KR20240060735A - Method and apparatus for extending the campaign life of stabilizers for a coating line - Google Patents

Abstract

Steel processing lines include rollers immersed in a volume of molten metal. The roller contains two journals. Each journal is received by an opening defined by a roller sleeve comprised of ceramic or refractory material. A roller sleeve is placed between each journal and bearing block to reduce or prevent journal wear. The inner dimension of each roller sleeve and the outer dimension of each journal form a gap. The inner dimensions of each roller sleeve and the outer dimensions of each journal are configured to maintain a gap as the roller and the pair of roller sleeves are heated by the molten metal.

Description

METHOD AND APPARATUS FOR EXTENDING THE CAMPAIGN LIFE OF STABILIZERS FOR A COATING LINE}

Coating is a common process used in steelmaking to provide a thin metallic coating (eg, aluminum, zinc and/or their alloys) on the surface of a steel substrate, such as an elongated steel sheet or strip. It should be understood that elongated steel sheets or strips are used herein and are to be understood as interchangeable. The coating process can generally be integrated into a continuous coating line that threads elongated steel sheets through a series of roll assemblies to subject the steel sheets to a variety of processing processes. In the coating portion of this process, the steel sheet is manipulated through a molten metal bath to coat the surface of the steel sheet.

To aid manipulation of the steel sheet, various components may be placed within the molten metal bath. Some of these components may wear out due to the harsh environment caused by constant movement of the components and/or the presence of molten metal. When wear reaches an unacceptable level, the continuous coating line is stopped and the components within it are reworked. This procedure typically results in increased costs and undesirable manufacturing delays. However, these costs and delays can be reduced by increasing the service life of the various components immersed within the metal bath.

Accordingly, it may be desirable to include various features within the coating line to improve the overall service life of the components subject to wear. To overcome this problem, roller sleeves made of ceramic or refractory materials are mechanically locked to the roller journals to protect them from wear. Alternatively, roller inserts made of ceramic or refractory materials are applied to the outer surface of the roller journals to prevent wear.

Steel journals for rolls rotating in molten metal baths face at least some wear and chemical attack when used in molten metal baths for aluminum plating processes. In some situations, the duty cycle of these rollers may be reduced due to wear and/or chemical attack. Accordingly, it is desirable to reduce wear and/or chemical attack occurring on steel journals used in coating processes.

Ceramic or refractory materials provide excellent resistance to wear and chemical attack encountered in an environment surrounded by molten metal. However, there are difficulties in incorporating ceramic or refractory materials into roller assemblies submerged in molten metal. Accordingly, this application relates to structures and/or methods for incorporating ceramic or refractory materials into a roller assembly between a journal and a bearing block.

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments and, together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the disclosure.
Figure 1 shows a schematic diagram of the coating part of a continuous steel processing line.
Figure 1a shows a schematic diagram of an alternative configuration for the coated portion of Figure 1;
Figure 2 shows a perspective view of a roll assembly that can be easily integrated into the coating portion of Figure 1;
Figure 3 shows a perspective view of the bearing block of the roll assembly of Figure 2;
Figure 4 shows a front view of a roll of the roll assembly of Figure 2;
Figure 5 shows a perspective view of the roller sleeve of the roll assembly of Figure 2;
Figure 6 shows another perspective view of the roller sleeve of Figure 5;
Figure 7 shows a partial front cross-sectional view of the engagement between the roll of Figure 4 and the roller sleeve of Figure 5;
Figure 8 shows a cross-sectional side view of an alternative journal and roller sleeve that can be easily incorporated into the step roll of Figure 4;
Figure 9 shows a perspective view of the journal and roller sleeve of Figure 8;
Figure 10 shows a perspective view of another alternative journal that could be easily incorporated into the roll of Figure 4.
Figure 11 shows a perspective view of another alternative journal that could be easily incorporated into the roll of Figure 4.
Figure 12 shows a perspective view of another roll assembly that can be easily integrated into the coating portion of Figure 1.
Figure 13 shows a perspective view of the bearing block of the roll assembly of Figure 12;
Figure 14 shows a front view of a roll of the roll assembly of Figure 12;
Figure 15 shows a perspective view of the roller sleeve of the roll assembly of Figure 12;
Figure 16 shows a front view of the roller sleeve of Figure 15;
Figure 17 shows a cross-sectional view of the roller sleeve of Figure 15 taken along line 17-17 in Figure 16.
Figure 18 shows a partial front cross-sectional view of the engagement between the roll of Figure 14 and the roller sleeve of Figure 15;
Figure 19 shows a perspective view of another roller sleeve that can be easily integrated into the roll assembly of Figure 12.
Figure 20 shows a front view of the roller sleeve of Figure 19;
Figure 21 shows a top view of the roller sleeve of Figure 19;
Figure 22 shows a cross-sectional view of the roller sleeve of Figure 19 taken along line 22-22 in Figure 20.
Figure 23 shows a front view of the roller sleeve of Figure 19 assembled with a journal.

This application generally relates to structures and/or methods for incorporating ceramic or refractory materials into roll assemblies immersed in molten metal. In some examples, this includes incorporating a ceramic or refractory material between the journal and bearing block. In such a configuration, the presence of a ceramic or refractory material has been found to reduce wear of the journal that may occur through rotation of the journal relative to the bearing block. The presence of a ceramic or refractory material may also reduce the journal's tendency to undergo chemical attack from molten metal.

Figure 1 shows a schematic cross-sectional view of a coating portion 10 of a steel processing line 2, such as a continuous steel processing line. Although not shown, it should be understood that prior to entry the steel plate 60 may be subjected to a variety of other steel processing operations in other parts of the steel processing line 2. For example, the steel sheet 60 may be subjected to hot or cold rolling, various heat treatments, pickling, etc. Alternatively, other steel processing operations may be eliminated such that coating portion 10 may be configured as a stand-alone coating line in some instances.

In the illustrated embodiment, the coating portion 10 includes a hot dip tank 20, a snout 30, and one or more roll assemblies 40, 50, and 70. As will be appreciated, the coating portion 10 is generally configured to receive an elongated steel sheet 60 for coating the steel sheet 60 . Hot dip galvanizing tank 20 is defined by solid walls configured to contain molten metal 22, such as aluminum, zinc and/or alloys thereof. The inlet portion 30 is configured to be partially immersed within the molten metal 22 . Accordingly, inlet 30 generally provides an airtight seal around steel plate 60 while entering molten metal 22. In some cases, the inlet 30 is filled with a protective or reducing gas, such as hydrogen and/or nitrogen, to limit chemical oxidation reactions that may occur while the steel sheet 60 enters the molten metal 22.

One or more roll assemblies (40, 50, 70) are positioned relative to the hot dip galvanizing tank (20) to support the steel sheet (60) over the coated portion (10). For example, the port or sink roll assembly 70 may be immersed in the molten metal 22 such that the port roll assembly 70 is generally configured to rotate and thereby redirect the steel plate 60 out of the hot dip galvanizing tank 20. there is. One or more stabilizer and straightening roll assemblies 40 may then be positioned relative to the hot dip galvanizing tank 20 to stabilize the steel sheet 60 as it exits the molten metal 22. For example, the stabilizer and straightening roll assembly 40 may be used to position the steel sheet 60 as it enters the air knife 35. The stabilizer and straightening roll assembly 40 may also be used to improve the shape of the steel plate 60. The deflector roll assembly 50 may be generally configured to redirect the steel sheet 60 to another portion of the steel processing line 2 after the steel sheet 60 has been coated. Although the coating portion 10 in this example is shown with only one of the port roll assembly 70, the stabilizer and straightening roll assembly 40, and the deflector roll assembly 50, some other variations may include an appropriate number of roll assemblies 40. , 50, 70) can be used.

1A shows an alternative configuration of coating portion 10 in which the stabilizer and straightening roll assembly 40 is omitted. Instead of or as an alternative to the stabilizer and straightening roll assembly 40, the alternative configuration shown in FIG. 1A includes two sink roll assemblies 42 positioned entirely within the hot dip galvanizing tank 20. Sink roll assembly 42 generally operates similarly to other roll assemblies described herein. For example, sink roll assembly 42 is generally configured to manipulate steel sheet 60 through various portions of a coating process. In this example, sink roll assembly 42 manipulates steel sheet 60 within molten metal 22 to promote complete coating of steel sheet 60. Sink roll assembly 42 further provides an increased amount of travel path through molten metal 22. This feature generally increases the time that the steel sheet 60 is placed within the molten metal 22. Once the steel sheet 60 passes through the sink roll assembly 42, the steel sheet 60 can be redirected in a desired direction by the port roll assembly 70 and the deflector roll assembly 50. 1 and 1A both show separate configurations for coating portion 10, but in other examples coating portion 10 may have other alternative configurations that combine various elements of the configuration shown in FIGS. 1 and 1A. You must understand that it includes

Roll assemblies incorporating roller sleeves comprising refractory ceramic materials are discussed in more detail below. It should be understood that such roller sleeves may be incorporated into any one or more roll assemblies in a continuous coating line because such roller sleeves may reduce wear, corrosion and/or abrasion of the roll assembly. These roll assemblies may include, but are not limited to, any of the stabilizing and straightening roll assemblies 40, sink roll assemblies 42, deflector roll assemblies 50, and/or port roll assemblies 70 as described above. It doesn't work.

2, roll assembly 100 includes two bearing blocks 72, rolls 80, and a roller sleeve 90 disposed between each bearing block 72 and roll 80. . Each bearing block 72 is generally configured to receive at least a portion of a roll 80 to facilitate rotation of the roll 80 about the bearing block 72. Although not shown, it should be understood that each bearing block 72 is generally coupled to a fixture or other structure to hold each bearing block 72 in place within the hot dip galvanizing tank 20.

An exemplary bearing block 72 is best seen in FIG. 3 . As can be seen, bearing block 72 includes a generally octagonal body 74. The octagonal shape of body 74 is generally configured to provide a surface on which fixtures or other structures can be attached to bearing block 72 to position bearing block 72 within hot dip galvanizing tank 20. Although the body 72 in this example is shown as an octagonal structure, it should be understood that other suitable structures such as squares, hexagons, triangles, circles, etc. may be used in other examples.

Regardless of the particular shape used for body 74, body 74 defines a receiving bore 76 through the center of bearing block 72. Receiving bore 76 is generally defined as cylindrical. As described in more detail below, the receiving bore 76 is configured to receive at least a portion of the roller sleeve 90 and the roll 80 so that the roller sleeve 90 can rotate freely within the bore 76. .

The bearing block 72 includes a ceramic material that has high strength and is resistant to wear at high temperatures. This ceramic material may additionally have a low coefficient of thermal expansion, thermal shock resistance, resistance to wetting by molten metal, corrosion resistance and is substantially chemically inert to molten non-ferrous metals. By way of example only, suitable ceramic materials may include a grade of ceramic known as SiAlON ceramic. SiAlON ceramic is a high-temperature refractory material that can be used to handle molten aluminum. SiAlON ceramics generally exhibit excellent thermal shock resistance, high strength at high temperatures, excellent wetting resistance by molten aluminum, and high corrosion resistance in the presence of molten non-ferrous metals. Bearing block 72 in this example includes CRYSTON CN178 manufactured by Saint-Gobain High-Performance Refractories, but many SiAlON grade ceramics may be used.

Roll 80 is shown in Figure 4. As can be seen, roll 80 includes a roll portion 82 and a journal 86 extending from each side of roll portion 82. Typically, roll portion 82 and journal 86 include steel or another metal alloy. Roll portion 82 generally includes an elongated cylindrical shape. The cylindrical shape of roll portion 82 is generally configured to receive steel sheet 60 such that at least a portion of steel sheet 60 can be wrapped around at least a portion of roll portion 82 . Accordingly, it should be understood that the width of the roll portion 82 generally corresponds to the width of the steel plate 60 and that the width of the roll portion 82 is wider than the steel plate 60 . This can compensate for the strip tracking through the coating portion 10.

As described above, each journal 86 extends outwardly from roll portion 82. Each journal 86 includes a generally cylindrical shape with an outer diameter that is less than the outer diameter defined by roll portion 82. Each journal 86 is sized to be received by the bore 76 of each bearing block 72. However, as explained in more detail below, each journal 86 typically has a bearing block 72 to allow space for a roller sleeve 90 disposed between the bearing block 72 and the journal 86. ) is smaller than the bore (76).

In one embodiment, each journal 86 further includes threads 88 disposed on an outer surface of each journal 86. As described in more detail below, threads 88 are generally configured to engage corresponding features of each roller sleeve 90 to couple each roller sleeve 90 to each journal 86. do. In this example, the threads 88 of each journal 86 are oriented to take into account the rotation of the step roll 80. For example, if one journal 86 includes right-handed threads, the opposite journal 86 includes left-handed threads. This configuration of the threads 88 prevents each roller sleeve 90 from loosening or otherwise unscrewing when the step roll 80 is rotated by friction between the steel plate 60 and the roll portion 82. . In some examples, threads 88 may include a rounded peak to accommodate changes in the internal geometry of roller sleeve 90, as described in more detail below.

An exemplary roller sleeve 90 is shown in FIGS. 5 and 6. Roller sleeve 90 is generally configured to provide a durable, non-reactive barrier between each journal 86 and each bearing block 72. As will be appreciated, roller sleeve 90 generally rotates with journal 86 such that roller sleeve 90 rotates within bearing block 72 relative to bearing block 72 . Accordingly, a portion of the outer surface of each roller sleeve 90 directly contacts a portion of the inner surface of the bore 76 of the bearing block 72. Accordingly, the roller sleeve 90 can form a plane bearing with each journal 86 without using rollers or rolling bodies. Thereby, each journal 86 and roller sleeve 90 can rotate together within the fixed bearing block 72.

As can be seen, roller sleeve 90 includes a generally cylindrical body 92. In the depicted embodiment, at least one side of body 92 includes a chamfered or beveled edge 94. Edges 94 are generally configured to contact the interface between each journal 86 and roll portion 82. Although edges 94 are generally shown as having a chamfered or beveled shape, it should be understood that any other suitable shape may be used, such as a fillet shape, square shape, j-groove, etc.

Body 92 defines a cylindrical bore 96 extending through roller sleeve 90. The interior of bore 96 includes threads 98 that extend at least partially through the length of bore 96. The threads 98 are generally configured to engage threads 88 on the outer diameter of each journal 86. Accordingly, it should be understood that the threads in bore 96 are configured to mechanically secure roller sleeve 90 to each journal 86.

The inner diameter of the bore 96 generally corresponds to the outer diameter of each journal 86. However, as can best be seen in Figure 7, this example includes a predetermined gap d between the inner diameter of bore 96 and the outer diameter of journal 86. Initially, this gap d is such that the thermal expansion ratio of journal 86 is such that as both journal 86 and roller sleeve 90 approach the temperature of hot dip galvanizing tank 20, this gap d is substantially eliminated. A theory is put forward that it can be derived from the difference between the thermal expansion ratio of and the roller sleeve 90. However, in this example, the gap d between bore 96 and journal 86 is unexpectedly not limited only to the thermal expansion ratio of journal 86 and roller sleeve 90. In particular, a slight gap d between the journal 86 and the roller sleeve 90 at the temperature of the hot dip galvanizing tank 20 has been found to be beneficial in improving the durability of the roller sleeve 90 during the aluminum plating procedure. Accordingly, it should be understood that in this example at least some gap d is maintained between the inner diameter of the bore 96 and the outer diameter of the journal 86 through the aluminum plating procedure. In some examples, a suitable clearance (d) may be about 0.220 inches. In other examples, gap d may be about 0.220 to 0.200 inches. In some examples the width of the thread 88 may also provide an arbitrary width gap. In these examples, this width gap can vary from about 0.005 inches to about 0.030 inches.

Although the gap d between the inner diameter of the bore 96 and the outer diameter of the journal 86 described above is described as beneficial for improving the durability of the roller sleeve 90, it should be understood that this gap d is also limited in the present example. do. For example, if the gap d between the inner diameter of the bore 96 and the outer diameter of the journal 86 is too large, the molten aluminum 22 may be slightly wetted, causing the molten aluminum 22 to form a gap between the inner diameter of the bore 96 and the journal 86. It can be transported through the gap (d) between the outer diameters. This may depend, at least in part, on the material of the roller sleeve 90, but in this example the gap d between the inner diameter of the bore 96 and the outer diameter of the journal 86 is such that the molten aluminum 22 has a gap d It should be understood that restrictions are placed to minimize or prevent movement to .

The roller sleeve 90 includes a ceramic material that has high strength and is wear-resistant at high temperatures. This ceramic material may additionally have a low coefficient of thermal expansion, thermal shock resistance, resistance to wetting by molten metal, corrosion resistance, and is substantially chemically inert to molten metal. By way of example only, suitable ceramic materials may include a grade of ceramic known as SiAlON ceramic. As mentioned above, SiAlON ceramic is a high temperature refractory material that can be used to handle molten aluminum. SiAlON ceramics generally exhibit excellent thermal shock resistance, high strength at high temperatures, excellent moisture resistance by molten aluminum, and high corrosion resistance in the presence of molten non-ferrous metals. The roller sleeve 90 of this example includes ADVANCER® nitride bonded silicon carbide manufactured by Saint-Gobain Ceramics, but many SiAlON grade ceramics may be used.

In an exemplary use, steel sheet 60 is wound around roll assembly 100. Friction between the steel plate 60 and the roll portion 82 of the roll 80 causes the roll 80 to rotate as the steel plate 60 moves relative to the roll assembly 100. Rotation of the roll 80 causes a corresponding rotation of each journal 86, which also causes rotation of each roller sleeve 90 through engagement between threads 88 and 98. Due to the opposing threads 88 of each journal 86, each roller sleeve 90 remains fixed to each journal 86 due to rotation of each journal 86. It should be understood that in some instances only a portion of the threads 88 of the journal 86 may be in contact with the threads 98 of the roller sleeve 90 at any given time. For example, during operation, the steel plate 60 may pull the roll 80 in a particular direction. This will cause the journal 86 to move laterally within the roller sleeve 90 due to the gap such that the journal 86 and roller sleeve 90 are not exactly coaxially aligned. In this case, depending on the size of the gap d, one side of the thread 88 of the journal 86 may be released from the thread 98 of the roller sleeve 90. Although some disengagement may occur, the engagement function of the threads 88, 98 on opposite sides of the journal 86 and the roller sleeve 90 can still be maintained because the threads 88, 98 are fully engaged. Accordingly, each journal 86 and each roller sleeve 90 rotate together within each bearing block 72, while each bearing block 72 fixes the axial position of the roll 80. . Other suitable configurations for roller sleeve 90 and/or roll assembly 100 will be apparent to those skilled in the art in light of the teachings herein.

For example, FIGS. 8 and 9 illustrate exemplary alternative journals 186 and roller sleeves 190 that can be easily incorporated into the roll assembly 100 described above. Unless otherwise stated herein, it should be understood that journal 186 and roller sleeve 190 are substantially similar to journal 86 and roller sleeve 90, respectively, described above. Journal 186 in this example includes a generally square side cross-section. As explained in more detail below, this generally square shape allows journal 186 to engage roller sleeve 190 and induce rotation of roller sleeve 190 relative to each bearing block 72. As will be appreciated, this configuration allows for a similar structure to the threads 88 of the journal 86 to be omitted from the journal 186.

Roller sleeve 190 generally includes a cylindrical body 192 configured to fit into journal 186. Body 192 defines a bore 196 that extends fully through roller sleeve 190. Bore 196 in this example defines a square-shaped lateral cross-section that generally corresponds to the shape of journal 186 described above.

Bore 196 in this example is generally sized to accommodate journal 186. Bore 196 in this example is generally sized to accommodate journal 186, although bore 196 in this example also has journals ( It should be understood that it is sized to provide at least some clearance to the outside of the 186). As with the gap d described above, the gap associated with the roller sleeve 90 and the journal 86 is generally caused by the heat generated within the hot dip galvanizing tank 20. It is configured to be maintained throughout the coating procedure despite expansion. As also described above, the gap associated with the roller sleeve 190 and journal 186 is also sized to minimize or prevent transport of molten metal 22 into the cavity defined by the gap.

As discussed above, the corresponding square shape defined by the journal 186 and bore 196 of the roller sleeve 190 is generally configured such that the journal 186 can transmit rotational motion to the roller sleeve 190. Although a corresponding square shape is shown herein, it should be understood that many alternative cross-sectional shapes may be used. For example, in some examples the journal 186 and bore 196 of roller sleeve 190 define corresponding triangular, oval, or rectangular shapes. In other examples, both the journal 186 and the bore 196 of the roller sleeve 190 may be keyed to define a generally cylindrical shape but still allow rotational communication from the journal 186 to the roller sleeve 190. Of course, many alternative geometries for the journal 186 and bore 196 of roller sleeve 190 will be apparent to those skilled in the art in light of the teachings herein. In each case, there is a mechanical locking function. Threads or other mechanical locking arrangements limit the movement of the roller sleeve relative to the journal, allowing both parts to rotate with the bore.

10 shows an alternative journal 286 that can be easily incorporated into the roll assembly 100 described above. Unlike the journal 86 described above, the journal 286 in this example is not configured for use in a structure similar to the roller sleeve 90. Instead, journal 86 incorporates a series of cylindrical ceramic inserts 290 longitudinally oriented around the outer surface of journal 286. To receive inserts 290, journal 286 is machined to include a plurality of channels (not shown) configured to receive inserts 290. However, the channel on the outer surface of the journal 286 is sized to accommodate only a portion of each insert 290 such that each inactive portion 290 protrudes from the outer surface of the journal 286. Accordingly, it should be understood that each inert 290 is configured to engage with the interior of the bearing block 72 to separate the outer surface of the journal 286 from the interior of the bearing block 72.

The coupling between journal 286 and insert 290 may be achieved by any suitable means. For example, in this example insert 290 is welded or joined to journal 286 by ultrasonic welding, friction welding, brazing, and/or other processes suitable for welding or joining dissimilar materials. Alternatively, in some examples insert 290 is secured to journal 286 by a mechanical fastener. In still other examples, the channels of journal 286 and insert 290 may include complementary engagement features to provide a slide-in or snap fit. Of course, in other examples, insert 290 may be coupled to journal 286 by any other suitable means that will be apparent to those skilled in the art given the teachings herein.

In some examples, it may be desirable to fully integrate insert 290 into journal 286. For example, Figure 11 shows an alternative journal 386 that can be easily integrated into the roll 80 of the roll assembly 100. Instead of including a structure similar to the insert 290 described above as a separate component, the journal 386 itself includes a ceramic material consistent with the properties described above for the roller sleeve 90. In this example, journal 386 may be removably coupled to roll portion 82 of roll 80 instead of being integral with roll portion 82. Accordingly, the journal 386 of the present example includes a roller plug 388 configured to fit into a corresponding opening that may be drilled into the roll portion 82 of the step roll 80. Although not shown, it should be understood that in this example journal 386 is mechanically locked to rolling 80 by a series of pins or other mechanical fasteners.

In other examples, the entire roll 80 may include ceramic material so that there is no need to separate the journal 386 from the roll portion 82. Of course, various alternative configurations for journal 286 may be apparent to those skilled in the art in light of the teachings herein.

12-17 show an exemplary alternative roll assembly 470 that can be easily integrated into the coating line described above. Unless otherwise stated herein, it should be understood that roll assembly 470 is substantially similar to roll assembly 100 described above. As can be seen in Figure 12, roll assembly 470 includes two bearing blocks 472, rolls 480, and a roller sleeve 490 disposed between each bearing block 472 and roll 480. Includes. Each bearing block 472 is generally configured to receive at least a portion of a roll 480 to facilitate rotation of the roll 480 about the bearing block 472. Although not shown, it should be understood that each bearing block 472 is generally coupled to a fixture or other structure to hold each bearing block 472 in place within hot dip galvanizing tank 20.

An exemplary bearing block 472 is best seen in FIG. 13 . As can be seen, bearing block 472 includes a generally octagonal body 474. The octagonal shape of body 474 is generally configured to provide a surface on which fixtures or other structures can be attached to bearing block 472 to position bearing block 472 within hot dip galvanizing tank 20. Although the body 472 in this example is shown as an octagonal structure, it should be understood that other suitable structures such as squares, hexagons, triangles, circles, etc. may be used in other examples. Regardless of the particular shape used for body 474, body 474 defines a receiving bore 476 through the center of bearing block 472. Receiving bore 476 is defined as generally cylindrical. As described in more detail below, receiving bore 476 is configured to receive at least a portion of roller sleeve 490 and roll 480 such that roller sleeve 490 can rotate freely within bore 476. .

As shown in FIG. 14 , roll 480 includes a roll portion 482 and a journal 486 extending from each side of roll portion 482 . Typically, roll portion 482 and journal 486 include steel or other metal alloy. In some variations, roll 480 may be formed from composite or other suitable material. Roll portion 482 includes a generally elongated cylindrical shape. The cylindrical shape of roll portion 482 is generally configured to receive steel sheet 60 so as to enable at least a portion of steel sheet 60 to wrap around at least a portion of roll portion 482 .

As described above, each journal 486 extends outwardly from roll portion 482. Each journal 486 includes a generally cylindrical shape with an outer diameter that is less than the outer diameter defined by roll portion 482. In this embodiment, each journal 486 is configured so that the outer surface of each journal 486 maintains a substantially circular profile about the outer perimeter of each journal 486 along the length of each journal 486. and a substantially continuous smooth outer surface free of mechanical locking features. Accordingly, a substantially smooth exterior of journal 486 may be more cost effective to manufacture than a journal that includes locking features. Each journal 486 is sized to be received by the bore 476 of each bearing block 472. However, as explained in more detail below, each journal 486 typically has a bearing block 472 to allow space for a roller sleeve 490 disposed between the bearing block 472 and the journal 486. ) is small in size relative to the bore 476.

An exemplary roller sleeve 490 is shown in FIGS. 15-17. Roller sleeve 490 is generally configured to provide a durable, non-reactive barrier between each journal 486 and each bearing block 472. As can be seen, roller sleeve 490 includes a generally cylindrical body 492 that defines a cylindrical bore 496 extending through roller sleeve 490. The interior of the bores 496 in this embodiment is mechanically locked so that the inner surface of each bore 496 maintains a substantially circular profile around the inner perimeter of each bore 496 along the length of each bore 496. It has a substantially continuous smooth inner surface with no features. Accordingly, a smooth inner surface of bore 496 may be more cost effective to manufacture than a bore containing locking features. The inner diameter of bores 496 generally corresponds to the outer diameter of each journal 486, as discussed in greater detail below. Accordingly, roller sleeve 490 is positioned about journal 486 such that journal 486 is received within bore 496 of roller sleeve 490. The fit between each journal 486 and the corresponding bore 496 and the weight of each journal 486 are determined by the roller sleeve (486) even if the journal 486 and roller sleeve 490 are not mechanically coupled to the locking mechanism. 490) generally rotates simultaneously with the journal 486. This allows roller sleeve 490 to rotate within bearing block 472 relative to bearing block 472 to prevent wear of journal 486.

At least one side of the body 492 of the roller sleeve 490 may include a chamfered or beveled edge 494. Edges 494 are generally configured to contact the interface between each journal 486 and roll portion 482. Although edges 494 are generally shown as having a chamfered or beveled shape, it should be understood that any other suitable shape may be used, such as a fillet shape, square shape, j-groove, etc.

Bearing block 472 and roller sleeve 490 may be made of ceramic. For example, bearing block 472 and roller sleeve 490 may each include a refractory ceramic material that is resistant to impact, abrasion and/or thermal shock. These refractory materials may include silicon carbide (SiC), alumina (Al ₂ O ₃ ), fused silica (SiO ₂ ), or combinations thereof. In some variations, the refractory ceramic material includes from about 5% to about 100% silicon carbide and/or alumina.

By way of example only, suitable refractory ceramic materials may include a class of ceramics known as SiAlON ceramics. SiAlON ceramics are high-temperature refractory materials that can be used to handle molten metals. SiAlON ceramics generally exhibit excellent thermal shock resistance, high strength at high temperatures, excellent moisture resistance by molten aluminum, and high corrosion resistance in the presence of molten metal. Such SiAlON ceramics may include CRYSTON CN178 manufactured by Saint-Gobain High-Performance Refractories of Worcester, Massachusetts, although a number of SiAlON grade ceramics may be used.

Other suitable refractory ceramic materials may include ceramics with about 73% Al ₂ O ₃ and about 8% SiC. This ceramic may include GemStone® 404A manufactured by Wahl Refractory Solutions of Fremont, Ohio. In other embodiments, harder ceramics with higher amounts of SiC, such as about 70% SiC, may be used. In some variations, stainless steel wire needles can be added to the ceramic material, such as from about 0.5% to about 30% by weight of the material. Such ceramics may include ADVANCER® nitride bonded silicon carbide manufactured by Saint-Gobain Ceramics of Worcester, MA or Hexology® silicon carbide also manufactured by Saint-Gobain Ceramics of Worcester, MA. Other suitable refractory materials will be apparent to those skilled in the art in light of the teachings herein.

Each bearing block 472 and/or roller sleeve 490 may be manufactured by casting a refractory ceramic material. In some other variations, bearing blocks 472 and/or roller sleeves 490 may be manufactured by pouring liquid ceramic into a mold and using heat to bake the ceramic to remove moisture. The outer surface of bearing block 472 and/or roller sleeve 490 may then be polished to provide a smooth outer surface. Other suitable methods for manufacturing the components of roll assembly 480 will be apparent to those skilled in the art in light of the teachings herein.

Accordingly, bearing block 472 and roller sleeve 490 may be made of the same refractory material or different refractory materials. In one embodiment, bearing block 472 comprises a castable ceramic having about 73% Al ₂ O ₃ and about 8% SiC, such as GemStone® 404A, while roller sleeve 490 has about 70% SiC, such as It may contain harder ceramics with higher amounts of SiC. These ceramics may include ADVANCER® nitride bonded silicon carbide. This may cause the bearing block 472 to wear out before the roller sleeve 490. This may be desirable because it may be more cost-effective to replace bearing block 472 compared to roller sleeve 490. In some other variations, the bearing block 472 may include ADVANCER® ceramic and/or the roller sleeve may include GemStone® 404A ceramic.

Accordingly, roller sleeves 490 may be positioned between journals 486 and bearing blocks 472 to provide a durable, non-reactive barrier between each journal 486 and each bearing block 472. Referring to FIG. 18, this example includes a predetermined gap d between the inner diameter of the bore 496 and the outer diameter of the journal 486. Initially, this gap d is determined by the thermal expansion ratio of the journal 486 and A theory is raised that it can be derived from the difference between the thermal expansion ratios of the roller sleeve 490. However, in this example, the gap d between bore 496 and journal 486 is unexpectedly not limited to the thermal expansion ratio of journal 486 and roller sleeve 490. In particular, a slight gap d between the journal 486 and the roller sleeve 490 at the temperature of the hot dip galvanizing tank 20 has been found to be beneficial to improve the durability of the roller sleeve 490 during the coating procedure. Accordingly, it should be understood that in this example at least some gap d may be maintained between the inner diameter of bore 496 and the outer diameter of journal 486 throughout the coating procedure.

The gap d between the inner diameter of the bore 496 and the outer diameter of the journal 486 is described as advantageous for improving the durability of the roller sleeve 490, but this gap d is also limited in the present example. You must understand. For example, if the gap d between the inner diameter of the bore 496 and the outer diameter of the journal 486 is too large, some wetting of the molten aluminum 22 may occur, causing the molten metal 22 to be pushed into the inner diameter of the bore 496. It can be transported in the gap (d) between the outer diameter of and the journal 486. This may depend, at least in part, on the material of the roller sleeve 490, but in this example the gap d between the inner diameter of the bore 496 and the outer diameter of the journal 486 is such that the molten metal 22 has a gap d It should be understood that restrictions are placed on minimizing or preventing transport to The gap d between the bore 496 and the journal 486 is between the roller sleeve 490 and the journal 486 when the roll 480 rotates due to friction between the steel plate 60 and the roll portion 482. may be restricted to prevent slipping.

Accordingly, the inner diameter of the bore 496 of the roller sleeve 490 is sized to correspond to the outer diameter of the journal 486 to provide a gap fit between the journal 486 and the roller sleeve 490. This gap fit provides a minimum gap d sufficient to prevent cracking of the roller sleeve 490 upon thermal expansion of the journal 486 and to prevent molten metal 22 from transporting into the gap d. Alternatively, it may have a maximum gap (d) to prevent slippage between the roller sleeve 490 and the journal 486. In some examples, a suitable clearance (d) at operating temperature may be between about 0.001 inch and 0.012 inch.

In an exemplary use, steel sheet 60 is wound around roll assembly 470. Friction between the steel plate 60 and the roll portion 482 of the roll 480 causes the roll 480 to rotate as the steel plate 60 moves relative to the roll assembly 470. Rotation of the roll 480 causes a corresponding rotation of each journal 486, which also causes a substantially continuous smooth inner surface of the bore 496 of the roller sleeve 490 and a substantially continuous inner surface of the journal 486. Engagement between the smooth outer surfaces causes rotation of each roller sleeve 490. Due to the fit between each journal 486 and the corresponding bore 496 and the weight of each journal 486, the journal 486 and roller sleeve 490 are not mechanically engaged with the locking mechanism, but the roller Sleeve 490 generally rotates simultaneously with journal 486. Other suitable configurations for roller sleeve 490 and/or roll assembly 470 will be apparent to those skilled in the art in light of the teachings herein.

For example, FIGS. 19-22 show roller sleeve 490 except that roller sleeve 590 includes a pair of notches 598 extending inward from the top and bottom portions of roller sleeve 590. Another embodiment of a similar roller sleeve 590 is shown. The illustrated embodiment shows roller sleeve 590 including two notches 598 in the top and bottom portions of roller sleeve 590, but roller sleeve 590 has approximately random grooves around roller sleeve 590. may include any suitable number of notches 598 positioned at appropriate locations. Accordingly, roller sleeve 590 may be assembled with journal 586 as shown in FIG. 23 such that roller sleeve 590 is positioned around journal 586 with a notch 598 at the free end of journal 586. is located in Bar 599 may then be inserted into notches 598 of roller sleeve 590 along the free end of roller sleeve 590 . A bar 599 may be fixed to the free end of the journal 586 to mechanically couple the journal 586 with the roller sleeve 590 through the bar 599.

examples

The following examples relate to various non-exclusive ways in which the teachings herein can be combined or applied. It should be understood that the following examples are not intended to limit the scope of claims that may be presented at any time in this application or in subsequent applications to this application. No waiver is intended. The following examples are provided for illustrative purposes only. It is contemplated that the various teachings herein may be arranged and applied in a variety of different ways. It is also contemplated that in some variations certain features mentioned in the examples below may be omitted. Accordingly, none of the aspects or features mentioned below should be considered important unless explicitly stated otherwise by the inventor or the inventor's interested successor. If a claim is made in this application or in a subsequent application related to this application that includes additional features beyond those mentioned below, such additional features will not be considered added for any reason related to patentability.

A series of tests were performed to evaluate the journal 86 and roller sleeve 90 described above to determine the desired gap d. This series of tests is detailed in the examples below. It should be understood that the following examples are for illustrative purposes only and that various alternative features in other examples may be understood by those skilled in the art in light of the teachings herein.

Example 1

In initial tests, a structure similar to the journal 86 described above was tested to establish the measured coefficient of thermal expansion of the journal. The journal tested was prepared as a mock-up part of the staff roll, consisting of the journal attached to a hub corresponding to the end of the staff roll. While the journal was at room temperature (e.g., approximately 70°F), measurements of all surfaces of the journal were obtained: outer diameter, thread peak, and thread root. The journal was then heated to a temperature of 1,350°F. Immediately after heating, the same measurement was performed while the journal was in the heated state. The values measured at room temperature were compared with the values measured with the journal heated. This comparison was used to calculate the coefficient of thermal expansion based on experiments on journals. Therefore, the coefficient of thermal expansion based on experiments in the journal was calculated to be 9.1 x 10 ^-6 in/in/℉. Based on this calculation, it was assumed that the desired gap d between journal 86 and roller sleeve 90 is about 0.020 inches.

Example 2

In a second attempt, the experimentally based coefficient of thermal expansion and the corresponding assumed desired gap (d) between journal 86 and roller sleeve 90 (identified in Example 1) were tested for verification under operating temperature. A roller sleeve similar to the roller sleeve 90 described above is manufactured by St. Provided by Gobain Ceramics. The inner diameter of the roller sleeve is tapered and has some burrs. Also, the roller sleeve was slightly out of round. Nevertheless, the test continued.

Processing was performed on the journal prior to testing. The journals are machined to provide a gap of at least 0.042" between the inside diameter of the roller sleeve and the outside diameter of the journal. This gap is to provide an approximate size-to-size fit between the journal and roller sleeve at elevated temperatures (e.g., 1,150°F). It has been set.

After processing, the roller sleeve and journal were aligned. After registration, it was observed that there was little or no clearance in some localized areas around the outer diameter of the journal due to the rounded nature of the roller sleeve. To improve clearance and provide an overall loose fit, the roller sleeve was unscrewed from the journal approximately ¼ turn. In this configuration, the roller sleeve and journal were subjected to furnace-based heat treatment.

The heat treatment included heating the roller sleeve and journal from 150°F to 1,150°F at intervals. The assembly of roller sleeves and journals was removed from the furnace at 500°F and 900°F to observe clearance. At 500°F, it was observed that there was “still sufficient clearance” after the assembly was pounded with a 4-inch x 4-inch block of elongated wood. At 900°F, it was observed that there was no visually detectable gap. Additionally, it was observed that the roller sleeve had broken and formed visible cracks. At this stage, it was assumed that chipping and cracking could be avoided by reducing the outside diameter of the journal by 0.030 to 0.040 inches.

After heat treatment was completed, additional chips were observed on the roller sleeve. This test suggested that clearance was necessary to aid installation and avoid the possibility of roller sleeve failure during operation. Additionally, an additional assumption was made that the durability of the roller sleeve could be improved by machining the threads of the roller sleeve or journal to engage only ½ of the thread depth. The thread depth at the time of testing was 0.200". Therefore, applying the assumed thread depth reduction, the additional durability of the roller sleeve could be achieved with only 0.100" of threads interlocking. Based on this, it was suggested that up to 0.060" of material could be removed from both threads of the roller sleeve and journal to provide the desired fit.

Example 3

After the trials described above in Example 2, field trials were performed. For this field trial, a step roll assembly similar to the step roll assembly 70 described above was prepared. Like the step roll assembly 70, the step roll assembly includes two journals. However, two journals were prepared so that one journal consisted of a control journal and the other journal consisted of a test journal. The control journals were prepared according to standard practice such that a metal journal to bearing block configuration was formed through the control journals. The test journal was prepared similarly to that described above with respect to journal 86 and included a roller sleeve similar to roller sleeve 90 described above.

Both the test journal and the corresponding roller sleeve are constructed to provide a maximum clearance of 0.220" between the test journal and the corresponding roller sleeve. During operation at constant temperature, size-to-size fit between the journal and roller sleeve is not required. Instead, it was assumed that the force applied to the step roll during operation would cause the threads on one side of the journal to engage the threads of the roller sleeve, that is, fully engaged on one side of the journal and the other. However, some limitation to the clearance between the journal and the roller sleeve was still desirable to support the load imposed during operation of the step roll assembly because limited engagement could occur. Some limitation on the clearance was still desirable to prevent this penetration, so both the test journal and the corresponding roller sleeve were configured to provide a maximum clearance of 0.220 inches. Therefore, the roller sleeve only partially covered the test journal throughout the test.

The step roll assembly was then inserted into a molten aluminum bath for use in aluminum plating the steel sheet. A total of 583,521 feet of steel plate was processed by the in-service staff roll assembly. When the step roll assembly was removed, damage was visible on the outside of the bearing block. When removing the bearing block from the step roll fixture, the bearing block is separated into four separate parts. Upon separation, each fragment cross-section was completely coated with aluminum metal. This coating pattern suggests that failure of the bearing block occurred during service rather than cooling through thermal shock. Large voids were present on the surfaces of the two matched fragments. Therefore, it was determined that the cracking of the bearing blocks was not related to the use of the roller sleeve and test journal combination.

The roller sleeves were grooveless and generally exhibited limited visible wear as indicated by limited thickness loss. The part of the roller sleeve that was broken before testing showed a slight increase in the broken area. However, the fracture did not extend along the length of the roller sleeve and did not affect roller sleeve serviceability. Compared to control journals, roller sleeves generally exhibit less wear and control journals exhibit more normal wear. From a quantitative point of view, the wear rate of the roller sleeve was substantially reduced compared to that of the control journal, based on a comparison between measurements of the inner diameter of the bearing block (before and after testing), the outer diameter of the control journal, and general observations of the wear appearance. .

Example 4

Another journal similar to the above-mentioned journal (86) was prepared. The journals were prepared to provide a clearance of 0.220 inches +0 inches/0.005 inches when coupled to roller sleeves similar to roller sleeve 90 described above. The journal's threads are machined to provide rounded peaks to better accommodate the irregular inner diameter shape presented by the roller sleeve. Measurements of lateral movement between the journal and roller sleeve were obtained. This measurement resulted in a lateral movement of 0.020 inch to 0.040 inch, which was considered acceptable, and a range of 0.060 inch to 0.155 inch.

Example 5

A roll assembly similar to roll assembly 470 described above was prepared to conduct field trials. Like roll assembly 470, it includes two journals each having a roller sleeve similar to roller sleeve 490 described above. In the trials, the roller sleeves were manufactured from ADVANCER® material and the bearing blocks were manufactured from GemStone® 404A material. Each journal and its corresponding roller sleeve are both constructed to provide a maximum clearance of 0.040" between the journal and its corresponding roller sleeve at hot dip galvanizing tank temperature. The roll assembly is then preheated and ready for use in aluminum plating the steel sheet. When inserted into a molten aluminum bath for 5 days and 12 hours and using 1.9 MM feet of steel, the journals were found to rotate within their corresponding roller sleeves, which resulted in too much space between the journals and the roller sleeves. It indicates that there is a gap.

Example 6

A roll assembly similar to roll assembly 470 described above was prepared to conduct another field trial. Like roll assembly 470, it includes two journals each having a roller sleeve similar to roller sleeve 490 described above. In the trials, the roller sleeves were manufactured from ADVANCER® material and the bearing blocks were manufactured from GemStone® 404A material. Each journal and corresponding roller sleeve are configured to provide a maximum clearance of 0.006" between the journal and the corresponding roller sleeve at operating temperature. The roll assembly is then preheated and placed in a molten aluminum bath for use in aluminizing steel sheet. A total of 733,895 feet of steel plate was placed in service with the roll assemblies. When the roll assemblies were removed, minimal wear was found in each bearing block: 0.140 inches in block 1 and 0.085 inches in block 2. Wear of individual roller sleeves was also found to be minimal, with 0.005 inches in diameter removed from sleeve 1 and 0.024 inches in diameter removed from each roller sleeve with a slight tap from the hammer. There was no sign of rotation of the journal within roller sleeve 1, but there was evidence of slight rotation of the journal within roller sleeve 2, indicating that there may be too much clearance between the journal and roller sleeve.

Example 7

A roll assembly similar to roll assembly 470 described above was prepared to conduct another field trial. Like roll assembly 470, it includes two journals each having a roller sleeve similar to roller sleeve 490 described above. In the trials, the roller sleeves were manufactured from ADVANCER® material and the bearing blocks were manufactured from GemStone® 404A material. Each journal and its corresponding roller sleeve are both configured to provide a maximum clearance of 0.004 inch between the journal and its corresponding roller sleeve at operating temperature. The roll assembly was then preheated and inserted into a molten aluminum bath for use in aluminizing the steel sheet for 7 days, using 3MM feet of steel. The attempt was considered successful.

Example 8

A roll assembly similar to roll assembly 470 described above was prepared to conduct another field trial. Like roll assembly 470, it includes two journals each having a roller sleeve similar to roller sleeve 490 described above. In the trials, the roller sleeves were manufactured from ADVANCER® material and the bearing blocks were manufactured from GemStone® 404A material. Each journal and its corresponding roller sleeve are both configured to provide a maximum clearance of 0.004 inch between the journal and its corresponding roller sleeve at operating temperature. The roll assembly was then preheated and inserted into a molten aluminum bath for use in aluminizing the steel sheet for 7 days, using 3MM feet of steel. When the roll assembly was removed, one of the roller sleeves was in good condition with a diameter loss of approximately 0.021 inch. This attempt was considered successful.

Example 9

A roll assembly similar to roll assembly 470 described above was prepared to conduct another field trial. Like roll assembly 470, it includes two journals each having a roller sleeve similar to roller sleeve 490 described above. In the trials, the roller sleeves were manufactured from ADVANCER® material and the bearing blocks were manufactured from GemStone® 404A material. Each journal and its corresponding roller sleeve are both configured to provide a maximum clearance of 0.004 inch between the journal and its corresponding roller sleeve at operating temperature. The roll assembly was then preheated in a molten aluminum bath for use in aluminum plating steel sheets over 4 days and 23.5 hours, using 2.3MM feet of steel. The attempt was considered successful. Both roller sleeves were intact and the journal did not rotate within the roller sleeves. When removing the roll assembly, the wear rate of the roller sleeve was determined to be 0.010 inches per MM foot of strip. The calculated wear rate for the bearing block was determined to be 0.04 inches to 0.09 inches per MM foot of strip.

Example 10

In a thermal expansion trial, a roller sleeve similar to roller sleeve 490 described above was placed over the journal at room temperature to provide a gap of approximately 0.027 inches. In the trial, the roller sleeve was made of ADVANCER® material and the journal was made of steel. The roller sleeve and journal were then heated to 1300°F at a heating rate of less than 100°F per hour. After a 4-hour soak period, the roller sleeves were visually inspected to ensure that there were no cracks in the roller sleeves. Soak the roller sleeve and journal for 2 hours and heat to 1350°F. The roller sleeves were visually inspected to ensure that there were no cracks in the roller sleeves. This process was repeated at 1400℉, 1450℉, 1550℉, etc. up to 1700℉. No cracks were observed in the roller sleeve during trials. It was therefore determined that thermal expansion between the journal and roller sleeve with these materials and clearances would not cause failure of the roller sleeve.

Example 11

A roller assembly, the roller assembly configured to be immersed in molten metal, the roller assembly comprising: (a) a roller comprising a roll portion and at least one journal extending axially from the roll portion, the roller having at least one journal; The roller is substantially cylindrical; (b) a roller sleeve comprising a bore extending through the roller sleeve, the roller sleeve being substantially cylindrical, the roller sleeve being positioned about the journal; and (c) a bearing block defining an opening therein, wherein the roller sleeve is disposed within the opening of the bearing block between the bearing block and the at least one journal.

Example 12

The roller assembly of Example 11, wherein the roller sleeve and at least one journal are configured to rotate together about the bearing block.

Example 13

The roller assembly of Example 11 or Example 12 wherein the bore of the roller sleeve is sized to provide a gap fit between the inner surface of the bore and the outer surface of the at least one journal.

Example 14

The roller assembly of Example 13, wherein the gap fit is maintained when the roller assembly is immersed in molten metal.

Example 15

The roller assembly of Example 13 or Example 14 wherein the gap fit is sized to prevent ingress of molten metal between the roller sleeve and the at least one journal.

Example 16

The roller assembly of any of Examples 11-15, wherein the roller sleeve comprises a ceramic material.

Example 17

The roller assembly of Example 16, wherein the ceramic material includes silicon carbide.

Example 18

The roller assembly of any of Examples 11-17, wherein the bearing block includes a ceramic material.

Example 19

The roller assembly of Example 18, wherein the ceramic material includes silicon carbide.

Example 20

A roller assembly, the roller assembly being configured to be immersed in molten metal, the roller assembly comprising: (a) a roller including a roll portion and two journals projecting from opposite ends of the roll portion, each journal substantially said roller comprising a continuous smooth exterior surface; (b) a pair of roller sleeves, each roller sleeve including a bore extending therethrough configured to receive a corresponding journal therein, the bore of each roller sleeve having a substantially continuous smooth inner surface; Containing, said pair of roller sleeves; and (c) a pair of bearing blocks, each bearing block defining an opening therein, the opening of each bearing block being configured to receive a corresponding roller sleeve with a corresponding journal disposed within the roller sleeve. A roller assembly comprising the pair of bearing blocks.

Example 21

The roller assembly of Example 20 wherein the bore of each roller sleeve is sized to provide a gap between the inner surface of the bore and the outer surface of the corresponding journal.

Example 22

The roller assembly of Example 21 wherein the gap is maintained when the roller assembly is immersed in molten metal.

Example 23

The roller assembly of Example 21 or Example 22 wherein the gap is sized to prevent ingress of molten metal between the roller sleeve and the corresponding journal.

Example 24

The roller assembly of any of Examples 21-23, wherein the gap is about 0.001 inch to 0.012 inch.

Example 25

The roller assembly of any of Examples 20-24, wherein each roller sleeve is ceramic.

Example 26

The roller assembly of Example 25, wherein the ceramic of each roller sleeve includes at least about 5% silicon carbide.

Example 27

The roller assembly of any of Examples 20-26, wherein each bearing block is ceramic.

Example 28

The roller assembly of Example 27, wherein the ceramic of each bearing block includes at least about 5% silicon carbide.

Example 29

The roller assembly of any of Examples 20-28, wherein each roller sleeve includes a greater amount of silicon carbide than each bearing block.

Example 30

A method of operating a roller assembly in a steel coating line, the method comprising: positioning a journal of a roller within a bore of a ceramic roller sleeve, wherein an outer surface of the journal is substantially smooth and an inner surface of the bore of the roller sleeve is substantially smooth. positioning the journal of the roller to be smooth; positioning the roller sleeve within an opening in a ceramic bearing block; and rotating the journal and roller sleeve together within the bearing block.

Although various embodiments of the invention have been shown and described, further applications of the methods and systems described herein may be achieved by appropriate modifications by those skilled in the art without departing from the scope of the invention. Some of such potential variations have been mentioned and others will be apparent to those skilled in the art. For example, the examples, embodiments, geometries, materials, dimensions, proportions, steps, etc. discussed above are illustrative and not required. Accordingly, the scope of the invention should not be limited to the details of structure and operation shown and described in the specification and drawings, but should be considered in light of any claims that may be presented.

Claims (18)

A roller assembly, wherein the roller assembly is configured to be immersed in molten metal, wherein the roller assembly:
(a) a roller having a roll portion and at least one journal extending axially from the roll portion, the at least one journal being cylindrical;
(b) the roller sleeve having a bore extending through the roller sleeve, the bore of the roller sleeve being cylindrical, the roller sleeve positioned around the at least one journal, the inner surface of the bore of the roller sleeve is sized to define a gap fit between the outer surfaces of the at least one journal to form a gap without mechanical engagement, such that the gap fit between the bore of the roller sleeve and the at least one journal is and sized to cause the roller sleeve to rotate simultaneously with the at least one journal when the at least one journal is rotated and to prevent slippage between the roller sleeve and the at least one journal, wherein the gap is 0.001 inches. The roller sleeve is between and 0.012 inches; and
(c) a bearing block defining an opening therein, wherein the roller sleeve is disposed within the opening of the bearing block between the bearing block and the at least one journal. According to paragraph 1,
and wherein the gap fit is maintained when the roller assembly is immersed in molten metal. According to paragraph 1,
and wherein the gap fit is sized to prevent ingress of molten metal between the roller sleeve and the at least one journal. According to paragraph 1,
The roller assembly of claim 1, wherein the gap is greater than 0.001 inch and less than 0.006 inch. According to paragraph 1,
A roller assembly, wherein the gap is greater than or equal to 0.001 inch and less than or equal to 0.004 inch. According to paragraph 1,
A roller assembly, wherein the roller sleeve includes a ceramic material. According to clause 6,
A roller assembly, wherein the ceramic material includes silicon carbide. According to paragraph 1,
A roller assembly, wherein the bearing block includes a ceramic material. According to clause 8,
A roller assembly, wherein the ceramic material includes silicon carbide. A roller assembly, wherein the roller assembly is configured to be immersed in molten metal, wherein the roller assembly:
(a) a roller having a roll portion and two journals projecting from opposite ends of the roll portion, each journal having a continuous smooth outer surface along the length of each journal to define a first mating surface; to the roller;
(b) a pair of roller sleeves, each roller sleeve having a bore extending therethrough configured to receive a corresponding journal therein, the bore of each roller sleeve forming a second engagement surface; and a continuous smooth inner surface along the length of each roller sleeve, wherein the first and second mating surfaces provide an interface between the first and second mating surfaces so that the first and second mating surfaces The roller sleeve and the corresponding journal are aligned with each other to rotate together based on the combination of the weight of the journal within the roller sleeve and the interface between the first and second engagement surfaces, wherein the interface between the first and second engagement surfaces is a pair of roller sleeves sized to define a gap fit defining a mechanically engagement-free gap between the first and second mating surfaces, the gap being between 0.001 inch and 0.012 inch; and
(c) a pair of bearing blocks, each bearing block defining an opening therein, the opening of each bearing block being configured to receive a corresponding roller sleeve with a corresponding journal disposed within the roller sleeve, A roller assembly comprising the pair of bearing blocks. According to clause 10,
The gap is maintained when the roller assembly is immersed in molten metal. According to clause 11,
wherein the gap is sized to prevent ingress of molten metal between the roller sleeve and the corresponding journal. According to clause 10,
A roller assembly, each roller sleeve being ceramic. According to clause 13,
A roller assembly, wherein the ceramic of each roller sleeve has at least 5% silicon carbide. According to clause 13,
Roller assembly, each bearing block being ceramic. According to clause 15,
A roller assembly, wherein the ceramic of each bearing block has at least 5% silicon carbide. According to clause 15,
A roller assembly, wherein each roller sleeve has a greater amount of silicon carbide than each bearing block. 1. A method of operating a roller assembly in a steel coating line, comprising:
Positioning a journal of a roller within a bore of a ceramic roller sleeve, wherein the outer surface of the journal is smooth, the inner surface of the bore of the roller sleeve is smooth, and the inner surface of the bore of the roller sleeve has a gap without mechanical engagement. The gap fit between the bore of the roller sleeve and the journal is such that when the roller sleeve and the journal are rotated, the roller sleeve is sized to define a gap fit between the outer surface of the journal. and sized to prevent slippage between the roller sleeve and the journal, wherein the gap between the inner surface of the bore of the roller sleeve and the outer surface of the journal is between 0.001 inch and 0.012 inch, or positioning the journal of the roller to be greater than or equal to 0.001 inch and less than 0.006 inch, or greater than or equal to 0.001 inch and less than or equal to 0.004 inch;
positioning the roller sleeve within an opening in a ceramic bearing block; and
A method of operating a roller assembly, comprising rotating the journal and roller sleeve together within the bearing block.

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