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
  • B22D11/045—Continuous casting of metals, i.e. casting in indefinite lengths into open-ended moulds for horizontal 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
  • B22D11/04—Continuous casting of metals, i.e. casting in indefinite lengths into open-ended moulds
  • B22D11/055—Cooling the moulds

Definitions

• the present invention relates to an apparatus for the continuous casting of metal bars, pipes and sheets, and particularly to an apparatus which has a chill mold for receiving the molten metal, a cooling member fitted around least the rear part of the chill mold as seen in the withdrawing direction, a refractory lining protecting at least the cooling member, and members for the continuous withdrawing, from the chill mold, of the bar, pipe or sheet which has solidified in the chill mold.
• the object of the present invention is to promote the transfer of heat from the material being cast and thereby to increase the casting rate and obtain a more advantageous crystal structure in the casting, at least when copper or copper alloys are being cast.
• the chill mold may be made of graphite, and during casting the heat transferred from the solidifying molten metal and the solidified metal is directed further to a cooling medium circulating in the cooler. It is very important that this transfer of heat is effective, for it decides the rate at which the continuous casting can be carried out.
• a metal bar, pipe or sheet contracts when solidifying and cooling, and thereby a gap forms between the piece being cast and the chill mold; the gap is known to complicate the transfer of heat from the piece being cast to the chill mold. This gap cannot be completely eliminated because, if it is, then there is the risk that the casting adheres to the chill mold if the mold converges in the withdrawing direction. Owing to the low heat conductivity of air and gases, even a very narrow gap caused by contraction constitutes a considerable obstacle to the transfer of heat.
• the object of the present invention is therefore to provide an apparatus for the continuous casting of metal bars, pipes or sheets, an apparatus in which the transfer of heat from the solidifying melt and the cooling metal piece is more effective than previously so that the casting rate can be increased and simultaneously a product with improved crystal structure can possibly be obtained.
• the gap or gaps between the chill mold and the cooler are filled with a medium having a good thermal conductivity, such as molten metal or molten salt, in which case this gap is advantageously connected to an outside expansion vessel.
• a medium having a good thermal conductivity such as molten metal or molten salt
• a liquid with a good thermal conductivity such as a molten metal
• the heat-transferring medium does not come into contact with the metal being cast and, owing to the drop of temperature between the walls of the chill mold, the boiling point of the heat-transferring medium need not necessarily be higher than the solidification point of the metal being cast. Also, there is no fear of leakage problems in this case.
• the molten metal or salt is in a flowing motion, but it can just as well be completely stationary.
• the effectiveness of the heat-transferring medium is based on its thermal conductivity, which is far superior to that of gas, a decisive factor in this connection. It is important that the heat-transferring material fills as completely as possible the gaps between the chill mold and the cooler so that no gas pockets appear in these spaces. Therefore, it is advantageous to connect the gap or gaps to an 'expansion vessel for the heat-transferring medium so that heat-transferring medium can flow into the gap or gaps between the chill mold and the cooler and back as the volume of the gaps varies according to the thermal expansion movement of the surrounding walls.
• Figures 1 and 2 depict cross sectional side elevations of two preferred embodiments of the invention.
• the melt to be cast is indicated by reference numeral 1.
• the melt to be cast can be in a melt container the wall of which in general is indicated by 2 and to which a chill mold 4 made of graphite is attached to receive the melt. Outside the container wall 2 there is, fitted around the chill mold 4, a cooler 3, in which ducts for the cooling medium have been made in a known manner.
• the melt 1 flowing into the chill mold 4 yields heat to the walls of the chill mold 4 and forms, at a certain distance from the inlet of the chill mold 4, a solidification front, which is indicated by a dotted line in the drawing.
• the solidified metal is withdrawn in the form of a bar 7 from the chill mold 4 by means of withdrawal members 9.
• a gap 6 which in accordance with the invention is filled with a medium which transfers heat well
• the transfer of heat from the chill mold 4 to the cooler 3 is more effective than normally.
• the gap 6 between the chill mold 4 and the cooler 3 is connected by means of a pipe 8 to an expansion vessel 10, which is partly filled with a medium which transfers heat well.
• the expansion vessel 10 is at a higher level than the gap 6, in which there thus prevails a metallostatic pressure when molten metal is use as the cooling medium.
• the metal in the expansion vessel can be maintained in a molten state by, for example, fitting a heating resistor around the vessel.
• reference numeral 2 in Figure 1 indicates a refractory lining which prevents the melt from coming into direct contact with the cooler 3, which in this case must be lowered at least partly to a level below the melt surface.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Continuous Casting (AREA)

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• 1980
  • 1980-10-17 FI FI803270A patent/FI77586C/fi not_active IP Right Cessation
• 1981
  • 1981-10-16 WO PCT/FI1981/000076 patent/WO1982001332A1/en not_active Ceased
  • 1981-10-16 EP EP19810902986 patent/EP0062676B1/de not_active Expired

Non-Patent Citations (1)

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