KR20210120077A - Method and apparatus for extending the service life of ballasts for coating lines - Google Patents

Abstract

A steel processing line includes rollers immersed in a certain amount of molten metal. The roller contains two journals. Each journal is received by an opening defined by a roller sleeve comprising a ceramic or refractory material. A roller sleeve is placed between each journal and the bearing block to reduce or prevent wear of the journals. The inner dimension of each roller sleeve and the outer dimension of each journal define a gap. The inner dimensions of each roller sleeve and the outer dimensions of each journal are configured such that a gap is maintained as the roller and pair of roller sleeves are heated by the molten metal.

Description

Method and apparatus for extending the service life of ballasts for coating lines

Coating is a common process used in steel making to provide a thin metallic coating (eg, aluminum, zinc and/or alloys thereof) to the surface of a steel substrate such as an elongated steel sheet or strip. It is to be understood that elongate 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 the elongated steel sheet through a series of roll assemblies to apply the steel sheet to a variety of processing processes. In the coating part of this process, the steel sheet is manipulated through a molten metal bath to coat the surface of the steel sheet.

To aid in the manipulation of the steel sheet, various components may be disposed within the molten metal bath. Some of these components can wear out due to the constant movement of the components and/or the harsh environment due to the presence of molten metal. When wear reaches unacceptable levels, the continuous coating line is interrupted and the components within it are reworked. This procedure generally 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 in the metal bath.

Accordingly, it may be desirable to include various features within the coating line to improve the overall service life of components to be worn. 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 material are applied to the outer surface of the roller journal to prevent wear.

Steel journals for rotating rolls in a molten metal bath face at least some wear and chemical attack when used in a molten metal bath for an aluminum plating process. In some circumstances, this wear and/or chemical attack can reduce the duty cycle of these rollers. Accordingly, it is desirable to reduce wear and/or chemical attack occurring in steel journals used in coating processes.

Ceramics or refractory materials provide excellent resistance to chemical attack and abrasion resistance encountered in environments surrounded by molten metal. However, there are difficulties in incorporating ceramic or refractory materials into roller assemblies immersed in molten metal. Accordingly, the present application relates to a structure and/or method for incorporating a ceramic or refractory material 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 detailed description of the embodiments given below, serve to explain the principles of the disclosure.
1 shows a schematic view of a coated part of a continuous steel processing line;
1a shows a schematic diagram of an alternative configuration for the coated part of FIG. 1 ;
FIG. 2 shows a perspective view of a roll assembly that can be readily incorporated into the coated portion of FIG. 1 ;
3 shows a perspective view of a bearing block of the roll assembly of FIG. 2 ;
Figure 4 shows a front view of the roll of the roll assembly of Figure 2;
5 shows a perspective view of a roller sleeve of the roll assembly of FIG. 2 ;
6 shows another perspective view of the roller sleeve of FIG. 5 ;
7 shows a partial front cross-sectional view of the engagement between the roll of FIG. 4 and the roller sleeve of FIG. 5 ;
FIG. 8 shows a cross-sectional side view of an alternative journal and roller sleeve that can be easily incorporated into the step roll of FIG. 4 ;
9 shows a perspective view of the journal and roller sleeve of FIG. 8 ;
FIG. 10 shows a perspective view of another alternative journal that can be easily incorporated into the roll of FIG. 4 ;
FIG. 11 shows a perspective view of another alternative journal that can be easily integrated into the roll of FIG. 4 ;
12 shows a perspective view of another roll assembly that may be readily incorporated into the coating portion of FIG. 1 ;
13 shows a perspective view of a bearing block of the roll assembly of FIG. 12 ;
14 shows a front view of the roll of the roll assembly of FIG. 12;
15 shows a perspective view of a roller sleeve of the roll assembly of FIG. 12 ;
Fig. 16 shows a front view of the roller sleeve of Fig. 15;
FIG. 17 shows a cross-sectional view of the roller sleeve of FIG. 15 taken along line 17-17 of FIG. 16 ;
Fig. 18 shows a partial front cross-sectional view of the engagement between the roll of Fig. 14 and the roller sleeve of Fig. 15;
19 shows a perspective view of another roller sleeve that may be readily incorporated into the roll assembly of FIG. 12;
20 shows a front view of the roller sleeve of FIG. 19 ;
Fig. 21 shows a top view of the roller sleeve of Fig. 19;
Fig. 22 shows a cross-sectional view of the roller sleeve of Fig. 19 taken along line 22-22 of Fig. 20;
23 shows a front view of the roller sleeve of FIG. 19 assembled with the journal;

This application relates generally 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 the 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 ceramic or refractory materials may also reduce the tendency of the journal to be subjected to chemical attack from the molten metal.

1 shows a schematic cross-sectional view of a coated part 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 sheet 60 may be subjected to a variety of different steel processing operations in different portions of the steel processing line 2 . For example, the steel plate 60 may be subjected to hot or cold rolling, various heat treatments, pickling, and the like. Alternatively, other steel machining operations may be eliminated such that the coated portion 10 is configured as a stand-alone coating line in some examples.

In the illustrated embodiment, the coated portion 10 includes a hot dip tank 20 , a snout 30 , and one or more roll assemblies 40 , 50 , 70 . As will be appreciated, the coated portion 10 is generally configured to receive an elongate steel sheet 60 for coating the steel sheet 60 . The hot-dip tank 20 is defined by a solid wall configured to contain molten metal 22 such as aluminum, zinc and/or alloys thereof. The inlet 30 is configured to be partially immersed in the molten metal 22 . Thus, the inlet 30 generally provides a hermetic seal around the steel plate 60 while entering the 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 plating tank 20 to support the steel sheet 60 through the coated portion 10 . For example, the pot or sink roll assembly 70 may be immersed in the molten metal 22 such that the pot roll assembly 70 is configured to rotate generally and thereby redirect the steel sheet 60 out of the hot dip tank 20 . have. One or more stabilizer and straightening roll assemblies 40 may then be positioned relative to the hot-dip tank 20 to stabilize the sheet 60 as the sheet 60 exits the molten metal 22 . For example, the stabilizer and straightening roll assembly 40 may be used to position the plate 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 generally be configured to redirect the steel plate 60 to another portion of the steel processing line 2 after the steel plate 60 has been coated. Coated portion 10 in this example is shown as only one of pot roll assembly 70 , stabilizer and straightening roll assembly 40 , and deflector roll assembly 50 , although in some other variations an appropriate number of roll assemblies 40 . , 50, 70) can be used.

1A shows an alternative configuration of the coated 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 assemblies 40 , the alternative configuration shown in FIG. 1A includes two sink roll assemblies 42 completely disposed within the hot-dip 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 sheet 60 through various portions of a coating process. In this example, sink roll assembly 42 manipulates steel plate 60 within molten metal 22 to promote complete coating of steel plate 60 . The sink roll assembly 42 further provides an increased amount of travel path through the molten metal 22 . This feature generally increases the time the steel plate 60 is placed in the molten metal 22 . As the plate 60 passes through the sink roll assembly 42 , the plate 60 may be redirected in a desired direction by the pot roll assembly 70 and the deflector roll assembly 50 . 1 and 1A both show separate configurations for the coated portion 10, in other examples the coated portion 10 may have another alternative configuration combining the various elements of the configuration shown in FIGS. 1 and 1A. It should be understood that including

A roll assembly incorporating a roller sleeve comprising a refractory ceramic material is 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, as such roller sleeves may reduce wear, corrosion and/or abrasion of the roll assemblies. Such 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 pot roll assemblies 70 as described above. it doesn't happen

Referring to FIG. 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 the roll 80 to facilitate rotation of the roll 80 relative to 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 tank 20 .

An exemplary bearing block 72 is best seen in FIG. 3 . As can be seen, the bearing block 72 includes a generally octagonal body 74 . The octagonal shape of the body 74 is generally configured to provide a surface on which a fixture or other structure can be attached to the bearing block 72 for positioning the bearing block 72 within the hot-dip tank 20 . Although the body 72 of this example is shown in an octagonal configuration, it should be understood that other suitable structures may be used in other examples, such as square, hexagonal, triangular, circular, and the like.

Regardless of the particular shape used for the body 74 , the body 74 defines a receiving bore 76 through the center of the bearing block 72 . Receiving bore 76 is generally defined to be cylindrical. As will be described in more detail below, the receiving bore 76 is configured to receive the roller sleeve 90 and at least a portion of the roll 80 such that the roller sleeve 90 is free to rotate 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 further have a low coefficient of thermal expansion, resistance to thermal shock, resistance to wetting by molten metal, resistance to corrosion, and is substantially chemically inert to the molten non-ferrous metal. By way of example only, suitable ceramic materials may include a grade of ceramic known as SiAlON ceramic. SiAlON ceramics are high-temperature refractory materials that can be used to handle molten aluminum. SiAlON ceramics generally exhibit good 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, although many SiAlON grade ceramics may be used.

A roll 80 is shown in FIG. 4 . As can be seen, the roll 80 includes a roll portion 82 and a journal 86 extending from each side of the roll portion 82 . Generally, roll portion 82 and journal 86 comprise steel or other metal alloy. Roll portion 82 includes a generally elongate cylindrical shape. The cylindrical shape of the roll portion 82 is generally configured to receive the steel plate 60 such that at least a portion of the steel plate 60 can wrap around at least a portion of the roll portion 82 . Accordingly, it should be understood that the width of the roll portion 82 generally corresponds to the width of the steel sheet 60 , the width of the roll portion 82 being wider than the steel sheet 60 . This may compensate for strip tracking through the coated portion 10 .

As discussed above, each journal 86 extends outwardly from the roll portion 82 . Each journal 86 includes a generally cylindrical shape having an outer diameter less than the outer diameter defined by the roll portion 82 . Each journal 86 is sized to be received by a bore 76 of a respective bearing block 72 . However, as will be described in more detail below, each journal 86 generally 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 in size than the bore 76 .

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

An exemplary roller sleeve 90 is shown in FIGS. 5 and 6 . The 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, the roller sleeve 90 generally rotates with the journal 86 such that the roller sleeve 90 rotates within the bearing block 72 relative to the bearing block 72 . Accordingly, a portion of the outer surface of each roller sleeve 90 is in direct contact with a portion of the inner surface of the bore 76 of the bearing block 72 . Thus, the roller sleeve 90 can form a plain bearing with the respective journal 86 without the use of rollers or rolling bodies. This allows each journal 86 and roller sleeve 90 to rotate together within the fixed bearing block 72 .

As can be seen, the roller sleeve 90 includes a generally cylindrical body 92 . In the illustrated embodiment, at least one side of the body 92 includes a chamfered or beveled edge 94 . Edge 94 is generally configured to abut the interface between each journal 86 and roll portion 82 . Although the edge 94 is 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, a square shape, a j-groove, and the like.

The body 92 defines a cylindrical bore 96 that extends through the roller sleeve 90 . The interior of the bore 96 includes a thread 98 that extends at least partially through the length of the bore 96 . 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 respective journal 86 .

The inner diameter of bore 96 generally corresponds to the outer diameter of each journal 86 . However, as best seen in FIG. 7 , this example includes a predetermined gap d between the inner diameter of the bore 96 and the outer diameter of the journal 86 . Initially, this gap d is the thermal expansion ratio of the journal 86 such that when both the journal 86 and the roller sleeve 90 approach the temperature of the hot-dip tank 20, the gap d is substantially eliminated. It is theorized 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 the bore 96 and the journal 86 is unexpectedly not only constrained by the thermal expansion ratio of the journal 86 and the 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 plating 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. A suitable gap d may be about 0.220 inches in some examples. In other examples, the gap d may be about 0.220 to 0.200 inches. The width of the thread 88 may also provide any width gap in some examples. In these examples, this width gap may vary from about 0.005 inches to about 0.030 inches.

Although the aforementioned gap d between the inner diameter of the bore 96 and the outer diameter of the journal 86 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 this 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 will be slightly wetted and cause the molten aluminum 22 to move between the inner diameter of the bore 96 and the journal 86 . can be carried by the gap (d) between the outer diameters of 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 the gap d between the molten aluminum 22 and the gap d. It should be understood that they are limited 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, resistance to thermal shock, resistance to wetting by molten metal, resistance to corrosion, and is substantially chemically inert to the molten metal. By way of example only, suitable ceramic materials may include a grade of ceramic known as SiAlON ceramic. As mentioned above, SiAlON ceramics are high-temperature refractory materials that can be used to handle molten aluminum. SiAlON ceramics generally exhibit good 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. The roller sleeve 90 in this example includes ADVANCER® nitride-bonded silicon carbide manufactured by Saint-Gobain Ceramics, although any number of SiAlON grade ceramics may be used.

In exemplary use, a sheet of steel 60 is wound around roll assembly 100 . Friction between the plate 60 and the roll portion 82 of the roll 80 causes the roll 80 to rotate as the plate 60 moves relative to the roll assembly 100 . Rotation of roll 80 causes a corresponding rotation of each journal 86 , which also causes rotation of each roller sleeve 90 through engagement between threads 88 , 98 . Due to the opposing threads 88 of each journal 86 , each roller sleeve 90 remains secured to the respective journal 86 due to rotation of the respective journal 86 . It should be understood that in some instances only a portion of the threads 88 of the journal 86 may contact 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 so that the journal 86 and roller sleeve 90 are not accurately 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 unscrewed from the thread 98 of the roller sleeve 90 . Although some disengagement may occur, the engagement function of the threads 88, 98 may still be maintained because the threads 88, 98 on opposite sides of the journal 86 and roller sleeve 90 are fully engaged. Thus, each journal 86 and each roller sleeve 90 rotate together within a respective 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 view of the teachings herein.

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

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

Bore 196 in this example is generally sized to receive journal 186 . The bore 196 in this example is generally sized to receive the journal 186 , but in this example the bore 196 is also a journal ( ), similar to that described above with respect to the roller sleeve 90 and journal 86 . 186) is sized to provide at least some clearance to the exterior. As with the gap d described above, the gap associated with the roller sleeve 90 and journal 86 is generally due to heat generated within the hot-dip tank 20 of the roller sleeve 190 and/or journal 86. configured to remain throughout the coating procedure despite swelling. As also noted above, the gap associated with 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 journal 186 of the roller sleeve 190 and the corresponding square shape defined by the bore 196 are generally configured such that the journal 186 can transmit rotational motion to the roller sleeve 190 . Although corresponding square shapes are shown herein, it should be understood that many alternative cross-sectional shapes may be used. For example, in some examples journal 186 and bore 196 of roller sleeve 190 define a corresponding triangular, oval, or rectangular shape. In other examples journal 186 and bore 196 of roller sleeve 190 both define a generally cylindrical shape but may be keyed to still allow rotational communication from journal 186 to roller sleeve 190 . Of course, many alternative geometries for 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. A threaded or other mechanical locking arrangement restricts movement of the roller sleeve relative to the journal, allowing the two parts to rotate with the bore.

10 shows an alternative journal 286 that may be readily incorporated into the roll assembly 100 described above. Unlike journal 86 described above, journal 286 in this example is not configured for use with a structure similar to 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 the insert 290 , the journal 286 is machined to include a plurality of channels (not shown) configured to receive the insert 290 . However, the channels at the outer surface of journal 286 are sized to receive only a portion of each insert 290 such that each inactive portion 290 protrudes from the outer surface of journal 286 . Accordingly, it should be understood that each inert 290 is configured to engage the interior of the bearing block 72 to separate the outer surface of the journal 286 from the interior of the bearing block 72 .

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 mating 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 one of ordinary skill in the art in view of the teachings herein.

In some examples, it may be desirable to fully integrate insert 290 into journal 286 . For example, FIG. 11 shows an alternative journal 386 that may be readily incorporated into roll 80 of roll assembly 100 . Instead of including a structure similar to the insert 290 described above as a separate component, the journal 386 itself comprises 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 integrated with roll portion 82 . Accordingly, the journal 386 of this example includes a roller plug 388 configured to fit within a corresponding opening that may be drilled in 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 a ceramic material and 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 view of the teachings herein.

12-17 show an exemplary alternative roll assembly 470 that can be readily incorporated into the coating line described above. Unless stated otherwise herein, it should be understood that roll assembly 470 is substantially similar to roll assembly 100 described above. 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 the roll 480 to facilitate rotation of the roll 480 relative to 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 the hot dip tank 20 .

An exemplary bearing block 472 is best seen in FIG. 13 . As can be seen, the bearing block 472 includes a generally octagonal body 474 . The octagonal shape of the body 474 is generally configured to provide a surface on which a fixture or other structure can be attached to the bearing block 472 for positioning the bearing block 472 within the hot-dip tank 20 . Although body 472 in this example is shown in an octagonal configuration, it should be understood that other suitable structures may be used in other examples, such as square, hexagonal, triangular, circular, and the like. 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 generally defined to be cylindrical. As will be described in more detail below, the receiving bore 476 is configured to receive the roller sleeve 490 and at least a portion of the roll 480 such that the roller sleeve 490 can rotate freely within the bore 476 . .

14 , roll 480 includes roll portion 482 and journal 486 extending from each side of roll portion 482 . Generally, roll portion 482 and journal 486 include steel or other metal alloy. In some variations, roll 480 may be formed of a composite or other suitable material. Roll portion 482 includes a generally elongate cylindrical shape. The cylindrical shape of the roll portion 482 is generally configured to receive the steel plate 60 to allow at least a portion of the steel plate 60 to wrap around at least a portion of the roll portion 482 .

As noted above, each journal 486 extends outwardly from the roll portion 482 . Each journal 486 includes a generally cylindrical shape having an outer diameter less than the outer diameter defined by roll portion 482 . In this embodiment, each journal 486 is such 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 from mechanical locking features. Thus, the substantially smooth outer surface of journal 486 may be more cost effective to manufacture than journals that include locking features. Each journal 486 is sized to be received by a bore 476 of a respective bearing block 472 . However, as will be described in more detail below, each journal 486 generally 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 with respect to the bore 476 .

An exemplary roller sleeve 490 is shown in FIGS. 15-17 . The 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, the roller sleeve 490 includes a generally cylindrical body 492 that defines a cylindrical bore 496 that extends through the roller sleeve 490 . The interior of the bore 496 of this embodiment has mechanical locking such that the inner surface of each bore 496 maintains a substantially circular profile around the interior perimeter of each bore 496 along the length of each bore 496 . and a substantially continuous smooth inner surface free of features. Thus, the smooth inner surface of bore 496 may be more cost effective to manufacture than bores that include locking features. The inner diameter of bore 496 generally corresponds to the outer diameter of each journal 486 as discussed in greater detail below. Accordingly, the roller sleeve 490 is positioned around the journal 486 such that the journal 486 is received within the bore 496 of the roller sleeve 490 . The fit between each journal 486 and the corresponding bore 496 and the weight of each journal 486 is such that even if journal 486 and roller sleeve 490 are not mechanically engaged with the locking mechanism, the roller sleeve ( Allow 490 to rotate generally concurrently with journal 486 . This allows the roller sleeve 490 to rotate within the bearing block 472 relative to the bearing block 472 to prevent wear of the journal 486 .

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

Bearing block 472 and roller sleeve 490 may be made of ceramic. For example, bearing block 472 and roller sleeve 490 may each comprise a refractory ceramic material that is resistant to impact, abrasive and/or thermal shock. Such 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 comprises from about 5% to about 100% silicon carbide and/or alumina.

By way of example only, suitable refractory ceramic materials may include a grade of ceramic known as SiAlON ceramic. SiAlON ceramics are high-temperature refractory materials that can be used to handle molten metal. 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 metal. Such SiAlON ceramics may include CRYSTON CN178 manufactured by Saint-Gobain High-Performance Refractories of Worcester, MA, although many SiAlON grade ceramics may be used.

Other suitable refractory ceramic materials may _{include ceramics having 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, a harder ceramic with a higher amount of SiC, such as about 70% SiC, may be used. In some variations, stainless steel wire needles may be added to the ceramic material, such as, for example, 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 view 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 block 472 and/or roller sleeve 490 may be made 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. Another suitable method for making the components of roll assembly 480 will be apparent to those skilled in the art in view of the teachings herein.

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

Accordingly, the roller sleeve 490 may be positioned between the journal 486 and the bearing block 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 gap d between the inner diameter of the bore 496 and the outer diameter of the journal 486 . This gap d is equal to the thermal expansion ratio of journal 486 such that initially this gap d is substantially eliminated when both journal 486 and roller sleeve 490 approach the temperature of hot-dip tank 20 . It is theorized 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 the bore 496 and the journal 486 is unexpectedly not limited to the thermal expansion ratio of the journal 486 and the 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 tank 20 has been found to be beneficial in improving the durability of the roller sleeve 490 during the coating procedure. Accordingly, it should be understood that at least some gap d may be maintained between the inner diameter of the bore 496 and the outer diameter of the journal 486 throughout the coating procedure in this example.

Although the gap d between the inner diameter of the bore 496 and the outer diameter of the journal 486 described above is described as advantageous for improving the durability of the roller sleeve 490, it is noted that this gap d is also limited in this example. you have to 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 will occur, causing the molten metal 22 to move into the inner diameter of the bore 496 . and the gap d between the outer diameter of 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 the gap d between the molten metal 22 and the gap d. It should be understood that they are restricted to minimize or prevent transport to The gap d between the bore 496 and the journal 486 is between the roller sleeve 490 and the journal 486 as 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 is provided with a minimum gap d sufficient to prevent cracking of the roller sleeve 490 upon thermal expansion of the journal 486 and to prevent transport of molten metal 22 into the gap d and/or Alternatively, it may have a maximum clearance d to prevent slipping between the roller sleeve 490 and the journal 486 . In some examples, a suitable gap d at operating temperature may be between about 0.001 inches and 0.012 inches.

In exemplary use, a sheet of steel 60 is wound around a roll assembly 470 . Friction between plate 60 and roll portion 482 of roll 480 causes roll 480 to rotate as plate 60 moves relative to roll assembly 470 . Rotation of roll 480 causes a corresponding rotation of each journal 486 , which also results in a substantially continuous smooth inner surface of bore 496 of roller sleeve 490 and a substantially continuous smooth inner surface of journal 486 . The engagement between the smooth outer surfaces results in 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 concurrently with journal 486 . Another suitable configuration for roller sleeve 490 and/or roll assembly 470 will be apparent to those skilled in the art in view of the teachings herein.

For example, FIGS. 19-22 show the roller sleeve 490 and the roller sleeve 490 except that the roller sleeve 590 includes a pair of notches 598 extending inwardly from the top and bottom portions of the roller sleeve 590. Another embodiment of a similar roller sleeve 590 is shown. While the illustrated embodiment shows a roller sleeve 590 including two notches 598 in an upper portion and a bottom portion of the roller sleeve 590 , the roller sleeve 590 is approximately arbitrary around the roller sleeve 590 . may include any suitable number of notches 598 positioned at suitable locations in Thus, the roller sleeve 590 may be assembled with the journal 586 as shown in FIG. 23 , such that the roller sleeve 590 is around the journal 586 having a notch 598 at the free end of the journal 586 . is located in The bar 599 may then be inserted into the notch 598 of the roller sleeve 590 along the free end of the roller sleeve 590 . A bar 599 may be secured to the free end of the journal 586 to mechanically engage the journal 586 with the roller sleeve 590 via the bar 599 .

examples

The following examples relate to various non-exclusive ways in which the teachings herein may be combined or applied. It is to be understood that the following examples are not intended to limit the scope of application of claims that may be presented at any time in this application or subsequent applications of 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 other ways. It is also contemplated that certain features mentioned in the examples below may be omitted in some variations. Accordingly, none of the aspects or features recited below should be construed as critical unless otherwise expressly stated later by the inventor or his/her interested successor. If an assertion is made in this application or a subsequent application related to this application that includes additional functionality beyond those mentioned below, such additional functionality 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 ascertain 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 an initial test, a structure similar to the journal 86 described above was tested to establish the journal's measured coefficient of thermal expansion. The journal being tested was prepared as a mock-up part of the step roll to consist of a journal attached to a hub corresponding to the end of the step roll. While the journal was at room temperature (eg about 70°F), measurements of all surfaces such as the journal's outer diameter, thread peak and thread root were acquired. The journal was then heated to a temperature of 1,350°F. Immediately after heating, the same measurements were made while the journal was in the heated state. The values measured at room temperature were compared with those measured with the journal heated. This comparison was used to calculate the coefficient of thermal expansion based on experiments for the journal. Therefore, the coefficient of thermal expansion based on the journal's experiments ^{was calculated to be 9.1 x 10 -6} in/in/°F. Based on this calculation, it has been assumed that the desired gap d between journal 86 and roller sleeve 90 is about 0.020 inches.

Example 2

In a second trial, experimentally based coefficients of thermal expansion and corresponding hypothesized desirable 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 the St. Provided by Gobain Ceramics. The inner diameter of the roller sleeve is tapered and has some burrs. Also, the roller sleeves were slightly not rounded. Nevertheless, the test continued.

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

After machining, the roller sleeve and journal were mated. After mating, little or no gaps were observed in some localized areas around the outer diameter of the journal due to the round nature of the roller sleeve. To improve clearance and provide a loose fit throughout, the roller sleeve was unscrewed from the journal by about ¼ turn. In this configuration, the roller sleeve and journal were subjected to furnace-based heat treatment.

Heat treatment included heating the roller sleeve and journal from 150° F. to 1,150° F. with a time gap. The assembly of roller sleeves and journals was removed from the furnace at 500°F and 900°F to observe gaps. At 500°F, it was observed that there was "still enough clearance" after the assembly was struck with a 4 inch by 4 inch elongate block of wood. At 900°F, no visually detectable gap was observed. In addition, it was observed that the roller sleeve broke and formed noticeable cracks. In this step, it was assumed that chipping and cracking could be avoided by reducing the outer diameter of the journal by 0.030 inches to 0.040 inches.

After completion of the heat treatment, additional chips were observed on the roller sleeve. This test suggested that clearance was necessary to aid in installation and to avoid the possibility of roller sleeve breakage during operation. In addition, it was further hypothesized that the durability of the roller sleeve could be improved by machining the threads of the roller sleeve or journal to engage only one-half the depth of the thread. The thread depth at the time of testing was 0.200". So, applying the assumed thread depth reduction, additional durability of the roller sleeve can be achieved with only 0.100" threads interlocking. Based on this, it is proposed that up to 0.060" of material can 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, a field trial was conducted. A staff roll assembly similar to the step roll assembly 70 described above was prepared for this field trial. Like the staff roll assembly 70, the staff roll assembly includes two journals. However, two journals were prepared so that one journal was configured as a control journal and the other journal was configured as a test journal. The control journal was prepared according to standard practice so that a metal journal-to-bearing block configuration was formed through the control journal. 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 were configured to provide a maximum clearance of 0.220" between the test journal and the corresponding roller sleeve. No size-to-size fit between the journal and the roller sleeve is required during operation at constant temperature. Instead, it was assumed that the force applied to the step roll during operation would cause the threads of one side of the journal to engage the threads of the roller sleeve, i.e. full engagement on one side of the journal and full engagement on the other side of the journal. ½ thread engagement was totally necessary because limited engagement could occur.However, some restriction on clearance is still desirable to support the load provided during operation of the step roll assembly.Also, molten aluminum between journal and roller sleeve. Some restrictions on the clearance were still desirable to prevent this penetration. Therefore, both the test journal and the corresponding roller sleeve were configured to provide a maximum clearance of 0.220 inches. Before the start of the test, some of the roller sleeves were broken. Thus, 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 aluminizing the steel sheet. A total of 583,521 feet of steel sheets were processed by the staff roll assembly in service. When the step roll assembly was removed, damage to the outside of the bearing block was seen. When removing the bearing block from the step roll fixture, the bearing block separates into four separate parts. Upon separation, each fragment cross-section was completely coated with aluminum metal. This coating pattern suggests that the failure of the bearing block occurred during service and not cooling via thermal shock. Large voids were present on the surfaces of the two mating fragments. Therefore, it was determined that the cracking of the bearing block was not related to the use of the roller sleeve and test journal combination.

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

Example 4

Another journal similar to journal 86 described above was prepared. The journal was prepared to provide a clearance of 0.220 inches +0 inches/0.005 inches when joined to a roller sleeve similar to the roller sleeve 90 described above. The threads of the journal were machined to provide a rounded peak to better accommodate the irregular inner diameter shape provided by the roller sleeve. Lateral movement measurements between the journal and the roller sleeve were obtained. This measurement resulted in a lateral travel of 0.020 inches to 0.040 inches, which was considered acceptable from 0.060 inches to 0.155 inches.

Example 5

A roll assembly similar to roll assembly 470 described above was prepared for conducting field trials. Like roll assembly 470, roll assembly includes two journals, each having a roller sleeve similar to roller sleeve 490 described above. In the trial, the roller sleeve was made of ADVANCER® material and the bearing block was made of GemStone® 404A material. Each journal and corresponding roller sleeve were both configured to provide a maximum clearance of 0.040" between the journal and the corresponding roller sleeve at hot dip tank temperature. It was then prepared for use in preheating the roll assembly and aluminizing the steel sheet. Inserted in a molten aluminum bath for 5 days 12 hours and using 1.9 MM feet of steel When removing the staff roll assembly, the journals were found to rotate within their corresponding roller sleeves, indicating that there was too much space between the journal and roller sleeves. indicates that there is a gap.

Example 6

A roll assembly similar to roll assembly 470 described above was prepared for another field trial. Like roll assembly 470, roll assembly includes two journals, each having a roller sleeve similar to roller sleeve 490 described above. In the trial, the roller sleeve was made of ADVANCER® material and the bearing block was made of GemStone® 404A material. Each journal and corresponding roller sleeve was constructed to provide a gap of up to 0.006" between the journal and corresponding roller sleeve at operating temperature. The roll assembly was then preheated and a bath of molten aluminum for use in aluminizing steel sheets. A total of 733,895 feet of steel was processed into a roll assembly in service. When the roll assembly was removed, minimal wear was found in each bearing block: 0.140 inches of wear in block 1 and 0.085 inches of wear in block 2. Also, the wear of each roller sleeve was minimized, with a 0.005 inch diameter removed from sleeve 1 and a 0.024 inch diameter removed from sleeve 2. Each roller sleeve was removed with a slight tap from the hammer to the corresponding journal. There was no evidence of journal rotation in roller sleeve 1 but slight rotation of the journal in 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 for another field trial. Like roll assembly 470, roll assembly includes two journals, each having a roller sleeve similar to roller sleeve 490 described above. In the trial, the roller sleeve was made of ADVANCER® material and the bearing block was made of GemStone® 404A material. Each journal and corresponding roller sleeve were both configured to provide a gap of up to 0.004 inches between the journal and the 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, and 3MM feet of steel was used. The attempt was considered successful.

Example 8

A roll assembly similar to roll assembly 470 described above was prepared for another field trial. Like roll assembly 470, roll assembly includes two journals, each having a roller sleeve similar to roller sleeve 490 described above. In the trial, the roller sleeve was made of ADVANCER® material and the bearing block was made of GemStone® 404A material. Each journal and corresponding roller sleeve were both configured to provide a gap of up to 0.004 inches between the journal and the 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, and 3MM feet of steel was used. When the roll assembly was removed, one of the roller sleeves was in good condition with a diameter loss of about 0.021 inches. This attempt was considered successful.

Example 9

A roll assembly similar to roll assembly 470 described above was prepared for another field trial. Like roll assembly 470, roll assembly includes two journals, each having a roller sleeve similar to roller sleeve 490 described above. In the trial, the roller sleeve was made of ADVANCER® material and the bearing block was made of GemStone® 404A material. Each journal and corresponding roller sleeve were both configured to provide a gap of up to 0.004 inches between the journal and the corresponding roller sleeve at operating temperature. The roll assembly was then preheated in a molten aluminum bath for use in aluminizing the steel sheet for 4 days 23.5 hours, using 2.3 mm feet of steel. The attempt was considered successful. Both roller sleeves were intact and the journal did not rotate within the roller sleeves. When the roll assembly was removed, the wear rate of the roller sleeves was determined to be 0.010 inches per MM foot of strip. Calculated wear rates for the bearing blocks were determined to be between 0.04 inches and 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 about 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 4 hours of soaking time, the roller sleeve was visually inspected to ensure that there were no cracks in the roller sleeve. Immerse 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°F, 1450°F, 1550°F, and up to 1700°F. No cracks were observed in the roller sleeve during the trial. Therefore, it was determined that the thermal expansion between the journal and the 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 at least one journal is substantially cylindrical; (b) a roller sleeve comprising a bore extending through the roller sleeve, the roller sleeve being substantially cylindrical, the roller sleeve 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 the at least one journal are configured to rotate together relative to the bearing block.

Example 13

The roller assembly of Examples 11 or 12, wherein the bore of the roller sleeve is sized to provide a gap fit between an inner surface of the bore and an 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 the molten metal.

Example 15

The roller assembly of Examples 13 or 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 comprises silicon carbide.

Example 18

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

Example 19

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

Example 20

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 two journals projecting from opposite ends of the roll portion, each journal substantially the roller comprising a continuous smooth outer surface; (b) a pair of roller sleeves, each roller sleeve including a bore extending through the roller sleeve configured to receive a corresponding journal therein, the bore of each roller sleeve having a substantially continuous smooth inner surface comprising, the pair of roller sleeves; and (c) a pair of bearing blocks, each bearing block defining an opening therein, the opening of each bearing block configured to receive a corresponding roller sleeve with a corresponding journal disposed within the roller sleeve; and a 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 an inner surface of the bore and an outer surface of a corresponding journal.

Example 22

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

Example 23

The roller assembly of Examples 21 or 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 between about 0.001 inches and 0.012 inches.

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 comprises 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 comprises at least about 5% silicon carbide.

Example 29

The roller assembly of any of Examples 20-28, wherein each roller sleeve comprises 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 positioning a smooth, journal of the roller; positioning the roller sleeve within an opening in a ceramic bearing block; and rotating the journal and roller sleeve together within the bearing block.

While various embodiments of the present 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 present invention. A few of such potential variations have been mentioned, 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 present invention should be considered in light of any claims that may be presented without being limited to the details of structure and operation shown and described in the specification and drawings.

Claims (20)

A roller assembly, wherein the roller assembly is 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 at least one journal being substantially cylindrical;
(b) the roller sleeve including a bore extending through the roller sleeve, the roller sleeve being substantially cylindrical, the roller sleeve 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. According to claim 1,
and the roller sleeve and the at least one journal are configured to rotate together relative to the bearing block. According to claim 1,
and 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. 4. The method of claim 3,
and the gap fit is maintained when the roller assembly is immersed in molten metal. 4. The method of claim 3,
and the gap fit is sized to prevent ingress of molten metal between the roller sleeve and the at least one journal. According to claim 1,
wherein the roller sleeve comprises a ceramic material. 7. The method of claim 6,
wherein the ceramic material comprises silicon carbide. According to claim 1,
wherein the bearing block comprises a ceramic material. 9. The method of claim 8,
wherein the ceramic material comprises silicon carbide. A roller assembly, wherein the roller assembly is configured to be immersed in molten metal, the roller assembly comprising:
(a) a roller comprising a roll portion and two journals projecting from opposite ends of the roll portion, each journal comprising a substantially continuous smooth outer surface;
(b) a pair of roller sleeves, each roller sleeve including a bore extending through the roller sleeve configured to receive a corresponding journal therein, the bore of each roller sleeve having a substantially continuous smooth inner surface comprising: the 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. 11. The method of claim 10,
and 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. 12. The method of claim 11,
and the gap is maintained when the roller assembly is immersed in molten metal. 13. The method of claim 12,
and the gap is sized to prevent ingress of molten metal between the roller sleeve and the corresponding journal. 12. The method of claim 11,
and the gap is between about 0.001 inches and 0.012 inches. 12. The method of claim 11,
wherein each roller sleeve is ceramic. 16. The method of claim 15,
and the ceramic of each roller sleeve comprises at least about 5% silicon carbide. 16. The method of claim 15,
Each bearing block is ceramic. 18. The method of claim 17,
wherein the ceramic of each bearing block comprises at least about 5% silicon carbide. 18. The method of claim 17,
wherein each roller sleeve comprises a greater amount of silicon carbide than each bearing block. 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 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 roller sleeve within an opening in a ceramic bearing block; and
and rotating the journal and roller sleeve together within the bearing block.

Images