SE1651347A1

SE1651347A1 - Roller for a continuous casting machine

Info

Publication number: SE1651347A1
Application number: SE1651347A
Authority: SE
Inventors: Johansson Mats
Original assignee: Skf Ab
Priority date: 2016-10-14
Filing date: 2016-10-14
Publication date: 2016-11-09

Abstract

The present disclosure relates to a roller (10) for a continuous casting machine, which comprises, a first axial end (11) and a second axial end (12), a cylindrical outer peripheral surface (13) meant to receive and support a steel slab, said surface extending in a longitudinal direction between the first and second axial ends (11, 12). At least one cooling channel (14) extends in a longitudinal direction in the roller (10) along at least a portion of the cylindrical outer surface (13), wherein said at least one cooling channel (14) is skewed in relation to the outer peripheral surface (13).(Figure elected for publication: Figure 4)

Description

15 20 25 30 SKF Ref: 201600111 2 The object is achieved by a roller for a continuous casting machine, comprising, a first axial end and a second axial end and a cylindrical outer peripheral surface meant to receive and support a steel slab, said surface extending in a Iongitudinal direction between the first and second axial ends. Further, at least one cooling channel extends in a Iongitudinal direction in the roller along at least a portion of the cylindrical outer surface, wherein said at least one cooling channel is skewed in relation to the outer peripheral surface. lt has been realized by the inventor that by providing a skewed cooling channel it will result in a more equalized heat distribution as the cooling channels are not aligned with the casted steel line contact on the outer peripheral surface of the roller. Since the cooling channel is not parallell with the steel slab's line contact a smoothing heat distribution will be obtained, wherein the cooling channel will get one or several intersections which moves along the steel slab's line contact during rotation of the roller. A more equalized heat distribution is advantageous in that it may lead to an increased service life of the rollers, but also a more equalized heat distribution may improve the quality of the casted steel. ln this document, the expressions axial and radial are used. lf not stated differently for any of the presented embodiments of the disclosure, it refers and relates to the geometry of the roller. An axial direction refers to the longitudinal direction of the roller along an axial line (roller axis) around which the roller is intented to rotate and radial refers to a direction being perpendicular to the axial direction. ln an embodiment, the at least one cooling channel is in the form of a straight hole. ln an embodiment, the at least one cooling channel extends in the Iongitudinal direction of the roller along a vast majority of the cylindrical outer surface. A vast majority of the roller length may be seen as at least 70%, 80%, 90%, or even 95 % of the roller length. ln an embodiment, the at least one cooling channel is located at a radial distance from the outer peripheral surface such tha a sufficient cooling of the roller can be performed. ln an embodiment, the at least one cooling channel is located at a 10 15 20 25 30 SKF Ref: 201600111 3 maximum radial distance from the outer peripheral surface which corresponds to 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% or 50 % of the radius of the roller. ln an embodiment, the at least one cooling channel extends in the longitudinal direction of the roller from the first axial end to the second axial end. ln an embodiment, the at least one cooling channel presents an inlet at the first axial end and an outlet at the second axial end. ln an alternative embodiment, the at least one cooling channel presents an inlet and an outlet on one of the first or second axial end. ln an embodiment, the inlet radial distance to the roller axis is equal to the outlet radial distance to the roller axis. ln an embodiment, the inlet is located at a different angle of rotation compared to the outlet in relation the roller axis. ln an embodiment, the at least one cooling channel is a straight drilled hole. ln an embodiment, the roller further presents an axial through hole meant to receive a shaft. ln an embodiment, the roller is in the form of a solid roller body and further presents a first and a second axially extending portions on each respective axial ends, said portions being meant to be mounted into a first and second respective bearing housing of a roll line. 15 20 25 30 SKF Ref: 201600111 2 The object is achieved by a roller for a continuous casting machine, comprising, a first axial end and a second axial end and a cylindrical outer peripheral surface meant to receive and support a steel slab, said surface extending in a longitudinal direction between the first and second axial ends. Further, at least one cooling channel extends in a longitudinal direction in the roller along at least a portion of the cylindrical outer surface, where said at least one cooling channel is skewed in relation to the outer peripheral surface. lt has been realized by the inventor that by providing a skewed cooling channel it will result in a more equalized heat distribution as the cooling channels are not aligned with the casted steel line contact on the outer peripheral surface of the roller. Since the cooling channel is not parallel to the steel slab's line contact a smoothing heat distribution will be obtained, where the cooling channel will get one or several intersections which moves along the steel slab's line contact during rotation of the roller. A more equalized heat distribution is advantageous in that it may lead to an increased service life of the rollers, but also a more equalized heat distribution may improve the quality of the casted steel. In this document, the axial and radial expressions are used. lf not stated differently for any of the presented embodiments of the disclosure, it refers and relates to the geometry of the roller. An axial direction refers to the longitudinal direction of the roller along an axial line (roller axis) around which the roller is intented to rotate and radial refers to a direction being perpendicular to the axial direction. ln an embodiment, the at least one cooling channel is in the form of a straight hole. ln an embodiment, the at least one cooling channel extends in the Iongitudinal direction of the roller along a vast majority of the cylindrical outer surface. A vast majority of the roller length may be seen as at least 70%, 80%, 90%, or even 95% of the roller length. ln an embodiment, the at least one cooling channel is located at a radial distance from the outer peripheral surface such tha a sufficient cooling of the roller can be performed. ln an embodiment, the at least one cooling channel is located at a 10 15 20 25 30 SKF Ref: 201600111 3 maximum radial distance from the outer peripheral surface which corresponds to 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% or 50% of the radius of the roller. ln an embodiment, the at least one cooling channel extends in the longitudinal direction of the roller from the first axial end to the second axial end. ln an embodiment, the at least one cooling channel presents an inlet at the first axial end and an outlet at the second axial end. ln an alternative embodiment, the at least one cooling channel presents an inlet and an outlet on one of the first or second axial end. ln an embodiment, the inlet radial distance to the roller axis is equal to the outlet radial distance to the roller axis. ln an embodiment, the inlet is located at a different angle of rotation compared to the outlet in relation the roller axis. ln an embodiment, the at least one cooling channel is a straight drilled hole. ln an embodiment, the roller further presents an axial through hole meant to receive a shaft. ln an embodiment, the roller is in the form of a solid roller body and further presents a first and a second axially extending portions on each respective axial ends, said portions being meant to be mounted into a first and second respective bearing housing of a roll line.

According to a second aspect of the invention, the object is achieved by a roll line for a continuous casting machine, comprising at least one roller according to any of the preceding embodiments. A roll line is generally a number of rollers mounted along an axial line in relation to each other, in which all the rollers will support the casted steel slab. There are different types of roll line designs. One roll line design is to mount a number of rollers (which comprises axial through holes) onto a shaft. The shaft is supported in support blocks either via bearings or directly mounted in the support 10 15 20 25 30 SKF Ref: 201600111 4 blocks. The shaft may be rotating or non-rotating, depending on the design. Another known roll line design is to make use of a number of solid rollers, also known as roll bodies, which are located along an axial extension and rotatably supported in bearing housings. The different kinds of roll line designs is something which is well recognized by the person skilled in the art and the present invention is not limited to anyone of these designs, but can be used in any roll line that comprises internal cooling channels.According to a second aspect of the invention, the object is achieved by a roll line for a continuous casting machine, comprising at least one roller according to any of the preceding embodiments. A roll line is generally a number of rollers mounted along an axial line in relation to each other, in which all the rollers will support the casted steel slab. There are different types of roll line designs. One roll line design is to mount a number of rollers (which comprises axial through holes) onto a shaft. The shaft is supported in support blocks either via bearings or directly mounted in the support 10 15 20 25 30 SKF Ref: 201600111 4 blocks. The shaft may be rotating or non-rotating, depending on the design. Another known roll line design is to make use of a number of solid rollers, also known as roll bodies, which are located along an axial extension and rotatably supported in bearing housings. The different kinds of roll line designs is something which is well recognized by the person skilled in the art and the present invention is not limited to anyone of these designs, but can be used in any roll line that comprises internal cooling channels.

BRIEF DESCRIPTION OF DRAWINGS Exemplifying embodiments of the present invention will now be described in more detail, with reference to the accompanying drawings, wherein: Figure 1 shows a continuous casting machine.BRIEF DESCRIPTION OF DRAWINGS Exemplifying embodiments of the present invention will now be described in more detail, with reference to the accompanying drawings, in which: Figure 1 shows a continuous casting machine.

Figure 2 shows a schematic cross sectional view of a roller according to an embodiment of the present invention.Figure 2 shows a schematic cross sectional view of a roller according to an embodiment of the present invention.

Figure 3 shows another schematic cross sectional view of a roller according to an embodiment of the present invention.Figure 3 shows another schematic cross sectional view of a roller according to an embodiment of the present invention.

Figure 4 shows a three dimensional view of a roller according to an embodiment of the invention.Figure 4 shows a three dimensional view of a roller according to an embodiment of the invention.

The drawings show diagrammatic exemplifying embodiments of the present invention and are thus not necessarily drawn to scale. lt shall be understood that the embodiments shown and described are exemplifying and that the invention is not limited to these embodiments. lt shall also be noted that some details in the drawings may be exaggerated in order to better describe and illustrate the invention.The drawings show diagrammatic exemplifying embodiments of the present invention and are thus not necessarily drawn to scale. lt shall be understood that the embodiments shown and described are exemplifying and that the invention is not limited to these embodiments. lt shall also be noted that some details in the drawings may be exaggerated in order to better describe and illustrate the invention.

DETAILED DESCRIPTION OF DRAWINGS Figure 1 shows a continuous slab casting process in which molten metal 100 is tapped into a ladle 120. After undergoing any ladle treatments, such as alloying and degassing, and arriving at the correct temperature, molten metal 100 from the ladle 120 is transferred via a refractory shroud to a tundish 140. Metal is drained from the 10 15 20 25 30 SKF Ref: 201600111 5 tundish 140 into the top of an open-base mould 160. The mould 160 is water-cooled to solidify the molten metal directly in contact with it. ln the mould 160, a thin shell of metal next to the mould walls solidifies before the middle section, now called a slab, exits the base of the mould 160 into a cooling chamber 180; the bulk of metal within the walls of the slab is still molten. The slab is supported by closely spaced, water cooled roll lines 200, comprising rollers 10 according to the present invention, which act to support the walls of the slab against the ferrostatic pressure of the still- solidifying liquid within the slab. To increase the rate of solidification, the slab is sprayed with large amounts of water as it passes through the cooling chamber 180.DETAILED DESCRIPTION OF DRAWINGS Figure 1 shows a continuous slab casting process in which molten metal 100 is tapped into a ladle 120. After undergoing any ladle treatments, such as alloying and degassing, and arriving at the correct temperature, molten metal 100 from the ladle 120 is transferred via a refractory shroud to a tundish 140. Metal is drained from the 10 15 20 25 30 SKF Ref: 201600111 5 tundish 140 into the top of an open-base mold 160. The mold 160 is water-cooled to solidify the molten metal directly in contact with it. ln the mold 160, a thin shell of metal next to the mold walls solidifies before the middle section, now called a slab, exits the base of the mold 160 into a cooling chamber 180; the bulk of metal within the walls of the slab is still molten. The slab is supported by closely spaced, water cooled roll lines 200, comprising rollers 10 according to the present invention, which act to support the walls of the slab against the ferrostatic pressure of the still-solidifying liquid within the slab. To increase the rate of solidification, the slab is sprayed with large amounts of water as it passes through the cooling chamber 180.

Final solidification of the slab may take place after the slab has exited the cooling chamber 180. The roller 10 according to the invention is not restricted to the area of the cooling chamber 180, but may in other embodiments also be placed in other parts of the machine along the casted steel slab. ln the illustrated embodiment the slab exits the mould 160 vertically (or on a near vertical curved path) and as it travels through the cooling chamber 180, the roll lines 200 gradually curve the slab towards the horizontal plane. (ln a vertical casting machine, the slab stays vertical as it passes through the cooling chamber 180).Final solidification of the slab may take place after the slab has exited the cooling chamber 180. The roller 10 according to the invention is not restricted to the area of the cooling chamber 180, but may in other embodiments also be placed in other parts of the machine along the casted steel slab. ln the illustrated embodiment the slab exits the mold 160 vertically (or on a near vertical curved path) and as it travels through the cooling chamber 180, the roll lines 200 gradually curve the slab towards the horizontal plane. (ln a vertical casting machine, the slab stays vertical as it passes through the cooling chamber 180).

After exiting the cooling chamber 180, the slab passes through straightening roll lines (if cast on other than a vertical machine) and withdrawal roll lines. Finally, the slab is cut into predetermined lengths by mechanical shears or by travelling oxyacetylene torches 220 and either taken to a stockpile or the next forming process. ln many cases the slab may continue through additional roll lines and other mechanisms which might ﬂatten, roll or extrude the metal into its final shape.After exiting the cooling chamber 180, the slab passes through straightening roll lines (if cast on other than a vertical machine) and withdrawal roll lines. Finally, the slab is cut into predetermined lengths by mechanical shears or by traveling oxyacetylene torches 220 and either taken to a stockpile or the next forming process. In many cases the slab may continue through additional roll lines and other mechanisms which might ﬂ atten, roll or extrude the metal into its final shape.

Figure 2 illustrates a cross sectional schematic view of a roller 10 according to an embodiment of the invention. The cross section is a plane in the longitudinal and axial extension of the roller 10. The roller 10 comprises a first axial end 11 and a second axial end 12 and a cylindrical outer peripheral surface 13 meant to receive and support a steel slab (not shown), said surface 13 extending in a longitudinal direction between the first and second axial ends 11 and 12. An axial roller center line (roller axis) A can also be seen in the figure. Further, at least one cooling channel 14 extends in a longitudinal direction in the roller 10 along at least a portion 10 15 20 25 30 SKF Ref: 201600111 6 of the cylindrical outer surface 13, wherein said at leat one cooling channel 14 is skewed in relation to the outer peripheral surface 13. ln this embodiment, the cooling channel 14 is in the form of a straight hole and presents an inlet 141 on the first axial end 11 and an outlet 142 on the second axial end 12. The inlet and outlet 141 and 142 are in this embodiment located at a radial distance r1 and rz to the roller axis A, which is equal. Furthermore, not seen in this figure, but instead better illustrated in figure 3, the inlet 141 and the outlet 142 are located at a different angle of rotation in relation the roller axis A. Due to this configuration, the cooling channel 14 will be skewed in relation to the outer peripheral surface 13. ln other words, the cooling channel 14 will be located at a non-constant radial distance to the outer peripheral surface 13 along the axial extension of the roller 10. ln this embodiment, the channel 14 will present its largest radial distance to the outer peripheral surface 13 at the axial center of the roller 10. Due to this configuration the integrated cooling will result in a more equalized heat distribution as the cooling channel 14 is not aligned with the casted steel line contact on the outer peripheral surface 13 of the roller 10. lt shall be noted that the invention is by no means restricted to only one cooling channel in the roller 10. There may be several cooling channels 14 located around the circumference of the roller 10, which also will lead to an improved cooling. ln an embodiment, the cooling channels 14 are equally angularly distributed around the circumference of the roller 10. Furthermore, in this embodiment, the cooling channel 14 is drilled as a straight hole. Drilling a straight hole is a cost-efficient way of producing the cooling channel 14. The inlet 141 and outlet 142 may be used as an inlet and outlet for cooling fluid, such as water. Alternatively, the inlet 141 and/or the outlet 142 may also be plugged and sealed, wherein the cooling fluid instead is introduced into the cooling channel 14 via another distribution channel (not seen in this figure) in the roller. A distribution channel would be located further to the radial center of the roller 10 and would thus not provide sufficient cooling to the roller 10.Figure 2 illustrates a cross sectional schematic view of a roller 10 according to an embodiment of the invention. The cross section is a plane in the longitudinal and axial extension of the roller 10. The roller 10 comprises a first axial end 11 and a second axial end 12 and a cylindrical outer peripheral surface 13 meant to receive and support a steel slab (not shown ), said surface 13 extending in a longitudinal direction between the first and second axial ends 11 and 12. An axial roller center line (roller axis) A can also be seen in the figure. Further, at least one cooling channel 14 extends in a longitudinal direction in the roller 10 along at least a portion 10 15 20 25 30 SKF Ref: 201600111 6 of the cylindrical outer surface 13, where said at leat one cooling channel 14 is skewed in relation to the outer peripheral surface 13. ln this embodiment, the cooling channel 14 is in the form of a straight hole and presents an inlet 141 on the first axial end 11 and an outlet 142 on the second axial end 12. The inlet and outlet 141 and 142 are in this embodiment located at a radial distance r1 and rz to the roller axis A, which is equal. Furthermore, not seen in this figure, but instead better illustrated in figure 3, the inlet 141 and the outlet 142 are located at a different angle of rotation in relation the roller axis A. Due to this configuration, the cooling channel 14 will be skewed in relation to the outer peripheral surface 13. ln other words, the cooling channel 14 will be located at a non-constant radial distance to the outer peripheral surface 13 along the axial extension of the roller 10. ln this embodiment, the channel 14 will present its largest radial distance to the outer peripheral surface 13 at the axial center of the roller 10. Due to this configuration the integrated cooling will result in a more equalized heat distribution as the cooling channel 14 is not aligned with the casted steel line contact on the outer peripheral surface 13 of the roller 10. lt shall be noted that the invention is by no means restricted to only one cooling channel in the roller 10. There may be several cooling channels 14 l ocated around the circumference of the roller 10, which will also lead to an improved cooling. ln an embodiment, the cooling channels 14 are equally angularly distributed around the circumference of the roller 10. Furthermore, in this embodiment, the cooling channel 14 is drilled as a straight hole. Drilling a straight hole is a cost-efficient way of producing the cooling channel 14. The inlet 141 and outlet 142 may be used as an inlet and outlet for cooling fluid, such as water. Alternatively, the inlet 141 and / or the outlet 142 may also be plugged and sealed, where the cooling fluid instead is introduced into the cooling channel 14 via another distribution channel (not seen in this figure) in the roller. A distribution channel would be located further to the radial center of the roller 10 and would thus not provide sufficient cooling to the roller 10.

The roller 10 may be in the form of a roll mantle with a through hole 15 in which a shaft is located. ln an alternative embodiment, the roller 10 is in the form of a solid roller body and presents axial end protrusions which are meant to be mounted into respective bearing housings. These different designs of a roller 10 are well known by the person skilled in the art. The roller 10 according to the invention is not restricted to any type of roller designs for a continuous casting machine, but several alternative designs may be used within the scope of the claims. 10 15 20 25 SKF Ref: 201600111 Figure 3 illustrates a schematic radial cross sectional view of a roller 10 according to the invention. The outer peripheral surface 13 can be seen. ln addition, the cooling channel 14 is seen by a line wherein the channel presents an inlet 141 on the first axial side and an outlet 142 on the second axial side. The inlet 141 is located at a different angle of rotation compared to the outlet 142 in relation the roller axis A. The difference of the angles of the inlet 141 and outlet 142 is represented by the angle A in this illustration. As can be seen, the cooling channel 14 will present its largest radial distance to the outer peripheral surface in-between the inlet 141 and the outlet 142. ln other words, the radial distance dz is larger than the radial distances d1 and ds seen from the outer peripheral surface 13.The roller 10 may be in the form of a roll mantle with a through hole 15 in which a shaft is located. In an alternative embodiment, the roller 10 is in the form of a solid roller body and presents axial end protrusions which are meant to be mounted into respective bearing housings. These different designs of a roller 10 are well known by the person skilled in the art. The roller 10 according to the invention is not restricted to any type of roller designs for a continuous casting machine, but several alternative designs may be used within the scope of the claims. 10 15 20 25 SKF Ref: 201600111 Figure 3 illustrates a schematic radial cross sectional view of a roller 10 according to the invention. The outer peripheral surface 13 can be seen. In addition, the cooling channel 14 is seen by a line where the channel presents an inlet 141 on the first axial side and an outlet 142 on the second axial side. The inlet 141 is located at a different angle of rotation compared to the outlet 142 in relation to the roller axis A. The difference of the angles of the inlet 141 and outlet 142 is represented by the angle A in this illustration. As can be seen, the cooling channel 14 will present its largest radial distance to the outer peripheral surface in-between the inlet 141 and the outlet 142. ln other words, the radial distance dz is larger than the radial distances d1 and ds seen from the outer peripheral surface 13.

Figure 4 shows a three dimensional view of a roller 10 according to an embodiment of the invention. ln this embodiment, a plurality of cooling channels 14 can be seen.Figure 4 shows a three dimensional view of a roller 10 according to an embodiment of the invention. In this embodiment, a plurality of cooling channels 14 can be seen.

The cooling channels 14 are in this embodiment in the form of straight holes, preferably made by drilling. The roller 10 presents an outer peripheral surface 13 onto which a steel slab (not shown) is meant to be received. Furthermore, the roller 10 presents a first axial end 11 and a second axial end 12. The cooling channels 14 are drilled such that the channels 14 are skewed in relation to the outer peripheral surface 13 as seen in the axial direction of the roller 10. ln addition, in this embodiment, there is a through hole 15 in which a shaft (not shown) is meant to be located. The invention is not limited to the embodiments and advantages as described and illustrated in this disclosure, but other embodiments and also modifications to the embodiments described are possible within the scope of the claims.The cooling channels 14 are in this embodiment in the form of straight holes, preferably made by drilling. The roller 10 presents an outer peripheral surface 13 onto which a steel slab (not shown) is meant to be received. Furthermore, the roller 10 presents a first axial end 11 and a second axial end 12. The cooling channels 14 are drilled such that the channels 14 are skewed in relation to the outer peripheral surface 13 as seen in the axial direction of the roller 10. In addition, in this embodiment, there is a through hole 15 in which a shaft (not shown) is meant to be located. The invention is not limited to the embodiments and advantages as described and illustrated in this disclosure, but other embodiments and also modifications to the embodiments described are possible within the scope of the claims.

Claims

1. 0 15 20 25 30

2. SKF Ref: 201600111 8

CLAIMS

4. A roller (10) for a continuous casting machine, comprising, - a first axial end (11) and a second axial end (12), - a cylindrical outer peripheral surface (13) meant to receive and support a steel slab, said surface (13) extending in a longitudinal direction between the first and second axial ends (11, 12), - at least one cooling channel (14) extending in a longitudinal direction in the roller (10) along at least a portion of the cylindrical outer surface (13), - wherein said at least one cooling channel (14) is skewed in relation to the outer peripheral surface (13).

5. A roller (10) according to claim 1, - wherein the at least one cooling channel (14) is in the form of a straight hole.

6. A roller (10) according to any of the preceding claims, - wherein the at least one cooling channel (14) extends in the longitudinal direction of the roller (1 O) along a vast majority of the cylindrical outer surface (13) .

7. A roller (10) according to any of the preceding claims, - wherein the at least one cooling channel (14) extends in the longitudinal direction of the roller (10) from the first axial end (11) to the second axial end (12).

8. A roller (10) according to any of the preceding claims, - wherein the at least one cooling channel (14) presents an inlet (141) at the first axial end (11) and an outlet (142) at the second axial end (12).

9. A roller (10) according to claim 5, - wherein the inlet radial distance to the roller axis (A) is equal to the outlet radial distance to the roller axis (A). 10 15 20

10.

11. SKF Ref: 201600111 9 A roller (10) according to any of claims 5 or 6, - wherein the inlet (11) is located at a different angle of rotation compared to the outlet (12) in relation the roller axis (A ). A roller (10) according to any of the preceding claims, - wherein the at least one cooling channel (14) is a straight drilled hole. A roller (10) according to any of the preceding claims, - wherein the roller (10) further presents an axial through hole (15) meant to receive a shaft. A roller (10) according to any of claims 1-8, - wherein the roller (10) is in the form of a solid roller body and further presents a first and a second axially extending portions on each respective axial ends (11, 12 ), said portions being meant to be mounted into a first and second respective bearing housing of a roll line. A roll line for a continuous casting machine, comprising, - at least one roller (10) according to any of the preceding claims.