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
  • B22D11/04—Continuous casting of metals, i.e. casting in indefinite lengths into open-ended moulds
  • B22D11/041—Continuous casting of metals, i.e. casting in indefinite lengths into open-ended moulds for vertical casting
• • 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
  • B22D11/14—Plants for continuous casting
  • B22D11/145—Plants for continuous casting for upward casting
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
  • B22D11/10—Supplying or treating molten metal
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
  • B22D11/12—Accessories for subsequent treating or working cast stock in situ
  • B22D11/124—Accessories for subsequent treating or working cast stock in situ for cooling
• • 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
  • B22D11/14—Plants for continuous casting
  • B22D11/141—Plants for continuous casting for vertical casting

Definitions

• the invention relates to an up-drawing continuous casting apparatus and an up-drawing continuous casting method.
• JP 2012-61518 A Japanese Patent Application Publication No. 2012-61518
• a starter is first immersed into the surface of molten metal (a molten metal surfade), and then when the starter is drawn up, molten metal is also drawn out following the starter by surface tension and the surface film of the molten metal.
• a casting that has a desired sectional shape is able to be continuously cast by drawing out the molten metal via a shape determining member arranged near the molten metal surface, and cooling it (i.e., the drawn out molten metal).
• the sectional shape and the shape in the longitudinal direction are both determined by a mold.
• the solidified metal i.e., the casting
• the shape determining member in the free casting method determines only the sectional shape of the casting, the shape in the longitudinal direction is not determined.
• the shape determining member is able to move in a direction parallel to the molten metal surface (i.e., horizontally), so castings of various shapes in the longitudinal direction are able to be obtained.
• JP 2012-61518 A describes a hollow casting (i.e., a pipe) formed in a zigzag shape or a helical shape, not a linear shape in the longitudinal direction.
• a hollow casting i.e., a pipe
• the molten metal drawn out via the shape determining member is cooled by only cooling gas, so the casting speed is slow, which is problematic in terms of productivity.
• the invention thus provides an up-drawing continuous casting apparatus and an up-drawing continuous casting method that increases casting speed, and thus offers excellent productivity.
• a first aspect of the invention relates to an up-drawing continuous casting apparatus.
• This up-drawing continuous casting apparatus includes a holding furnace that holds molten metal; a shape determining member that is arranged near a molten metal surface of the molten metal held in the holding furnace, and that determines a sectional shape of a casting by the molten metal passing through the shape determining member; a cooling portion that cools and solidifies the molten metal that has passed through the shape determining member; and a molten metal cooling portion that lowers a temperature of the molten metal held in the holding furnace.
• casting speed is able to be increased, so productivity is able to be improved.
• the molten metal cooling portion may be provided directly below the shape determining member.
• the temperature of the molten metal positioned directly below the shape determining member is able to be lowered in a short period of time, so the casting speed is able to be increased.
• the up-drawing continuous casting apparatus of the first aspect described above may also include an actuator that moves the molten metal cooling portion in a top-bottom direction inside the holding furnace.
• cooling gas may pass through an inside of the molten metal cooling portion.
• the molten metal cooling portion may be made of ceramic.
• the up-drawing continuous casting apparatus of the first aspect described above may also include a partition wall that surrounds the molten metal, and an ambient temperature regulating portion that regulates a temperature of an atmosphere surrounded by the partition wall.
• the quality of a casting is able to be made stable.
• a second aspect of the invention relates to an up-drawing continuous casting method that uses a casting apparatus having a shape determining member that determines a sectional shape of a casting, a holding furnace that holds a molten metal, and a molten metal cooling portion provided in the holding furnace.
• the up-drawing continuous casting method includes arranging the shape determining member near a molten metal surface of the molten metal held in the holding furnace; lowering a temperature of the molten metal held in the holding furnace, with the molten metal cooling portion; passing the molten metal that has been lowered in temperature through the shape determining member and drawing up the molten metal; and cooling the molten metal that has passed through the shape determining member, and been drawn up.
• casting speed is able to be increased, so productivity is able to be improved.
• the molten metal cooling portion may be provided directly below the shape determining member.
• the temperature of the molten metal positioned directly below the shape determining member is able to be lowered in a short period of time, so the casting speed is able to be increased.
• the up-drawing continuous casting method of the second aspect described above may also include moving the molten metal cooling portion in a top-bottom direction inside the holding furnace.
• lowering the temperature of the molten metal may be done by leading cooling gas into the molten metal cooling portion.
• the molten metal cooling portion may be made of ceramic.
• the up-drawing continuous casting method of the second aspect described above may also include surrounding the molten metal with a partition wall, and regulating a temperature of an atmosphere surrounded by the partition wall.
• the quality of a casting is able to be made stable.
• a third aspect of the invention relates to an up-drawing continuous casting apparatus.
• This up-drawing continuous casting apparatus includes a holding furnace that holds molten metal; a shape determining member that is arranged near a molten metal surface of the molten metal held in the holding furnace, and that determines a sectional shape of a casting by the molten metal passing through the shape determining member; and a cooling portion that cools and solidifies the molten metal that has passed through the shape determining member with a starter.
• the starter has a cooling mechanism that is integrated with the starter.
• casting speed is able to be increased, so productivity is able to be improved.
• the cooling mechanism may include a pipe that is attached to the starter and into which coolant is introduced.
• the cooling mechanism may be the starter itself that is formed by a pipe into which coolant is introduced.
• a fourth aspect of the invention relates to an up-drawing continuous casting method that uses a casting apparatus having a shape determining member that determines a sectional shape of a casting, a holding furnace that holds a molten metal, a starter, and a cooling mechanism that is integrated with the starter.
• the up-drawing continuous casting method includes arranging the shape determining member hear a molten metal surface of the molten metal held in the holding furnace; passing the molten metal through the shape determining member and drawing up the molten metal with the starter; cooling and solidifying the molten metal that has passed through the shape determining member and been drawn up; and cooling the starter with the cooling mechanism.
• casting speed is able to be increased, so productivity is able to be improved.
• the cooling mechanism may be formed by attaching a pipe to the starter and introducing coolant into the pipe.
• the cooling mechanism may be formed by introducing coolant into the starter itself that is formed by a pipe.
• FIG. 1 is a sectional view of a free casting apparatus according to a first example embodiment of the invention
• FIG. 2 is a plan view of an inner shape determining member and an outer shape determining member
• FIG. 3 is a plan view of a detailed configuration example of a molten metal cooler
• FIG. 4 is a plan view of another detailed configuration example of the molten metal cooler
• FIG 5 is a sectional view of a free casting apparatus according to a second example embodiment of the invention.
• FIG. 6 is a sectional view of a free casting apparatus according to a third example embodiment of the invention.
• FIG. 7 is a sectional view of a free casting apparatus according to a fourth example embodiment of the invention.
• FIG. 1 is a sectional view of the free casting apparatus according to the first example embodiment.
• the free casting apparatus according to the first example embodiment includes a molten metal holding furnace 101, an inner shape determining member 102a, an outer shape determining member 102b, support rods 103 and 104, an actuator 105, a cooling gas nozzle 106, a molten metal cooler 107, a coolant conduit 108, and an actuator 109.
• the molten metal holding furnace 101 holds molten metal Ml such as aluminum or an aluminum alloy, for example, and keeps it at a predetermined temperature.
• molten metal Ml such as aluminum or an aluminum alloy, for example, and keeps it at a predetermined temperature.
• molten metal Ml is not replenished into the molten metal holding furnace 101, so the surface of the molten metal Ml (i.e., the molten metal level) drops as casting proceeds.
• molten metal may also be instantly replenished into the molten metal holding furnace 101 during casting such that the molten metal level is kept constant.
• the molten metal Ml may be another metal or alloy other than aluminum.
• the inner shape determining member 102a and the outer shape determining member 102b are made of ceramic or stainless steel, for example, and are arranged near the molten metal surface. In the example shown in FIG. 1, the inner shape determining member 102a and the outer shape determining member 102b are arranged contacting the molten metal surface. However, the inner shape determining member 102a and the outer shape determining member 102b may also be arranged with a main surface thereof that is on the lower side (i.e., the molten metal side) not contacting the molten metal surface. More specifically, a predetermined gap (such as approximately 0.5 mm) may be provided between the molten metal surface and the lower-side main surface of both the inner shape determining member 102a and the outer shape determining member 102b.
• a predetermined gap such as approximately 0.5 mm
• the inner shape determining member 102a determines the inner shape of a casting M3, and the outer shape determining member 102b determines the outer shape of the casting M3.
• the casting M3 shown in FIG 1 is a hollow casting (i.e., a pipe) with a tube-shaped cross-section in the left-right direction (hereinafter referred to as "transverse section"). That is, more specifically, the inner shape determining member 102a determines an inner diameter of the transverse section of the casting M3, and the outer shape determining member 102b determines an outer diameter of the transverse section of the casting M3.
• FIG. 2 is a plan view of the inner shape determining member 102a and the outer shape determining member 102b.
• the sectional view of the inner shape determining member 102a and the outer shape determining member 102b in FIG. 1 corresponds to the sectional view taken along line I - I in FIG. 2.
• the outer shape determining member 102b has a rectangular planar shape, for example, and has a circular open portion in the center portion.
• the inner shape determining member 102a has a circular planar shape, for example, and is arranged in the center portion of the open portion of the outer shape determining member 102b.
• a gap between the inner shape determining member 102a and the outer shape determining member 102b is a molten metal passage portion 102c through which molten metal passes.
• the connecting member 102 is formed by the inner shape determining member 102a, the outer shape determining member 102b, and the molten metal passage portion 102c.
• the molten metal Ml is drawn up following the casting M3 by the surface tension and the surface film of the molten metal, and passes through the molten metal passage portion 102c.
• the molten metal that is drawn up from the molten metal surface following the casting M3 by the surface film and the surface tension of the molten metal will be referred to as "retained molten metal M2".
• the interface between the casting M3 and the retained molten metal M2 is a solidification interface.
• the support rod 103 supports the inner shape determining member 102a and the support rod 104 supports the outer shape detemining member 102b.
• the positional relationship between the inner shape determining member 102a and the outer shape determining member 102b is able to be maintained by these support rods 103 and 104.
• having the support rod 103 be a pipe structure flowing cooling gas through the support rod 103, and moreover, providing blow holes in the inner shape determining member 102a, enables the casting M3 to be cooled from the inside as well.
• the support rods 103 and 104 are both connected to the actuator 105.
• This actuator 105 enables the support rods 103 and 104 to move in the top-bottom direction, (the perpendicular direction) and the left-right direction, while maintaining the positional relationship between the inner shape determining member 102a and the outer shape determining member 102b.
• the inner shape determining member 102a and the outer shape determining member 102b are able to be moved downward as the molten metal level drops as casting progresses.
• the inner shape determining member 102a and the outer shape determining member 102b are able to be moved in the left-right direction, so the shape of the casting M3 in the longitudinal direction is able to be changed freely.
• a cooling gas nozzle (a cooling portion) 106 is used to spray cooling gas (e.g., air, nitrogen, argon, or the like) at the casting M3 to cool the casting M3.
• the casting M3 is cooled by the cooling gas while being drawn up by a drawer, not shown, that is connected to a starter ST. Accordingly, the retained molten metal M2 near the solidification interface solidifies sequentially, thus forming the casting M3.
• the temperature of the cooling gas is preferably made as low as possible.
• an extremely low temperature gas such as cooling gas that has been cooled by liquefied gas or cooling gas of liquefied gas (e.g., liquid nitrogen or liquid argon) has been vaporized may be used.
• the molten metal cooler (a molten metal cooling portion) 107 is designed to lower the temperature of the molten metal Ml positioned directly below the inner shape determining member 102a and the outer shape determining member 102b. Coolant is circulated through the molten metal cooler 107 only when the temperature of the molten metal Ml is to be lowered.
• the provision of the molten metal cooler 107 is one characteristic of the free casting apparatus according to this example embodiment.
• the coolant conduit 108 introduces the coolant into the molten metal cooler 107, circulates the coolant through the molten metal cooler 107, and leads the coolant that has removed the heat from the molten metal Ml out of the molten metal cooler 107. Also, the coolant conduit 108 supports the molten metal cooler 107.
• the coolant is not particularly limited, but from the viewpoint of safety, cooling gas (e.g., air, nitrogen, argon, or the like) is preferable. Also, as a method for circulating the coolant, a suction-type method is more preferable than a pressure-type method from the viewpoint of safety.
• the material of the molten metal cooler 107 and the coolant conduit 108 is not particularly limited.
• the material may be ceramic or stainless steel.
• FIG. 3 is a plan view of a detailed configuration example of the molten metal cooler 107.
• the inner shape determining member 102a and the support rod 103 are both shown by dotted lines to facilitate understanding of the planar positional relationship.
• the molten metal cooler 107 shown in FIG 3 is formed by a single coiled pipe. That is, the molten metal cooler 107 and the coolant conduit 108 are integrally formed. As shown in FIG. 3, a circular open portion is formed in the center portion of the molten metal cooler 107.
• the support rod 103 passes through this open portion. This kind of structure inhibits interference between the support rod 103 and the molten metal cooler 107.
• FIG 4 is a plan view of another detailed configuration example of the molten metal cooler 107.
• the molten metal cooler 107 shown in FIG. 4 is formed by a single winding pipe (the entire pipe is serpentine-like), with linear portions 107a and U-shaped portions 107b alternately repeating. That is, the molten metal cooler 107 and the coolant conduit 108 are integrally formed.
• the interval between two adjacent linear portions 107a is larger, and the support rod 103 passes through here. This kind of structure inhibits interference between the support rod 103 and the molten metal cooler 107.
• the structure of the molten metal cooler 107 shown in FIGS. 3 and 4 is only one example. Various other configuration examples are also possible.
• the coolant conduit 108 is connected to the actuator 109. As shown in FIG. 1, the actuator 109 enables the molten metal cooler 107 to move in a top-bottom direction in the molten metal Ml. The molten metal cooler 107 is also able to be moved in the left-right direction to conform to the inner shape determining member 102a and the outer shape determining member 102b.
• coolant may be circulated inside the molten metal cooler 107, and the molten metal cooler 107 may be raised so that it moves closer to the inner shape determining member 102a and the outer shape determining member 102b.
• circulation of the coolant in the molten metal cooler 107 may be stopped, and the molten metal cooler 107 may be lowered so that it moves away from the inner shape determining member 102a and the outer shape determining member 102b.
• the temperature of the molten metal Ml is always maintained at a predetermined appropriate temperature by the molten metal holding furnace 101.
• the appropriate temperature is a temperature for keeping the solidification interface at an appropriate height.
• the height of the solidification interface is maintained by a balance between heat removal from the casting M3 and up-drawing speed. For example, when the thickness of the casting M3 is thick during casting, the heat capacity of the retained molten metal M2 increases, so the balance becomes off, the position of the solidification interface rises, and the desired shape becomes difficult to obtain. That is, moldability deteriorates.
• the free casting apparatus is provided with the molten metal cooler 107, so the temperature of the molten metal Ml can be lowered in a short period of time.
• the molten metal cooler 107 is positioned directly below the inner shape determining member 102a and the outer shape determining member 102b, so the temperature of only the molten metal Ml near the inner shape determining member 102a and the outer shape determining member 102b (or more specifically, directly below the inner shape determining member 102a and the outer shape determining member 102b) is able to be lowered in a short period of time. Therefore, the casting speed does not need to be slowed, so the casting speed can be faster than it is with the free casting apparatuses until now. As a result, the casting time is shorter, so productivity is improved.
• the free casting method according to the first example embodiment will be described with reference to FIG. 1.
• the starter ST is lowered so that it passes through the molten metal passage portion 102c between the inner shape determining member 102a and the outer shape determining member 102b, and the tip end of the starter ST is immersed in the molten metal Ml .
• the starter ST starts to be drawn up at a predetermined speed.
• the retained molten metal M2 that follows the starter ST and is drawn up from the molten metal surface by the surface film and surface tension is formed.
• the retained molten metal M2 is formed in the molten metal passage portion 102c between the inner shape determining member 102a and the outer shape determining member 102b. That is, the inner shape determining member 102a and the outer shape determining member 102b give the retained molten metal M2 its shape.
• the starter ST is cooled by cooling gas blown from the cooling gas nozzle 106, so the retained molten metal M2 solidifies sequentially from the upper side toward the lower side, thus forming the casting M3. In this way, the casting M3 is able to be continuously cast.
• FIG. 5 is a sectional view of the free casting apparatus according to the second example embodiment.
• the free casting apparatus according to the second example embodiment includes a molten metal holding furnace 101, an inner shape determining member 102a, an outer shape determining member 102b, support rods 103 and 104, an actuator 105, a cooling gas nozzle 106, a molten metal cooler 107, a coolant conduit 108, an actuator 109, a partition wall 110, and an ambient temperature regulating portion 111. That is, the partition wall 110 and the ambient temperature regulating portion 111 are added to the free casting apparatus according to the first example embodiment shown in FIG. 1.
• the other structure is the same as it is in the first example embodiment, so a description thereof will be omitted.
• the molten metal Ml and the casting M3 are housed in a space partitioned off by the partition wall 110. Also, the ambient temperature regulating portion 111 is provided on a ceiling portion of the partition wall 110.
• the temperature in the space partitioned off by the partition wall 110 is maintained at a predetermined temperature (such as 25 °C for example) by the ambient temperature regulating portion 111. Because the temperature of the atmosphere of the molten metal Ml and the casting M3 is kept constant, the quality of the casting M3 is able to be more stable than it is with the free casting apparatus according to the first example embodiment. Also, by keeping the temperature of the atmosphere at 25°C, for example, the temperature of the atmosphere drops farther than it does when the temperature of the atmosphere is not controlled, so the casting speed is able to be faster than is with the free casting apparatus according to the first example embodiment.
• the location where the ambient temperature regulating portion 111 is arranged is not particularly limited. Also, as shown in FIG 5, an air flow port 110a may be provided in an upper portion of the partition wall 110 so that heated air trapped inside the partitioned space is able to escape.
• FIG. 6 is a sectional view of the free casting apparatus according to the third example embodiment.
• the free casting apparatus according to the third example embodiment includes a molten metal holding furnace 101, an inner shape determining member 102a, an outer shape determining member 102b, support rods 103 and 104, an actuator 105, a cooling gas nozzle 106, and a coolant conduit 112. That is, the molten metal cooler 107, the coolant conduit 108, and the actuator 109 in the free casting apparatus according to the first example embodiment shown in FIG. 1 are not provided, and instead, the coolant conduit 112 is provided.
• the other structure is the same as it is in the first example embodiment, so a description thereof will be omitted.
• the free casting apparatus according to the third example embodiment includes the coolant conduit (a cooling mechanism) 112 that is wound in a helical shape around a starter ST. That is, the free casting apparatus according to the third example embodiment has a cooling mechanism that is integrated with the starter ST. According to this kind of structure, the starter ST is cooled.
• the coolant is not particularly limited, but cooling gas (e.g., air, nitrogen, argon, or the like), or cooling water may be used, for example. Cooling the starter ST enables heat removal from the casting M3 to be increased and casting speed to be faster while retaining good moldability.
• the casting speed may be increased even more by combining the first example embodiment with the third example embodiment, or the second example embodiment with the third example embodiment.
• FIG. 7 is a sectional view of the free casting apparatus according to the fourth example embodiment.
• the free casting apparatus according to the fourth example embodiment includes a molten metal holding furnace 101, an outer shape determining member 102b, a support rod 104, an actuator 105, and a cooling gas nozzle 106. That is, the inner shape determining member 102a, the support rod 103, and the coolant conduit 112 in the free casting apparatus according to the third example embodiment shown in FIG. 6 are not provided.
• the starter ST itself is a coolant conduit (a cooling mechanism). That is, the free casting apparatus according to the fourth example embodiment is also provided with a cooling mechanism that is integrated with the starter ST.
• the other structure is the same as it is in the third example embodiment, so a description thereof will be omitted.
• the casting M3 cast with the free casting apparatus according to the fourth example embodiment is a solid structure (a rod), not a hollow structure (a pipe). Therefore, the inner shape determining member 102a is not used. Only the outer shape determining member 102b according to the example embodiment described above is used. In this case, the open portion provided in the outer shape determining member 102b as it is serves as a molten metal passage portion 102c.
• the starter ST itself is the coolant conduit, so the starter ST is cooled.
• the coolant is not particularly limited, but cooling gas (e.g., air, nitrogen, argon, or the like) may be used, for example.
• the flow rate of the coolant may be controlled at the start of casting and during casting. More specifically, the flow rate of the coolant may be lower at the start of casting than it is during casting.
• cooling water may also be used.
• cooling gas may be used at the start of casting, and cooling water may be used during casting.
• cooling the starter ST enables heat removal from the casting M3 to be increased and casting speed to be faster, just like the third example embodiment. Also, because the starter ST is cooled, material with a lower melting point than the molten metal temperature may be used as the starter ST. Furthermore, the coolant temperature on the inlet side and the coolant temperature on the outlet side may be monitored and fed back to the casting control. After casting, heat treatment for texture control may be performed by circulating heat treating oil instead of coolant through the starter ST.
• a normal starter ST is removed after casting, but the starter ST according to the fourth example embodiment is able to be used as it is as a product.
• pipe for a heat exchanger may be used as the normal starter ST.
• an even more complicated cooling circuit may also be used as the starter ST.
• a casting that includes a pipe therein can also be formed by immersing the starter ST in the molten metal.
• the casting speed may be increased even more by combining the first example embodiment with the fourth example embodiment, or the second example embodiment with the fourth example embodiment.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Continuous Casting (AREA)
• Molds, Cores, And Manufacturing Methods Thereof (AREA)

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• 2012
  • 2012-09-18 JP JP2012204463A patent/JP2014057980A/ja not_active Withdrawn
• 2013
  • 2013-09-13 EP EP13773840.7A patent/EP2861363A2/en not_active Withdrawn
  • 2013-09-13 AU AU2013319899A patent/AU2013319899A1/en not_active Abandoned
  • 2013-09-13 CN CN201380038109.8A patent/CN104487190A/zh active Pending
  • 2013-09-13 IN IN350DEN2015 patent/IN2015DN00350A/en unknown
  • 2013-09-13 US US14/415,440 patent/US20150196952A1/en not_active Abandoned
  • 2013-09-13 RU RU2015101255A patent/RU2015101255A/ru unknown
  • 2013-09-13 BR BR112015000766A patent/BR112015000766A2/pt not_active IP Right Cessation
  • 2013-09-13 WO PCT/IB2013/002129 patent/WO2014045115A2/en active Application Filing
  • 2013-09-13 CA CA2879339A patent/CA2879339A1/en not_active Abandoned
  • 2013-09-13 KR KR20157000669A patent/KR20150022000A/ko not_active Withdrawn

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