Roll line unit and continuous casting apparatus

Abstract

A roll line unit for a continuous casting apparatus includes a roll mantle having two ends and a non-rotatable shaft including a coolant line. The roll mantle is rotatably mounted on the non-rotatable shaft by means of a first bearing located in a first end region of the roll mantle and a second bearing located in a second end region of the roll mantle. The roll mantle includes at least one coolant channel having at least one fluid inlet that is arranged to be in fluid communication with the coolant line. The roll line unit includes two outer seals located on an axially outward side of each of the first and second bearings, whereby the outer seals and the first and second bearings are located axially inwards of the ends of the roll mantle.

Claims

1. A roll line unit for a continuous casting apparatus comprising: a roll mantle having a first end, a second end and an outer working surface configured to support a metal strand and extending entirely between the first end and the second end; a non-rotatable shaft including a coolant line; first and second bearings rotatably mounting the roll mantle to the shaft, the first bearing being located within a first end of the roll mantle outer working surface and the second bearing being located within a second end of the roll mantle outer working surface; and first and second outer seals, the first outer seal being located on an axially outward side of the first bearing and entirely axially inward of the first end of the roll mantle outer working surface, the second outer seal being located on an axially outward side of the second bearing and entirely axially inward of the second end of the roll mantle outer working surface; wherein the roll mantle has at least one coolant channel with at least one fluid inlet arranged to be in fluid communication with the coolant line of the shaft.

2. The roll line unit according to claim 1, wherein the at least one fluid inlet is located between the first and second bearings.

3. The roll line unit according to claim 1, wherein the roll mantle is manufactured in one piece or in a plurality of pieces.

4. The roll line unit according to claim 1, wherein the at least one coolant channel is arranged to extend longitudinally across at least one of the first bearing and the second bearing.

5. The roll line unit according to claim 1, wherein the at least one coolant channel includes a section that extends at a constant distance from an outer surface of the roll mantle.

6. The roll line unit according to claim 1, wherein the at least one coolant channel includes a section that extends at a non-constant distance from an outer surface of the roll mantle.

7. The roll line unit according to claim 1, wherein the roll mantle includes at least one fluid outlet arranged to be in fluid communication with the coolant line.

8. The roll line unit according to claim 7, wherein the at least one fluid outlet is located between the first and second bearings.

9. The roll line unit according to claim 8, wherein the at least one coolant channel extends from the at least one fluid inlet to the at least one fluid outlet in a continuous path.

10. A continuous casting apparatus comprising: at least one roll line unit including: a roll mantle having a first end, a second end and an outer working surface configured to support a metal strand and extending entirely between the first end and the second end; a non-rotatable shaft including a coolant line; first and second bearings rotatably mounting the roll mantle to the shaft, the first bearing being located within a first end of the roll mantle outer working surface and the second bearing being located within a second end of the roll mantle outer working surface; and first and second outer seals, the first outer seal being located on an axially outward side of the first bearing and entirely axially inward of the first end of the roll mantle outer working surface, the second outer seal being located on an axially outward side of the second bearing and entirely axially inward of the second end of the roll mantle outer working surface; wherein the roll mantle has at least one coolant channel with at least one fluid inlet arranged to be in fluid communication with the coolant line of the shaft.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will hereinafter be further explained by means of non-limiting examples with reference to the appended schematic figures. It should be noted that the drawings have not been drawn to scale and that the dimensions of certain features have been exaggerated for the sake of clarity. In the drawings:

(2) FIG. 1 shows a continuous casting apparatus;

(3) FIG. 2 shows a roll line unit according to an embodiment of the invention comprising a roll mantle mounted on a non-rotatable shaft;

(4) FIG. 3 shows a roll mantle of a roll line unit according to an embodiment of the invention;

(5) FIG. 4 shows a cross section of one end of a roll line unit according to an embodiment of the invention;

(6) FIG. 5 shows a two-piece roll mantle of a roll line unit according to an embodiment of the invention; and

(7) FIG. 6 shows a continuous caster comprising four roll line units according to an embodiment of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

(8) FIG. 1 shows a continuous casting apparatus in which molten metal 10 is tapped into a ladle 12. After undergoing any ladle treatments, such as alloying and degassing, and arriving at the correct temperature, molten metal 10 from the ladle 12 is transferred via a refractory shroud to a tundish 14. Metal is drained from the tundish 14 into the top of an open-base mold 16. The mold 16 is water-cooled to solidify the molten metal directly in contact with it. In the mold 16, a thin shell of metal next to the mold walls solidifies before the middle section, now called a strand, exits the base of the mold 16 into a cooling chamber 18; the bulk of metal within the walls of the strand is still molten. The strand is supported by closely spaced, water-cooled roll lines 20 which act to support the walls of the strand against the ferrostatic pressure of the still-solidifying liquid within the strand. To increase the rate of solidification, the strand is sprayed with large amounts of water as it passes through the cooling chamber 18. Final solidification of the strand may take place after the strand has exited the cooling chamber 18.

(9) In the illustrated embodiment the strand exits the mold 16 vertically (or on a near vertical curved path) and as it travels through the cooling chamber 18, the roll lines 20 gradually curve the strand towards the horizontal. (In a vertical casting machine, the strand stays vertical as it passes through the cooling chamber 18).

(10) After exiting the cooling chamber 18, the strand passes through straightening roll lines (if cast on other than a vertical machine) and withdrawal roll lines. Finally, the strand is cut into predetermined lengths by mechanical shears or by travelling oxyacetylene torches 22 and either taken to a stockpile or the next forming process. In many cases the strand may continue through additional roll lines and other mechanisms which might flatten, roll or extrude the metal into its final shape.

(11) FIG. 2 shows a roll line unit 24 according to an embodiment of the invention. The roll line unit 24 comprises a roll mantle 26 having two, first and second ends 26a, 26b, respectively, and a non-rotatable shaft 28 comprising a coolant line (not shown in FIG. 2). The roll mantle 26 is rotatably mounted on the non-rotatable shaft 28 by means of a first bearing 30a located in a first end region ER1 of the roll mantle 26 and adjacent to the first end 26a of the mantle 26, and a second bearing 30b located in a second end region ER2 of the roll mantle 26 and adjacent to the second end 26b of the mantle 26. The roll mantle 26 comprises at least one coolant channel (not shown in FIG. 2) having at least one fluid inlet that is arranged to be in fluid communication with, i.e., fluidly connected with, the coolant line of the non-rotatable shaft 28, as described below. The roll line unit 24 comprises two outer seals 32 located on an axially outward side of each of the first and second bearings 30a, 30b, whereby the outer seals 32 and the first and second bearings 30a, 30b are located axially inwards of the ends 26a, 26b, respectively, of the roll mantle 26. More specifically, a first outer seal 32 is located on an axially outward side of first bearing 30a and axially inward of the first end 26a of the roll mantle 26 and a second outer seal 32 is located on an axially outward side of the second bearing 30b and axially inward of the second end 26b of the roll mantle 26.

(12) FIG. 3 shows a roll mantle 26 comprising a plurality of fluid channels 34 that may be used to conduct coolant through the roll mantle 26 when the roll mantle 26 is in use, whereby only two fluid channels 34 have been illustrated. The length L of a roll mantle 26 may be between 100 millimeters (mm) and 1200 mm, or any other desired and/or appropriate length. Further, the roll mantle 26 is not necessarily cylindrical and does not necessarily have a continuous or a smooth outer surface. It can have any uniform or non-uniform, symmetric or non-symmetric shape, size and/or cross section. According to an embodiment of the invention the roll mantle 26 including the at least one coolant channel 34 may be produced or fabricated in a single piece from a single material, preferably a corrosion resistant material, or in a plurality of pieces from one or more materials.

(13) A plurality of axial fluid channels 34 may extend in any suitable manner inside the roll mantle 26. A roll mantle 26 may for example be provided with peripheral bore cooling (also called revolver cooling) and skewed fluid channels 34. The at least one fluid channel 34 of a roll mantle 26 according to the present invention may contain one or more fluid channels 34 arranged in any axial, non-axial, radial, non-radial, symmetrical, non-symmetrical, regular or irregular manner, as desired. One or more coolant channels 34 may for example be arranged in a spiral or circumferential arrangement. The fluid inlets 36 and outlets 38 may be arranged in one or both end regions ER1 and/or ER2 of the roll mantle 26 or in a central region CR of the roll mantle 26.

(14) FIG. 4 shows one end of a roll line unit 24 according to an embodiment of the invention. The roll line unit 24 comprises a roll mantle 26 having two ends and a non-rotatable shaft 28 comprising a coolant line 29, whereby the roll mantle 26 is rotatably mounted on the non-rotatable shaft 28 by means of the first bearing 30a located in the first end region ER1 of the roll mantle 26 and the second bearing 30b (not shown in FIG. 4) located in the second end region ER2 (not shown in FIG. 4) of the roll mantle 26. The roll line unit 24 preferably includes outer seals 32 located on an axially outward side of each of the first and second bearings 30a, 30b and inner seals 33 located on an axially inward side of each of the first and second bearings 30a, 30b. Thereby, the outer seals 32, the inner seals 33 and the first and second bearings 30a, 30b are located axially inwards of the adjacent ends 26a, 26b, respectively, of the roll mantle 26. The outer seals 32 may for example be provided between the non-rotatable shaft 28 and the roll mantle 26 and/or between the first and second bearings 30a, 30b and the adjacent end 26a, 26b, respectively, of the roll mantle 26. The outer seals 32 may be bearing seals formed or configured to protect the first and second bearings 30a, 30b from contamination. Further, the inner seals 33 may be coolant seals.

(15) The first and second bearings 30a, 30b, respectively, rotatably connect the roll mantle 26 to a support block 40. The support block 40 does not house the first and second bearings 30a, 30b or the outer seals 32 and the inner seals 33 since these components are contained within the roll mantle 26. The support block 40 provides an extra barrier against humidity, corrosion and contamination.

(16) The size of a support block 40 of a roll line according to the present invention may thereby be minimized and its design can be simplified compared to conventional housings since space is not needed to house bearings and outer seals axially outwards of the ends 26a, 26b of the roll mantle 26. The support block 40 of a roll line according to the present invention will therefore occupy less space and/or may be used to house components such as lubrication system components. A roll line unit 24 according to the present invention is thereby particularly suitable for use in a continuous casting apparatus, where there is a space limitation around the roll line unit(s) 24, such in the corners of a frame on which a plurality of roll line units 24 are mounted or between roll line units 24.

(17) The non-rotatable shaft 28 includes a coolant line 29 and the fluid channels 34 of the roll mantle 26 are arranged to be in fluid communication with/fluidly connected with the coolant line 29 of the non-rotatable shaft 28. Coolant, such as water or any other suitable fluid or mixture of fluids, may be supplied to the coolant line 29 of the non-rotatable shaft 28, directly or via the support block 40, or via a sub-frame supporting the at least one roll line unit 24, for example. Coolant may then be fed from the coolant line 29 of the non-rotatable shaft 28 to the fluid channels 34 of the roll mantle 26 via one or more fluid inlets 36 at the center of the roll mantle 26 and/or at one or both end regions ER1 and/or ER2 of the roll mantle 26.

(18) Coolant may flow out of the roll mantle 26 via one or more fluid outlets 38 located at the center of the roll mantle 26, and/or at one or both end regions ER1 and/or ER2 of the roll mantle 26, and/or at the sides of the roll mantle 26, whereby coolant that has passed through the at least one fluid channel 34 of the roll mantle 26 may be returned to a coolant line 29 of the non-rotatable shaft 28 or to a support block or sub-frame supporting the at least one roll line unit 24. Coolant may be arranged to be fed from one roll line unit 24 to an adjacent roll line unit 24 via one or more support blocks 40 or via a sub-frame supporting a plurality of roll line units 24. Coolant may enter a roll mantle at one end region ER1, flow through the roll mantle 26 in any desired manner, and then leave the roll mantle 26 at the opposite end region ER2. Alternatively, coolant may enter and leave the roll mantle 26 within the same end region ER1 or ER2, i.e. near the same side 26a or 26b of the roll mantle 26.

(19) Since a roll mantle 26 of a roll line unit 24 according to the present invention rotates with respect to a non-rotatable shaft 28, coolant has to be supplied from a stationary coolant line 29 of a non-rotatable shaft 28 to a rotating roll mantle 26, i.e. there is a static to dynamic coupling between the non-rotatable shaft 28 and the roll mantle 26.

(20) At least one fluid inlet 36 and at least one fluid outlet 38 of a fluid channel 34 may be in fluid communication with a coolant line 29 of a non-rotatable shaft 28 via one or more radial or non-radial channels in the non-rotatable shaft 28. It should however be noted that fluid communication between the fluid inlet 36 of a fluid channel 34 and the coolant line 29 of a non-rotatable shaft 28 may be provided in any suitable manner.

(21) Coolant from a coolant line 29 of a non-rotatable shaft 28 may be made to flow (by means of pumps, valves and fluid distributors for example) into a plurality of fluid inlets 36 that may be arranged around the inner surface of the roll mantle 26 in an end region ER1 thereof. Coolant then flows in a continuous path along coolant channels 34 in the roll mantle 26 and is returned to the coolant line 29 in the non-rotatable shaft 28 via at least one fluid outlet 38 that may be arranged around the inner surface of the roll mantle 26 in the opposite end region ER2 thereof.

(22) In the illustrated embodiment, when the roll mantle 26 is in use, coolant enters the coolant channel 34 via a fluid inlet 36 in the end region ER1 of the roll mantle 26 and flows longitudinally across the first bearing 30a radially above and/or below (i.e., located radially outwardly from) the first bearing 30a in the direction indicated by the dotted arrows in FIG. 4. A fluid outlet 38 may be located at the opposite end region ER2 of the roll mantle 26, whereby coolant is arranged to flow substantially along the whole length of the roll mantle 26, within the first end region ER1 or within the central region CR.

(23) A roll mantle 26 of a roll line 24 according to an embodiment of the invention may comprise a plurality of fluid channels 34 having any suitable cross section, such as a circular cross section, which extend mainly in the longitudinal direction of the roll mantle 26.

(24) According to an embodiment of the invention the at least one coolant channel 34 includes a section 34a that extends at a constant distance from an outer surface 26c of the roll mantle 26 (as shown in FIG. 4 for example). Alternatively or additionally, the at least one coolant channel 34 includes a section 34b that extends at a non-constant distance from an outer surface 26c of the roll mantle 26 (as also shown in FIG. 4), which may be arranged to extend at an angle of less than 90° to the coolant line 29 of a non-rotatable shaft 28 on which the roll mantle 26 is rotatably mounted when in use. The one or more coolant channels 34 may however be arranged at any suitable location and have any suitable section so as to provide efficient cooling of the roll mantle 26. Further, each coolant channel 34 may have a uniform or non-uniform cross-section and a uniform or non-uniform cross-sectional area.

(25) FIG. 5 shows a two-piece roll mantle of a roll line unit according to an embodiment of the invention. A first part 26d of the roll mantle 26 comprises the outer roll mantle surface 26c and a second part 26e of the roll mantle 26 comprises a plurality of cavities, such as spiral, axial or circumferential cavities that form at least one coolant channel 34 when the two-piece roll mantle 26 is in use. The first and second parts 26d, 26e of a roll mantle 26 may be manufactured in any suitable manner.

(26) FIG. 6 shows a continuous caster 42, such as a bloom caster, billet caster, slab caster or beam blank caster, comprising four roll line units 24 according to an embodiment of the invention. In the illustrated embodiment the roll line units 24 are of two different lengths which are mounted end to end in on a frame 44 in a rectangular formation. It should be noted that a roll line 20 can contain any number of roll line units 24 arranged in any suitable manner, such as end to end or side by side in a straight line.

(27) Each roll line unit 24 comprises an exposed roll mantle surface 26c that is rotatable relative to a support block 40. A support block 40 may be placed at each end of a roll line unit 24. The roll mantle surface 26c is arranged to come into contact with steel strands, blooms, billets, slabs or beam blanks for example, which are transported through the frame 44 in a direction at a right angle into or out of the plane of the paper.

(28) Representative, non-limiting examples of the present invention were described above in detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the invention.

(29) Moreover, combinations of features and steps disclosed in the above detailed description may not be necessary to practice the invention in the broadest sense and are instead taught merely to particularly describe representative examples of the invention. Furthermore, various features of the above-described representative examples, as well as the various independent and dependent claims below, may be combined in ways that are not specifically and explicitly enumerated in order to provide additional useful embodiments of the present teachings.

(30) All features disclosed in the description and/or the claims are intended to be disclosed separately and independently from each other for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter, independent of the compositions of the features in the embodiments and/or the claims. In addition, all value ranges or indications of groups of entities are intended to disclose every possible intermediate value or intermediate entity for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter. The invention is not restricted to the above-described embodiments, and may be varied within the scope of the following claims.