US3884290A - Method of direct chill continuous casting - Google Patents

Method of direct chill continuous casting Download PDF

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Publication number
US3884290A
US3884290A US434784A US43478474A US3884290A US 3884290 A US3884290 A US 3884290A US 434784 A US434784 A US 434784A US 43478474 A US43478474 A US 43478474A US 3884290 A US3884290 A US 3884290A
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Prior art keywords
ingot
speed
crack
withdrawal
casting
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Expired - Lifetime
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US434784A
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English (en)
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John Gordon Mccubbin
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Alcan Research and Development Ltd
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Alcan Research and Development Ltd
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    • 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
    • B22D11/103—Distributing the molten metal, e.g. using runners, floats, distributors
    • 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
    • B22D11/128—Accessories for subsequent treating or working cast stock in situ for removing

Definitions

  • ABSTRACT [30] Fm-e'gn Apphc'anonrrmnty Data In the production of aluminium ingots, particularly Jan. 24, 1973 United Kingdom 3699/73 round ingots f aluminium magnesium Sflicide alloys having hot-short characteristics, by the direct chili [52] US. Cl. 164/82; 164/283 MS Continuous casting process the Casting Speed is held [51] Int. Cl.
  • molten metal is introduced into a mould, the bottom end of which is initially closed by means of a stool, which may be lowered at a desired speed under the control of the operator to withdraw the ingot from the mould.
  • a stool which may be lowered at a desired speed under the control of the operator to withdraw the ingot from the mould.
  • the metal is poured into the mould a solid skin forms at the periphery where the molten metal contacts the mould wall.
  • the stool is lowered and heat is removed from the metal by application of coolant directly to the solidified surface skin of the metal exposed between the bottom margin of the mould and the stool.
  • the rate at which the cast ing is produced is dependent upon the rate at which the stool is lowered while maintaining a substantially constant head of metal in the mould.
  • molten metal is introduced into one end of a horizontally-arranged mould and withdrawn from the opposite end of the mould by a withdrawing member.
  • Hot-short cracking may be defined as a tendency to tearing or cracking wherein the growth tip of the crack is at a zone of the ingot which is above the solidus temperature.
  • the casting speed may be increased after the crack has healed to a speed, which if applied at an earlier instant in the travel of the stool would have led to an unsound ingot with a more or less continuous centre crack.
  • C.P.S. crack propagating speed
  • a process for the production of aluminium (including aluminium alloy) ingots by the direct chill casting method includes casting a length of ingot at a speed below the C.P.S. to develop a crack-free centre and thereafter raising the casting speed to a speed above the C.P.S. but below the C.I.S.
  • the process is particularly applicable to the .production of round and square ingots.
  • the initial casting speed is maintained below the C.P.S. until a crack-free core has been developed, in some circumstances it might be desirable to employ a high initial casting speed in excess of the C.P.S. and accept the resultant crack, the casting speed then being decreased below the C.P.S. until the desired crack-free centre had been developed.
  • the casting speed may then be again increased above the C.P.S. and held at such a speed (but below the C.I.S.) during the casting of the remainder of the ingot.
  • a speed substantially below the C.P.S. during the first few inches of the drop.
  • a speed substantially below the C.P.S. during the first few inches of the drop.
  • this speed will be somewhat smaller or larger, respectively.
  • the speed is raised over the distance of about another /2 ingot diameter to a speed slightly below the C.P.S., such as /2-l in./min.
  • the maximum casting speed employed is preferably /24 in./min. less than the C.l.S.
  • a speed above the C.P.S. is usually reached after casting about 3 /2 diameters of ingot.
  • the crack-free length to be cast before increasing to the speed between C.P.S. and C.I.S. should be about 2 and 4 diameters, respectively. Where the ingot is of rectangular section this distance should be related to the minimum transverse dimension of the ingot (its thickness) in place of the diameter.
  • the transition from the casting speed below the CPS. to the speed between the CPS. and the C.l.S. is carried out in progressive increments of about one-half in./min., each speed increment being applied slowly, for example in -30 seconds. Whilst for convenience of operation the speed is increased in separate increments at intervals of, say 1 minute, it may in some circumstances be possible to increase the casting speed progressively from the first speed below the CPS. to the speed between the CPS. and the C.l.S. at a substantially constant rate of acceleration of, for example As-5 in./min. per minute, so that the casting speed is increased from a speed slightly below the C.P.S. to the final casting speed in /2-15 minutes.
  • the procedure of the present invention is of particular value in the production of round ingots formed of those alloys which exhibit sensitivity to hot-short cracking.
  • the process of the present invention has been found to be of value in casting Al-Mg-Si alloys having the respective percentage contents of magnesium and silicon as follows:
  • the CPS. and C.l.S. for the production of ingots from a given alloy depend on a number of factors, which arise in part from the casting conditions and in part from the metal composition and condition.
  • the temperature at which the metal is poured into the mould all influence the value of the C.P.S. and the C.l.S.
  • the determination of the values of the CPS. and C.l.S. can only be made empirically by casting an ingot from a melt of the alloy. For example, with a 7-inch diameter ingot of AA6063 alloy the casting speed should be increased by steps from an initial speed of, say, 4 ins./min., progressively by increments of, for example, one-half in./min. as discussed above, at intervals of cast length of, say, 24 inches until the expected C.l.S. is substantially exceeded and then progressively decreasing the casting speed in like manner.
  • Determination of the casting speed at which the centre crack ceased during the decrease of the casting speed will indicate the value of the CPS. and, more particularly, a speed below the CPS. at which the drop may be carried out at the beginning of the casting cycle in order to develop a sound centre.
  • Fifi. 'l is a diagrammatic part-sectional view of a continuous casting apparatus
  • FIG. 2 is a sectional view on the line 2-2 of FIG. 1.
  • FIG. l shows an axially vertical annular mould 10 to which molten aluminium ll is supplied for casting an ingot l2.
  • the mould 10 is constructed of a metal (such as aluminium) suitable for casting aluminium and has an inner wall 14 which defines an axially vertical casting zone.
  • a cooling jacket 15 Surrounding the outer surface of the mould wall 14 is a cooling jacket 15 defining an annular chamber completely laterally surrounding the casting zone.
  • the chamber is supplied with cooling water, for chilling the mould l4, and is provided with an outlet slot 22 through which water is applied to the surface of the growing ingot 12 in the conventional manner.
  • the lower end of the casting zone is closed by a stool 18 which is carried on a platform 19 supported on a hydraulic ram 20.
  • a stool 18 which is carried on a platform 19 supported on a hydraulic ram 20.
  • the stool l8 and platform 19 are lowered by operation of the hydraulic ram 20 at a speed controlled by the operator.
  • Molten aluminium is supplied to the mould from a launder 26 positioned above the mould l0 and having an axially vertical dip tube 28 extending coaxially into the mould.
  • the lower end of dip tube 28 opens beneath the level of the molten aluminium 11 in the casting zone; this prevents surface turbulence in the casting zone pool.
  • a float 30 surrounds the lower end of dip tube 28 and is buoyantly supported in the molten metal ll.
  • the float comprises a relatively thick rigid disc-shaped body 3i having a central bore 32 of slightly larger diameter than the dip tube 28.
  • the lower surface of body 31 has a central recess 34 into which the bore 32 opens.
  • a rigid baffle portion 36 of the float extends across the recess'34, immediately beneath the bore 32.
  • the baffle portion 36 has an upper surface wider than the internal diameter of the dip tube 28.
  • a pair of wire supports 38 are carried by the float, and are bent outward to project over opposite sides of the top wall of the mould to prevent descent of the float beyond a predetermined level.
  • the ram 20 In operating the apparatus in accordance with the present invention the ram 20 is initially positioned so that the stool lll closes the lower end of the casting zone. Cooling water is continuously supplied to the mould cooling jacket for chilling the mould wall 14 and molten aluminium supplied from the launder 26 flows downwardly by gravity through the dip tube 28 to till the casting zone with molten aluminium ll to the desired level.
  • the hydraulic ram 24 is then operated to lower the stool 18 at a low initial speed, such as 3-4 ins/min. for ingots in the size range of 49 inch diameter, in the conventional manner whilst the stool travels through a distance, d typically 2-5 inches for these size of ingots.
  • the operator slowly increases the dropping speed of the stool as it descends through a further distance 41;, typically 25 inches to a speed slightly below the CPS.
  • a length of ingot corresponding to about 2 /2 ingot diameters is cast at this same speed, following which the operator gradually increases the dropping speed to a speed exceeding the C.P.S., but below the C.l.S.
  • the CPS. and the C.l.S. of a particular Al-Mg-Si alloy was determined by the procedure set out above.
  • the CPS. was found to be about 66 /2 ins/min. and the C.I.S. was found to be about 8 ins./-
  • a method of producing light metal ingots by the direct chill casting process in which molten metal is introduced into one end of an openended mould and a solidified ingot is withdrawn from the opposite end of the mould, fluid coolant being applied directly to the solidified surface of the ingot emerging from the mould, in which, in the course of forming the ingot, at one stage the ingot is withdrawn from the mould at a speed below the crack propagating speed for a sufficient distance to develop a crack-free centre in the emerging ingot, the speed of ingot withdrawal then being increased to a speed above the crack propagating speed and below the crack initiating speed.
  • a method according to claim 1 in which an aluminium alloy is cast to form a round ingot or square ingot of 49 inches diameter or minimum transverse dimension, the ingot withdrawal speed being held at a speed below the crack propagating speed during the withdrawal of a length of ingot of at least 2 /2 ingot diameters or 2 /2 minimum transverse dimensions.
  • aluminium alloy is an aluminiumymagnesium silicon alloy having hot-short characteristics.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
US434784A 1973-01-24 1974-01-21 Method of direct chill continuous casting Expired - Lifetime US3884290A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB369973A GB1456661A (en) 1973-01-24 1973-01-24 Casting light metal ingots by the direct chill casting process

Publications (1)

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US3884290A true US3884290A (en) 1975-05-20

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US434784A Expired - Lifetime US3884290A (en) 1973-01-24 1974-01-21 Method of direct chill continuous casting

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US (1) US3884290A (da)
JP (1) JPS558267B2 (da)
BE (1) BE810107A (da)
BR (1) BR7400520D0 (da)
CA (1) CA1000024A (da)
CH (1) CH574781A5 (da)
DE (1) DE2403194B2 (da)
DK (1) DK143486C (da)
ES (1) ES422552A1 (da)
FR (1) FR2214542B1 (da)
GB (1) GB1456661A (da)
IT (1) IT1003453B (da)
NL (1) NL7400917A (da)
NO (1) NO138752B (da)
SE (1) SE388142B (da)
ZA (1) ZA74513B (da)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4015655A (en) * 1974-06-25 1977-04-05 Vereinigte Osterreichische Eisen- Und Stahlwerke-Alpine Montan Aktiengesellschaft Process and apparatus for continuously casting strands of unkilled or semi-killed steel
US4126487A (en) * 1974-11-15 1978-11-21 Alcan Research And Development Limited Producing improved metal alloy products (Al-Fe alloy and Al-Fe-Si alloy)
US4126486A (en) * 1974-11-15 1978-11-21 Alcan Research And Development Limited Producing improved metal alloy products
US5664023A (en) * 1994-11-14 1997-09-02 Jbl Incorporated Low TCR wire in high power audio coils
CN112139466A (zh) * 2020-10-09 2020-12-29 中国航发北京航空材料研究院 7000系铝合金直冷半连续铸锭的分级间歇停顿式起铸方法

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2692410A (en) * 1949-11-24 1954-10-26 Ici Ltd Method and apparatus for continuous or semicontinuous casting of metals
US2708297A (en) * 1953-09-03 1955-05-17 Kaiser Aluminium Chem Corp Continuous casting apparatus
US2983972A (en) * 1960-11-17 1961-05-16 Reynolds Metals Co Metal casting system
US3381741A (en) * 1963-06-07 1968-05-07 Aluminum Co Of America Method and apparatus for continuous casting of ingots
US3441079A (en) * 1966-10-24 1969-04-29 Aluminium Lab Ltd Casting of aluminum ingots
US3672431A (en) * 1970-09-25 1972-06-27 Alcan Res & Dev Apparatus and procedures for continuous casting of metal ingots
US3713479A (en) * 1971-01-27 1973-01-30 Alcan Res & Dev Direct chill casting of ingots

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2692410A (en) * 1949-11-24 1954-10-26 Ici Ltd Method and apparatus for continuous or semicontinuous casting of metals
US2708297A (en) * 1953-09-03 1955-05-17 Kaiser Aluminium Chem Corp Continuous casting apparatus
US2983972A (en) * 1960-11-17 1961-05-16 Reynolds Metals Co Metal casting system
US3381741A (en) * 1963-06-07 1968-05-07 Aluminum Co Of America Method and apparatus for continuous casting of ingots
US3441079A (en) * 1966-10-24 1969-04-29 Aluminium Lab Ltd Casting of aluminum ingots
US3672431A (en) * 1970-09-25 1972-06-27 Alcan Res & Dev Apparatus and procedures for continuous casting of metal ingots
US3713479A (en) * 1971-01-27 1973-01-30 Alcan Res & Dev Direct chill casting of ingots

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4015655A (en) * 1974-06-25 1977-04-05 Vereinigte Osterreichische Eisen- Und Stahlwerke-Alpine Montan Aktiengesellschaft Process and apparatus for continuously casting strands of unkilled or semi-killed steel
US4126487A (en) * 1974-11-15 1978-11-21 Alcan Research And Development Limited Producing improved metal alloy products (Al-Fe alloy and Al-Fe-Si alloy)
US4126486A (en) * 1974-11-15 1978-11-21 Alcan Research And Development Limited Producing improved metal alloy products
US5664023A (en) * 1994-11-14 1997-09-02 Jbl Incorporated Low TCR wire in high power audio coils
CN112139466A (zh) * 2020-10-09 2020-12-29 中国航发北京航空材料研究院 7000系铝合金直冷半连续铸锭的分级间歇停顿式起铸方法
CN112139466B (zh) * 2020-10-09 2022-11-01 中国航发北京航空材料研究院 7000系铝合金直冷半连续铸锭的分级间歇停顿式起铸方法

Also Published As

Publication number Publication date
NO138752B (no) 1978-07-31
CA1000024A (en) 1976-11-23
DE2403194B2 (de) 1979-10-18
NO740216L (no) 1974-07-25
GB1456661A (en) 1976-11-24
FR2214542A1 (da) 1974-08-19
FR2214542B1 (da) 1979-05-11
ES422552A1 (es) 1976-04-16
NL7400917A (da) 1974-07-26
IT1003453B (it) 1976-06-10
CH574781A5 (da) 1976-04-30
DE2403194A1 (de) 1974-08-01
JPS558267B2 (da) 1980-03-03
BE810107A (fr) 1974-05-16
SE388142B (sv) 1976-09-27
DK143486C (da) 1982-01-25
DK143486B (da) 1981-08-31
AU6477674A (en) 1975-07-24
JPS49104833A (da) 1974-10-03
ZA74513B (en) 1974-12-24
BR7400520D0 (pt) 1974-10-29

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Griffiths et al. Macrostructural development in aluminium alloys solidified vertically downwards