Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D19/00—Casting in, on, or around objects which form part of the product
  • B22D19/16—Casting in, on, or around objects which form part of the product for making compound objects cast of two or more different metals, e.g. for making rolls for rolling mills
• • 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
  • B22D11/008—Continuous casting of metals, i.e. casting in indefinite lengths of clad ingots, i.e. the molten metal being cast against a continuous strip forming part of the cast product

Definitions

• the present invention relates to a process f and a device for producing a metalli ⁇ envelope on a core of elongated shape and of metallurgical composition * different from that of said envelope,
• the present invention also relates to a rolling mill cylinder obtained by this process.
• the methods of producing a metal casing on an elongated core 10 consist of moving the core vertically and coaxially in an ingot mold, the internal wall of which provides space with the external wall of the core and whose internal section corresponds substantially to the section of said envelope, to pour, into said space, a molten filler metal 15, intended to form said envelope, to heat the upper part of the mold and to cool the part bottom of said mold to solidify said filler metal.
• A-6160256 a process for producing a metal casing on a core, in which the molten filler metal intended to form said casing is kept at temperature, before it solidifies, in an ingot mold
• the supply of molten filler metal is maintained at temperature by a coil with high frequency induction.
• a preheating of the filler metal supplying the conical upper part of the mold is carried out, as well as an enameling of the core in order to facilitate the connection between the filler metal intended to form the envelope and the metal constituting the core.
• the object of the invention is to avoid the drawbacks mentioned above by proposing a method and a device for producing a metal casing on an elongated core, particularly simple to implement and making it possible to provide a hot pickling of the external wall of the core just before the deposition of the filler metal.
• the subject of the invention is therefore a method of producing a metal casing on a core of elongated shape and of metallurgical composition different from that of said casing, to form a bimetallic composite product, such as for example a rolling mill cylinder, process in which :
• the core is moved vertically and coaxially in an ingot mold, the internal wall of which provides space with the external wall of the core and the internal section of which corresponds substantially to the section of said envelope,
• the core is moved in the mold by communicating to it a continuous vertical oscillation associated with the vertical downward movement of said core,
• the molten filler metal is covered, inside the ingot mold and at the upper part of said ingot mold, with an electrically conductive slag, - the electroconductive slag is heated to a temperature above 1450 ° C. ,
• the molten filler metal is poured into the space formed between the internal wall of the ingot mold and the external wall of the core, by pouring said previously molten metal into an oven associated with said ingot mold,
• a subject of the invention is also a device for producing a metal casing on an elongated core, for implementing the method mentioned above, said device comprising an ingot mold of internal section corresponding substantially to the section of said envelope and the internal wall of which forms a space with the external wall of said core for a molten filler metal intended to form said envelope, said ingot mold comprising at its lower part cooling means for solidifying the metal of contribution, characterized in that the mold is formed by an upper ring for heating and rotating an electroconductive slag placed above the filler metal in said mold, a lower ring provided with said cooling means and a electrically insulating ring and separating said rings.
• the upper ring is split vertically to form an induction coil with a turn and a first heating electrode by Joule effect of the electroconductive slag, a second heating electrode by Joule effect of said slag being formed by the core, device comprises a furnace for maintaining the temperature of the molten filler metal associated with the ingot mold,
• the subject of the invention is also a rolling mill cylinder of the type comprising a core of elongated shape and a metal casing of metallurgical composition different from that of said core, characterized in that it is obtained by the process mentioned above.
• the invention will be better understood with the aid of the description which follows, given solely by way of example and made with reference to the single appended figure which represents a perspective view partially broken away of the device according to the invention.
• the device shown in the figure is intended for producing a metal casing 2 of hard alloy on an elongated core, such as for example a shaft 1 of structural steel of the XC38 or 35CD4 type to form a bimetallic composite product and in particular a rolling mill cylinder.
• the device comprises an ingot mold 10 intended to receive a molten filler metal 5 constituting the metallic envelope 2 and which is crossed by the shaft 1.
• the shaft 1 is moved vertically and coaxially in the ingot mold 10 and for this, this shaft 1 is, on the one hand, suspended at its upper end la for example by a flange 3 to a suitable support member, not shown, and, on the other hand guided at its lower end lb .
• the shaft 1 is also driven in a vertical oscillating movement at the same time as the vertical downward movement in the mold 10.
• This ingot mold 10 has an internal section corresponding substantially to the section of the envelope 2.
• the internal wall 10a of the mold 10 provides a space 4 with the external wall 1c of the shaft
• the ingot mold 10 is formed of an upper ring 11, a lower ring 12 and an electrically insulating ring 13 separating said rings 11 and 12.
• the rings 11 and 12 are hollow and are for example made of copper.
• the upper ring 11 is connected to a power source, not shown, in direct current on which is superimposed a low frequency current.
• the upper ring 11 has a vertical slot 11a so as to form an induction coil with a turn and a first Joule heating electrode.
• a second heating electrode is formed by the shaft 1.
• the rings 11 and 12 comprise cooling means, not shown, which are formed for example by at least one water circulation circuit formed in said rings.
• the upper ring 11 also comprises a funnel 14 intended to ensure the flow of the filler metal 5 in the space 4 and which is contained in an oven 6 for maintaining the temperature of said filler metal.
• This oven 6 is for example constituted by an induction oven.
• the molten filler metal 5 contained in the furnace 6 is poured by successive sips into the space 4 by the intermediary ⁇ diary of the funnel 14.
• the filler metal 5 in the space 4 is covered with an electroconductive slag 7 at the level of the upper ring 11 of the ingot mold 10.
• This electroconductive slag 7 is heated by Joule effect at a temperature above 1450 ⁇ C and for example at 1500 ° C. by the heating electrodes formed respectively by the upper ring 11 and the shaft 1.
• the split upper ring 11 which forms an induction coil, rotates the electroconductive slag 7 in the mold 10 and around the shaft 1 using the low frequency current.
• the speed of rotation of the electroconductive slag 7 is equal to approximately 1 revolution per second, which makes it possible to carry out a stripping of the external wall 1c of the shaft 1 just before this wall comes into contact with the filler metal. 5 in fusion intended to form the envelope 2.
• the rotational movement of the electro slag conductor 7 makes it possible to put the shaft 1 in an ideal condition for achieving perfect welding between the metal of the shaft 1 and the metal of the casing 2.
• the molten filler metal 5 poured by successive sips into the space 4 passes through the electroconductive slag 7 and gradually solidifies by coming into contact with the lower ring 12 which is cooled.
• the molten filler metal 5 is distributed homogeneously around the shaft 1 thanks in particular to the rotation of the electroconductive slag 7.
• the casing 2 is formed progressively on said shaft 1.
• the solidified part of the casing 2 forms a movable bottom of the mold 10.
• a ring can be mounted on the shaft 1 to form the movable bottom of the ingot mold 10 at the start of the casting of the filler metal 5 in fusion in said ingot mold.
• the vertical downward movement of the shaft 1 according to a continuous oscillation allows the gradual demolding of the composite product thus produced, from the ingot mold 10.
• the device according to the invention makes it possible to pour and solidify approximately 10 kg / min. of working metal.
• the device according to the invention can allow the filler metal to flow more quickly, but, in this case, the height of the filler metal in the ingot mold 10 must be small in order to prevent the two solidification fronts formed by the lower ring 12 and by the shaft 1 produce porosities at the interface of these two fronts.
• the method and the device according to the invention are perfectly suited for the production of hot and cold rolling mill rolls.
• the molten filler metal which can be protected during casting by a jet of argon, is then purified in particular in oxidized inclusions by the action of said electroconductive slag.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Manufacture And Refinement Of Metals (AREA)
• Manufacture Of Alloys Or Alloy Compounds (AREA)
• Furnace Details (AREA)
• Metal Rolling (AREA)
• Wire Processing (AREA)
• Metal Extraction Processes (AREA)
• Furnace Charging Or Discharging (AREA)
• Continuous Casting (AREA)

Applications Claiming Priority (3)

Publications (2)

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ID=9445702

Family Applications (1)

Country Status (6)

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Citations (4)

Family Cites Families (3)

• 1993
  • 1993-04-02 FR FR9303927A patent/FR2703278B1/fr not_active Expired - Lifetime
• 1994
  • 1994-04-01 WO PCT/FR1994/000372 patent/WO1994022619A1/fr not_active Ceased
  • 1994-04-01 ES ES94912583T patent/ES2106526T3/es not_active Expired - Lifetime
  • 1994-04-01 AT AT94912583T patent/ATE156398T1/de active
  • 1994-04-01 EP EP94912583A patent/EP0693011B1/de not_active Expired - Lifetime
  • 1994-04-01 DE DE69404832T patent/DE69404832T2/de not_active Expired - Lifetime

Patent Citations (4)

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