CA1060629A - Thin gauge casting wheel band - Google Patents
Thin gauge casting wheel bandInfo
- Publication number
- CA1060629A CA1060629A CA255,680A CA255680A CA1060629A CA 1060629 A CA1060629 A CA 1060629A CA 255680 A CA255680 A CA 255680A CA 1060629 A CA1060629 A CA 1060629A
- Authority
- CA
- Canada
- Prior art keywords
- band
- wheel
- casting
- flexible
- flexible band
- 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.)
- Expired
Links
- 238000005266 casting Methods 0.000 title claims abstract description 99
- 230000009975 flexible effect Effects 0.000 claims abstract description 38
- 229910052751 metal Inorganic materials 0.000 claims abstract description 27
- 239000002184 metal Substances 0.000 claims abstract description 27
- 230000002093 peripheral effect Effects 0.000 claims abstract description 10
- 239000000463 material Substances 0.000 claims description 14
- 239000003779 heat-resistant material Substances 0.000 claims description 4
- 239000007921 spray Substances 0.000 claims description 4
- 238000010276 construction Methods 0.000 claims description 3
- 239000002699 waste material Substances 0.000 claims description 3
- 239000010425 asbestos Substances 0.000 claims description 2
- 239000000110 cooling liquid Substances 0.000 claims description 2
- 229910052895 riebeckite Inorganic materials 0.000 claims description 2
- 239000002826 coolant Substances 0.000 abstract description 13
- 238000001816 cooling Methods 0.000 abstract description 9
- 238000009749 continuous casting Methods 0.000 description 19
- 238000012546 transfer Methods 0.000 description 7
- 230000004048 modification Effects 0.000 description 4
- 238000012986 modification Methods 0.000 description 4
- 230000035882 stress Effects 0.000 description 4
- 238000005452 bending Methods 0.000 description 3
- 230000006835 compression Effects 0.000 description 3
- 238000007906 compression Methods 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000007769 metal material Substances 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 238000007712 rapid solidification Methods 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 239000011889 copper foil Substances 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 230000003292 diminished effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- -1 for example Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 230000037303 wrinkles Effects 0.000 description 1
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
- B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
- B22D11/0637—Accessories therefor
- B22D11/0648—Casting surfaces
- B22D11/0654—Casting belts
Abstract
ABSTRACT OF THE DISCLOSURE
Apparatus for continuously casting molten metal wherein the flexible band element used to enclose the peripheral groove of the casting wheel of a wheel-band type machine is relatively untensioned and supported along at least a portion of its path of travel by a highly flexible porous support belt through which a coolant may be directed to impinge upon the external surface of the flexible band. The flexible band element, in cooperation with the support belt, provides improved cooling efficiency and a longer life expectancy for the band.
Apparatus for continuously casting molten metal wherein the flexible band element used to enclose the peripheral groove of the casting wheel of a wheel-band type machine is relatively untensioned and supported along at least a portion of its path of travel by a highly flexible porous support belt through which a coolant may be directed to impinge upon the external surface of the flexible band. The flexible band element, in cooperation with the support belt, provides improved cooling efficiency and a longer life expectancy for the band.
Description
iZ~
_ACKGROUND OF THE INVENTION
This invention relates generally to metal founaing, and more particularly to improved apparatus for casting molten metal in a continuous casting machine of the wheel-band type.
In a known continuous casting system, molten metal is flowed into a mold formed by enclosing an arcuate portion of the peripheral groove of a rotatable casting wheel with a flexible endless metal band. As the casting wheel rotates, a coolant is applied to the external surfaces of the wheel adjacent the peripheral groove and to the flex-ible band to prevent excessive heating thereof and to achieve rapid solidification of the molten metal. Typically, a relatively thick (.060 in. or greater) metal band is positioned about and urged into engagement with the flanges of the groove by one of a number of known arrangements of band tensioning, positioning and guide wheels~ ~any of these arrangements necessitate the bending or flexing of the bana about the periphery of one or more wheels of significantly smaller diameter than that of the casting wheel. Several such arrangements are shown in U.S. Patent No. 3,596,705.
As e~plained in the aformentioned U.S. Patent No. 3,596,705, the continual bending and fle~ing of the band about the casting and band wheels subjects the band to un-desirable strain which is proportional both to band thick-ness and to the diameter of the band wheels. This strain tends to cause rapid deterioration of the band and resultant failure after only a few hours of operation. It will be .,' ~
10~0~
appreciated by those skilled in the art that the short life expectancy of the band and the time-consuming replacement thereof are major problems concerning the efficient opera-tion and maintenance of continuous casting machines.
When continuously casting metals in machines of the above-described type, such as, for example, copper, aluminum and steel, it is highly advantageous to solidify the molten metal in as short a period of time as possible in order to maintain a high casting rate. Moreover, when casting metals containing alloying elements, rapid solidifi-cation is desirable in order to maintain intermetallic co~pounds in solid solution and to limit the size of the particles that do precipitate out of solution. However, the low cooling efficiency and non-uniformity of heat transfer inherent in the thick metal bands of prior art casting machines preclude attainment of the high casting rates and metallurgic effects desired. This is especially so if the band is fabricated of a material having a relatively low rate of heat transfer even though coolant is applied to the external band surface at maximum practicab3.e pressure and volume.
It should be apparent, therefore, that to improve the casting rate of continuous casting machines of the type described concomitantly with the life expectancy of the flexible band element, bands formed of thin gauge materials having a high heat transfer rate could be advan-tageously utilized to achieve such improvements. However, the prior art recognizes several problems in attempting to fabricate the band from thin gauge, high heat transfer ... ....
~0~06;~
materials. Notably, one problem encountered when fabrica-ting mold components of high heat transfer rate materials is the typically low structural strength of such materials which adversely affects their useful life, as explained in U.S. Patent No. 3,464,483.
While reducing band thickness would tend $o reduce band strain exerted by the band wheels on a band formed of a high heat transfer rate material, the structural strength of the band would, of course, be further diminished so that little advantage in terms of band life could be realized.
A further problem associated with the use of thin gauge band elements for continuous casti.ng machines is explained in U.S. Patent No. 3,533,463, wherein the paten-tees recognize the susceptibility of damage to a thin gauge band, particularly at the edges thereof, when it is ade-quately tensioned to prevent leakage of molten metal from between the band and casting wheel groove. It is further noted in the aforesaid patent that the band wheel flanges used to steer the band into position for enclosing the groove are especially damaging to the edges of a thin gauge band.
British Patent Specification No. 861,273 dis-closes a wheel-band type continuous casting machine wherein it is recognized that the tension in the casting band, necessary to close the casting groove, is highly detrimental to the band. Consequently, according to British Patent Specification No. 861,273, a casting system is provided in which a tight fit of the casting band against the edges of Z~
the casting groove is no longer insured by a high tensile strength applied to the band, but rather by means o~ a compression of the band upon the edges of the casting wheel, which compression is exerted radially upon the metal band in the direction of its thickness. This compression is provided by means of a linked endless chain comprising a plurality of rigid bars, generally made of steel, which are movable in a path against the rear surface of the casting band in the region where the casting band engages the periphery of the casting wheel.
It has been found, however, that while the apparatus of the aforementioned British patent is satis~
factory for casting thin wide metal strips, it does not provide a sufficient cooling gradient for the casting of generally rectangular metal bars wherein a high cooling capacity is necessary to solidify the molten core of the cast bar. Thus, it has been found in accordance with the instant invention that the large thick support bars dis-closed in the aforementioned British Patent Specification No. 861,273 will impede cooling of the casting band, and further are not sufficiently articulated so as to permit support of the casting band about an extended arcuate por-tion of the casting wheel which is necessary to facilitate high production rate operation.
_ATEMENT OF THE INVENTION
In view of the foregoing, it should be apparent that there still exists a need in the art for a wheel-band type continuous casting machine that is characterized both 1060~ '3 by an increased band life as well as a cooling capacity that will permit high production or casting rate operation.
There is, therefore, provided in accordance with this invention a wheel-band type casting machine for continuously casting molten metal into a cast bar comprising a rotatable casting wheel having a casting groove formed in the periphery thereof, a flexible band arranged to close an arcuate portion of said peripheral groove to form a casting mold therewith, said flexible band being supported in such a manner as to be in a substantially untensioned state, means for extracting heat from the molten metal in the casting mold, and means for applying an inward radial force against said flexible band to maintain said band in closed relationship with the periphery of said casting wheel;
characterized in that said means for applying an inward radial force against said flexible band is a support belt comprising a plurality of articulated support elements, each of said support elements being either perforated or of open mesh or grid construction, and wherein said means for extracting heat from the molten metal includes a plurality of spray nozzles adapted to spray a cooling liquid directly through the perforations or between the mesh or grids of each of the individual support elements and against the flexible band.
More particularly, the invention is character- -ized in that as a result of the substantially untensioned state of the flexible band, extraction of heat from the molten metal is improved by fabricating the band from a thin gauge material having a thickness less than 0.060 inches.
. ~ , , . . , - - : . . .
10~0~ 3 In certain of the embodiments of the invention disclosed herein, the flexible band element and its support belt travel along substantially the same path over the casting wheel and band wheel peripheries. The band element is, however, slightly longer than the support belt so that during casting the band is under relatively little tensile stress, the force of the band tensioning wheels being applied primarily in tension to the porous, highly flexible support belt. The portion of the band element closing the groove is under a primarily compressive load exerted radi-ally of the casting wheel by the support belt. In casting machine arrangements where necessary, means are provided for taking up slack in the flexible band element and for guiding it along its path of travel. In other embodiments of the invention, the support belt is arranged to travel about the band wheels of variously-configured continuous casting machines in the usual manner, while the flexible band element travels along a different path, only a portion of which coincides with the path of the support belt. As in the previously mentioned embodiments, the band element is relatively untensioned, most of the ~ensile force being exerted by the band tensioning wheels on the support belt.
Since the support belt is formed of a highly flexible open-grid chain, wire mesh or other suitable material, it is not particularly susceptible to flexural or bending stresses and, consequently, can be expected to have a long life expectancy. Moreover, the support belt may be employed on casting machines having significantly smaller diameter band wheels thereby allowing wheel and band - - . , - . . .................... . ...... ...
.. ... .
arrangements not heretofore feasible in continuous casting machines. In arrangements having small diameter band wheels, the flexible band element is preferably guided over a path of travel which differs from and has greater radii of curvature than the path of travel of the belt. A flexible band element formed of either a thin gauge high heat trans-fer metal band or a thin gauge non-metallic band utilized with the highly flexible support belt results in improved cooling efficiency and a substantial reduction of tensile stresses in the band thereby yielding a significant increase in band life. Thus, high casting rates and greater overall operating efficiencies are possible.
BRIFF DES~RIPTION OF THE DRAWINGS
Figure 1 is a schematic elevation view of one embodiment of a wheel-band type continuous casting machine in accordance with the present invention wherein the support belt and band element travel along substantially the same path;
Figure 2 is a schematic elevation view of an alternate embodiment of a wheel-band continuous casting machine according to the invention wherein the support belt and band element travel along substantially th~ same path;
Figure 3 is a schematic elevation view of a modification of the wheel-band continuous casting machine of Figure 2;
Figuxe 4 is a schematic elevation view of another alternate embodiment of a wheel-band continuous . .
1~0~
casting machine according to the invention wherein the support belt and band element travel along substantially the same path;
Figure 5 is a schematic elevation view of the wheel-band continuous casting machine of Figure 4 wherein the support belt and band element travel along different paths having different lengths.
Figure 6 is a schematic elevation view of a modification of the wheel-band continuous casting machine of Figure l;
Figure 7 is a cross-sectional view taken along the line 7-7 of Figure 6, and illustrates the band element interposed between the casting wheel periphery and the support belt;
Figure 8 is a schematic elevation view of another alternate embodiment of a wheel-band continuous casting machine in accordance with the present invention wherein a band element is cycled through the machine from a supply roll to either a waste receptacle or a recycle roll.
Figures 9a-9c are fragmentary perspective views of three embodiments of support belt constructions suitable for use in the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now in detail to the drawings wherein like parts are designated by like reference numerals throu~h-out, there is illustrated in Figure 1 a wheel-band type continuous casting machine designated generally by reference ~0~ 3 numeral 10. The casting machine 10 includes a casting wheel 12 and band guide wheels 14, 16, 18 and 20. An endless flexible band element 22 extends about an arcuate portion of casting wheel 12 and defines a mold in conjunc-tion with a groove (not shown) in the periphery of the casting wheel 12 extending from an inlet point A to an out-let point B. The band 22 is further guided about the band wheels 14, 16, 18 and 20 and is of a length somewhat in excess of the tangential path about the casting machine wheels so as to form a slight catenary 24 between guide wheels 16 and 18. A porous endless support belt 26, preferably contructed of an open-grid or mesh material, is similarly guided along substantially the same path as the band 22 except that the support belt 26 coincides with the tangential path between the guide wheels 16 and 18 as shown.
It will be apparent, therefore, that the tension applied by the guide wheel arrangement is exerted primarily upon the support belt 26 and the band 22 is relatively untensioned.
Further, closure of the peripheral groove of casting wheel 12 is accomplished by the essentially compressive force applied radially of the casting wheel 12 to the outwardly facing surface of the band 22 over the arcuate portion A-B.
As the casting wheel 12 is rotated in the direction shown, molten metal is flowed from a crucible 23 via spout 25 into the peripheral mold and exits as solidi-fied bar 28, having traveled over the arcuate portion A-B
of the casting wheel 12. A plurality of band headers 30, 32 and 34 are arranged about the arcuate portion A-B of the casting wheel 12 in confronting relation with the support l()~()~Z~3 belt 26. Coolant is supplied via a conduit (not shown) to a plurality of nozzles 36 which impinge liquid coolant, such as water or oil, against the surface of band 22 through the open-grid or mesh of the porous belt 26. Other band headers (not shown) are arranged to supply coolant to the external peripheral groove surfaces. An arrangement of a band and wheel cooling system which may ~e adapted to supply coolant to the band and belt of the present invention is more fully described in U.S. Patent No. 3,596,702.
With the above-described arrangement of the invention, heat may be rapidly transferred from the molten metal through the thin gauge band element 22 to the coolant so that the molten metal is quickly solidified. Since the band 22 is relatively thin and untensioned and, further, is supported by the belt 26 over the entire arcuate portion A-B
of casting wheel 12, the mechanical and thermal stresses to which the band is subjected are substantially minimized resulting in longer band life.
Figure 2 illustrates another embodiment of a continuous casting machine having a lower casting wheel 38 and an upper tension wheel 40. An endless thin gauge band element 42 having a length slightly greater than the tan-gential path about the wheels 38, 40 is employed to close the groove (not shown) in casting wheel 38. Reinforcing the band 4~ along the greater portion of its path of travel is a porous support belt 44, the length of which is approximately equal to the tangential path about the wheels 38, 40. A pair of idler wheels 46, 48 are positioned near the upper wheel to take up the sla~k in the longer length ~061)6'~
band 42 by applying a small tensile force to the band. A
band positioning wheel 50 is arranged adjacent the casting wheel 38 to urge the band 42 and belt 44 into engagement with the casting wheel periphery at the point of introduc-tion of molten metal into the casting wheel groove.
In Figure 3 there is shown a casting machine similar to that of Figure 2 except that a thin gauge band 52 is arranged to follow the tangential path about the casting wheel 38 and upper wheel 40 with substantially no slack. A support belt 54 reinforces the band 52 along the greater portion of its path. It will be appreciated that in this arrangement greater tensile forces may be exerted upon the band 52 than upon the bands of Figures 1 and 2.
However, the tensile forces in band 52 are still compara-tively small with respect ~o the tensile force exerted upon the support belt 54 by tensioning wheels 56, 58.
The continuous casting machine of the embodi-ment illustrated in Figure 4 is designated generally at 60 and includes a rotatable casting wheel 62 having a peri-pheral groove (not shown), guide wheels 64, 66, an endless thin gauge band element 68 supported by support belt 70, band positianing wheel 72 and take-up wheel 74.
Figure 5 illustrates a modification of the casting ~achine in Figure 4 wherein the thin gauge band 76 comprises a relatively "free wheeling" loop of a shorter length than the tangential path about the casting wheel 62 and guide wheels 64, 66. The small idler wheels 78 support and guide the free wheeling portion of the band 76.
lllustrated in Figures 6 and 7 is yet another 10~
alternative embodiment of a continuous casting machine according to the present invention and is designated generally by the numeral 80. The casting machine 80 in-cludes a casting wheel 82 and guide wheels 84, 86, 88 and 90 which are of substantially smaller diameter than the guide wheels of the apparatus shown in Figure 1. A thin gauge band element 92 extends about the arcuate portion C-D of casting wheel 82 to form the closure for a casting groove 94 (Fig. 7) formed in the periphery of the casting wheel 82. A support belt 96 of greater flexibility than the band 92 is tangentially guided about the casting wheel 82 by the guide wheels 84, 86, 88 and 90 and urges the band 92 against the periphery of the casting wheel 82 over the arcuate portion of C-D. The small diameter guide wheels 84, 86, 88 and 90 may be in the form of sprockets arranged to engage edge portions of the support belt 96 as idlers or as positively driven elements. If desired, a band straightening roller set 97 may be provided in any convenient location, preferably near the point where the band is guided away from the casting wheel. The purpose of the roller set 97 is to roll out minor discontinuities or wrinkles in the band element 92.
The band 92 is relatively free-wheeling except over arcuate portion C-D and is guided away from the casting wheel 82 at points C and D by small idler wheels 98 and 100 over paths having greater radii of curvature than the small diameter wheels 84, 86, 88 and 90 so as to minimize flexural stresses in the band 92. Band headers 102, 104 and 106 are arranged as in t~e embodiment of 10~
Figure 1 to impinge coolant via nozzles 108 onto the external surface 110 of band 92 through openings 99 in support belt 96. Side coolant headers 105 and casting wheel header 107 shown in Figure 7 are arranged to supply coolant via their respective nozzles to the external surfaces of the peripheral groove 94.
Figure 8 illustrates another embodiment accord-ing to the invention wherein a support belt 112 is guided tangentially about a casting wheel 114 and small diameter guide wheels or sprockets 116, 118 and 120. A roll 122 of flexible band material, which may be either a thin gauge metallic material, such as, for example, copper foil, or a non-metallic material, such as asbestos paper or other suitable heat resistant material, is positioned to feed between the periphery of casting wheel 114 and the support belt 112 to form a band 124 for closing the groove in the casting wheel periphery over arcuate portion E-F. The band 124 may be recovered in a receptacle 126 as waste or wound onto another roll 128 for recycling.
Figures 9A-9C illustrate alternative embodi-ments of open-grid and wire-mesh configurations suitable for use as the support belt of the present invention.
Figure 9A illustrates a portion of an open-grid support belt formed of a plurality of shaped flat wire sections 130 having openings 132 therethrough. The sections 130 are interconnected by rods 134 extending alternately through the openings 132 of a pair of adjacently disposed flat-wire sections 130.
.
The support belt portion of Figure 9B comprises a chain-like member 136 formed of links 138, and having attached transversely thereof at each link 138, a perforated plate 140 which may have a slightly curved surface as shown so as to conform to the radius of curvature of the casting wheel with which it is employed. Coolant is applied to the flexible band element through apertures 141 suitably arranged in the plates 140.
Figure 9C illustrates a portion of a double weave wire mesh 142 reinforced with rods 144 for added strength. At the edges thereof (only one shown) is a roller chain 146 for engagement with a sprocket wheel which may be provided at the ends of the guide wheels of the casting machines of the previously described embodiments.
In view of the foregoing, it should be apparent that there is provided by the present invention a novel wheel-band type continuous casting machine which includes a flexible band element supported by a highly flexible support belt of open-grid construc.tion for the introduction of coolant therethrough so that cooling efficiency is increased thereby making possible higher casting rates.
In addition, the novel method of supporting the thin gauge band in a relatively untensioned state yields improved band life expectancies.
Although only preferred embodiments are speci-fically illustrated and described herein, it will be appreciated that many modifications and variations of the present invention are possible in light of the above ~o~
teachings and within the purview of the appended claims without departing from the spirit and intended scope of the invention.
_ACKGROUND OF THE INVENTION
This invention relates generally to metal founaing, and more particularly to improved apparatus for casting molten metal in a continuous casting machine of the wheel-band type.
In a known continuous casting system, molten metal is flowed into a mold formed by enclosing an arcuate portion of the peripheral groove of a rotatable casting wheel with a flexible endless metal band. As the casting wheel rotates, a coolant is applied to the external surfaces of the wheel adjacent the peripheral groove and to the flex-ible band to prevent excessive heating thereof and to achieve rapid solidification of the molten metal. Typically, a relatively thick (.060 in. or greater) metal band is positioned about and urged into engagement with the flanges of the groove by one of a number of known arrangements of band tensioning, positioning and guide wheels~ ~any of these arrangements necessitate the bending or flexing of the bana about the periphery of one or more wheels of significantly smaller diameter than that of the casting wheel. Several such arrangements are shown in U.S. Patent No. 3,596,705.
As e~plained in the aformentioned U.S. Patent No. 3,596,705, the continual bending and fle~ing of the band about the casting and band wheels subjects the band to un-desirable strain which is proportional both to band thick-ness and to the diameter of the band wheels. This strain tends to cause rapid deterioration of the band and resultant failure after only a few hours of operation. It will be .,' ~
10~0~
appreciated by those skilled in the art that the short life expectancy of the band and the time-consuming replacement thereof are major problems concerning the efficient opera-tion and maintenance of continuous casting machines.
When continuously casting metals in machines of the above-described type, such as, for example, copper, aluminum and steel, it is highly advantageous to solidify the molten metal in as short a period of time as possible in order to maintain a high casting rate. Moreover, when casting metals containing alloying elements, rapid solidifi-cation is desirable in order to maintain intermetallic co~pounds in solid solution and to limit the size of the particles that do precipitate out of solution. However, the low cooling efficiency and non-uniformity of heat transfer inherent in the thick metal bands of prior art casting machines preclude attainment of the high casting rates and metallurgic effects desired. This is especially so if the band is fabricated of a material having a relatively low rate of heat transfer even though coolant is applied to the external band surface at maximum practicab3.e pressure and volume.
It should be apparent, therefore, that to improve the casting rate of continuous casting machines of the type described concomitantly with the life expectancy of the flexible band element, bands formed of thin gauge materials having a high heat transfer rate could be advan-tageously utilized to achieve such improvements. However, the prior art recognizes several problems in attempting to fabricate the band from thin gauge, high heat transfer ... ....
~0~06;~
materials. Notably, one problem encountered when fabrica-ting mold components of high heat transfer rate materials is the typically low structural strength of such materials which adversely affects their useful life, as explained in U.S. Patent No. 3,464,483.
While reducing band thickness would tend $o reduce band strain exerted by the band wheels on a band formed of a high heat transfer rate material, the structural strength of the band would, of course, be further diminished so that little advantage in terms of band life could be realized.
A further problem associated with the use of thin gauge band elements for continuous casti.ng machines is explained in U.S. Patent No. 3,533,463, wherein the paten-tees recognize the susceptibility of damage to a thin gauge band, particularly at the edges thereof, when it is ade-quately tensioned to prevent leakage of molten metal from between the band and casting wheel groove. It is further noted in the aforesaid patent that the band wheel flanges used to steer the band into position for enclosing the groove are especially damaging to the edges of a thin gauge band.
British Patent Specification No. 861,273 dis-closes a wheel-band type continuous casting machine wherein it is recognized that the tension in the casting band, necessary to close the casting groove, is highly detrimental to the band. Consequently, according to British Patent Specification No. 861,273, a casting system is provided in which a tight fit of the casting band against the edges of Z~
the casting groove is no longer insured by a high tensile strength applied to the band, but rather by means o~ a compression of the band upon the edges of the casting wheel, which compression is exerted radially upon the metal band in the direction of its thickness. This compression is provided by means of a linked endless chain comprising a plurality of rigid bars, generally made of steel, which are movable in a path against the rear surface of the casting band in the region where the casting band engages the periphery of the casting wheel.
It has been found, however, that while the apparatus of the aforementioned British patent is satis~
factory for casting thin wide metal strips, it does not provide a sufficient cooling gradient for the casting of generally rectangular metal bars wherein a high cooling capacity is necessary to solidify the molten core of the cast bar. Thus, it has been found in accordance with the instant invention that the large thick support bars dis-closed in the aforementioned British Patent Specification No. 861,273 will impede cooling of the casting band, and further are not sufficiently articulated so as to permit support of the casting band about an extended arcuate por-tion of the casting wheel which is necessary to facilitate high production rate operation.
_ATEMENT OF THE INVENTION
In view of the foregoing, it should be apparent that there still exists a need in the art for a wheel-band type continuous casting machine that is characterized both 1060~ '3 by an increased band life as well as a cooling capacity that will permit high production or casting rate operation.
There is, therefore, provided in accordance with this invention a wheel-band type casting machine for continuously casting molten metal into a cast bar comprising a rotatable casting wheel having a casting groove formed in the periphery thereof, a flexible band arranged to close an arcuate portion of said peripheral groove to form a casting mold therewith, said flexible band being supported in such a manner as to be in a substantially untensioned state, means for extracting heat from the molten metal in the casting mold, and means for applying an inward radial force against said flexible band to maintain said band in closed relationship with the periphery of said casting wheel;
characterized in that said means for applying an inward radial force against said flexible band is a support belt comprising a plurality of articulated support elements, each of said support elements being either perforated or of open mesh or grid construction, and wherein said means for extracting heat from the molten metal includes a plurality of spray nozzles adapted to spray a cooling liquid directly through the perforations or between the mesh or grids of each of the individual support elements and against the flexible band.
More particularly, the invention is character- -ized in that as a result of the substantially untensioned state of the flexible band, extraction of heat from the molten metal is improved by fabricating the band from a thin gauge material having a thickness less than 0.060 inches.
. ~ , , . . , - - : . . .
10~0~ 3 In certain of the embodiments of the invention disclosed herein, the flexible band element and its support belt travel along substantially the same path over the casting wheel and band wheel peripheries. The band element is, however, slightly longer than the support belt so that during casting the band is under relatively little tensile stress, the force of the band tensioning wheels being applied primarily in tension to the porous, highly flexible support belt. The portion of the band element closing the groove is under a primarily compressive load exerted radi-ally of the casting wheel by the support belt. In casting machine arrangements where necessary, means are provided for taking up slack in the flexible band element and for guiding it along its path of travel. In other embodiments of the invention, the support belt is arranged to travel about the band wheels of variously-configured continuous casting machines in the usual manner, while the flexible band element travels along a different path, only a portion of which coincides with the path of the support belt. As in the previously mentioned embodiments, the band element is relatively untensioned, most of the ~ensile force being exerted by the band tensioning wheels on the support belt.
Since the support belt is formed of a highly flexible open-grid chain, wire mesh or other suitable material, it is not particularly susceptible to flexural or bending stresses and, consequently, can be expected to have a long life expectancy. Moreover, the support belt may be employed on casting machines having significantly smaller diameter band wheels thereby allowing wheel and band - - . , - . . .................... . ...... ...
.. ... .
arrangements not heretofore feasible in continuous casting machines. In arrangements having small diameter band wheels, the flexible band element is preferably guided over a path of travel which differs from and has greater radii of curvature than the path of travel of the belt. A flexible band element formed of either a thin gauge high heat trans-fer metal band or a thin gauge non-metallic band utilized with the highly flexible support belt results in improved cooling efficiency and a substantial reduction of tensile stresses in the band thereby yielding a significant increase in band life. Thus, high casting rates and greater overall operating efficiencies are possible.
BRIFF DES~RIPTION OF THE DRAWINGS
Figure 1 is a schematic elevation view of one embodiment of a wheel-band type continuous casting machine in accordance with the present invention wherein the support belt and band element travel along substantially the same path;
Figure 2 is a schematic elevation view of an alternate embodiment of a wheel-band continuous casting machine according to the invention wherein the support belt and band element travel along substantially th~ same path;
Figure 3 is a schematic elevation view of a modification of the wheel-band continuous casting machine of Figure 2;
Figuxe 4 is a schematic elevation view of another alternate embodiment of a wheel-band continuous . .
1~0~
casting machine according to the invention wherein the support belt and band element travel along substantially the same path;
Figure 5 is a schematic elevation view of the wheel-band continuous casting machine of Figure 4 wherein the support belt and band element travel along different paths having different lengths.
Figure 6 is a schematic elevation view of a modification of the wheel-band continuous casting machine of Figure l;
Figure 7 is a cross-sectional view taken along the line 7-7 of Figure 6, and illustrates the band element interposed between the casting wheel periphery and the support belt;
Figure 8 is a schematic elevation view of another alternate embodiment of a wheel-band continuous casting machine in accordance with the present invention wherein a band element is cycled through the machine from a supply roll to either a waste receptacle or a recycle roll.
Figures 9a-9c are fragmentary perspective views of three embodiments of support belt constructions suitable for use in the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now in detail to the drawings wherein like parts are designated by like reference numerals throu~h-out, there is illustrated in Figure 1 a wheel-band type continuous casting machine designated generally by reference ~0~ 3 numeral 10. The casting machine 10 includes a casting wheel 12 and band guide wheels 14, 16, 18 and 20. An endless flexible band element 22 extends about an arcuate portion of casting wheel 12 and defines a mold in conjunc-tion with a groove (not shown) in the periphery of the casting wheel 12 extending from an inlet point A to an out-let point B. The band 22 is further guided about the band wheels 14, 16, 18 and 20 and is of a length somewhat in excess of the tangential path about the casting machine wheels so as to form a slight catenary 24 between guide wheels 16 and 18. A porous endless support belt 26, preferably contructed of an open-grid or mesh material, is similarly guided along substantially the same path as the band 22 except that the support belt 26 coincides with the tangential path between the guide wheels 16 and 18 as shown.
It will be apparent, therefore, that the tension applied by the guide wheel arrangement is exerted primarily upon the support belt 26 and the band 22 is relatively untensioned.
Further, closure of the peripheral groove of casting wheel 12 is accomplished by the essentially compressive force applied radially of the casting wheel 12 to the outwardly facing surface of the band 22 over the arcuate portion A-B.
As the casting wheel 12 is rotated in the direction shown, molten metal is flowed from a crucible 23 via spout 25 into the peripheral mold and exits as solidi-fied bar 28, having traveled over the arcuate portion A-B
of the casting wheel 12. A plurality of band headers 30, 32 and 34 are arranged about the arcuate portion A-B of the casting wheel 12 in confronting relation with the support l()~()~Z~3 belt 26. Coolant is supplied via a conduit (not shown) to a plurality of nozzles 36 which impinge liquid coolant, such as water or oil, against the surface of band 22 through the open-grid or mesh of the porous belt 26. Other band headers (not shown) are arranged to supply coolant to the external peripheral groove surfaces. An arrangement of a band and wheel cooling system which may ~e adapted to supply coolant to the band and belt of the present invention is more fully described in U.S. Patent No. 3,596,702.
With the above-described arrangement of the invention, heat may be rapidly transferred from the molten metal through the thin gauge band element 22 to the coolant so that the molten metal is quickly solidified. Since the band 22 is relatively thin and untensioned and, further, is supported by the belt 26 over the entire arcuate portion A-B
of casting wheel 12, the mechanical and thermal stresses to which the band is subjected are substantially minimized resulting in longer band life.
Figure 2 illustrates another embodiment of a continuous casting machine having a lower casting wheel 38 and an upper tension wheel 40. An endless thin gauge band element 42 having a length slightly greater than the tan-gential path about the wheels 38, 40 is employed to close the groove (not shown) in casting wheel 38. Reinforcing the band 4~ along the greater portion of its path of travel is a porous support belt 44, the length of which is approximately equal to the tangential path about the wheels 38, 40. A pair of idler wheels 46, 48 are positioned near the upper wheel to take up the sla~k in the longer length ~061)6'~
band 42 by applying a small tensile force to the band. A
band positioning wheel 50 is arranged adjacent the casting wheel 38 to urge the band 42 and belt 44 into engagement with the casting wheel periphery at the point of introduc-tion of molten metal into the casting wheel groove.
In Figure 3 there is shown a casting machine similar to that of Figure 2 except that a thin gauge band 52 is arranged to follow the tangential path about the casting wheel 38 and upper wheel 40 with substantially no slack. A support belt 54 reinforces the band 52 along the greater portion of its path. It will be appreciated that in this arrangement greater tensile forces may be exerted upon the band 52 than upon the bands of Figures 1 and 2.
However, the tensile forces in band 52 are still compara-tively small with respect ~o the tensile force exerted upon the support belt 54 by tensioning wheels 56, 58.
The continuous casting machine of the embodi-ment illustrated in Figure 4 is designated generally at 60 and includes a rotatable casting wheel 62 having a peri-pheral groove (not shown), guide wheels 64, 66, an endless thin gauge band element 68 supported by support belt 70, band positianing wheel 72 and take-up wheel 74.
Figure 5 illustrates a modification of the casting ~achine in Figure 4 wherein the thin gauge band 76 comprises a relatively "free wheeling" loop of a shorter length than the tangential path about the casting wheel 62 and guide wheels 64, 66. The small idler wheels 78 support and guide the free wheeling portion of the band 76.
lllustrated in Figures 6 and 7 is yet another 10~
alternative embodiment of a continuous casting machine according to the present invention and is designated generally by the numeral 80. The casting machine 80 in-cludes a casting wheel 82 and guide wheels 84, 86, 88 and 90 which are of substantially smaller diameter than the guide wheels of the apparatus shown in Figure 1. A thin gauge band element 92 extends about the arcuate portion C-D of casting wheel 82 to form the closure for a casting groove 94 (Fig. 7) formed in the periphery of the casting wheel 82. A support belt 96 of greater flexibility than the band 92 is tangentially guided about the casting wheel 82 by the guide wheels 84, 86, 88 and 90 and urges the band 92 against the periphery of the casting wheel 82 over the arcuate portion of C-D. The small diameter guide wheels 84, 86, 88 and 90 may be in the form of sprockets arranged to engage edge portions of the support belt 96 as idlers or as positively driven elements. If desired, a band straightening roller set 97 may be provided in any convenient location, preferably near the point where the band is guided away from the casting wheel. The purpose of the roller set 97 is to roll out minor discontinuities or wrinkles in the band element 92.
The band 92 is relatively free-wheeling except over arcuate portion C-D and is guided away from the casting wheel 82 at points C and D by small idler wheels 98 and 100 over paths having greater radii of curvature than the small diameter wheels 84, 86, 88 and 90 so as to minimize flexural stresses in the band 92. Band headers 102, 104 and 106 are arranged as in t~e embodiment of 10~
Figure 1 to impinge coolant via nozzles 108 onto the external surface 110 of band 92 through openings 99 in support belt 96. Side coolant headers 105 and casting wheel header 107 shown in Figure 7 are arranged to supply coolant via their respective nozzles to the external surfaces of the peripheral groove 94.
Figure 8 illustrates another embodiment accord-ing to the invention wherein a support belt 112 is guided tangentially about a casting wheel 114 and small diameter guide wheels or sprockets 116, 118 and 120. A roll 122 of flexible band material, which may be either a thin gauge metallic material, such as, for example, copper foil, or a non-metallic material, such as asbestos paper or other suitable heat resistant material, is positioned to feed between the periphery of casting wheel 114 and the support belt 112 to form a band 124 for closing the groove in the casting wheel periphery over arcuate portion E-F. The band 124 may be recovered in a receptacle 126 as waste or wound onto another roll 128 for recycling.
Figures 9A-9C illustrate alternative embodi-ments of open-grid and wire-mesh configurations suitable for use as the support belt of the present invention.
Figure 9A illustrates a portion of an open-grid support belt formed of a plurality of shaped flat wire sections 130 having openings 132 therethrough. The sections 130 are interconnected by rods 134 extending alternately through the openings 132 of a pair of adjacently disposed flat-wire sections 130.
.
The support belt portion of Figure 9B comprises a chain-like member 136 formed of links 138, and having attached transversely thereof at each link 138, a perforated plate 140 which may have a slightly curved surface as shown so as to conform to the radius of curvature of the casting wheel with which it is employed. Coolant is applied to the flexible band element through apertures 141 suitably arranged in the plates 140.
Figure 9C illustrates a portion of a double weave wire mesh 142 reinforced with rods 144 for added strength. At the edges thereof (only one shown) is a roller chain 146 for engagement with a sprocket wheel which may be provided at the ends of the guide wheels of the casting machines of the previously described embodiments.
In view of the foregoing, it should be apparent that there is provided by the present invention a novel wheel-band type continuous casting machine which includes a flexible band element supported by a highly flexible support belt of open-grid construc.tion for the introduction of coolant therethrough so that cooling efficiency is increased thereby making possible higher casting rates.
In addition, the novel method of supporting the thin gauge band in a relatively untensioned state yields improved band life expectancies.
Although only preferred embodiments are speci-fically illustrated and described herein, it will be appreciated that many modifications and variations of the present invention are possible in light of the above ~o~
teachings and within the purview of the appended claims without departing from the spirit and intended scope of the invention.
Claims (7)
1. A wheel-and-band type casting machine for continuously casting molten metal into a cast bar comprising a rotatable casting wheel having a casting groove formed in the periphery thereof, a flexible band arranged to close an arcuate portion of said peripheral groove to form a casting mold therewith, means for extracting heat from the molten metal in the casting mold, and means for applying an inward radial force against said flexible band to maintain said band in sealingly closed relationship with the periphery of said casting wheel;
characterized in that said means for applying an inward radial force against said flexible band is a support belt comprising a plurality of articulated support elements, each of said support elements being either perforate or of open-grid or -mesh material construction, and wherein said means for extracting heat from the molten metal includes a plurality of spray nozzles adapted to spray a cooling liquid directly through the perforations or openings of the open-grid or -mesh material of each of the individual support elements and against the flexible band, said band being in a substantially untensioned state whereby said sealingly closed relationship is obtained substantially entirely by said inward radial force without any substantial longitudinal tensile forces acting along said band.
characterized in that said means for applying an inward radial force against said flexible band is a support belt comprising a plurality of articulated support elements, each of said support elements being either perforate or of open-grid or -mesh material construction, and wherein said means for extracting heat from the molten metal includes a plurality of spray nozzles adapted to spray a cooling liquid directly through the perforations or openings of the open-grid or -mesh material of each of the individual support elements and against the flexible band, said band being in a substantially untensioned state whereby said sealingly closed relationship is obtained substantially entirely by said inward radial force without any substantial longitudinal tensile forces acting along said band.
2. A wheel-and-band type casting machine according to claim 1; characterized in that the band is fabricated from a thin gauge material having a thickness less than 0.060 inches.
3. A wheel-and-band type casting machine according to either of claims 1 or 2; characterized in that said support belt is sufficiently flexible to permit support of the flexible band over at least a 180° arcuate portion of the casting wheel.
4. A wheel-and-band type casting machine according to claim 1, characterized in that said flexible band is formed of a non-metallic, heat-resistant material.
5. A wheel-and-band type casting machine according to claim 4, further characterized in that said material is asbestos paper.
6. A wheel-and-band type casting machine according to either of claims 4 or 5, characterized in that said flexible band of non-metallic, heat-resistant material is wound upon itself in the form of a supply roll, said supply roll being arranged to supply the flexible band therefrom into closed relationship with said casting groove.
7. A wheel-and-band type casting machine according to either claims 4 or 5 characterized in that said flexible band of non-metallic, heat-resistant material is wound upon its self in the form of a supply roll, said supply roll being arranged to supply the flexible band therefrom into closed relationship with said casting groove, and a waste receptacle is provided for receiving the flexible band departing from the casting wheel periphery.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/590,236 US4030537A (en) | 1975-06-25 | 1975-06-25 | Thin gauge casting wheel band |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1060629A true CA1060629A (en) | 1979-08-21 |
Family
ID=24361418
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA255,680A Expired CA1060629A (en) | 1975-06-25 | 1976-06-25 | Thin gauge casting wheel band |
Country Status (11)
| Country | Link |
|---|---|
| US (1) | US4030537A (en) |
| JP (1) | JPS524430A (en) |
| AU (1) | AU502240B2 (en) |
| BE (1) | BE843369A (en) |
| CA (1) | CA1060629A (en) |
| ES (1) | ES449239A1 (en) |
| FR (1) | FR2317033A1 (en) |
| GB (1) | GB1537158A (en) |
| IT (1) | IT1065609B (en) |
| NO (1) | NO147740C (en) |
| SE (1) | SE7607323L (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2853868C2 (en) * | 1977-12-14 | 1985-07-18 | Southwire Co., Carrollton, Ga. | Process for the continuous casting of steel as well as the correspondingly produced steel strand |
| US4276923A (en) * | 1979-09-04 | 1981-07-07 | Mislan Joseph D | Method for pressure casting metal objects |
| US4579169A (en) * | 1980-04-29 | 1986-04-01 | Southwire Company | Continuous casting band system |
| US4649983A (en) * | 1983-10-26 | 1987-03-17 | Allied Corporation | Chill roll casting of metal strip |
| DE3438482A1 (en) * | 1984-10-17 | 1986-04-17 | Korf Engineering GmbH, 4000 Düsseldorf | CONTINUOUS CASTING DEVICE |
| US5301741A (en) * | 1991-06-03 | 1994-04-12 | Olin Corporation | Casting of metal strip |
| US5251687A (en) * | 1991-09-03 | 1993-10-12 | Olin Corporation | Casting of metal strip |
| WO2001089741A1 (en) * | 2000-05-20 | 2001-11-29 | Sms Demag Aktiengesellschaft | Device for continuously casting metal, particularly steel |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2206930A (en) * | 1938-07-29 | 1940-07-09 | William R Webster | Continuous molding machine |
| US3228072A (en) * | 1958-03-17 | 1966-01-11 | Hazelett Strip Casting Corp | Feeding means for strip casting |
| GB861273A (en) * | 1959-05-21 | 1961-02-15 | Cie Metaux Doverpelt Lommel | Improvements in and relating to the casting of non-ferrous metals |
| CH426114A (en) * | 1964-12-11 | 1966-12-15 | Alusuisse | Method for casting strip-shaped wide metal plates and machine therefor |
-
1975
- 1975-06-25 US US05/590,236 patent/US4030537A/en not_active Expired - Lifetime
-
1976
- 1976-06-24 SE SE7607323A patent/SE7607323L/en unknown
- 1976-06-24 AU AU15231/76A patent/AU502240B2/en not_active Expired
- 1976-06-24 FR FR7619225A patent/FR2317033A1/en active Granted
- 1976-06-24 BE BE168280A patent/BE843369A/en not_active IP Right Cessation
- 1976-06-24 NO NO762189A patent/NO147740C/en unknown
- 1976-06-25 IT IT50159/76A patent/IT1065609B/en active
- 1976-06-25 JP JP51074539A patent/JPS524430A/en active Granted
- 1976-06-25 CA CA255,680A patent/CA1060629A/en not_active Expired
- 1976-06-25 GB GB26494/76A patent/GB1537158A/en not_active Expired
- 1976-06-25 ES ES449239A patent/ES449239A1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| ES449239A1 (en) | 1977-07-16 |
| US4030537A (en) | 1977-06-21 |
| GB1537158A (en) | 1978-12-29 |
| FR2317033A1 (en) | 1977-02-04 |
| JPS524430A (en) | 1977-01-13 |
| JPS5442849B2 (en) | 1979-12-17 |
| NO147740B (en) | 1983-02-28 |
| FR2317033B1 (en) | 1979-03-02 |
| NO147740C (en) | 1983-06-08 |
| AU502240B2 (en) | 1979-07-19 |
| SE7607323L (en) | 1976-12-26 |
| AU1523176A (en) | 1978-01-05 |
| IT1065609B (en) | 1985-03-04 |
| NO762189L (en) | 1976-12-28 |
| BE843369A (en) | 1976-10-18 |
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