JP2649281B2 - Roll bearing in molten metal bath - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is to hold a roll in a molten metal bath such as a sink roll, a support roll, etc., which is used when a steel plate is subjected to metal plating such as zinc plating. In particular, the present invention relates to a bearing whose structure such as a material and / or shape is improved in order to prolong its life.

[Prior art] Conventionally, as a method of performing metal plating or the like on a steel sheet, a steel sheet is immersed in a molten metal bath such as a galvanizing bath, and the steel sheet is turned in a bath through a roll installed in the bath. A method of immersion holding for a required time has been performed.

Conventionally, the roll used in the molten metal bath as described above is made of chromium-based heat-resistant steel or the like, and its bearing is also made of heat-resistant steel. However, the rolls and bearings are severely damaged because they are constantly immersed in a metal bath that is melted at a high temperature of about 450 to 500 ° C. In particular, the conventional bearings have a life of only about 10 days in continuous use. Was something. For this reason, conventionally, it has been necessary to frequently replace a bearing which is very troublesome, and development of a more durable bearing has been desired.

Therefore, attempts have been made to apply a spray treatment to the sliding surface of the above-mentioned conventional metal bearing with the roll shaft, or to use ceramics as the material of the bearing. However, the life of any of the bearings has not been extended so much.

[Problems to be Solved by the Invention] The present invention has been made to solve the problems of such conventionally used bearings, and an object thereof is to provide a bearing of a roll in a molten metal bath having excellent durability. And Specifically, the present invention is to provide a bearing having a very long life which can achieve continuous use without variation for at least 30 days or more, which can not be achieved conventionally, and about 35 to 40 days or more depending on the construction requirements. Aim.

[Means for Solving the Problems] The present inventors have conducted intensive studies in order to solve the above problems, and as a result, the structure of the bearing, that is, the material of the specific member, as one of the following a) to c) It has been found that a bearing having a long life can be obtained by improving the shape and the like, and the present invention has been completed.

a) The material of the sliding portion with the roll shaft is a carbon material having silicon carbide filled in pores and having a Shore hardness of 60 to 120.

b) The material of the sliding portion with the roll shaft is carbon material, and the thickness of the sliding portion gradually increases continuously from the opposite side so that the portion where the load received from the roll shaft is large becomes thick. To do it.

c) The material of the sliding portion with the roll shaft is made of a carbon material, and a backup ring made of a metal material is fixed to the outer periphery of the sliding portion so as to be slidable with each other without being fixed.

Hereinafter, the bearing of the present invention will be described in more detail with reference to the drawings.

FIG. 5 is a schematic side view showing an example of a state in which metal plating is applied to a steel plate. In FIG. 5, 1 is a roll (sink roll), 2 is a molten metal bath, 3 is a hanger, 4 is a steel plate,
Reference numeral 4 'denotes a metal-plated steel sheet, 5 denotes a support roll, and 6 denotes a die.

The roll 1 is suspended and hung by a hanger 3 in a molten metal bath 2 such as a hot dip galvanizing bath. Then, the steel sheet 4 that has exited the annealing furnace (not shown) in the preceding step turns in the molten metal bath 2 via the roll 1 and similarly passes between the support rolls 5 immersed in the molten metal bath 2. After that, the excess metal is squeezed by the die 6. The steel plate 4 'thus subjected to metal plating is sent to the next step (solidification step).

1 and 2 are cross-sectional views (cross-section AA ′ in FIG. 5) showing an example of a state where the roll 1 is held using the bearing of the present invention.

1 and 2, 7 is a roll shaft, 8 is a bearing, 9 is a sliding portion, 10 is a sliding surface, 11 is a backup ring, and other symbols are the same as those in FIG. Show.

As shown in FIGS. 1 and 2, the roll shaft 7 of the roll 1 is suspended and held by a hanger 3 via a bearing 8. The bearing 8 includes at least a hollow member having a sliding portion 9 with the roll shaft 7, that is, a sliding surface 10 with the roll shaft 7.

The present inventors have first found that the durability of the bearing 8 is improved when the material of the sliding portion 9 is a carbon material having a shore hardness of 60 to 120 in which silicon carbide is filled in pores as described in the above a). .

That is, the sliding portion 9 of the bearing 8 of the present invention is made of a carbon material having a shore hardness of 60 to 120 and silicon carbide in the pores. If the Shore hardness is less than the above range, the wear is severe, and if it exceeds the above range, it is extremely difficult to manufacture industrially.

As the carbon material used in the present invention, coke powder, carbon black and the like are kneaded with a binder such as a pitch, and after pressure molding, heated to about 800 to 2800 ° C.
Sintered carbonaceous or graphitic materials are preferred.

Further, as the carbon material filled with silicon carbide in the pores used in the present invention, by impregnating the above-described carbon material with a liquid compound that is converted into silicon carbide by heating, followed by heat treatment at 400 to 2000 ° C. Those obtained are preferred. As the above liquid compound, (1) an organosilicon polymer compound (such as polycarbosilane) containing silicon and carbon as main skeleton components or an organometallic compound (eg, alkoxytintan, alkoxyzirconium, etc.) is added. A polymerized compound, or (2) a curing agent such as a thermally dehydrated inorganic compound (for example, boron hydroxide), a thermosetting resin (for example, phenol resin) and / or the like; A compound to which a filler such as silicon carbide powder is added is exemplified as a preferable example.

The material of the carbon material to be used, the type of the liquid compound, the heat treatment conditions, and the like are appropriately selected so that the shore hardness of the carbon material becomes 60 to 120 after the holes are filled with silicon carbide.

The shape of the sliding portion 9 of the bearing 8 in the present invention may be a hollow member having a hole through which the roll shaft 7 is inserted, and the shape is not particularly limited, but a donut-shaped cross section is generally used. . The thickness of the sliding portion 9 is selected according to the size of the roll shaft 7 so as to withstand the sliding of the roll shaft 7, and is preferably 5 mm or more.

Further, as shown in FIG. 3 (a), the sliding portion 9 is generally concentric with the roll shaft 7 to be inserted and has a constant wall thickness. (B) As shown in the figure, the thickness is varied gradually and continuously, and a portion where the sliding portion 9 receives a large load from the roll shaft 7, preferably a portion where the load is the largest, is made thick and a direction in which no load is applied. It is preferable to have a structure in which the thickness is gradually and continuously reduced. In this case, if the difference (T = t ₁ −t ₂ ) between the maximum thickness (t ₁ ) and the minimum thickness (t ₂ ) of the sliding portion 9 is 5 to 15 mm, the roll shaft 7 slides well. This is preferable because the durability of the sliding portion 9 can be improved.

In the case where the sliding portion 9 has an uneven cross-sectional shape as shown in FIG. 3 (b), the material of the sliding portion 9 is a carbon material having pores filled with silicon carbide as described above. However, if the T value is in the range of 5 to 15 mm, the durability of the bearing 8 using a normal carbon material not filled with silicon carbide is considerably high.

Further, as described above, the bearing 8 of the present invention includes the sliding portion 9.
As shown in FIG. 1, it may be composed of only the sliding portion 9, or as shown in FIG. 2, the outer periphery may be reinforced with a backup ring 11 or the like.

When the backup ring 11 is used, the backup ring 11 is usually fixed to the outer periphery of the sliding portion 9, but in the present invention, the sliding portion 9 and the backup ring 11 are not fixed and can slide with each other. Is preferable because the durability of the bearing 8 is further improved.

As described above, the sliding portion 9 and the backup ring 11
As described above, the material of the sliding portion 9 is preferably a carbon material in which silicon carbide is filled in pores, but a bearing using a normal carbon material not filled with silicon carbide. Even with 8, the durability is considerably high.

The material of the backup ring 11 may be a metal such as stainless steel, but it is preferable that the surface of the bearing 8 is coated with silicon carbide from the viewpoint of improving the durability. This coating can be achieved by applying a liquid compound which is converted into silicon carbide by heating to the surface of the backup ring 11 and then performing a heat treatment to form a coating preferably having a thickness of 10 to 80 μm.

Further, in the bearing 8 of the present invention, if the groove 12 is provided on the sliding surface 10 side of the sliding portion 9 as shown in FIG. 4, it is more effective to improve the durability of the bearing 8. The shape of the hot water groove 12 may be any shape as long as it can remove carbon abrasion powder and sludge and the like in the bath, which have entered the gap between the roll shaft 7 and the sliding portion 9, but as shown in FIG. It is particularly preferable to provide a hot groove 12 in a spiral shape on the sliding surface 10 with the groove.

[Operation] A silicon carbide filled pore having a Shore hardness of 60 to 120.
The carbon material has excellent corrosion resistance and abrasion resistance to molten metal and does not scratch the roll axis. Therefore, a bearing whose sliding portion is made of such a carbon material has excellent durability.

Further, in the roll in the molten metal bath according to the present invention, generally, the load applied to the bearing is always in a fixed direction. Therefore, if the cross-sectional structure of the sliding portion is made thicker at the portion receiving the load of the sliding portion and gradually and continuously reduced in the direction in which no load is applied, the wear volume of the sliding portion is reduced. And the load applied to the sliding portion is dispersed, so that the durability of the bearing is improved.

Furthermore, without fixing the sliding part and the backup ring,
If the contact surfaces are slidably contacted with each other, the contact surfaces also slide when the roll shaft rotates. Therefore, the sliding surface increases, and the frictional force accompanying the rotation of the roll shaft is dispersed, so that the durability of the bearing is improved.

In addition, if the sliding groove is provided with a runner, carbon wear powder, sludge, and the like that have entered the gap between the roll shaft and the bearing are eliminated by the runner, so that the abrasion of the sliding surface is considerably prevented.

EXAMPLES Hereinafter, the present invention will be described more specifically based on Examples and Comparative Examples.

Examples 1 to 13 and Comparative Examples 1 to 5 Using a carbon material (C ₁ , carbonaceous or graphitic) having the physical properties shown in Table ₁ or a carbon material (C ₂ ) having pores filled with silicon carbide. Three sets of sink roll bearings each having the structure shown in Table 1 were produced.

Each bearing is 480 ° C solution zinc (Al content: 0.2 wt%
Below) Installed in bath, 0.25 ~ 2.
3mm thickness x 610-1375mm width steel plate with maximum line speed of 19
Continuous plating was performed at 5 mpm. Table 1 shows the results (continuous service life of each bearing).

The method of filling silicon carbide into the pores of the carbon material (C ₁ ) was as follows. That is, the carbon material (C ₁ ) was impregnated with a liquid compound obtained by adding and mixing 5 parts by weight of boric acid as a curing agent with respect to 100 parts by weight of polycarbosilane, and then heat-treated at 800 ° C.

The silicon carbide was coated on the backup ring by applying the above liquid compound to the surface of the backup ring made of a metal material and then heat-treating it at 800 ° C. to form a 50 μm thick film.

As is clear from Table 1, the bearing of the present invention can achieve continuous use for at least 30 days or more, and about 35 to 40 days or more depending on the constitutional requirements without variation, and has a very long life.

Comparative Example 6 A steel plate was continuously plated in the same manner as in Example 1, except that a bearing obtained by spraying stainless steel was used.

As a result, the stainless steel bearings became worn out in about 15 days and became unusable.

* 1: The bearing consists of only a sliding part as shown in FIG. 1 or a sliding part and a backup ring as shown in FIG.

* 2: Outer diameter: 185mm, shaft insertion hole diameter: 118mm, length: 105mm.

* 3: Outer diameter: 195 mm, inner diameter: 185 mm, length: 115 mm.

* 4: The number of days (lifespan) until three bearings are used continuously, and each bearing becomes unusable due to wear or the like.

* 5: A: The thickness is constant as shown in Fig. 3 (a).

B: As shown in FIG. 3 (b), the thickness is uneven (the difference between the maximum thickness and the minimum thickness is shown in parentheses).

* 6: A gutter provided spirally on the sliding surface of the sliding part as shown in Fig. 4.

* 7: S ₁ … Stainless steel backup ring.

S ₂ ... S ₁ coated with silicon carbide.

* 8: Sprayed stainless steel.

[Effect of the Invention] The bearing of the present invention is a bearing for holding a roll in a molten metal bath used when applying a metal plating such as a zinc plating to a steel plate.
It is extremely durable and can be used continuously for more than 35 days or more depending on the constituent requirements. Therefore, the roller bearing in the molten metal bath of the present invention is extremely useful in industry such as the galvanizing industry.

[Brief description of the drawings]

FIGS. 1 and 2 are cross-sectional views showing a state where the roll is held using the bearing of the present invention. FIGS. 3 (a) and 3 (b) show the bearing of the present invention, respectively. FIG. 4 is a cross-sectional view of the sliding portion, FIG. 4 is a cross-sectional view of the vicinity of the bearing, showing a state where a roll is held using another bearing of the present invention, and FIG. It is an outline side view showing an example of a state. 1: Roll, 7: Roll shaft, 8: Bearing, 9: Sliding part, 10: Sliding surface, 11: Backup ring, 12: Gutter.

Continued on the front page (72) Inventor Yasuhiko Saruwatari 1-1-16-711 Kurihama, Yokosuka City, Kanagawa Prefecture (72) Inventor Shiro Mitsuno 3-8-12 Raw Barley, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture (56) References JP Akira JP-A-3-79746 (JP, A) JP-A-2-153055 (JP, A) JP-A-54-162633 (JP, A) JP-A-57-74978 (JP, A) U) Japanese Utility Model Showa 55-142571 (JP, U)

Claims (8)

(57) [Claims] 1. A bearing having at least a sliding portion with a roll shaft, wherein the sliding portion is made of a carbon material having a shore hardness of 60 to 120 and silicon carbide filled in pores. Roll bearing in molten metal bath. 2. A bearing having at least a sliding portion with a roll shaft, wherein the sliding portion is made of a carbon material, and the sliding portion has a large thickness at a portion where a load received from the roll shaft is large. A bearing for a roll in a molten metal bath characterized in that the wall thickness is gradually and continuously increased from the opposite side. 3. The bearing for a roll in a molten metal bath according to claim 2, wherein the difference between the maximum thickness and the minimum thickness of the sliding portion is 5 to 15 mm. 4. The bearing for a roll in a molten metal bath according to claim 1, wherein a backup ring made of a metal material is fixedly arranged on the outer periphery of the sliding portion. 5. A bearing comprising at least a sliding portion for a roll shaft and a backup ring, wherein the sliding portion is made of a carbon material, the backup ring is made of a metal material,
And a bearing for a roll in a molten metal bath, wherein the backup ring is slidably contacted with each other without being fixed to the outer periphery of the sliding portion. 6. The bearing for a roll in a molten metal bath according to claim 2, wherein the sliding portion is made of a carbon material in which holes are filled with silicon carbide. 7. The backup ring is made of a metal material whose surface is coated with silicon carbide.
Or a roller bearing in a molten metal bath according to item 5. 8. The bearing for a roll in a molten metal bath according to claim 1, wherein a gutter is provided in the sliding portion.