US3743005A - Process for producing hot rolled three layer steel products from continuously cast hollow tubes - Google Patents

Process for producing hot rolled three layer steel products from continuously cast hollow tubes Download PDF

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Publication number
US3743005A
US3743005A US00181627A US3743005DA US3743005A US 3743005 A US3743005 A US 3743005A US 00181627 A US00181627 A US 00181627A US 3743005D A US3743005D A US 3743005DA US 3743005 A US3743005 A US 3743005A
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Prior art keywords
bar
hollow
casting
sheets
thickness
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Expired - Lifetime
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US00181627A
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English (en)
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G Veitl
E Bachner
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Voestalpine AG
Voest AG
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Voestalpine AG
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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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
    • B21B1/38—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling sheets of limited length, e.g. folded sheets, superimposed sheets, pack rolling
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D7/00—Casting ingots, e.g. from ferrous metals
    • B22D7/02—Casting compound ingots of two or more different metals in the molten state, i.e. integrally cast

Definitions

  • ABSTRACT The invention relates to a process for producing threelayer rolled products by rolling composite ingots.
  • the ingots are produced by casting bars according to the continuous casting process and guiding them, when issuing from the mould, along a curved path at first downwardly and then upwardly until a height at which the liquid core of the bar cannot ascend any further so that when casting and transportation is continued a hollow bar is obtained; said hollow bar then is cut into pieces which are permitted to solidify and then are poured full with a metal of a composition different from the composition of the bar.
  • This process permits a simple and low-cost production of sheets clad with layers which, compared to the overall thickness of the sheets, are very thin.
  • the invention relates to a process for producing rolled products comprising three layers, the medium layer having a composition different from the composition of two outer layers, particularly for producing metal sheets.
  • Composite ingots comprising three layers are produced by casting hot liquid metals into a mould.
  • the outer layers of the composite ingot, which are formed from a metal of the one composition are formed in the shape of a hollow body open on both ends which is permitted to solidify. Subsequently, this body which represents the form is poured full with a metal of another composition for the formation of the medium layer of the composite ingot.
  • the layer thickness on each side should amount to 0.1 to 0.5 mm, depending on what the material is used for; thus, compared to the overall thickness of the sheet, the coatings are very thin; e.g., in automobile sheets having a thickness from about 0.7 to 1mm, the cladding layers have a thickness of about 0.1 mm.
  • Multi-layer sheets are also used for agricultural machinery, for example as plough shares. These sheets are called three layer sheets and comprise as a rule two hard outer layers, for example made of structural steel having a tensile strength of 70 kp/mn, and a softer, tough middle layer, for example made of structural steel having a tensile strength of 37 kp/mn for particular purposes also a hard medium layer and softer outer layers may be provided.
  • Clad sheets are produced as a rule by roll cladding, the materials to be connected being welded by the rolling pressure at hot rolling temperature.
  • the surfaces of the materials to be welded together have to be metallically blank and above all there must be no oxide film, in particular no chromium oxide films.
  • For the production of two sheets clad on one side as a rule four sheets of the sheet bar type are laid one above the other and connected to form a cladding sandwich which is to be separated again after rolling, the two outer sheets being made of the basic material and the two inner sheets which are to be connected with the other sheets being made of the cladding material. In that process the margins of the basic material sheets project beyond the margins of the two medium sheets and are connected with each other by welding steel brackets.
  • Clad sheets may also be produced by rolling a composite steel ingot.
  • a process for producing such multi-layer composite steel ingots is described which are particularly used for the production of three layer sheets (plough share sheets).
  • a slightly conical mould of customary design is used which is placed on a bottom pouring plate; a partition wall is inserted in its middle so that two hollow mould spaces are obtained.
  • At first steel is cast into the two hollow mould spaces until they are filled up.
  • the partition wall is loosened and removed and the hollow space thus created is filled with liquid steel of another quality which welds with the steel first cast in.
  • the composite steel ingot thus produced which comprises three layers of about the same thickness then is rolled in the rolling mill.
  • liquid melt is guided to the upper end of a water cooled continuous casting mould and the bar issuing from the mould is guided along a curved path which descends at first and ascends then to a height at which the liquid part of the bar cannot ascend any further so that when casting and transportation of the bar iscontinued the liquid metal in the interior of this bar extends only to said height and the bar ascending beyond this height is formed to be hollow.
  • a continuous casting plant with an areshaped mould is used and the bar is guided along an arc until above the height of the casting level.
  • the hollow bodies produced according to this process have an absolutely dense wall. This advantage is explained by the fact that when melts solidify most porous areas or hollow spaces originate where solidifying fronts meet. But there is only one solidifying front which shifts from the bar surface into the interior and then, onwards from the place to which the liquid melt extends in the upwardly guided bar, forms the inner surface of the hollow bar. ln casting tests it has shown that the inner surface of the ho]- low bar formed in this manner is surprisingly smooth, so that a hollow bar thus produced represents a good starting material for the production of seamless tubes.
  • the invention pursues the task of creating a simple and cheap process for the production of rolled products comprising three layers by rolling composite steel ingots in which the thickness of the individual layers may easily be changed and in which particularly the thickness of the outer layers may be kept relatively small in relation to the total thickness of the ingot.
  • the invention resides in that the hollow body to be poured full with said metal of another composition is produced by continuous casting of a steel melt in particular by means of a continuous casting mould which is arranged to be substantially vertical, the liquid melt being supplied to the upper end of the continuous casting mould and the bar issuing from the mould being guided along a curved path falling at first and ascending then beyond a height at which the liquid part of the bar cannot rise any further so that when casting and transportation of the bar is continued, the liquid steel in its interior reaches only until said height and the bar ascending beyond said height is hollow, whereupon the endless bar is severed into hollow bar pieces open on both ends.
  • any mixing of the hot liquid metals is avoided.
  • the process according to the invention permits a continuous casting operation with a maximum yield.
  • the wall thickness may easily be regulated.
  • the hollow steel body is advantageously poured full in the red hot condition, preferably immediately after its solidification, its mean temperature amounting to more than 700C and its inner temperature ranging between 900 and 1,200C.
  • the hollow body prior to being poured full from above or from below, is placed on a floor plate or on a bottom pouring plate, respectively, it being supported at least at two lateral faces lying opposite each other.
  • the outer surface of the composite ingot may be cooled after pouring full is terminated.
  • FIG. 1 of the drawings show a schematic vertical section of a continuous casting plant for producing a hollow cast bar and FIGS. 2 and 3 show pouring stands for filling sections of the hollow bar.
  • EXAMPLE 1 In a circular arch type continuous casting plant (FIG. 1) for slabs with a bar guide comprising a semicircular first part 2 with a radius R which is joined by a second part 3 which is straight and vertical and extends beyond the casting level 4 of the steel 5 in the mould 6, a hollow bar 7 is cast having an outer cross section of 1,200 mm X300 mm and a wall thickness of 60 mm. The casting speed and the bar cooling rate are controlled so that the diameter of the liquid bar core 8 amounts to about 180 mm at the end of the semi-circular bar guide 2.
  • the hollow bar is cast from a steelwith a composition comprising 0.22 C, 0.40 Si, 0.50 Mn, 17.00 Cr and 2.00 Ni, the temperature measured in the tundish 9 above the continuous casting mould 6 amounting to l,530 C and the casting speed to 2.5 m/min.
  • the hollow bar 7 is cut into several bar pieces (7' in FIG. 2 each) having a length of 4,000 mm by means of two powder cutting means 10 which are synchronously moved together with the hollow bar 7.
  • the direction of movement of the cutting means 10 is indicated by a double arrow.
  • Each of these bar pieces 7 is immediately thereafter set on a floor plate 11 which is arranged next to the continuous casting plant 1, the support surface 12 being sealed by asbestos strips or asbestos cords 13 in customary manner so that the hollow bar pieces 7' subsequently may be filled up from above by casting (FIG. 2).
  • a rimming deep drawing steel 14 comprising 0.07 C and 0.50 Mn, the temperature of which measured in the casting ladle 15 amounts to 1,550 C.
  • the temperature of the hollow bar pieces at the beginning of filling up amounts, at the inside, to about l,l00 C and at the outside to about 900 C.
  • a supporting means is fixed on the floor plate 11, surrounding the wall of the hollow bodies; this supporting means may, for example, comprise a closed casting body 15 or a roller corset 16 and is necessary in partcular for supporting the broad sides of the hollow bodies.
  • This supporting means may also be water cooled so that the composite steel ingot is solidified more rapidly; for example, cooling spraying nozzles 17 may be used.
  • the ingot is heated to l,l80 C in a continuous type furnace and rolled out on a break-down stand and a six-stand broad strip street; in the break-down stand seven passes are carried out so as to produce a pre-strip of 25 mm thickness; at the end of the hot broad strip street the thickness of the hot strip amounts to 3 mm and the issuing temperature amounts to 880 C.
  • the hot strip is divided by flying shears into sheet plates which are piled at a temperature of 750 C and then annealed at a temperature of 950 C. After the annealing process the sheet plates are cut in a circular knife shearing street, straightened and pickled.
  • the final size of the sheet plate amounts to l,l00 X2,500 X3 mm, the thickness of the cladding layer on both sides amounting to 0.5 mm; with an initial thickness of 60 mm and an abrasion of 10 mm on each side, this corresponds to a hundrcdfold shaping of the cladding layers.
  • a hollow bar is cast having an outer cross section of 1,600 mm 250 mm and a wall thickness of 60 mm.
  • the hollow bar is cast from a steel with a composition comprising 0.06 C, 0.40 Si, 1.30 Mn, l8.00 Cr and 9.00 Ni, the temperature measured in the tundish 9 above the continuous casting mould 6 amounting to l,490 C and the casting speed to 2.5 m/min.
  • the hollow bar is cut into several bar pieces having a length of 4,000 mm each which are immediately thereafter set on a bottom pouring plate 18 (FIG. 3).
  • the temperature of the hollow bar piece 19 amounts at the inside to 1,000 C and at the outside to about 800 C.
  • a killed steel comprising 0.10 C, 0.30 Si, 0.40 Mn and 0.01 A1 and having a temperature, measured in the casting ladle, of 1,570 C is poured into the hollow bar piece 19.
  • a funnel 22 is used for casting.
  • the steel is covered immediately after termination of pouring by an exothermal piping powder.
  • the solidified composite steel ingot of 1,600 mm width, 250 mm thickness and 4,000 mm height then is similarly treated as explained in Example 1: after an ultrasound test, abrasion of its surface and heating in the continuous type furnace to l,220 C the composite steel ingot is rolled on a breakdown stand by seven passes so as to produce a prestrip of 25 mm thickness which leaves the hot broad-strip street with an issuing temperature of 900 C and a thickness of 4 mm.
  • the hot strip is reeled at a temperature range of 550 to 600 C and finally pickled in a pickling plant designed for high-grade steels. Then local faults are abraded off.
  • the pickled and abraded hot strip is cold rolled, then annealed at 950 C under protective gas, then dressed, straightened and sheared to plates having a final size of 1,500 X2,000 Xl mm.
  • the thickness of the cladding layers amounts to 0.166 mm on each side; with an ini tial thickness of 60 mm and an abrasion of 10 mm on each side of the composite ingot, this corresponds to a threee hundred-fold shaping of the cladding layers.
  • the process according to the invention may also be used for producing three-layer composite steel ingots for three layer sheets in which as described at the beginning the ratio of the thicknesses of the layers is substantially l l 1.
  • the casting and cooling conditions in the continuous casting plant have to be changed so that hollow bars with a greater wall thickness can be produced.
  • hollow billets may be produced by continuous casting which filled up in similar manner serve as starting product for merchant bar or wire.
  • a process for producing three-layer rolled metal products having two outer layers of a first composition and an inner layer of a second composition comprising:
  • each of the hollow sections with a liquid metal melt of a second composition while the mean temperature of the hollow sections is at least 700C 900C to 1,200C, and

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Metal Rolling (AREA)
  • Pressure Welding/Diffusion-Bonding (AREA)
  • Manufacturing Of Steel Electrode Plates (AREA)
  • Continuous Casting (AREA)
US00181627A 1970-09-22 1971-09-17 Process for producing hot rolled three layer steel products from continuously cast hollow tubes Expired - Lifetime US3743005A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AT854670A AT302223B (de) 1970-09-22 1970-09-22 Verfahren zur Erzeugung von dreischichtigen Walzprodukten

Publications (1)

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US3743005A true US3743005A (en) 1973-07-03

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US00181627A Expired - Lifetime US3743005A (en) 1970-09-22 1971-09-17 Process for producing hot rolled three layer steel products from continuously cast hollow tubes

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US (1) US3743005A (en])
JP (1) JPS5114448B1 (en])
AT (1) AT302223B (en])
BE (1) BE772865A (en])
BR (1) BR7106240D0 (en])
CA (1) CA944127A (en])
CH (1) CH531382A (en])
DE (1) DE2146227A1 (en])
ES (1) ES395228A1 (en])
FR (1) FR2107855B1 (en])
GB (1) GB1312590A (en])
IT (1) IT938805B (en])

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5232740A (en) * 1989-05-16 1993-08-03 Mannesmannufer Aktiengesellschaft Method of manufacturing plated hollow blocks
US10124372B2 (en) 2013-06-24 2018-11-13 Thyssenkrupp Steel Europe Ag Screen bar, bar screen and method for producing a screen bar

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS52137443U (en]) * 1976-04-13 1977-10-19
AT374704B (de) * 1980-12-02 1984-05-25 Voest Alpine Ag Verfahren zum herstellen eines grobbleches aus stahl
JPH0266353U (en]) * 1988-11-11 1990-05-18
CN114472834B (zh) * 2022-02-17 2023-10-24 山东钢铁股份有限公司 一种复合铸坯的连续生产系统及连续生产方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3346036A (en) * 1964-01-16 1967-10-10 Boehler & Co Ag Geb Process for the continuous casting of tubular products
DE1281115B (de) * 1965-11-04 1968-10-24 Boehler & Co Ag Geb Verfahren zum Stranggiessen von Hohlkoerpern
US3421571A (en) * 1965-03-09 1969-01-14 New York Wire Co Process for casting clad metal bars
US3421569A (en) * 1966-03-11 1969-01-14 Kennecott Copper Corp Continuous casting
US3482259A (en) * 1965-12-14 1969-12-02 Boehler & Co Ag Geb Process of producing ledeburitic tool steel

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR81698E (fr) * 1960-10-26 1963-10-25 Bras articulé pour biberon

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3346036A (en) * 1964-01-16 1967-10-10 Boehler & Co Ag Geb Process for the continuous casting of tubular products
US3421571A (en) * 1965-03-09 1969-01-14 New York Wire Co Process for casting clad metal bars
DE1281115B (de) * 1965-11-04 1968-10-24 Boehler & Co Ag Geb Verfahren zum Stranggiessen von Hohlkoerpern
US3482259A (en) * 1965-12-14 1969-12-02 Boehler & Co Ag Geb Process of producing ledeburitic tool steel
US3421569A (en) * 1966-03-11 1969-01-14 Kennecott Copper Corp Continuous casting

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5232740A (en) * 1989-05-16 1993-08-03 Mannesmannufer Aktiengesellschaft Method of manufacturing plated hollow blocks
US10124372B2 (en) 2013-06-24 2018-11-13 Thyssenkrupp Steel Europe Ag Screen bar, bar screen and method for producing a screen bar

Also Published As

Publication number Publication date
CH531382A (de) 1972-12-15
AT302223B (de) 1972-10-10
GB1312590A (en) 1973-04-04
BE772865A (fr) 1972-01-17
IT938805B (it) 1973-02-10
BR7106240D0 (pt) 1973-04-17
FR2107855B1 (en]) 1975-07-18
JPS5114448B1 (en]) 1976-05-10
CA944127A (en) 1974-03-26
DE2146227A1 (de) 1972-03-23
FR2107855A1 (en]) 1972-05-12
ES395228A1 (es) 1973-11-16

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