JP2000273614A - Roll for molten glass manufacturing equipment, and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration in the quality of flat glass products caused by the build-up of fused tin and its oxide liable to occur at the surface of a lift-out roll, a lehr roll or the like, which are used for molten glass manufacturing equipment and also to prolong the service life of a film formed on the surface. SOLUTION: The surface of a base material for roll is provided with a hot- melt-splay-coating of two-layer structure prepared by thermal spraying executing, as an undercoat, a cermet having excellent adhesion and heat resistance and consisting of chromium carbide containing Cr3C2 as a principal component and a heat resistant alloy containing two or more metals selected from Co, Ni, and Cr and further forming, as a topcoat, a ZrO2 type ceramic coating on the above undercoat; or is provided with a composite hot-melt-splay-coating of three-layer structure prepared by providing an internal coat of a heat resistance alloy containing two or more metals selected from Co, Ni, Cr, Al, Y, Ta, and Si to the intermediate part between the undercoat and the topcoat.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lift-out roll for pulling a molten glass sheet or the like manufactured by a float method or the like from a molten tin bath and a transport roll for transporting the molten glass sheet to a slow cooling kiln. The present invention relates to a roll for molten glass production equipment and a method for producing the same, which can be applied as a roll for heat-treating a glass product after molding.

[0002]

2. Description of the Related Art Conventionally, in a manufacturing process of a molten sheet glass by a float method or the like, a transport roll such as a lift-out roll for lifting the molten sheet glass from a tin bath or a layer roll for transporting the molten sheet glass to an annealing furnace. Is used. Examples of such transport rolls include (1) transport rolls in which a heat-resistant alloy made of a Co-based alloy or the like is spray-coated on the surface of a roll made of an alloy steel such as Cr-Ni steel (JP-A-4-260629, JP-A-4-260629). (See JP-A-8-175828), (2) a transport roll in which an asbestos-based material is coated on the surface of a roll made of an alloy steel such as Cr-Ni steel;
Transport rolls in which oxide ceramics or a mixture of ceramics and metal is spray-coated on the surface of a roll of alloy steel such as Ni steel (JP-A-4-260622, JP-A-4-26062)
No. 623) has been developed and used.

[0003]

However, none of these prior arts is sufficiently satisfactory as a roll of molten glass transport. For example, the above prior art
In (1), although the effect of maintaining the mechanical strength and the shape of the roll itself in a high-temperature environment is recognized, the molten tin component adhered to the lower surface of the molten sheet glass from the molten tin bath and brought out is gradually reduced by the glass sheet. When cooled, it is oxidized by oxygen present in the atmosphere and becomes hard foreign matter and adheres to the roll surface. Such a fixed substance is generally called a build-up, and is present as a large number of point-like projections on the roll surface, thereby causing a surface scratch on a glass product passing on the roll. Also,
The prior art (2) has problems to be solved, such as strength deterioration at around 700 ° C. and environmental pollution of asbestos itself. And
In the above prior art (3), although the above-mentioned drawback that the molten tin component is fixed as an oxide and fixed can be prevented, the thermal conductivity of the base metal roll is large, so that the molten sheet glass undergoes excessive cooling history, There has often been the problem of adversely affecting glass quality. Moreover, this prior art (3)
Since the thermal expansion coefficient of the ceramic material, which is the coating layer, is smaller than the thermal expansion coefficient of the base metal, the spalling resistance (spatter resistance) against sudden changes in the roll surface temperature, such as when changing rolls, is observed. (Removability), and fine cracks are generated, resulting in a remarkable reduction in the service life.

[0004] As described above, the prior art is based on the problem that the number of defective glass products increases due to the molten tin and its oxides attached to the lower surface of the molten glass from the molten tin bath and the spalling resistance of the film. There have been various problems such as shortening of the use period due to the decrease and deterioration of the glass quality due to the excessive cooling rate of the film. Therefore, in recent years, the roll body of such a roll is formed of fused silica, and a transport roll or the like having a metal shaft mounted thereon has been put to practical use, and improvement in mechanical properties under a high temperature environment has been recognized. . However, such a transport roll has room for improvement in build-up resistance, and is insufficient in surface function and practicality as a roll for producing high-quality glass. Insufficient ability as a roll.

Therefore, the present invention has been made to solve the above-mentioned problems of the prior art, and has as its main object to obtain a roll having excellent surface characteristics. It is another object of the present invention to provide a roll having excellent build-up resistance, and having a large film adhesion and excellent durability.

[0006]

In order to achieve the above object, the present invention employs the following technical means.
That is, on the surface of the roll substrate in contact with the molten glass, a composite thermal spray coating consisting of two layers, an undercoat made of a chromium carbide cermet thermal spray coating and a top coat made of a ZrO ₂ ceramic spray coating applied thereon, , A roll for a molten glass manufacturing facility.

Further, the present invention provides an undercoat made of a chromium carbide-based cermet sprayed coating on a surface of a roll substrate in contact with the molten glass, and Co, Ni, Cr,
An internal coat consisting of a thermal sprayed coating of a heat-resistant alloy consisting of two or more metals selected from Al, Y, Ta and Si;
A roll for molten glass production equipment, characterized in that a composite sprayed coating composed of three layers of a ZrO ₂ ceramic sprayed coating and a top coat formed thereon is further formed thereon.

In the present invention, the undercoat chromium carbide cermet contains 45 to 95 wt% of one or more chromium carbides selected from Cr ₃ C _2, Cr ₇ C ₃ and C ₂₃ C ₆ , and Co, Ni
And 5 to 55 wt% of a heat-resistant alloy composed of two or more metals selected from Cr and Cr.

In the present invention, the top coat is a ZrO ₂ -based ceramic containing 5 to 40% by weight of at least one crystal stabilizing component selected from Y ₂ O _3, CaO, MgO, CeO ₂ , SiO _{2 and the} like. It is.

The roll according to the present invention has a chromium carbide-based cermet undercoat having a thickness of 30 to 300 μm on the surface of a steel or nonmetallic roll base material by a plasma spraying method or a high-speed flame spraying method. Then, a top coat of ZrO ₂ ceramics is applied on the undercoat by any one of the above-mentioned thermal spraying methods.
It can be manufactured by forming a composite sprayed coating having a thickness of 0 μm.

In another manufacturing method according to the present invention, an undercoat of a chromium carbide-based cermet is formed on a steel or nonmetallic roll base material by a plasma spraying method or a high-speed flame spraying method. A heat-resistant alloy composed of at least two metals selected from Co, Ni, Cr, Al, Y, Ta, and Si on the undercoat by any of the above thermal spraying methods. An internal coat of 30 to 300 μm in thickness is formed, and then a ZrO ₂ ceramic is formed to a thickness of 50 to 500 μm as a top coat of the uppermost layer by any of the above thermal spraying methods. A method for producing a roll for molten glass production equipment, which comprises forming a composite thermal spray coating.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The details of a roll for a molten glass manufacturing facility according to the present invention (hereinafter simply referred to as a "conveying roll") and a manufacturing method thereof will be described together with a manufacturing process. (1) Construction of undercoat with chromium carbide cermet material Metal or non-metallic, so-called, the surface of the transfer roll substrate in contact with the molten glass, after degreasing and cleaning,
Roughening treatment is performed by spraying Al ₂ O ₃ particles, and then Cr ₃ C by plasma spraying or high-speed flame spraying.
Apply a chromium carbide cermet material containing ₂ as a main component as an undercoat to a thickness of 30 to 300 μm.
The role of the undercoat is to ensure good adhesion between the roll base material and the chromium carbide sprayed coating, and to secure bonding strength with the ZrO ₂ ceramic sprayed coating formed thereon. That is, the adhesion of the chromium carbide cermet sprayed material to the roll base material is higher than that of the conventional heat-resistant alloy coating (Ni-Cr, Ni-Al, MCrAlX).
It is much larger and also exhibits excellent adhesion to heat-resistant alloys and thermal sprayed ZrO ₂ ceramics applied on this chromium carbide cermet undercoat. Therefore, as long as such an undercoat is used, the undercoat does not peel off from the roll substrate under ordinary processing conditions such as conveyance of molten glass. In addition, a chromium carbide cermet containing Cr ₃ C ₂ as a main component (hereinafter simply referred to as “Cr ₃ C ₂ cermet”) is an undercoat because of its good heat resistance, Can be maintained for a long time.

As such a Cr ₃ C ₂ cermet spray material, those having the following chemical components are used. That is,
The cermet sprayed material according to the present invention is mainly composed of Cr ₃ C ₂
45 to 95 wt% of chromium carbide consisting of a heat-resistant alloy containing two or more metals selected from Co, Ni, and Cr as a metal component to be added as a binder in a ratio of 5 to 55 wt%. It is desirable to use a sprayed material powder obtained by sintering and crushing and sizing these mixtures to adjust the particle diameter to a range of 5 to 80 μm. Note that the commercially available Cr ₃ C ₂ cermet spraying material, in addition to the Cr ₃ C _2, a small amount of Cr ₂₃ C _6, Cr ₇ C
₃ may be included, but such a material can also be used as the thermal spraying material for the undercoat of the present invention, and is not limited to a strict Cr ₃ C ₂ compound.

The thickness of the undercoat is 30 to 300 μm.
The range of m is good, and if it is thinner than 30 μm, the uniformity of the sprayed coating is inferior. On the other hand, if it is thicker than 300 μm, no remarkable improvement in its function and effect can be expected. The undercoat of Cr ₃ C ₂ cermet can be formed not only on a steel roll base material but also on a nonmetallic roll such as a silicon oxide roll base material. This is due to the film forming ability peculiar to the thermal spraying method, and the good adhesion is not limited to the steel roll base material alone.

(2) Internal coat using heat-resistant alloy
Formation of (Intermediate Layer) This internal coat is applied on Cr ₃ C ₂ cermet undercoat if necessary,
A heat-resistant alloy composed of two or more metals selected from Co, Ni, Cr, Al, Y, Ta and Si is formed to a thickness of 30 to 300 μm by a plasma spraying method or a high-speed flame spraying method. On this internal coat, a ZrO ₂ -based ceramic top coat described later is further applied to form a composite sprayed coating having a three-layer structure. The internal coat, which is an intermediate layer made of this heat-resistant alloy, exhibits good adhesion to both the undercoat and the top coat, and is used as a roll for conveying molten glass.
This layer plays a role in preventing the undercoat from being oxidized and consumed by air (oxygen) entering into the inside through minute cracks and pores existing in the ZrO ₂ ceramic top coat.

A more important role of the internal coat is to form a top coat or undercoat by forming the internal coat when a roll having a thick sprayed coating is required depending on operating conditions. It is an object of the present invention to obtain a suitable molten glass transport roll without impairing its performance.

In the present invention, the above Cr ₃ C ₂ cermet undercoat, an internal coat of a heat-resistant alloy and Zr
The thermal expansion coefficient of each of the O ₂ -based ceramic top coats is similar to that of a steel base material (10 to 12 × 10 ^-6 / K), and the generation of stress due to thermal changes is small.
Excellent thermal shock resistance.

(3) Formation of Top Coat of ZrO ₂ Ceramics This top coat is formed directly on the above-mentioned Cr ₃ C ₂ cermet undercoat or indirectly through a heat-resistant alloy internal coat. It is formed on the base material.
In this process, a ZrO ₂ ceramic sprayed material powder is sprayed on a base material to a thickness of 50 to 500 μm by a plasma spraying method or a high-speed flame spraying method. In general, ZrO ₂ ceramics have excellent heat resistance, do not react with molten tin, can be easily peeled off even if molten tin adheres, and have an appropriate hardness.
(Vickers hardness 700 to 850), so it exhibits good wear resistance. ZrO ₂ ceramics used in the present invention include Y ₂ O _3, CaO, MgO, CeO ₂ and SiO ₂
It is preferable to contain 5 to 40% by weight of a crystal stabilizing component composed of one or more oxides selected from the above. It inferior and less than 5 wt% in spalling resistance, whereas, in addition to the film is more than 40 wt% is easily injured by softening, and 5 to 40 wt% because the high temperature properties of the ZrO ₂ is not appropriate reduced did.

[0019]

EXAMPLES (1) Example 1 In this example, a stainless steel (SUS410) test piece having a width of 50 mm, a length of 100 mm and a thickness of 5 mm was used as a base material, and a plasma spraying method and a high-speed flame were applied to the surface thereof. After forming various alloys, oxide ceramics, and chromium carbide cermets by the thermal spraying method, the adhesion and thermal shock characteristics of the obtained thermal sprayed coatings were examined. Table 1 summarizes the test results. As shown in Table 1, Al ₂ O ₃ , C
The r ₂ O ₃ film (Nos. 1 and 2) not only had low adhesion but also easily peeled off by repeated heating and cooling. Further, although the WC-12Co film (Nos. 5 and 6) has strong adhesion, the film was significantly oxidized and consumed due to poor high-temperature oxidation resistance. In this regard, the Cr ₃ C ₂ cermet sprayed coating (Nos. 7 and 8) that meets the conditions of the present invention has good adhesion to the substrate,
Excellent performance was exhibited in both thermal shock resistance, and the same tendency was observed in the case where the ZrO ₂ -based ceramic as the top coat was formed by thermal spraying (Nos. 9 to 12).

In addition, the adhesion test of the thermal sprayed film was performed according to JI
The test was performed in accordance with the method for testing the adhesion of ceramic sprayed coatings specified in SH8666. However, the coatings of test pieces Nos. 6 to 8 showed strong adhesion and did not peel off easily. (Epoxy resin) It evaluated by the load at the time of peeling from the interface.

[0021]

[Table 1]

(2) Example 2 In this example, the adhesion of molten tin in contact with the surface of the ZrO ₂ -based ceramic top coat was experimentally investigated. A test film was produced in the same manner as in Example 1, and tin heated and melted at 700 ° C. was dropped, and solidification and adhesion, mechanical forced removal, and re-dropping were repeated and evaluated.
Table 2 shows the test results at this time. In the first drop test, regardless of the type of thermal spray coating, the molten tin has poor wettability and can be easily peeled off after solidification. However, as the number of drops increases, the carbide cermet-based coating
In (Nos. 5 to 7), it was confirmed that peeling of the dropped tin after solidification became difficult, and that the film surface after peeling was rough. In contrast, oxide ceramic coatings
(Nos. 1 to 4) showed that the solidified molten tin could be easily peeled off even after the dropping was repeated 5 times, and the surface after peeling was smooth. The Al ₂ O ₃ (No. 4) film was excluded from the applicable examples of the present invention because the results of the thermal shock test performed in Example 1 were not sufficient.

[0023]

[Table 2]

(3) Embodiment 3 In this embodiment, the effect of applying the composite sprayed coating of the present invention to a roll for conveying molten glass will be described.
The surface of a steel roll having a diameter of 192 mm and a surface length of 3718 mm was degreased and blasted, and then Cr ₃ C ₂ -20 wt% Ni-5
Cermet of wt% Cr is sprayed by high-speed flame spraying to 150
8 μm Y ₂ O ₃ .ZrO ₂ was formed thereon to a thickness of 350 μm by plasma spraying. Thereafter, the surface of _{8wt% Y 2 O 3 · ZrO} 2 sprayed coating (top coat) and cylindrical grinding using a synthetic diamond grindstone, coating thickness
Finished to 250 μm ± 50 μm, arithmetic average roughness Ra ≦ 3 μm. In addition, using rolls of the same dimensions, Cr ₃ C ₂ -20wt%
Ni-5wt% Cr undercoat 100μm on top of 25Cr-10
Ni-7Al-5Ta-1Y - a heat-resistant alloy of the remaining Co (wt%) as the internal layer, formed by plasma spraying, further on the uppermost layer portion, plasma 24wt% MgO · ZrO ₂ with a thickness of 300 [mu] m A roll was formed by spraying to form a top coat, and the surface of the top coat was ground and finished.

When each of the rolls manufactured in this manner was applied as a lift-out roll and a rare roll used in a molten glass production process, both rolls had very little build-up of molten tin and its oxides, and were high quality sheet glass. Could be maintained for a long time.

The present invention is not limited to the above-described transport roll for transporting the molten glass sheet and the method of manufacturing the same, but can also be applied to a transport roll widely used for transporting a high-temperature transport object. The use and usage are not limited.

[0027]

As described in detail above, according to the present invention,
A composite coating consisting of a chromium carbide cermet undercoat and a ZrO ₂ ceramic spray coating applied directly or indirectly on it has a large adhesion to the substrate and a high thermal shock resistance Excellent build-up phenomena of molten tin and its oxides,
High quality sheet glass can be stably manufactured for a long period of time. Therefore, the frequency of replacing the rolls is reduced, the productivity is improved, and a great effect can be expected to reduce the product cost.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hiroyuki Kitaaki 4-13-4 Fukae Kitamachi, Higashinada-ku, Kobe City, Hyogo Prefecture F-term (reference) 4K031 AA02 AA04 AA08 AB03 AB04 AB08 AB09 CB21 CB27 CB26 CB27 CB32 CB42 CB45 DA01 DA04

Claims (8)

[Claims] 1. A composite comprising two layers: an undercoat made of a chromium carbide cermet sprayed coating and a topcoat made of a ZrO ₂ ceramic sprayed coating applied on the surface of a roll base material in contact with the molten glass. A roll for a molten glass manufacturing facility, wherein a sprayed coating is formed. 2. An undercoat consisting of a chromium carbide-based cermet sprayed coating on the surface of a roll substrate in contact with the molten glass, and selected from Co, Ni, Cr, Al, Y, Ta, and Si to be applied thereon. A composite spray coating consisting of three layers was formed: an internal coat consisting of a sprayed coating of a heat-resistant alloy consisting of two or more metals, and a top coat consisting of a ZrO ₂ ceramic sprayed coating applied thereon. A roll for molten glass production equipment, characterized by the above. 3. The undercoat chromium carbide cermet comprises 45 to 95 wt% of one or more chromium carbides selected from Cr ₃ C _2, Cr ₇ C ₃ and C ₂₃ C ₆ , Co, Ni and Cr. 3. The roll for a molten glass production facility according to claim 1, wherein the roll contains a heat-resistant alloy composed of at least two metals selected from the group consisting of 5 to 55 wt%. 4. The top coat according to claim 1, wherein the top coat is Y ₂ O _3, CaO, MgO,
3. The roll for a molten glass production facility according to claim 1, wherein the roll is a ZrO ₂ -based ceramic containing 5 to 40 wt% of one or more crystal stabilizing components selected from CeO ₂ , SiO _{2 and the} like. 5. A chromium carbide based cermet undercoat is applied to the surface of a steel or non-metallic roll base material by a plasma spraying method or a high-speed flame spraying method.
A thickness of 0 μm, and then a top coat of ZrO ₂ based ceramic is formed on the undercoat by any of the above thermal spraying methods to a thickness of 50 to 500 μm,
A method for producing a roll for molten glass production equipment, comprising forming a composite thermal spray coating. 6. A chromium carbide based cermet undercoat is applied to the surface of a steel or nonmetallic roll base material by a plasma spraying method or a high-speed flame spraying method.
0 μm thickness, and then the Co, Ni, Cr, A
An internal coat of a heat-resistant alloy composed of two or more metals selected from l, Y, Ta and Si is formed to a thickness of 30 to 300 μm, and then the uppermost layer is formed by any of the above thermal spraying methods. 50 top ZrO ₂ ceramics as top coat
A method for producing a roll for molten glass production equipment, comprising forming a composite thermal spray coating by forming the composite thermal spray coating to a thickness of about 500 μm. 7. The undercoat chromium carbide cermet comprises 45 to 95 wt% of one or more chromium carbides selected from Cr ₃ C _2, Cr ₇ C ₃ and C ₂₃ C ₆ , Co, Ni and Cr. 7. The method according to claim 5, wherein the heat-resistant alloy comprises two or more metals selected from the group consisting of 5 to 55 wt%. 8. The top coat according to claim 1, wherein the top coat is Y ₂ O _3, CaO, MgO,
The method for producing a roll for a molten glass production facility according to claim 5 or 6, which is a ZrO ₂ -based ceramic containing 5 to 40% by weight of one or more crystal stabilizing components selected from CeO ₂ , SiO _{2 and the} like.