋼4の凝固を抑制することができる。これにより、取鍋1での溶鋼4の再注出時(再注出工程)において、不開孔の発生をさらに抑制することができる。 (2) In the configuration of (1) above, in the gas blowing step, the blowing time, which is the time for blowing the inert gas, is set to 1 of the uniform mixing time of themolten steel 4 in the ladle 1 by stirring the inert gas. /4 or more.
According to the above configuration (2), the temperature of themolten steel 4 in the ladle 1 can be made uniform by stirring the inert gas, and the solidification of the molten steel 4 in the sliding nozzle device 3 can be suppressed. .. As a result, it is possible to further suppress the occurrence of non-open holes when the molten steel 4 is re-poured in the ladle 1 (re-pouring process).
上記(2)の構成によれば、不活性ガスの攪拌によって取鍋1内の溶鋼4の温度を均一にすることができ、スライディングノズル装置3内での溶鋼4の凝固を抑制することができる。これにより、取鍋1での溶鋼4の再注出時(再注出工程)において、不開孔の発生をさらに抑制することができる。 (2) In the configuration of (1) above, in the gas blowing step, the blowing time, which is the time for blowing the inert gas, is set to 1 of the uniform mixing time of the
According to the above configuration (2), the temperature of the
(3)上記(2)の構成において、ガス吹込み工程では、吹込み時間を、(1)式の攪拌動力ε(W/T)を用いた(2)式から求められる均一混合時間tm(s)の1/4以上とする。
上記(3)の構成によれば、簡易かつ精度の高い計算モデルで均一混合時間を算出することができ、簡易な計算方法で吹込み時間を算出することができる。 (3) In the configuration of the above (2), in the gas blowing step, the blowing time is a uniform mixing time t m obtained from the equation (2) using the stirring power ε(W/T) of the equation (1). It is 1/4 or more of (s).
With configuration (3) above, the uniform mixing time can be calculated with a simple and highly accurate calculation model, and the blowing time can be calculated with a simple calculation method.
上記(3)の構成によれば、簡易かつ精度の高い計算モデルで均一混合時間を算出することができ、簡易な計算方法で吹込み時間を算出することができる。 (3) In the configuration of the above (2), in the gas blowing step, the blowing time is a uniform mixing time t m obtained from the equation (2) using the stirring power ε(W/T) of the equation (1). It is 1/4 or more of (s).
With configuration (3) above, the uniform mixing time can be calculated with a simple and highly accurate calculation model, and the blowing time can be calculated with a simple calculation method.
(4)上記(1)~(3)のいずれかの構成において、注出工程では、取鍋2から溶鋼2の一部を注出する時間である注出時間を、5秒以上13秒以下とする。
上記(4)の構成によれば、注出される溶鋼4の顕熱によってスライディングノズル装置3を温めるに必要な溶鋼4の注出量が与えられ、スライディングノズル装置3内での溶鋼4の凝固を抑制することができる。これにより、溶鋼歩留まりの大幅な低下を伴わず、取鍋1での溶鋼4の再注出時(再注出工程)において、不開孔の発生をさらに抑制することができる。 (4) In any one of the above (1) to (3), in the pouring step, the pouring time, which is the time for pouring a part of themolten steel 2 from the ladle 2, is 5 seconds or more and 13 seconds or less. And
According to the above configuration (4), the sensible heat of themolten steel 4 that is poured out provides the amount of molten steel 4 that is needed to warm the sliding nozzle device 3 and solidifies the molten steel 4 in the sliding nozzle device 3. Can be suppressed. As a result, the occurrence of non-open holes can be further suppressed during re-pouring of the molten steel 4 in the ladle 1 (re-pouring process) without significantly lowering the molten steel yield.
上記(4)の構成によれば、注出される溶鋼4の顕熱によってスライディングノズル装置3を温めるに必要な溶鋼4の注出量が与えられ、スライディングノズル装置3内での溶鋼4の凝固を抑制することができる。これにより、溶鋼歩留まりの大幅な低下を伴わず、取鍋1での溶鋼4の再注出時(再注出工程)において、不開孔の発生をさらに抑制することができる。 (4) In any one of the above (1) to (3), in the pouring step, the pouring time, which is the time for pouring a part of the
According to the above configuration (4), the sensible heat of the
(5)本発明の一態様に係る鋳片の製造方法は、溶鋼4を収容した取鍋1から、取鍋1に設けられたスライディングノズル装置3を介して溶鋼4を注出し、注出した溶鋼4を鋳造する、鋳片の製造方法において、上記(1)~(4)のいずれかに記載のスライディングノズル装置3の制御方法を用い、再注出工程で注出された溶鋼4を鋳造する。
上記(5)の構成によれば、上記(1)~(4)の構成と同様な効果を得ることができる。特に、上記実施形態の注出工程において詰砂6の注出を必要とする鋼種である、高清浄度鋼を鋳造する場合には、鋳造製品の品質及び鋳造歩留りを向上することができる。 (5) In the method for manufacturing a cast product according to one aspect of the present invention, themolten steel 4 is poured out from the ladle 1 containing the molten steel 4 through the sliding nozzle device 3 provided in the ladle 1. In a method for manufacturing a slab for casting molten steel 4, a method for controlling the sliding nozzle device 3 according to any one of (1) to (4) above is used to cast the molten steel 4 poured in a re-pouring step. To do.
According to the configuration of (5) above, the same effects as those of the configurations of (1) to (4) above can be obtained. In particular, when casting high cleanliness steel, which is a steel type that requires pouring of the sand filling 6 in the pouring process of the above-described embodiment, the quality of the cast product and the casting yield can be improved.
上記(5)の構成によれば、上記(1)~(4)の構成と同様な効果を得ることができる。特に、上記実施形態の注出工程において詰砂6の注出を必要とする鋼種である、高清浄度鋼を鋳造する場合には、鋳造製品の品質及び鋳造歩留りを向上することができる。 (5) In the method for manufacturing a cast product according to one aspect of the present invention, the
According to the configuration of (5) above, the same effects as those of the configurations of (1) to (4) above can be obtained. In particular, when casting high cleanliness steel, which is a steel type that requires pouring of the sand filling 6 in the pouring process of the above-described embodiment, the quality of the cast product and the casting yield can be improved.
次に、本発明者らが行った実施例1について説明する。実施例では、上記実施形態に係る鋳片の製造方法を用いて鋳造を行い、再注出工程における開孔の成功率である、再開孔成功率を調査した。
実施例1では、溶鋼4の充填量が190tで、上ノズル2のノズル径が70mm(ノズル断面積3.8×10-3m2)の取鍋1を用いて調査を行なった。 Next, Example 1 performed by the present inventors will be described. In the example, casting was performed using the method for producing a slab according to the above-described embodiment, and the reopening hole success rate, which is the success rate of opening in the re-pouring process, was investigated.
In Example 1, the investigation was conducted using aladle 1 having a filling amount of the molten steel 4 of 190 t and a nozzle diameter of the upper nozzle 2 of 70 mm (nozzle cross-sectional area 3.8×10 −3 m 2 ).
実施例1では、溶鋼4の充填量が190tで、上ノズル2のノズル径が70mm(ノズル断面積3.8×10-3m2)の取鍋1を用いて調査を行なった。 Next, Example 1 performed by the present inventors will be described. In the example, casting was performed using the method for producing a slab according to the above-described embodiment, and the reopening hole success rate, which is the success rate of opening in the re-pouring process, was investigated.
In Example 1, the investigation was conducted using a
実施例1では、注出工程において、摺動プレート32を7秒間開位置にし、詰砂及び溶鋼を注出した。その後、摺動プレート32を閉位置に戻すとともに、第1ノズル孔311を介してガス吹込み孔322からArガスを取鍋1内の溶鋼4に吹込んだ。Arガスの流量は30.0NL/min(7.8Nm3/(min・m2))とした。
一方、比較として、注出工程において、摺動プレート32を3秒間開位置にして、詰砂及び溶鋼を注出した後、摺動プレート32を閉位置に戻し、第1ノズル孔311を介してガス吹込み孔322から30.0NL/minのArガスを取鍋1内の溶鋼4に吹込んだ場合について調査を行った(比較例1-1)。また、摺動プレート32を7秒間開位置にして、詰砂及び溶鋼を注出した後、摺動プレート32を閉位置に戻し、第1ノズル孔311を介してガス吹込み孔322から10.0NL/minのArガスを取鍋1内の溶鋼4に吹込んだ場合についても調査を行った(比較例1-2)。さらに、注出工程において、摺動プレート32を14秒間開位置にして、詰砂及び溶鋼を注出した後、摺動プレート32を閉位置に戻し、第1ノズル孔311を介してガス吹込み孔322から30.0NL/minのArガスを取鍋1内の溶鋼4に吹込んだ場合についても調査を行った(比較例1-3)。 In Example 1, in the pouring process, the slidingplate 32 was placed in the open position for 7 seconds, and the filling sand and the molten steel were poured out. Then, the sliding plate 32 was returned to the closed position, and Ar gas was blown into the molten steel 4 in the ladle 1 from the gas blowing hole 322 through the first nozzle hole 311. The flow rate of Ar gas was 30.0 NL/min (7.8 Nm 3 /(min·m 2 )).
On the other hand, as a comparison, in the pouring process, after the slidingplate 32 is opened for 3 seconds to pour the sand and molten steel, the sliding plate 32 is returned to the closed position, and the first nozzle hole 311 is used. A case was investigated in which Ar gas of 30.0 NL/min was blown into the molten steel 4 in the ladle 1 from the gas blowing hole 322 (Comparative Example 1-1). In addition, the sliding plate 32 is set to the open position for 7 seconds, the clogging sand and the molten steel are poured out, the sliding plate 32 is returned to the closed position, and the gas blowing holes 322 to 10. The investigation was also conducted when 0 NL/min of Ar gas was blown into the molten steel 4 in the ladle 1 (Comparative Example 1-2). Further, in the pouring process, the sliding plate 32 is left in the open position for 14 seconds to pour out the clogging sand and the molten steel, then the sliding plate 32 is returned to the closed position, and gas is blown through the first nozzle hole 311. An investigation was also conducted in the case where Ar gas of 30.0 NL/min was blown into the molten steel 4 in the ladle 1 through the hole 322 (Comparative Example 1-3).
一方、比較として、注出工程において、摺動プレート32を3秒間開位置にして、詰砂及び溶鋼を注出した後、摺動プレート32を閉位置に戻し、第1ノズル孔311を介してガス吹込み孔322から30.0NL/minのArガスを取鍋1内の溶鋼4に吹込んだ場合について調査を行った(比較例1-1)。また、摺動プレート32を7秒間開位置にして、詰砂及び溶鋼を注出した後、摺動プレート32を閉位置に戻し、第1ノズル孔311を介してガス吹込み孔322から10.0NL/minのArガスを取鍋1内の溶鋼4に吹込んだ場合についても調査を行った(比較例1-2)。さらに、注出工程において、摺動プレート32を14秒間開位置にして、詰砂及び溶鋼を注出した後、摺動プレート32を閉位置に戻し、第1ノズル孔311を介してガス吹込み孔322から30.0NL/minのArガスを取鍋1内の溶鋼4に吹込んだ場合についても調査を行った(比較例1-3)。 In Example 1, in the pouring process, the sliding
On the other hand, as a comparison, in the pouring process, after the sliding
調査の結果、実施例1の条件では再注出工程において問題なく開孔できたが、比較例1-1,1-2では不開孔が生じた。比較例1-1,1-2の取鍋については、酸素洗浄による強制開孔処理を行わず、取鍋中の溶鋼を転炉用の装入鍋に移し替えることにより空鍋とした。冷却後、スライディングノズル装置3の調査を行なったところ、比較例1-1,1-2の取鍋は、ともに上ノズル内が凝固した鋼で閉塞していた。また、比較例1-3の条件では再注出工程において開孔はできたが、注出前の溶鋼量に対して実際に鋳造した溶鋼量が、実施例1の条件では99.5%であったのに対し、比較例1-3の条件では98.9%に低下した。
As a result of the investigation, under the conditions of Example 1, it was possible to open the holes in the re-pouring process without any problem, but in Comparative Examples 1-1 and 1-2, non-opening occurred. The ladle of Comparative Examples 1-1 and 1-2 was not subjected to the forced opening treatment by oxygen cleaning, and the molten steel in the ladle was transferred to the charging pot for the converter to make an empty pot. After cooling, the sliding nozzle device 3 was examined. As a result, the ladle of Comparative Examples 1-1 and 1-2 were both clogged with solidified steel in the upper nozzle. Further, under the conditions of Comparative Example 1-3, holes were formed in the re-pouring process, but the amount of molten steel actually cast was 99.5% under the conditions of Example 1 with respect to the amount of molten steel before pouring. On the other hand, it decreased to 98.9% under the conditions of Comparative Example 1-3.
実施例2では、調査に先立ち、実機の条件における均一混合時間を算出した。算出の条件としては、溶鋼4の温度T1を1827(K)、溶鋼4の重量Wを190t、吹込み深さ(浴深さ)hvを2.29m、雰囲気圧力Paを0.1MPa、標準状態温度T0を300K、浴直径dvを3.375mとした。計算結果を図7に示す。図7に示すように、実機の条件であるArガスの吹込み流量が30.0NL/minの場合、均一混合時間の1/4は61.0sであることが確認できた。
In Example 2, prior to the investigation, the uniform mixing time under the conditions of the actual machine was calculated. As the calculation conditions, the temperature T 1 of the molten steel 4 was 1827 (K), the weight W of the molten steel 4 was 190 t, the blowing depth (bath depth) h v was 2.29 m, and the atmospheric pressure P a was 0.1 MPa. The standard temperature T 0 was 300 K, and the bath diameter d v was 3.375 m. The calculation result is shown in FIG. As shown in FIG. 7, it was confirmed that 1/4 of the uniform mixing time was 61.0 s when the Ar gas blowing flow rate of 30.0 NL/min, which is the condition of the actual machine.
そして、実施例2では、上記の結果から、均一混合時間の1/4を61.0sとして溶鋼の連続鋳造を行い、再開孔成功率を調査した。なお、実施例2では、均一混合時間の1/4を算出した条件と同じ条件で溶鋼4の連続鋳造を行い、吹込み工程では30.0NL/minの吹込み流量でArガスの吹込みを行った。また、実施例2では、比較として、吹込み時間が均一混合時間の1/4未満となる61.0s未満の条件でも連続鋳造を行い、再開孔成功率を調査した(比較例2)。
Then, in Example 2, from the above results, continuous casting of molten steel was performed with 1/4 of the uniform mixing time set to 61.0 s, and the reopening hole success rate was investigated. In Example 2, continuous casting of molten steel 4 was performed under the same conditions as those for calculating 1/4 of the uniform mixing time, and Ar gas was blown at a blowing flow rate of 30.0 NL/min in the blowing process. went. Further, in Example 2, as a comparison, continuous casting was performed under the condition of less than 61.0 s, which is less than ¼ of the uniform mixing time, and the success rate of reopening hole was investigated (Comparative Example 2).
図8に、実施例2及び比較例2における再開孔成功率の結果を示す。図8に示すように、吹込み時間が61.0s未満の比較例2の場合、再開孔率が75.0%(開孔成功回数12回/鋳造実施回数16回)と低位であった。これに対して、吹込み時間が61.0s以上の実施例2の場合、再開孔率が93.8%(開孔成功回数30回/鋳造実施回数32回)と再開孔率が大幅に向上することが確認できた。
FIG. 8 shows the results of the reopening hole success rate in Example 2 and Comparative Example 2. As shown in FIG. 8, in the case of Comparative Example 2 in which the blowing time was less than 61.0 s, the re-opening hole ratio was 75.0% (12 successful opening operations/16 casting operations), which was low. On the other hand, in the case of Example 2 in which the blowing time was 61.0 s or more, the re-opening hole ratio was 93.8% (30 successful opening operations/32 casting operations), and the re-opening hole rate was significantly improved. I was able to confirm that
1 取鍋
2 上ノズル
3 スライディングノズル装置
31 上プレート
311 第1ノズル孔
32 摺動プレート
321 第2ノズル孔
322 ガス吹込み孔
33 下部ノズル
34 下プレート
341 第3ノズル孔
4 溶鋼
5 スラグ
6 詰砂 1Ladle 2 Upper Nozzle 3 Sliding Nozzle 31 Upper Plate 311 First Nozzle Hole 32 Sliding Plate 321 Second Nozzle Hole 322 Gas Injection Hole 33 Lower Nozzle 34 Lower Plate 341 Third Nozzle Hole 4 Molten Steel 5 Slag 6 Filled Sand
2 上ノズル
3 スライディングノズル装置
31 上プレート
311 第1ノズル孔
32 摺動プレート
321 第2ノズル孔
322 ガス吹込み孔
33 下部ノズル
34 下プレート
341 第3ノズル孔
4 溶鋼
5 スラグ
6 詰砂 1
Claims (5)
- 溶鋼を収容した取鍋から、前記取鍋に設けられたスライディングノズル装置を介して前記溶鋼を注出する、スライディングノズル装置の制御方法であって、
前記スライディングノズル装置は、前記取鍋の底部に固定された上ノズルの下面に設けられ、第1ノズル孔を有する上プレートと、前記上プレートの下面に設けられ、第2ノズル孔を有する摺動プレートとを有し、
前記摺動プレートは、前記第2ノズル孔の少なくとも一部が前記第1ノズル孔に重畳する開位置から、前記第2ノズル孔が前記第1ノズル孔に重畳せず、前記摺動プレートによって前記第1ノズル孔が塞がれた閉位置までを、前記上プレートの下面を摺動することで移動可能に構成され、前記閉位置において、前記第1ノズル孔に不活性ガスを吹込む、ガス吹込み孔をさらに有し、
前記取鍋に前記溶鋼が収容された状態において、前記摺動プレートを前記開位置にし、前記第1ノズル孔及び前記第2ノズル孔を介して前記取鍋から前記溶鋼の一部を注出する抽出工程と、
前記抽出工程の後、前記摺動プレートを前記閉位置に移動させ、前記第1ノズル孔を介して前記ガス吹込み孔から前記不活性ガスを前記取鍋内の前記溶鋼に吹込む、ガス吹込み工程と、
前記ガス吹込み工程の後、前記摺動プレートを前記開位置にし、前記第1ノズル孔及び前記第2ノズル孔を介して前記取鍋から前記溶鋼を注出する、再注出工程と、
を備え、
前記ガス吹込み工程では、前記不活性ガスを前記上ノズルのノズル孔断面積あたり及び単位時間あたりに吹込む体積である、前記不活性ガスの吹込み流量を3.9Nm3/(min・m2)以上26.0Nm3/(min・m2)以下とする、スライディングノズル装置の制御方法。 From a ladle containing molten steel, pouring the molten steel through a sliding nozzle device provided in the ladle, a method for controlling a sliding nozzle device,
The sliding nozzle device is provided on a lower surface of an upper nozzle fixed to a bottom portion of the ladle and has an upper plate having a first nozzle hole, and a sliding member having a second nozzle hole provided on a lower surface of the upper plate. Has a plate and
In the sliding plate, the second nozzle hole does not overlap with the first nozzle hole from an open position where at least a part of the second nozzle hole overlaps with the first nozzle hole, and It is configured to be movable by sliding on the lower surface of the upper plate up to a closed position where the first nozzle hole is closed, and an inert gas is blown into the first nozzle hole at the closed position. Further having a blow hole,
In a state in which the molten steel is stored in the ladle, the sliding plate is set to the open position, and a part of the molten steel is poured out from the ladle via the first nozzle hole and the second nozzle hole. An extraction process,
After the extraction step, the sliding plate is moved to the closed position, and the inert gas is blown into the molten steel in the ladle from the gas blowing hole through the first nozzle hole. Including process,
A re-pouring step of pouring the molten steel from the ladle through the first nozzle hole and the second nozzle hole after the gas blowing step, the sliding plate in the open position,
Equipped with
In the gas blowing step, a blowing flow rate of the inert gas, which is a volume for blowing the inert gas per nozzle hole cross-sectional area of the upper nozzle and per unit time, is 3.9 Nm 3 /(min·m). 2 ) or more and 26.0 Nm 3 /(min·m 2 ) or less, the method for controlling the sliding nozzle device. - 前記ガス吹込み工程では、前記不活性ガスを吹込む時間である吹込み時間を、前記不活性ガスの攪拌による前記取鍋内の前記溶鋼の均一混合時間の1/4以上とする、請求項1に記載のスライディングノズル装置の制御方法。 In the gas blowing step, the blowing time, which is the time for blowing the inert gas, is set to 1/4 or more of the uniform mixing time of the molten steel in the ladle by stirring the inert gas. 2. The method for controlling the sliding nozzle device according to 1.
- 前記ガス吹込み工程では、前記吹込み時間を、(1)式の攪拌動力ε(W/T)を用いた(2)式から求められる均一混合時間tm(s)の1/4以上とする、請求項2に記載のスライディングノズル装置の制御方法。
Vg:不活性ガスの吹込み流量(Nm3/min)
T1:溶鋼の温度(K)
W:溶鋼の重量(t)
Pa:雰囲気圧力(Pa)
T0:標準状態温度(K)
hv:浴深さ(m)
dv:浴直径(m) In the gas blowing step, the blowing time is set to 1/4 or more of the uniform mixing time t m (s) obtained from the equation (2) using the stirring power ε(W/T) of the equation (1). The method for controlling the sliding nozzle device according to claim 2.
V g : Inflow rate of inert gas (Nm 3 /min)
T 1 : Temperature of molten steel (K)
W: Weight of molten steel (t)
P a : Atmospheric pressure (Pa)
T 0 : Standard state temperature (K)
h v : bath depth (m)
d v : bath diameter (m) - 前記注出工程では、前記取鍋から前記溶鋼の一部を注出する時間である注出時間を、5秒以上13秒以下とする、請求項1~3のいずれか1項に記載のスライディングノズル装置の制御方法。 The sliding according to any one of claims 1 to 3, wherein in the pouring step, a pouring time, which is a time for pouring a part of the molten steel from the ladle, is set to 5 seconds or more and 13 seconds or less. A method for controlling a nozzle device.
- 溶鋼を収容した取鍋から、前記取鍋に設けられたスライディングノズル装置を介して前記溶鋼を注出し、注出した前記溶鋼を鋳造する、鋳片の製造方法において、
請求項1~4のいずれか1項に記載のスライディングノズル装置の制御方法を用い、前記再注出工程で注出された前記溶鋼を鋳造する、鋳片の製造方法。 From a ladle containing molten steel, pouring the molten steel through a sliding nozzle device provided in the ladle, casting the poured molten steel, in a method for producing a slab,
A method for manufacturing a slab, which comprises casting the molten steel poured in the re-pouring step using the method for controlling a sliding nozzle device according to any one of claims 1 to 4.
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Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH06218530A (en) * | 1993-01-22 | 1994-08-09 | Nippon Steel Corp | Closing method of sliding type molten metal pouring device |
JPH0947862A (en) * | 1995-08-03 | 1997-02-18 | Nkk Corp | Device for boring pouring hole of molten metal and method therefor |
JP2000202599A (en) * | 1999-01-06 | 2000-07-25 | Nkk Corp | Continuous casting method |
JP2012161830A (en) * | 2011-02-09 | 2012-08-30 | Jfe Steel Corp | Method for opening sliding type opening/closing device of ladle |
JP2013107100A (en) * | 2011-11-21 | 2013-06-06 | Jfe Steel Corp | Method for producing high cleanliness steel |
JP2017177109A (en) * | 2016-03-28 | 2017-10-05 | 株式会社神戸製鋼所 | Injection starting method of molten steel when starting continuous casting |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3809146A (en) * | 1972-02-18 | 1974-05-07 | Steel Corp | Method of opening an intermediate vessel nozzle for continuous casting |
FR2490123A1 (en) * | 1980-09-15 | 1982-03-19 | Air Liquide | PLATE SHUTTER DEVICE FOR CONTAINER CASTING HOLES CONTAINING A FUSION METAL |
CA1200384A (en) * | 1982-04-22 | 1986-02-11 | Francis L. Kemeny, Jr. | Ladle slide gate collector nozzle |
JP2002346707A (en) * | 2001-05-25 | 2002-12-04 | Nkk Corp | Continuous casting method of steel |
CN101745630A (en) * | 2008-12-19 | 2010-06-23 | 鞍钢重型机械有限责任公司 | Method for pouring cast part |
CN102784908A (en) * | 2012-08-30 | 2012-11-21 | 南京钢铁集团冶金铸造有限公司 | Non-drainage pouring technology for steel ladle |
CN103008588B (en) * | 2013-01-09 | 2014-12-10 | 河北联合大学 | Nozzle slag line erosion resistant device and method for protecting pouring by using same |
JP6187773B2 (en) * | 2014-10-14 | 2017-08-30 | Jfeスチール株式会社 | Sliding nozzle device for molten metal holding container and method for pouring molten metal from this device |
CN108555273B (en) * | 2018-06-04 | 2020-03-31 | 东北大学 | Method for improving ladle self-opening rate by bottom blowing inert gas |
CN109128125A (en) * | 2018-10-30 | 2019-01-04 | 马鞍山钢铁股份有限公司 | A kind of Con casting ladle is without drainage casting apparatus and without drainage method for pouring |
-
2020
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- 2020-01-17 JP JP2020520082A patent/JP6733854B1/en active Active
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Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH06218530A (en) * | 1993-01-22 | 1994-08-09 | Nippon Steel Corp | Closing method of sliding type molten metal pouring device |
JPH0947862A (en) * | 1995-08-03 | 1997-02-18 | Nkk Corp | Device for boring pouring hole of molten metal and method therefor |
JP2000202599A (en) * | 1999-01-06 | 2000-07-25 | Nkk Corp | Continuous casting method |
JP2012161830A (en) * | 2011-02-09 | 2012-08-30 | Jfe Steel Corp | Method for opening sliding type opening/closing device of ladle |
JP2013107100A (en) * | 2011-11-21 | 2013-06-06 | Jfe Steel Corp | Method for producing high cleanliness steel |
JP2017177109A (en) * | 2016-03-28 | 2017-10-05 | 株式会社神戸製鋼所 | Injection starting method of molten steel when starting continuous casting |
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