US3709285A

US3709285A - Method and apparatus for guiding a continuous casting strand

Info

Publication number: US3709285A
Application number: US00072782A
Authority: US
Inventors: F Ruckstuhl
Original assignee: OLSSON E AG
Current assignee: OLSSON E AG
Priority date: 1970-09-16
Filing date: 1970-09-16
Publication date: 1973-01-09
Anticipated expiration: 1990-01-09

Abstract

A method and apparatus for continuous casting is disclosed wherein steps and means are provided for overcoming the tendency of a casting formed on an inclined or horizontal plane to have a thicker lower side because of the force of gravity acting on the casting. The casting formed by virtue of the invention is caused to be urged away from the lower surface of the chill or mold such that the influence of gravity is counteracted and the casting contacts the walls of the mold with substantially uniform pressure on all surfaces. Thus, a casting of substantially uniform thickness is discharged from the chill.

Description

United States Patent Ruckstuhl 1 Jan. 9, 1973 54 METHOD AND APPARATUS FOR 3,329,199 7 1967 Easton ..l64/282 x GUIDING A CONTINUOUS CASTING 3,339,623 9/1967 Rys et a1. ..l64/282 X STRAND 3,391,725 7/1968 Rossi ..l64/282 x 3,409,070 11/1968 Ciochetto... ...164/282 X Inventorl Franz Ruckstuhl, schwerzenbach, 3,415,306 12/1968 Olsson ..164/283 x Switzerland [73] Assignee: Erik Olsson A.G., Zurich, Switzer- Primary SPencer Amlear land Attorney-Parmelee, Utzler & Welsh [22] Filed: Sept. 16, 1970 57 ABSTRACT [21] Appl' 72,782 A method and apparatus for continuous casting is dis- Relaed Applicamn Data closed wherein steps and means are provided for overcoming the tendency of a casting formed on an 1 Continuation-impart of y 15, inclined or horizontal plane to have a thicker lower 1969, abandoned side because of the force of gravity acting on the casting. The casting formed by virtue of the invention is [52] [1.8. CI ..l64/282, 164/82 caused to be urged away from the lower Surface of the 2; chill or mold such that the influence of gravity is 1 0 counteracted and the casting contacts the walls of the mold with substantially uniform pressure on all sur- [56] References cued faces. Thus, a casting of substantially uniform UNITED STATES PATENTS thickness is discharged from the chill.

494,659 4/1893 Very ,.l64/283 X 13 Claims, 5 Drawing Figures Pmmnum 9191s 3.709.285

SHEET 1 [IF 3 INVENTOR. FRANZ RUCKSTUHL A r rarneys PATENTEDJAH s 1973 3.709.285

SHEET 2 BF 3 INVENTOR. FRANZ 'RUCKS TUHL WED- A! forneys PATENTEDJAN 9 197a SHEET 3 0F 3 INVENTOR. FRANZ RUG/f5 TUHL Ar forneys METHOD AND APPARATUS FOR GUIDING A CONTINUOUS CASTING STRAND This application is a continuation-in-part application of my copending application Ser. No. 841,833 filed July 15, l969,now abandoned.

This invention relates to a method and apparatus for continuous casting, and more particularly to a method and apparatus for continuous casting whereby a casting withdrawn from an inclined or horizontal mold or chill has a generally uniform thickness throughout its length.

When continuously casting metal, such as steel for example, in a mold or chill disposed in an inclined or horizontal plane, the force of gravity components of the casting tend to urge the casting toward the lower wall of the chill. As a result of this, the skin of the casting on the lower side is cooled more intensely and is thicker than the upper skin when the casting is withdrawn from the chill. Sometimes the effect of the force of gravity is so great as to cause the separation of the upper skin of the casting from the wall of the chill, in spite of the ferrostatic pressure inside the casting. The skin separation results in the upper skin of the casting being weaker than the lower skin. The same nonuniformity of thickness of the casting occurs when the inclined mold has a curved shape. Accordingly, it may be said that in all continuous casting apparatus in which force of gravity components acting on the casting and transversely to the longitudinal axis thereof, a uniform growth of the casting skin in the chill cannot be achieved.

1 overcome the problem mentioned above by virtue of my present invention in which the casting contacts the walls of the chill with substantially uniform pressure on all surfaces of the chill. I arrived at my invention by recognizing that forces can be shifted from the lower portion of the casting as it passes through the chill. The shifted forces will compensate for the adverse effect of the force of gravity components acting on the casting. More particularly, the apparatus of the invention is characterized by the axis of the chill or its tangent at the point of discharge, where the chill is arcuately shaped, being at an acute angle to the vertical, and intersects the axis of guide rolls or its tangent at the point of inlet to the guide rolls. The chill and guide rolls are longitudinally spaced from each other, and the intersection of the lines is at a point intermediate the spacing. In addition, the intersecting lines form a downwardly facing obtuse angle with each other. By virtue of this angular relationship a bending reaction force is developed through the casting within the chill, with the reaction force being opposite in direction to the force of gravity acting on the casting. The force of gravity component is substantially counteracted resulting in uniform pressure by the casting on the chill and thus uniform cooling thereof and consequent withdrawal of a casting having a uniform thickness throughout its length.

The method of this invention provides the same results as the apparatus, and comprises, preferably, the steps of: pouring a molten metal into a mold having a mold cavity extending at an acute angle to the vertical and in which the casting is formed of which a surface tends to be urged against one mold wall under the influence of gravity; and continuously withdrawing the casting from the mold in a manner to urge the casting away from the one mold wall and in a direction to counteract the influence of gravity so that the casting contacts all of the walls of the mold with substantially uniform pressure at all of its surfaces. In the preferred method of this invention the casting is withdrawn from the chill in an angular relationship, as set out above for the apparatus, to create a bending reaction force with counteracts the force of gravity components acting adversely on the casting. v 3

Other details and advantages of this invention will become apparent as the following description of a present preferred embodiment thereof and a preferred method of practicing same proceeds.

In the accompanying drawings I have shown a present preferred embodiment of this invention and have illustrated a present preferred method of the same in which:

FIGS. l-4 are schematic representations of various combinations of chill and guide sections of differing shapes, all of which form part of the present invention; and

FIG. 5 is a generally diagrammatic representation. in elevation and partly in section of a continuous casting apparatus embodying the present invention.

Referring now to the drawings, and especially to FIGS. I-4, wherein like reference numerals are directed to corresponding parts throughout those views, there is shown an elongated chill 5 which in all of the views is inclined at an acute angle to the horizontal. Longitudinally spaced from the chill 5 and arranged to receive a casting from chill 5 is an elongated support and and guide roll section 6 which also in all of the views is inclined at an acute angle to the horizontal. Both the chill 5 and guide rolls 6 could be of any well known shape and construction wherein molten metal would be directed through the chill and suitably formed, and the formed casting discharged from the chill into the guide rolls.

In FIG. 1, both chill 5 and guide rolls 6 are generally straight. The chill 5 is arranged such that its longitudinal axis 1 intersects the longitudinal axis 2 of guide rolls 6 at point 7'intermediate the longitudinal spacing between the chill and the guide rolls. Both the chill 5 and guide rolls'6 are disposedin positions relative to each other such that the intersection of their respective axes 1 and 2 form a downwardly facing obtuse angle a. The force of gravity acting on the casting in chill 5 has a tendency to press'downwardly on the casting with a component 4. By bending the casting in changing the direction 'of its axis through the angle a, which'is close to causes the section of the'ca sting in the guide rolls 6 to exert a bendingreactio'n force 3 on the section of casting found in the chill. The bending force is such that it compensates substantially for the adverse effect of the force of gravity component 4 acting on the casting section within the chill 5. As pointed out earlier in the introductory portion of this description, the force of gravity component 4 without any compensating op positely directed forces such as bending force 3, would tend to pull the upper skin of the casting away from the surface of the chill 5.

In FIG. 2, the chill 5 is arcuately shaped with its axis 1 being correspondingly shaped. The guide rolls 6 are straight. In this embodiment the tangent line 1' to the longitudinal axis 1 of chill 5 at point of discharge 8 of the chill is at an acute angle to the vertical and intersects the straight longitudinal axis 2 of guide rolls 6 at the intermediate point 7. As in FIG. 1, the tangent line 1 and axis 2 intersect to form a downwardly facing obtuse angle Thus, the same force of gravity component-counteracting bending reaction force 3 is created on the section of casting within chill 5.

In FIG. 3, the chill is shown as being straight while the guide rolls 6 are arcuately shaped with a correspondingly arcuate longitudinal axis 2. In this case the tangent line 2' to axis 2 and passing through point of entry 9 into the guide rolls, intersects the longitudinal axis 1 of chill 5 at the intermediate point 7. As with the other embodiments, tangent line 2' and axis 1 intersect to form downwardly facing obtuse angle a close to 180. Again, a favorable gravity counteracting bending reaction force 3 is created on the section of casting within chill 5.

In FIG. 4, both the chill 5 and the guide rolls 6 are arcuately shaped with correspondingly shaped axes 1 and 2, respectively. In this case the tangent line 1 to the axis 1 and passing through discharge point 8 intersects tangent line 2 to the axis 2 and passing through entry point 9, the intersection being at intermediate point 7. As in the previous embodiments, the lines 1' and 2 intersect to form a downwardly facing obtuse angle a, and thereby results in the creation of the gravity counteracting bending reaction force 3 on the section of casting within chill 5.

Thus, it can be said that the casting passing through chill 5 is provided with a discharge axis defined either by the straight longitudinal axis of the chill or by the tangent to the arcuate longitudinal axis of the chill at a point of discharge of the chill, and an entry axis defined either by the straight longitudinal axis of the guide rolls or by the tangent to the arcuate longitudinal axis of the guide rolls at a point of entry of the guide rolls. In this invention, the discharge axis of the casting is at an acute angle with the vertical, and intersects the entry axis at an intermediate point in the spacing between the chill and guide rolls. The intersecting casting axes form a downwardly facing obtuse angle, which results in the favorable bending reaction force being imparted to the section of casting within the chill.

FIG. 5 illustrates one form of apparatus embodying the present invention, with the respective axes of the chill and guide rolls following a straight pattern typical of that illustrated in FIG. 1. There is shown in FIG. 5, a foundation 10 on which table 14 is supported in an inclined position upon braces 12. A gusset 16 is arranged on top of table 14 and a frame 18 is supported at one end on the gusset while its other end is supported by set pin 20 which is arranged to permit upward adjustment through supporting lug 22 mounted'on table 14. A handwheel 24 secured to set pin 20 is provided for selectively turning the pin in either desired direction.

A molten metal storage and pouring container 26 is rigidly fixed on frame 18. Container 26 has a pouring nozzle 32 arranged to pour molten metal into a generally straight elongated chill 30 supported at an inclination to the horizontal on slide member 28 which in turn is slidably mounted on frame 18. A back and Elongated guide rolls 36 are arranged downstream of the discharge end of chili 30. The guide rolls 36 are generally straight and are arranged so that the entry thereof is longitudinally spaced from the discharge of the chill 30. The longitudinal axis of the chill intersects the longitudinal axis of the guide rolls 36 at a point intermediate the spacing therebetween, much in the same manner and for the same purpose as described in regard to FIG. 1. The obtuse angle formed by-the two axes is about 178 which may be varied as desired by rotating handwheel 24.

The continuous casting 40 passing from chill 30 into guide rolls 36 experiences a bending force which imparts a reaction force on the section of the casting within chill 30, the reaction force being opposite to the force of gravity components acting on the casting. Because of the bending reaction force, the section of the casting 40 in chill 30 will not rest with its total weight on the lower wall surface of the chill, but rather will be urged toward the upper wall surface of the chill whereby a substantially uniform pressure is exerted by the casting on all surfaces of the chill. Thus, a substantially uniform cooling of the periphery of the continuous casting is obtained.

While I have shown and described a present preferred embodiment of this invention and have illustrated a certain present preferred method of practicing the same, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.

Iclaim:

1. Apparatus for continuous casting, comprising:

molten metal storage and pouring container means;

elongatedchill means arranged below said container means to receive molten metal therefrom, said chill means having a mold cavity extending at an acute angle to the vertical and constructed'and arranged such that the casting formed therein has one surface which tends to be urged against one wall of the mold cavity under the influence of' gravity; and elongated casting support and guide means disposed in alignment with'and longitudinally spaced from -said chill means, said support and guide means being constructed and arranged to receive castings from said'chill means and to urge the castings in a direction to counteract the influence of gravityv so that the castings contact all the walls of said mold cavity with substantially uniform pressure at all of its surfaces.

2. The apparatus as set forth in claim 1 wherein said chill means and said support and guide means are generally straight, and wherein the respective axes thereof intersect at a point intermediate the spacing between said chill means and said support and guide means to form a downwardly facing obtuse angle.

3. The apparatus as set forth in claim 1 wherein said chill means is arcuately shaped in an upwardly facing curve and said support and guide means is generally straight, and wherein the tangent line to the axis of said chill means at the point of discharge thereof and the axis of said support and guide means intersect at a point intermediate the spacing between said chill means and said support and guide means to form a'downwardly facing obtuse angle.

4. The apparatus as set forth in claim 1 wherein said chill means is generally straight and said support and guide means is arcuately shaped in an upwardly facing curve, and wherein the axis of said chill means and the tangent line to the axis of said support and guide means at the point of entry thereof intersect at a point intermediate the spacing between said chill and said support means to form a downwardly facing obtuse angle.

5. The apparatus as set forth in claim 1 wherein both chill means and guide means are arcuately shaped in upwardly facing curves, and wherein the tangent line to the axis of said chill means at the point of discharge thereof and the tangent line to the axis of said support and guide means at the point of entry thereof intersects at a point intermediate the spacing between said chill means and said support and guide means to form a downwardly facing obtuse angle.

6. The apparatus as set forth in claim 1 wherein at least one of said chill means and said support and guide means is selectively adjustable such that the angle that its axis makes with the vertical may be varied.

7. The apparatus as set forth in claim 1 wherein said container means and said chill means are supported by a common support means which is selectively adjustable such that said acute angle of said chill means may be varied.

8. In an apparatus for continuous casting comprising molten metal storage and pouring container means; elongated chill means arranged below the container means to receive molten metal therefrom, and shaped to provide a discharge axis for castings defined by the straight longitudinal axis thereof or by the tangent to the arcuate longitudinal axis at the point of discharge thereof; elongated casting support and guide means aligned with and longitudinally spaced from the chill means, and shaped to define an inlet axis for castings defined by the straight longitudinal axis thereof or by the tangent to the arcuate longitudinal axis at the point of entry thereof; the improvement therein comprising:

said chill means being arranged such that said discharge axis extends at an angle with respect to the vertical and the mold cavity formed therein extends at an acute angle to the vertical,with said chill means further being constructed and arranged such that the casting formed in the mold cavity has one surface which tends to be urged against one wall of the mold cavity under the influence of gravity; and

said support and guide means being arranged such that said inlet axis intersects said discharge axis at a point intermediate the space in between said chill means and said support andguide means to form a downwardly facing obtuse angle whereby the castings received from said chill means are urged in a direction to counteract the influence of gravity so that the castings contact all of the walls of said mold cavity with substantially uniform pressure at all of its surfaces.

9. The improvement as set forth in claim 8 wherein at least one of said chill means and said support and guide means is arranged such that said obtuse angle may be varied.

10. The improvement as set forth in claim 8 wherein said container means and said chill means are arranged to be supported on a common supgort means which is selectively ad ustable such that sat acute angle of said discharge axis may be varied.

11. A method for forming a continuous strand of cast metal comprising the steps of:

pouring molten metal into a mold having a mold cavity extending at an acute angle to the vertical and in "which the casting is formed of which a surface'tends to be urged against one mold wall under the influence of gravity; and

continuously withdrawing the casting from the mold in a manner to urge the casting away from said one mold wall and in a direction to counteract the influence of gravity so that the casting contacts all of the walls of the mold with substantially uniform pressure at all of its surfaces.

12. The method as set forth in claim 11 wherein said withdrawing is made with the axis of the casting at the point of withdrawal forming an acute angle with the vertical; and wherein said withdrawing is further made such that the axis of the casting at a preselected point downstream from the point of withdrawal intersects the withdrawal axis of thecasting at a point inter-mediate the withdrawal and preselected downstream points to form a downwardly facing obtuse angle.

13. The method as set forth in claim 12 including the steps of directing the withdrawn casting into a support and guide means aligned with and spaced from the withdrawal point of the mold; and wherein I said preselected downstream point is at the point of 'entry of the support and guide means.

Claims

1. Apparatus for continuous casting, comprising: molten metal storage and pouring container means; elongated chill means arranged below said container means to receive molten metal therefrom, said chill means having a mold cavity extending at an acute angle to the vertical and constructed and arranged such that the casting formed therein has one surface which tends to be urged against one wall of the mold cavity under the influence of gravity; and elongated casting support and guide means disposed in alignment with and longitudinally spaced from said chill means, said support and guide means being constructed and arranged to receive castings from said chill means and to urge the castings in a direction to counteract the influence of gravity so that the castings contact all the walls of said mold cavity with substantially uniform pressure at all of its surfaces.

3. The apparatus as set forth in claim 1 wherein said chill means is arcuately shaped in an upwardly facing curve and said support and guide means is generally straight, and wherein the tangent line to the axis of said chill means at the point of discharge thereof and the axis of said support and guide means intersect at a point intermediate the spacing between said chill means and said support and guide means to form a downwardly facing obtuse angle.

8. In an apparatus for continuous casting comprising molten metal storage and pouring container means; elongated chill means arranged below the container means to receive molten metal therefrom, and shaped to provide a discharge axis for castings defined by the straight longitudinal axis thereof or by the tangent to the arcuate longitudinal axis at the point of discharge thereof; elongated casting support and guide means aligned with and longitudinally spaced from the chill means, and shaped to define an inlet axis for castings defined by the straight longitudinal axis thereof or by the tangent to the arcuate longitudinal axis at the point of entry thereof; the improvement therein comprising: said chill means being arranged such that said discharge axis extends at an angle with respect to the vertical and the mold cavity formed therein extends at an acute angle to the vertical,with said chill means further being constructed and arranged such that the casting formed in the mold cavity has one surface which tends to be urged against one wall of the mold cavity under the influence of gravity; and said support and guide means being arranged such that said inlet axis intersects said discharge axis at a point intermediate the space in between said chill means and said support and guide means to form a downwardly facing obtuse angle whereby the castings received from said chill means are urged in a direction to counteract the influence of gravity so that the castings contact all of the walls of said mold cavity with substantially uniform pressure at all of its surfaces.

10. The improvement as set forth in claim 8 wherein said container means and said chill means are arranged to be supported on a common support means which is selectively adjustable such that said acute angle of said discharge axis may be varied.

11. A method for forming a continuous strand of cast metal comprising the steps of: pouring molten metal into a mold having a mold cavity extending at an acute angle to the vertical and in which the casting is formed of which a surface tends to be urged against one mold wall under the influence of gravity; and continuously withdrawing the casting from the mold in a manner to urge the casting away from said one mold wall and in a direction to counteract the influence of gravity so that the casting contacts all of the walls of the mold with substantially uniform pressure at all of its surfaces.

12. The method as set forth in claim 11 wherein said withdrawing is made with the axis of the casting at the point of withdrawal forming an acute angle with the vertical; and wherein said withdrawing is further made such that the axis of the casting at a preselected point downstream from the point of withdrawal intersects the withdrawal axis of the casting at a point inter-mediate the withdrawal and preselected downstream points to form a downwardly facing obtuse angle.

13. The method as set forth in claim 12 including the steps of directing the withdrawn casting into a support and guide means aligned with and spaced from the withdrawal point of the mold; and wherein said preselected downstream point is at the point of entry of the support and guide means.