EP0073573A1 - Controlled transfer of molten metal - Google Patents

Controlled transfer of molten metal Download PDF

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Publication number
EP0073573A1
EP0073573A1 EP82304056A EP82304056A EP0073573A1 EP 0073573 A1 EP0073573 A1 EP 0073573A1 EP 82304056 A EP82304056 A EP 82304056A EP 82304056 A EP82304056 A EP 82304056A EP 0073573 A1 EP0073573 A1 EP 0073573A1
Authority
EP
European Patent Office
Prior art keywords
vessel
inlet
transfer tube
ladle
mould
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP82304056A
Other languages
German (de)
English (en)
French (fr)
Inventor
Michael Cornelius Ashton
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Steel Castings Research and Trade Association
Original Assignee
Steel Castings Research and Trade Association
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Steel Castings Research and Trade Association filed Critical Steel Castings Research and Trade Association
Publication of EP0073573A1 publication Critical patent/EP0073573A1/en
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D37/00—Controlling or regulating the pouring of molten metal from a casting melt-holding vessel
    • 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
    • B22D41/50—Pouring-nozzles

Definitions

  • the invention relates to the controlled transfer of molten metal. More particularly, the invention is concerned with the transfer of such metal from a vessel, e.g. a ladle, to another vessel, typically to a mould.
  • a vessel e.g. a ladle
  • Such ladles are usually provided with an opening at the base of the ladle, e.g. a stopper rod/nozzle assembly or sliding gate mechanism.
  • the ladle is normally moved until the bottom pour opening in the ladle is situated directly above the sprue of a mould and the bottom pour opening is opened, e.g. by lifting of a stopper rod or movement of a plate within a sliding gate mechanism.
  • a molten metal transfer system comprising a first metallurgical vessel (e.g. a ladle) having an outlet, a control valve for the outlet having an open position and a closed position, a second metallurgical vessel, e.g. a mould, having an inlet, a transfer tube connecting the outlet of the first vessel and the inlet of the second vessel, and means to allow molten metal to pass from the first vessel to the second vessel at a rate determined solely by the dimensions of the first vessel outlet, the transfer tube and/or the second vessel inlet.
  • a first metallurgical vessel e.g. a ladle
  • a control valve for the outlet having an open position and a closed position
  • a second metallurgical vessel e.g. a mould
  • the rate of flow of molten metal will be controlled by the smallest diameter of the first vessel outlet, the transfer tube and the second vessel inlet.
  • the volume of metal in a ladle is usually greater than that required to fill any one mould and so one ladle will typically be used to fill several moulds which may have gating systems of different diameters.
  • the nozzle of the ladle will be selected to have a diameter corresponding to the largest diameter of the different gating systems but when the ladle is used to fill a mould having a smaller diameter gating system the operative will tend to throttle the stream and this will give rise to castings of poor quality.
  • the rate of pour will be determined by the diameter of the ladle nozzle or the diameter of the gating -system where that is smaller. The rate of pour will be at a maximum in each case.
  • the first metallurgical vessel is a foundry ladle having a bottom pour outlet and the second metallurgical vessel is a foundry mould and the inlet is a gating system therefor.
  • the transfer tube is sealed to both vessels at each end.
  • the transfer tube will depend from the underside of the first vessel e.g. ladle, and is fixed to that vessel.
  • the lower end of the transfer tube is provided with spring biased sealing means for reception or engagement with the inlet of the second vessel e.g. mould or gating system therefor to form a sealed connection.
  • the transfer tube may be formed from a metal having a higher melting point than the molten metal in the ladle. It is preferred to provide a refractory lining in the tube or possibly a refractory pipe, which refractory lining or pipe can be contoured to eliminate so-called dead-zones in the molten metal flowing through the pipe. Preferably the refractory lining adjacent to the metal stream is heat insulating to minimise the likelihood of metal freezing in the transfer tube.
  • the tube may be straight or include angled portions.
  • the tube may be secured to the ladle but need not of necessity extend directly to the top of a mould proper.
  • the tube may, for instance, be received in sealed manner e.g. embedded in a trumpet feeding several moulds in an uphill pouring system or into the inlet of a continuous casting plant.
  • the invention further includes a method of transferring molten metal using the system outlined above.
  • the ladle is lowered on to a mould until the free end of the tube is located centrally about the sprue of the mould.
  • the tube is then received in the pouring cup, which may be moulded in sand or preformed in refractory material.
  • the bottom pour opening in the ladle is then fully opened and as soon as the metal reaches a desired position in the mould cavity, the bottom pour opening is closed and the remaining molten metal in the transfer tube flows into the sprue as the metal level equilibrates.
  • the ladle can then be lifted and positioned on the next mould.
  • the system is effectively sealed, the operator may fully open the ladle without any danger of being splashed by molten metal.
  • the rate at which the mould fills is independent of the operator and is dependent only on either the discharge characteristics of the ladle or the dimensions and design of the gating system, both of which are quantifiable. Consequently, the pouring time is completely predictable and it becomes possible to design a pouring system to ensure consistent achievement of the prescribed pouring rate.
  • the system is effectively sealed, the entrainment of air in the metal stream, which otherwise occurs to a marked degree, is prevented, eliminating a further source of reoxidation.
  • the air which would normally be entrained is carried through to the mould cavity which, as a consequence, is vented to provide channels through which the air may escape. The need for vents is therefore eliminated or substantially reduced by pouring in the manner described.
  • the mould is made by the Vacuum Moulding Process or V-Process.
  • Such moulds consist of loose sand held in place by a vacuum, the mould system being sealed by heat destructible plastic sheeting.
  • V-Process When pouring such moulds it is desirable that very high filling rates are achieved and that metal splashing onto the plastic cover on the top surface of the mould is avoided otherwise vacuum losses occur. In extreme cases, failure to meet these conditions can result in partial or even complete collapse of the mould.
  • splashing is completely eliminated and the required very high pouring rates can readily be achieved. It will be apparent that in a vacuum assisted moulding process the prevention of entrained or aspirated air achievable with the invention is also highly desirable.
  • inclusions typically refractory particles
  • a ceramic filter in the gating system which would trap any undesirable particles.
  • the limited permeability of the filter reduces the volume flow rate through the gating system so that with conventional pouring practice the gating system would back-fill and overflow at the pouring cup.
  • An advantage of the transfer system of this invention is that the system is sealed so that overflow does not occur and another advantage is that the increased ferrostatic head effectively forces molten metal through the filter element. It may be desirable to increase the cross-sectional area of the gating system to compensate for the choking effect of the filter element.
  • the filter element is located at the ingate(s) so that clean metal enters the mould cavity proper at a low velocity or the filter element may be located in the pouring cup to serve as a gasket to seal the transfer tube and to minimise the restriction to flow.
  • the invention includes a ladle and a foundry mould for use in the system or method and a casting made by the method.
  • a ladle 1 has a bottom pour opening 2 defined by a reverse taper nozzle 3 which may be closed by the end of a stopper rod 4. Part of the nozzle 3 extends below a retaining plate 5 to which is rigidly secured a transfer tube 6.
  • the tube comprises an outer steel pipe having an inner lining of refractory heat insulating material.
  • the outer face of the transfer tube 6 is accurately machined to form an accurate sliding fit with a tapered end piece or cap 7.
  • the tapered end piece is spring loaded circumferentially about a point 8 by springs 11 so that when the springs are relaxed the tapered end piece 7 extends beyond the end of the transfer tube 6 as shown in Figure 1(a).
  • molten metal is tapped into the ladle with the opening 2 closed by the stopper 4.
  • the ladle is moved to bring the tapered end piece over the pouring cup of the downrunner 9 in Figure 1(a).
  • the ladle is then lowered to locate the tapered end piece on a frustoconical compressible refractory gasket 10 which is positioned in the pouring cup 9.
  • the tapered end piece 7 slides up the transfer tube 6 against the resistance of the springs 11 which are compressed until two registers on the sliding part and fixed part are juxtaposed and the ends of the sliding piece 7 and fixed tube 6 are coincident, at point 12 in Figure 1(b).
  • the pressure of the springs in this. condition is great enough to create an effective seal on the gasket 10 so that ingress of liquid metal to the sliding faces is prevented and yet at the same time the downward force imposed is not so great as to damage the pouring cup or mould system.
  • the stopper rod 4 is then lifted to fully open the bottom pour opening and metal flows from the ladle into the mould at a rate determined either by the cross-sectional area of the nozzle 3 or the refractory lined tube 6 or the gating system 9.
  • the gating system may incorporate a choke, not shown, i.e. a point where the cross-sectional area is less than that of the nozzle 3 or transfer tube 6, to control the filling rate. Control of the rate of filling is exercised by the pouring system in a predictable manner and in such a way that exposure of the stream to atmosphere is more or less completely eliminated. (If such a choke is located at the base of the downrunner say, the downrunner is said to be pressurised and becomes completely full of liquid metal so that no air is aspirated).
  • the stopper 4 When the molten metal reaches the desired level in the mould, the stopper 4 is lowered to close the bottom pour opening, and molten metal in the nozzle block 3 and transfer tube 6 flows into the sprue as the metal level equilibrates. The ladle can then be lifted clear of the mould and positioned over the next mould to be poured.
  • a filter plate 13 of permeable erosion resistant refractory material e.g. zirconia or magnesia
  • the cap /A engages or is located adjacent the tapered inlet of the pouring cup 9.
  • the filter plate could not be used without the closed pouring system of the invention, since the backfilling of the pouring cup and splashing which would otherwise occur would present a hazard to the operator.
  • the closed system causes an increased ferrostatic head of pressure which urges the metal through the plate 13.
  • a filter plate is located in the gating system or adjacent the inlet to the mould cavity. The cross-sectional area of the gating system channel must be increased at the location point correspondingly to offset the restriction to flow caused by the filter.
  • the molten metal passing through the tube is subjected, at a controlled rate, to a treatment for example, deoxidation or desulphurisation of steel, desulphurisation of pig iron, nodularisation and inoculation, by introduction into the stream via a hole in the tube wall or inlet of gases, powders, wires, encapsulated powders in wire form or the like.
  • a treatment for example, deoxidation or desulphurisation of steel, desulphurisation of pig iron, nodularisation and inoculation

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
EP82304056A 1981-08-07 1982-08-02 Controlled transfer of molten metal Withdrawn EP0073573A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8124247 1981-08-07
GB8124247 1981-08-07

Publications (1)

Publication Number Publication Date
EP0073573A1 true EP0073573A1 (en) 1983-03-09

Family

ID=10523793

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82304056A Withdrawn EP0073573A1 (en) 1981-08-07 1982-08-02 Controlled transfer of molten metal

Country Status (2)

Country Link
EP (1) EP0073573A1 (ja)
JP (1) JPS5890370A (ja)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0197494A1 (de) * 1985-04-09 1986-10-15 Klöckner-Humboldt-Deutz Aktiengesellschaft Verfahren und Einrichtung zum Abgiessen von Metallschmelzen
EP0577909A1 (en) * 1992-07-10 1994-01-12 FLOCON ITALIANA S.r.l. Replaceable auxiliary nozzle
US5711367A (en) * 1996-01-11 1998-01-27 Larex A.G. Apparatus for delivering molten metal to a caster including wear strips
JP2010207894A (ja) * 2009-03-11 2010-09-24 Kurosaki Harima Corp 定形目地材
WO2016113196A1 (en) * 2015-01-12 2016-07-21 Vesuvius Crucible Company Casting nozzle with external resilient gasket

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH441633A (fr) * 1965-05-14 1967-08-15 Machin Anstalt Dispositif de réglage du débit d'une poche pour la coulée de métaux
US3511304A (en) * 1967-09-13 1970-05-12 American Smelting Refining Float control valve for continuous casting
DE2013215A1 (de) * 1969-03-20 1970-10-08 OSS Engineers and Consultants, Inc., Pittsburgh, Pa. (V.St.A.) Einlaßkonstruktion für umschlossene Gefäße
FR2050387A1 (ja) * 1969-05-01 1971-04-02 Uss Eng & Consult

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH441633A (fr) * 1965-05-14 1967-08-15 Machin Anstalt Dispositif de réglage du débit d'une poche pour la coulée de métaux
US3511304A (en) * 1967-09-13 1970-05-12 American Smelting Refining Float control valve for continuous casting
DE2013215A1 (de) * 1969-03-20 1970-10-08 OSS Engineers and Consultants, Inc., Pittsburgh, Pa. (V.St.A.) Einlaßkonstruktion für umschlossene Gefäße
FR2050387A1 (ja) * 1969-05-01 1971-04-02 Uss Eng & Consult

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0197494A1 (de) * 1985-04-09 1986-10-15 Klöckner-Humboldt-Deutz Aktiengesellschaft Verfahren und Einrichtung zum Abgiessen von Metallschmelzen
EP0577909A1 (en) * 1992-07-10 1994-01-12 FLOCON ITALIANA S.r.l. Replaceable auxiliary nozzle
US5711367A (en) * 1996-01-11 1998-01-27 Larex A.G. Apparatus for delivering molten metal to a caster including wear strips
JP2010207894A (ja) * 2009-03-11 2010-09-24 Kurosaki Harima Corp 定形目地材
WO2016113196A1 (en) * 2015-01-12 2016-07-21 Vesuvius Crucible Company Casting nozzle with external resilient gasket

Also Published As

Publication number Publication date
JPS5890370A (ja) 1983-05-30

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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Effective date: 19830902

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Withdrawal date: 19850119

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Inventor name: ASHTON, MICHAEL CORNELIUS