WO2020079783A1 - 鋳片の製造方法 - Google Patents
鋳片の製造方法 Download PDFInfo
- Publication number
- WO2020079783A1 WO2020079783A1 PCT/JP2018/038696 JP2018038696W WO2020079783A1 WO 2020079783 A1 WO2020079783 A1 WO 2020079783A1 JP 2018038696 W JP2018038696 W JP 2018038696W WO 2020079783 A1 WO2020079783 A1 WO 2020079783A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- pair
- cooling
- cooling drums
- drum
- end side
- Prior art date
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
- B22D11/0622—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars formed by two casting wheels
- B22D11/0625—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars formed by two casting wheels the two casting wheels being immersed in a molten metal bath and drawing out upwardly the casting strip
-
- 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
- B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
- B22D11/0622—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars formed by two casting wheels
-
- 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
- B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
-
- 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
- B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
- B22D11/0637—Accessories therefor
- B22D11/0648—Casting surfaces
- B22D11/0651—Casting wheels
-
- 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
- B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
- B22D11/0637—Accessories therefor
- B22D11/068—Accessories therefor for cooling the cast product during its passage through the mould surfaces
- B22D11/0682—Accessories therefor for cooling the cast product during its passage through the mould surfaces by cooling the casting wheel
-
- 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
-
- 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
- B22D11/20—Controlling or regulating processes or operations for removing cast stock
- B22D11/201—Controlling or regulating processes or operations for removing cast stock responsive to molten metal level or slag level
-
- 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
- B22D11/22—Controlling or regulating processes or operations for cooling cast stock or mould
Definitions
- the present invention relates to a slab manufacturing method for manufacturing a slab by supplying molten metal to a molten metal pool formed by a pair of cooling drums and a pair of side dams.
- a twin drum including a cooling drum having a water cooling structure inside.
- a manufacturing method using a continuous casting machine is provided.
- molten metal is supplied to a molten metal pool formed between a pair of rotating cooling drums, and solidified shells formed and grown on the peripheral surfaces of the pair of cooling drums are drum kiss points.
- the manufacturing method using such a twin-drum type continuous casting apparatus is applied to various metals.
- a dummy sheet is sandwiched between cooling drums, and molten metal is stored in a molten metal pool formed by a pair of cooling drums and a pair of side dams. Supply. Then, when a certain amount of molten metal is accumulated in the molten metal reservoir, the cooling drum is rotated to form a cast piece so as to be connected to the dummy sheet, and the dummy sheet and the dummy sheet are connected from between the cooling drums. The slab is pulled out.
- the deviation of the thickness of the solidified shell is large at a non-steady state immediately after the start of casting, and when the pressure control is performed as in Patent Document 1, the solidified shell may not be sufficiently pressed down at the drum kiss point. .
- an unsolidified portion is formed in the center of the thickness of the slab, the surface temperature of the slab becomes relatively high, the strength is insufficient, and the slab breaks, etc., and stable casting cannot be started.
- a hump-shaped thickened portion (hereinafter sometimes referred to as a thickened portion) is formed on the slab immediately after the start of casting. Therefore, when the thick portion passes through the drum kiss point, casting becomes unstable.
- Patent Document 2 proposes a method of switching the pressure control between a pair of cooling drums immediately after the start of casting and in a steady state. Specifically, in the first step until the thick portion of the slab passes the closest contact point (drum kiss point) of the cooling drum after the cooling drum is rotationally activated, the pair of cooling members is cooled without performing parallel control of the cooling drum. The drum is pressed at a relatively low pressure in the direction in which it approaches. Then, in the second step after the first step until the influence of shell washing by the discharge flow of molten steel from the nozzle disappears, the cooling drum is pressed at a higher pressure than that in the first step without performing parallel control. Further, in the third step after the second step, parallel control is performed so that the rotation axes of the pair of cooling drums are parallel to each other.
- the pair of cooling drums are simply pressed at a non-steady state immediately after the start of casting where the deviation of the thickness of the solidified shell is large, so the solidified shells should be sufficiently pressed down at the drum kiss point. Therefore, it is possible to suppress the formation of an unsolidified portion in the central portion of the thickness of the cast slab.
- the second step until the effect of shell washing due to the discharge flow of molten steel from the nozzle disappears is the period until the molten metal level rises sufficiently, and during this period the cooling drum rotates about 0.4 revolutions. To do.
- the present invention has been made in view of the above situation, in a twin-drum type continuous casting apparatus, it is possible to suppress the breakage of the slab, a method of manufacturing a slab capable of stably starting the casting, The purpose is to provide.
- the gist of the present invention is as follows.
- a first aspect of the present invention is to supply a molten metal to a molten metal pool formed by a pair of rotating cooling drums and a pair of side dams, and to solidify a shell on a peripheral surface of the pair of cooling drums.
- the thick portion of the cast slab passes through the closest contact points of the pair of cooling drums after the rotation of the cooling drum is started, one end side of the pair of cooling drums in the rotation axis direction and the other are formed.
- the second step from the first step to the one or more rotations of the pair of cooling drums by pressing the end sides with the same first pressure toward the direction in which the pair of cooling drums approach each other.
- the pair of cooling drums are pressed at a second pressure higher than the first pressure on one end side and the other end side in the rotation axis direction of the pair of cooling drums in a direction in which the pair of cooling drums are close to each other,
- the third step after the second step the total value of the reaction forces on the one end side and the other end side in the rotation axis direction of the pair of cooling drums becomes a predetermined value, and Pressure control is performed so that the mutual rotation axes are held in parallel.
- the second step may be a period from after the first step until the pair of cooling drums makes two or more revolutions.
- one end side and the other end side of the pair of cooling drums in the rotation axis direction are pressed with the same first pressure toward the direction in which the pair of cooling drums are close to each other.
- the thick portion can be relatively stably passed between the cooling drums.
- the solidified shells can be sufficiently pressed down at the drum kiss point, and the solidified shell is not solidified in the center portion of the thickness of the slab. It can suppress that a part is formed.
- the period until the cooling drum makes two or more rotations is the second step, so that the above-mentioned thermal expansion portion remains until the second rotation.
- one end side and the other end side of the pair of cooling drums in the rotation axis direction are pressed with the same pressure. Therefore, the solidified shells can be sufficiently pressed down at the drum kiss point, and it is possible to suppress the formation of an unsolidified portion in the thickness center portion of the cast slab. Thereby, breakage of the slab can be suppressed, and casting can be stably started.
- the twin-drum type continuous casting apparatus it is possible to provide a method for manufacturing a cast piece capable of suppressing breakage of the cast piece and stably starting casting. .
- FIG. 6 is a graph showing a relationship between a drum reaction force and a drum gap in a comparative example.
- 5 is a graph showing a relationship between a drum reaction force and a drum gap in Example 1 of the present invention.
- the inventors of the present invention have made earnest studies, and as a result, have obtained the following findings.
- the molten metal is supplied to the molten metal pool with the cooling drum stopped, at the closest contact point (drum kiss point) of the cooling drum, the molten metal The contact time with and is long, it heats locally and thermally expands, and a thermal expansion part is formed.
- the front side of the drum kissing point in the drum rotation direction is not in contact with the molten metal, it is not thermally expanded, and a large step is formed between the thermally expanded portion.
- molten steel is used as the molten metal, and the slab 1 made of steel is manufactured.
- the width of the cast slab 1 to be manufactured is within the range of 200 mm to 1800 mm, and the thickness is within the range of 0.8 mm to 5 mm.
- the twin-drum type continuous casting apparatus 10 shown in FIG. 1 is provided with a pair of cooling drums 11 and 11, pinch rolls 13 and 13 that support the cast piece 1, and a pair of cooling drums 11 and 11 at both ends in the width direction. And a tundish 18 for holding the molten steel 3 supplied to the molten steel pool portion 16 defined by the pair of cooling drums 11, 11 and the pair of side dams 15, 15. An immersion nozzle 19 for supplying the molten steel 3 from the tundish 18 to the molten steel pool portion 16 is provided.
- the molten steel 3 is brought into contact with the rotating cooling drums 11 and to be cooled, whereby the solidified shells 5 and 5 grow on the peripheral surfaces of the cooling drums 11 and 11. . Then, the solidified shells 5, 5 respectively formed on the pair of cooling drums 11, 11 are pressed against each other at the drum kiss points, so that the slab 1 having a predetermined thickness is cast.
- the molten steel pool portion 16 is defined by disposing the side dam 15 on the end surface of the cooling drum 11.
- the molten steel pool section 16 has a molten metal surface in a rectangular shape surrounded on all sides by the peripheral surfaces of the pair of cooling drums 11, 11 and the pair of side dams 15, 15.
- An immersion nozzle 19 is arranged at the center of the molten metal surface.
- the contact portion of the side dam 15 with the molten steel 3 has a substantially inverted triangular shape.
- the temperature of the side dam 15 is relatively low, so that the metal M is generated at this contact portion.
- the side weir 15 has a base plate 15a and a ceramic plate 15b arranged in a region in sliding contact with the cooling drum 11.
- the ceramic plate 15b is more than the base plate 15a.
- FIG. 4 is a horizontal cross section of the contact portion between the end surface of the cooling drum 11 and the ceramic plate 15b (point E in FIG. 5D).
- a dummy sheet (not shown) is inserted between the cooling drums 11 and 11 while the pair of cooling drums 11 and 11 are stopped, and the molten steel pool Molten steel 3 is supplied toward the portion 16. Then, the cooling drums 11, 11 are rotationally activated, and the cast piece 1 is pulled out from the lower side of the cooling drums 11, 11.
- the molten steel 3 of the molten steel pool portion 16 is solidified and the thickness of the slab 1 is increased, and the hump-shaped thick portion, that is, the plate thickness of the slab 1 is locally increased. The part that is present is formed. Further, in the molten steel pool portion 16, shell washing in which the discharge flow of the molten steel 3 from the immersion nozzle 19 flushes the solidified shell 5 occurs. The shell washing does not occur when the height of the molten metal surface in the molten steel pool portion 16 increases.
- the relationship between the cooling drum 11 and the side dam 15 immediately after the start of casting will be described with reference to FIG. First, as shown in FIG. 5A, the cooling drum 11 and the side dam 15 are in close contact with each other before the molten steel 3 is supplied.
- the molten steel 3 is supplied with the cooling drums 11, 11 stopped. Then, as shown in FIG. 5B, in the vicinity of the closest contact point P (drum kiss point) of the cooling drums 11, 11, the cooling drum 11 thermally expands due to the contact with the molten steel 3, and the thermal expansion portion E is formed. It A region on the front side of the cooling drums 11 and 11 in the drum rotation direction R with respect to the closest contact point P is not in contact with the molten steel 3 and therefore does not undergo thermal expansion and has a large gap with the thermal expansion portion E. Steps occur.
- the region on the rear side of the cooling drums 11 and 11 in the drum rotation direction R with respect to the closest contact point P is located in the molten steel pool portion 16, so that it is thermally expanded due to contact with the molten steel 3, but with the molten steel 3.
- the thermal expansion amount gradually decreases toward the rear side in the drum rotation direction R depending on the contact time. Therefore, the side weir 15 is in contact with the cooling drums 11 in an inclined state, but no large gap is formed.
- the cooling drum 11 further rotates, and the thermal expansion portion E (the portion located at the closest contact point P (drum kiss point) of the cooling drums 11 and 11 when the cooling drum 11 is stopped at the start of casting) becomes the side dam 15.
- the thermal expansion portion E the portion located at the closest contact point P (drum kiss point) of the cooling drums 11 and 11 when the cooling drum 11 is stopped at the start of casting
- the thermal expansion portion E becomes the side dam 15.
- a gap is created between the side dam 15 and the cooling drum 11, as shown in FIG.
- the size of the gap is, for example, 0.2 mm or more, the molten steel 3 is inserted into this gap.
- the metal M is formed on the surface of the side dam 15, and the molten steel 3 inserted in the gap between the side dam 15 and the cooling drum 11 is solidified. Then, it is integrated with the above-described base metal M and is caught between the cooling drums 11, 11. In the portion where the metal M is caught between the cooling drums 11 and 11, the plate thickness of the cast piece locally becomes thick in the width direction and the longitudinal direction.
- the pressure control of the cooling drums 11 and 11 is (A) From the state in which the pair of cooling drums 11 and 11 are stopped, the pair of cooling drums 11 and 11 are rotationally activated so that the thick portion of the cast slab 1 is the closest contact point P (drum kiss) of the pair of cooling drums 11 and 11.
- the first step until passing point) (B) a second step after the first step until the cooling drums 11, 11 make one rotation or more, (C) a third step after the second step, It is divided into two parts.
- FIG. 6, is an explanatory view showing the pressure control method of the cooling drum.
- the pair of cooling drums 11 and 11 are provided with predetermined pressure by hydraulic cylinders 21A and 21B arranged on one end side and the other end side in the rotation axis direction.
- the pressure presses the pair of cooling drums 11 and 11 in a direction in which they approach each other.
- hydraulic cylinders 21A and 21B are arranged on the cooling drum 11a on the moving side, and the cooling drum 11a on the moving side is moved toward the cooling drum 11b on the stationary side. It is configured to press.
- the hydraulic cylinders 21A and 21B are fixed to the side surfaces of the column, but the column is not shown for simplification.
- the first pressure is aimed at a value as high as possible within a range that does not affect the start-up of the cooling drum 11.
- the specific values are mainly the width of the cooling drum 11, the diameter, the molten metal type, and the drum maximum. It depends on the driving force. In reality, it is difficult to obtain an appropriate value by calculation in advance, so an appropriate value is obtained and set in an actual test.
- the pair of cooling drums 11 and 11 are predetermined by the hydraulic cylinders 21A and 21B arranged on one end side and the other end side in the rotation axis direction.
- the second pressure is aimed to be as high as possible within a range that does not damage the surface of the cooling drum 11 such as deformation, but the width, diameter, surface shape, surface material, molten metal of the cooling drum 11 are mainly used. It depends on the type and maximum drum pressure. In reality, as with the first pressure, an appropriate value is obtained and set in an actual test.
- the second pressure in the second step is set higher than the first pressure in the first step.
- the hydraulic cylinders are arranged on one end side and the other end side of the pair of cooling drums 11 and 11 in the rotation axis direction in the direction in which the pair of cooling drums 11 and 11 approach each other.
- 21A and 21B press the same pressure. Therefore, as described above, even if the metal M is caught, the cooling drums 11 are pressed in a direction in which they approach each other.
- the "same pressure" allows an error of 10%, but in order to start the casting more stably, the error range is allowed to be 5% or less, more preferably 1% or less. It is preferable to manage.
- the total value of the reaction forces on the one end side and the other end side of the pair of cooling drums 11 in the rotation axis direction becomes a predetermined value.
- pressure control is performed so that the rotation axes of the pair of cooling drums 11 and 11 are held parallel to each other.
- hydraulic cylinders 21A and 21B are arranged on the moving side cooling drum 11a, and load cells 22A and 22B are arranged on the fixed side cooling drum 11b.
- the load cells 22A and 22B are fixed to the side surfaces of the support, but the support is not shown for simplification.
- the reaction force signals measured by the load cells 22A and 22B are transmitted to the reaction force control unit 24, and the reaction force control unit 24 causes the hydraulic cylinders 21A and 21B to move back and forth so that the total load becomes a predetermined value.
- the predetermined value of the sum load is mainly intended to maintain the stability of the operation within a range that satisfies the quality of the cast slab 1, but is mainly determined by the width, diameter, and molten metal type of the cooling drum 11. It is a thing. In reality, like the first pressure and the second pressure, an appropriate value is obtained and set in an actual test.
- the second step it is preferable to set a period until the cooling drum 11 makes two or more revolutions after the first step.
- the switching timing from the second step to the third step is delayed, the amount of initial defects until obtaining the slab 1 having the controlled plate thickness increases, so that the third step before the cooling drum 11 makes three rotations. It is preferable to switch to.
- the pair of cooling By the hydraulic cylinders 21A and 21B arranged on one end side and the other end side of the drums 11 and 11 in the rotational axis direction, the pair of cooling drums 11 and 11 are directed toward each other at a predetermined pressure (second pressure). Since the thermal expansion portion E of the cooling drum 11 is located in a region in sliding contact with the side dam 15, a gap is formed between the side dam 15 and the cooling drum 11.
- the pair of cooling drums 11 and 11 are pressed in the direction of approaching each other, and the pair of cooling drums 11 and 11 are pressed.
- the solidified shells 5 and 5 can be sufficiently pressed down at the closest point P (drum kiss point). Therefore, the unsolidified portion in the central portion of the thickness of the cast piece 1 is hardly formed, and the cast piece strength is maintained. Thereby, breakage of the slab 1 can be suppressed and the casting can be stably started.
- the pair of cooling drums 11, 11 is rotationally activated from a state where the pair of cooling drums 11, 11 are stopped, and the thick portion of the cast slab 1 is In the first step before passing through the closest contact point P (drum kiss point) of the pair of cooling drums 11 and 11, the hydraulic cylinders arranged on one end side and the other end side of the pair of cooling drums 11 and 11 in the rotation axis direction. 21A and 21B press the relatively low first pressure toward the direction in which the pair of cooling drums 11 and 11 approach each other. Therefore, the thick portions of the slab 1 formed at the start of casting are compared.
- the cooling drums 11 and 11 can pass the cooling drums 11 and 11 between the cooling drums 11 in a stable manner and suppress the influence on casting. Further, in the second step, since the cooling drum 11 is pressed with the second pressure higher than the first pressure in the first step, the solidified shell 5 is pressed at the closest contact point P (drum kiss point) of the pair of cooling drums 11, 11. , 5 can be sufficiently rolled down. Therefore, the unsolidified portion in the central portion of the thickness of the cast piece 1 is hardly formed, and the cast piece strength can be maintained.
- the second step is a period until the cooling drum 11 makes two or more rotations after the first step
- the above-mentioned thermal expansion part E remains until the second rotation and the metal Even if M is caught, the solidified shells 5 and 5 can be sufficiently pressed at the closest contact points P (drum kiss point) of the pair of cooling drums 11 and 11. Thereby, breakage of the slab 1 can be suppressed and the casting can be stably started.
- the present invention is not limited to this and can be appropriately changed without departing from the technical idea of the invention.
- the twin-drum type continuous casting apparatus shown in FIG. 1 has been described as an example, but the present invention is not limited to this.
- the pressing method of the cooling drum is not limited to that shown in FIG. 6, and may be any configuration capable of performing pressure control as shown in the embodiment.
- Example 1 of the present invention switching from the first step to the second step is performed when the rotation speed of the cooling drum is 0.1 rotations, and the second step is performed when the rotation speed of the cooling drum is 1.3 rotations. Was switched to the third step.
- Example 2 of the present invention switching from the first step to the second step is performed when the rotation speed of the cooling drum is 0.1 rotations, and the second step is performed when the rotation speed of the cooling drum is 2.3 rotations. Was switched to the third step.
- switching from the first step to the second step is performed when the rotation speed of the cooling drum is 0.1 rotations, and when the rotation speed of the cooling drum is 0.4 rotations, the second step is started. Switching to 3 steps was performed. The switching from the second step to the third step in this case corresponds to the time point when the shell washing is completed.
- FIG. 7 shows changes in the drum reaction force and the drum gap in the comparative example
- FIG. 8 shows changes in the drum reaction force and the drum gap in the first example of the present invention.
- the fracture rate of the slab at the first and second rotations of the cooling drum was 25%, and the start of casting tended to be unstable.
- the fracture rate of the slab at the first and second rotations of the cooling drum was 0%.
- Example 1 of the present invention as shown in FIG. 8, the drum reaction force did not decrease in DS even when the metal was bitten by WS, and the solidified shells were strongly pressure-bonded to each other. Has a smaller drum gap. Therefore, there is almost no unsolidified portion in the thickness center portion of the cast piece, the surface temperature of the cast piece becomes relatively low, and the cast piece strength is maintained. This suppresses breakage of the cast slab.
- a twin-drum type continuous casting apparatus in a twin-drum type continuous casting apparatus, it is possible to provide a method for producing a cast piece capable of suppressing breakage of the cast piece and stably starting casting.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Continuous Casting (AREA)
Abstract
Description
そこで、特許文献1においては、一方の冷却ドラムの両端部の押付力を検出加算し、これに基づく信号により、一方の冷却ドラムの両端の押付力の和が所定の値となるように他方の冷却ドラムの両端を油圧シリンダーによって平行に移動させる方法が提案されている。
具体的は、冷却ドラムを回転起動した後に鋳片の肉厚部が冷却ドラムの最近接点(ドラムキス点)を通過するまでの第1ステップでは、冷却ドラムの平行制御を行うことなく、一対の冷却ドラムが近接する方向に比較的低圧で押圧する。そして、第1ステップの後からノズルからの溶鋼の吐出流によるシェル洗いの影響がなくなるまでの第2ステップでは、冷却ドラムの平行制御を行うことなく、第1ステップよりも高い圧力で押圧する。更に、第2ステップの後の第3ステップでは、一対の冷却ドラムの回転軸が互いに平行となるように平行制御を実施している。
(2)上記(1)に記載の鋳片の製造方法においては、前記第2ステップは、前記第1ステップ後から前記一対の冷却ドラムが2回転以上するまでの期間であってもよい。
また、第1ステップにおいては、一対の冷却ドラムの回転軸方向の一端側及び他端側を互いに同一の第1圧力で、一対の冷却ドラムが互いに近接する方向に向けて押圧しているので、肉厚部を比較的安定して冷却ドラム間に通過させることができる。
さらに、第2ステップでは、第1圧力よりも高い第2圧力で冷却ドラムを押圧しているので、ドラムキス点において凝固シェル同士を十分に圧下することができ、鋳片の厚み中央部分に未凝固部が形成されることを抑制できる。
双ドラム式連続鋳造装置においては、上述のように、冷却ドラムを停止した状態で溶融金属溜まり部に溶融金属を供給していることから、冷却ドラムの最近接点(ドラムキス点)においては、溶融金属との接触時間が長く、局所的に加熱されて熱膨張し、熱膨張部が形成される。一方、ドラムキス点よりもドラム回転方向の前方側は溶融金属と接触していないため、熱膨張しておらず、前記熱膨張部との間には大きな段差が生じる。
なお、時間が経過するに伴い、局所的な熱膨張は抑えられ、上述の熱膨張部の影響はなくなる。
ここで、本実施形態では、溶融金属として溶鋼を用いており、鋼材からなる鋳片1を製造する。また、本実施形態では、製造される鋳片1の幅が200mm以上1800mm以下の範囲内、厚さが0.8mm以上5mm以下の範囲内とされている。
図1に示す双ドラム式連続鋳造装置10は、一対の冷却ドラム11,11と、鋳片1を支持するピンチロール13,13と、一対の冷却ドラム11,11の幅方向両端部に配設された一対のサイド堰15,15と、これら一対の冷却ドラム11,11と一対のサイド堰15,15とによって画成された溶鋼プール部16に供給される溶鋼3を保持するタンディッシュ18と、このタンディッシュ18から溶鋼プール部16へと溶鋼3を供給する浸漬ノズル19と、を備えている。
溶鋼プール部16の湯面は、図2に示すように、一対の冷却ドラム11,11の周面と一対のサイド堰15,15によって四方を囲まれた矩形状をなしており、この矩形状をなす湯面の中央部に浸漬ノズル19が配設されている。
なお、サイド堰15においては、図4に示すように、ベースプレート15aと、冷却ドラム11と摺接する領域に配設されたセラミックプレート15bと、を有しており、セラミックプレート15bは、ベースプレート15aよりも硬質の耐火材で構成されている。なお、図4は、冷却ドラム11の端面とセラミックプレート15bの接触部(図5(d)のE点)の水平断面である。
そして、冷却ドラム11,11を回転起動し、鋳片1が冷却ドラム11,11の下方側から引抜かれていく。
また、溶鋼プール部16においては、浸漬ノズル19からの溶鋼3の吐出流が凝固シェル5を洗い流すシェル洗いが発生する。このシェル洗いは、溶鋼プール部16における湯面高さが高くなると発生しなくなる。
まず、図5(a)に示すように、溶鋼3を供給する前には冷却ドラム11とサイド堰15とは密着した状態である。
一方、冷却ドラム11,11の最近接点Pよりもドラム回転方向Rの後方側の領域は、溶鋼プール部16に位置するため、溶鋼3との接触によって熱膨張しているが、溶鋼3との接触時間によって熱膨張量は、ドラム回転方向Rの後方側に向かうにしたがい漸次小さくなっている。このため、サイド堰15は傾斜した状態で冷却ドラム11、11と当接しているが、大きな隙間は生じていない。
冷却ドラム11、11の間に地金Mが噛み込まれた部分は、鋳片の板厚が幅方向且つ長手方向で局所的に厚くなる。
(a)一対の冷却ドラム11,11を停止した状態から、一対の冷却ドラム11,11を回転起動させて、鋳片1の肉厚部が一対の冷却ドラム11,11の最近接点P(ドラムキス点)を通過するまでの第1ステップと、
(b)第1ステップの後、冷却ドラム11,11が1回転以上するまでの第2ステップと、
(c)第2ステップ後の第3ステップと、
に分けて実施している。
それぞれのステップについて、冷却ドラムの圧力制御方法を示す説明図である図6を参照して以下に説明する。
まず、第1ステップにおいては、図6(a)に示すように、一対の冷却ドラム11,11の回転軸方向の一端側及び他端側に配設された油圧シリンダー21A,21Bによって、所定の圧力(第1圧力)で一対の冷却ドラム11,11が互いに近接する方向に向けて押圧する。
本実施形態では、図6(a)に示すように、移動側の冷却ドラム11aに油圧シリンダー21A、21Bが配設されており、固定側の冷却ドラム11bに向けて移動側の冷却ドラム11aを押圧するように構成されている。尚、油圧シリンダー21A、21Bは、支柱の側面に固定されているが、簡略化のために支柱は図示していない。
第1圧力は、冷却ドラム11の起動に影響を与えない範囲で出来るだけ高い値を狙いとするが、その具体的数値は、主に、冷却ドラム11の幅、直径、溶融金属種類、ドラム最大駆動力から決まるものである。現実的には、事前の計算等にて適正値を求めるのは難しいため、実際の試験にて適正値を求めて設定される。
次に、第2ステップにおいては、図6(a)に示すように、一対の冷却ドラム11,11の回転軸方向の一端側及び他端側に配設された油圧シリンダー21A,21Bによって、所定の圧力(第2圧力)で一対の冷却ドラム11,11が互いに近接する方向に向けて押圧する。
なお、第2圧力は、冷却ドラム11の表面に変形等の損傷を与えない範囲で出来るだけ高い値を狙いとするが、主に冷却ドラム11の幅、直径、表面形状、表面材質、溶融金属種類、最大ドラム圧下から決まるものである。現実的には、第1圧力と同様に、実際の試験にて適正値を求めて設定される。
ここで、第2ステップにおける第2圧力は、第1ステップにおける第1圧力よりも高く設定されている。
尚、本願において、「同一の圧力」は、10%の誤差を許容するが、鋳造をより安定して開始させるためには誤差範囲を5%以下、より好ましくは1%以下に許容するように管理することが好ましい。
次に、第3ステップにおいては、図6(b)に示すように、一対の冷却ドラム11,11の回転軸方向の一端側及び他端側の反力の合計値が所定の値となるように、かつ、一対の冷却ドラム11,11の互いの回転軸が平行に保持されるように圧力制御を行う。
具体的には、図6(b)に示すように、移動側の冷却ドラム11aに油圧シリンダー21A、21Bが配設され、固定側の冷却ドラム11bにロードセル22A、22Bが配設されている。尚、ロードセル22A、22Bは、支柱の側面に固定されているが、簡略化のために支柱は図示していない。ロードセル22A、22Bによって測定された反力信号が反力制御部24に送信され、この反力制御部24において、和荷重が所定値になるように、油圧シリンダー21A、21Bにおいて前後進するように指令を与える。
これにより、一対の冷却ドラム11,11の互いの回転軸が平行に保持され、板厚制御された鋳片1が製造されることになる。なお、前記和荷重の所定値は、主に鋳片1の品質を満足する範囲で、操業の安定性の維持を狙いとするが、主に冷却ドラム11の幅、直径、溶融金属種類から決まるものである。現実的には、第1圧力、第2圧力と同様に、実際の試験にて適正値を求めて設定される。
ただし、第2ステップから第3ステップへの切り替えタイミングが遅くなると、板厚制御された鋳片1を得るまでの初期不良量が多くなるため、冷却ドラム11が3回転する前に、第3ステップに切り替えることが好ましい。
さらに、第2ステップでは、第1ステップの第1圧力よりも高い第2圧力で冷却ドラム11を押圧しているので、一対の冷却ドラム11,11の最近接点P(ドラムキス点)において凝固シェル5,5同士を十分に圧下することができる。このため、鋳片1の厚み中央部分の未凝固部がほとんど形成されず、鋳片強度を維持することができる。
本実施形態では、図1に示す双ドラム式連続鋳造装置を例に挙げて説明したが、これに限定されることはない。
また、冷却ドラムの押圧方式は、図6に示すものに限定されることはなく、実施形態で示したように圧力制御が実施可能な構成であればよい。
図1に示す双ドラム式連続鋳造装置を用いて、炭素量0.05mass%の炭素鋼からなる鋳片の製造を行った。
ここで、冷却ドラム径を600mm、冷却ドラム幅を400mmとした。また、定常鋳造の鋳片厚さを2.0mmとした。
本発明例2においては、冷却ドラムの回転数が0.1回転の時点で第1ステップから第2ステップへの切り替えを実施し、冷却ドラムの回転数が2.3回転の時点で第2ステップから第3ステップへの切り替えを実施した。
比較例においては、冷却ドラムの回転数が0.1回転の時点で第1ステップから第2ステップへの切り替えを実施し、冷却ドラムの回転数が0.4回転の時点で第2ステップから第3ステップへの切り替えを実施した。尚、この場合の第2ステップから第3ステップへの切り替えは、シェル洗いが終了した時点に該当する。
また、比較例におけるドラム反力とドラムギャップの変化を図7に、本発明例1におけるドラム反力とドラムギャップの変化を図8に示す。
これに対して、本発明例1,2においては、冷却ドラムの1~2回転目における鋳片の破断率が0%であった。
これに対して、本発明例1においては、図8に示すように、WSで地金を噛み込んだ時点でもDSではドラム反力が低下しておらず、凝固シェル同士が強く圧着され、DSのドラムギャップが小さくなっている。したがって、鋳片の厚み中央部分の未凝固部はほとんど存在せず、鋳片の表面温度が比較的低くなり、鋳片強度が維持される。これにより、鋳片の破断が抑制される。
3 溶鋼(溶融金属)
5 凝固シェル
10 双ドラム式連続鋳造装置
11 冷却ドラム
15 サイド堰
16 溶鋼プール部(溶融金属溜まり部)
Claims (2)
- 回転する一対の冷却ドラムと一対のサイド堰とによって形成された溶融金属溜まり部に溶融金属を供給し、前記一対の冷却ドラムの周面に凝固シェルを形成及び成長させて鋳片を製造する鋳片の製造方法であって、
鋳造開始時において前記一対の冷却ドラムを停止した状態で前記溶融金属溜まり部に前記溶融金属を供給した際に形成される前記鋳片の肉厚部が、前記冷却ドラムの回転起動後に前記一対の冷却ドラムの最近接点を通過するまでの第1ステップにおいては、前記一対の冷却ドラムの回転軸方向の一端側及び他端側を互いに同一の第1圧力で、前記一対の冷却ドラムが互いに近接する方向に向けて押圧し、
前記第1ステップ後から前記一対の冷却ドラムが1回転以上するまでの第2ステップにおいては、前記一対の冷却ドラムの回転軸方向の一端側及び他端側を互いに同一、かつ、前記第1圧力よりも高い第2圧力で、前記一対の冷却ドラムが互いに近接する方向に押圧し、
前記第2ステップ後の第3ステップにおいては、前記一対の冷却ドラムの回転軸方向の一端側及び他端側の反力の合計値が所定の値となるように、かつ、前記一対の冷却ドラムの互いの回転軸が平行に保持されるように圧力制御を行う
ことを特徴とする鋳片の製造方法。 - 前記第2ステップは、前記第1ステップ後から前記一対の冷却ドラムが2回転以上するまでの期間である
ことを特徴とする請求項1に記載の鋳片の製造方法。
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US17/274,469 US11458534B2 (en) | 2018-10-17 | 2018-10-17 | Cast strip manufacturing method |
PCT/JP2018/038696 WO2020079783A1 (ja) | 2018-10-17 | 2018-10-17 | 鋳片の製造方法 |
KR1020217008386A KR102526952B1 (ko) | 2018-10-17 | 2018-10-17 | 주편의 제조 방법 |
BR112021002414-0A BR112021002414B1 (pt) | 2018-10-17 | 2018-10-17 | Método de produção de tira lingotada |
CN201880097911.7A CN112752626B (zh) | 2018-10-17 | 2018-10-17 | 铸板的制造方法 |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/JP2018/038696 WO2020079783A1 (ja) | 2018-10-17 | 2018-10-17 | 鋳片の製造方法 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2020079783A1 true WO2020079783A1 (ja) | 2020-04-23 |
Family
ID=70284660
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2018/038696 WO2020079783A1 (ja) | 2018-10-17 | 2018-10-17 | 鋳片の製造方法 |
Country Status (5)
Country | Link |
---|---|
US (1) | US11458534B2 (ja) |
KR (1) | KR102526952B1 (ja) |
CN (1) | CN112752626B (ja) |
BR (1) | BR112021002414B1 (ja) |
WO (1) | WO2020079783A1 (ja) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP7364887B2 (ja) | 2019-12-04 | 2023-10-19 | 日本製鉄株式会社 | 薄肉鋳片の製造方法 |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS59193740A (ja) * | 1983-04-18 | 1984-11-02 | Nippon Kokan Kk <Nkk> | 金属板の連続鋳造方法 |
JPH01166863A (ja) * | 1987-12-23 | 1989-06-30 | Nippon Steel Corp | 双ドラム式連鋳機の圧下制御方法及び装置 |
JPH05228586A (ja) * | 1992-02-21 | 1993-09-07 | Nippon Steel Corp | 双ドラム式薄板連続鋳造装置及びその鋳造方法 |
JPH05305399A (ja) * | 1992-05-06 | 1993-11-19 | Nippon Steel Corp | 双ドラム式薄板連続鋳造方法及び装置 |
JP2000225444A (ja) * | 1999-02-05 | 2000-08-15 | Ishikawajima Harima Heavy Ind Co Ltd | 金属ストリップ連続鋳造装置 |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
MY113516A (en) | 1995-09-05 | 2002-03-30 | Nippon Steel Corp | Thin cast strip formed of molten steel, process for its production, and cooling drum for thin cast strip continuous casting apparatus |
CN102198495B (zh) * | 2010-03-26 | 2013-05-29 | 宝山钢铁股份有限公司 | 双辊薄带连铸侧封控制方法及装置 |
CN103008586B (zh) * | 2011-09-28 | 2015-04-22 | 宝山钢铁股份有限公司 | 一种双辊薄带连铸铸机固定辊调整方法和装置 |
CN103182492B (zh) * | 2011-12-30 | 2015-12-09 | 宝山钢铁股份有限公司 | 一种双辊薄带连铸铸辊的定位及辊缝调节方法及装置 |
-
2018
- 2018-10-17 CN CN201880097911.7A patent/CN112752626B/zh active Active
- 2018-10-17 BR BR112021002414-0A patent/BR112021002414B1/pt active IP Right Grant
- 2018-10-17 US US17/274,469 patent/US11458534B2/en active Active
- 2018-10-17 KR KR1020217008386A patent/KR102526952B1/ko active IP Right Grant
- 2018-10-17 WO PCT/JP2018/038696 patent/WO2020079783A1/ja active Application Filing
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS59193740A (ja) * | 1983-04-18 | 1984-11-02 | Nippon Kokan Kk <Nkk> | 金属板の連続鋳造方法 |
JPH01166863A (ja) * | 1987-12-23 | 1989-06-30 | Nippon Steel Corp | 双ドラム式連鋳機の圧下制御方法及び装置 |
JPH05228586A (ja) * | 1992-02-21 | 1993-09-07 | Nippon Steel Corp | 双ドラム式薄板連続鋳造装置及びその鋳造方法 |
JPH05305399A (ja) * | 1992-05-06 | 1993-11-19 | Nippon Steel Corp | 双ドラム式薄板連続鋳造方法及び装置 |
JP2000225444A (ja) * | 1999-02-05 | 2000-08-15 | Ishikawajima Harima Heavy Ind Co Ltd | 金属ストリップ連続鋳造装置 |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP7364887B2 (ja) | 2019-12-04 | 2023-10-19 | 日本製鉄株式会社 | 薄肉鋳片の製造方法 |
Also Published As
Publication number | Publication date |
---|---|
CN112752626B (zh) | 2022-08-26 |
BR112021002414B1 (pt) | 2023-11-28 |
US11458534B2 (en) | 2022-10-04 |
BR112021002414A2 (pt) | 2021-05-04 |
KR20210047905A (ko) | 2021-04-30 |
US20220048102A1 (en) | 2022-02-17 |
KR102526952B1 (ko) | 2023-04-28 |
CN112752626A (zh) | 2021-05-04 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP6252674B2 (ja) | 鋳片の連続鋳造方法 | |
JPH09507433A (ja) | 薄板圧延鋳造法 | |
WO2020079783A1 (ja) | 鋳片の製造方法 | |
JP6617615B2 (ja) | 薄肉鋳片製造設備、及び、薄肉鋳片の製造方法 | |
JP6784222B2 (ja) | 薄肉鋳片の製造方法 | |
JP5255461B2 (ja) | 双ロール式連続鋳造装置 | |
JP2006175488A (ja) | 双ロール式連続鋳造機及び双ロール式連続鋳造方法 | |
TWI696506B (zh) | 鑄片的製造方法 | |
JP2008023564A (ja) | 連続鋳造用のダミーバー及び鋼の連続鋳造方法 | |
JP6740767B2 (ja) | 薄肉鋳片の製造方法及び薄肉鋳片の製造装置 | |
JP2021087972A (ja) | 薄肉鋳片の製造方法 | |
JP2018103196A (ja) | 薄肉鋳片の製造装置及び薄肉鋳片の製造方法 | |
JP2023025988A (ja) | 冷却ロールの押圧荷重制御方法、および、薄肉鋳片の製造方法 | |
JP6569550B2 (ja) | 双ドラム式連続鋳造装置、冷却ドラム、及び、薄肉鋳片の製造方法 | |
JP2023026036A (ja) | 薄肉鋳片の製造方法 | |
CN112236248B (zh) | 薄壁铸板的制造方法 | |
EP2857122B1 (en) | Continuous casting method for slab | |
JP5881210B2 (ja) | サイドダムプレートならびにそれを用いた双ロール式連続鋳造装置および金属板の製造方法 | |
JP2007283357A (ja) | 連続鋳造装置 | |
JPH01249246A (ja) | 薄鋳片連続鋳造機およば薄鋳片連続鋳造方法 | |
JP2001071102A (ja) | 鋼鋳片の連続鋳造方法 | |
JPH1157951A (ja) | 薄鋳片の連続鋳造方法 | |
JP2006239769A (ja) | 連続鋳造装置 | |
JPH08141715A (ja) | 連続鋳造装置及び連続鋳造方法 | |
JP2017221954A (ja) | 双ロール式縦型鋳造装置 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 18936921 Country of ref document: EP Kind code of ref document: A1 |
|
REG | Reference to national code |
Ref country code: BR Ref legal event code: B01A Ref document number: 112021002414 Country of ref document: BR |
|
ENP | Entry into the national phase |
Ref document number: 20217008386 Country of ref document: KR Kind code of ref document: A |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
ENP | Entry into the national phase |
Ref document number: 112021002414 Country of ref document: BR Kind code of ref document: A2 Effective date: 20210209 |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 18936921 Country of ref document: EP Kind code of ref document: A1 |
|
NENP | Non-entry into the national phase |
Ref country code: JP |