JP5316418B2 - Roll for conveying float plate glass, method for producing the same, and method for producing float plate glass using the same - Google Patents

Description

  The present invention relates to a roll for conveying a float plate glass, a method for producing the roll, and a method for producing a float plate glass using the roll.

In the float process, plate glass (glass ribbon) formed by a float bath is conveyed to a slow cooling step by a float plate glass conveyance roll, and gradually cooled while being conveyed.
As such a float plate glass conveyance roll, conventionally, a roll having a ceramic film, a metal film, or a mixed film of ceramic and metal on the surface of the roll body has been proposed.

  In Patent Document 1, a ceramic sprayed coating is laminated and formed on the surface of a metal base material of a roll body as an undercoat with a metal thermal spray coating having an intermediate thermal expansion coefficient between the base metal and the ceramic. A roll for producing float glass is described.

  In Patent Document 2, Cr: 10 to 40%, Al: 2 to 20%, Ti: 2 to 20%, Y: 0.1 to 2%, and the balance substantially on the surface of the metal base material of the roll body. A float glass manufacturing roll is described in which a thermal spray coating of a cobalt-based alloy made of Co is formed.

  In Patent Document 3, a thermal spray coating having a uniform mixed composition of ceramic and metal having a ceramic / metal ratio of 60/40 (weight ratio) or more is formed on the surface of the metal substrate of the roll body. A roll for producing float glass is described.

  The rolls described in Patent Documents 1 to 3 have extremely stable corrosion resistance against molten tin adhering to the glass ribbon, and there is almost no adhesion of tin on the surface, and the surface is smooth and beautiful over a long period of time. It is described that maintaining the state and improving its useful life can provide various effects such as a significant reduction in roll maintenance, an improvement in line productivity, and a high stabilization of glass quality.

JP-A-4-260623 JP-A-8-175828 JP-A-4-260622

  However, when using the conventional rolls described in Patent Documents 1 to 3, etc., the cullet (glass fragments) of the plate glass that is broken during the slow cooling in the slow cooling step causes burrs and scratches on the surface of the roll body, or In some cases, the surface of the body portion was stabbed, and as a result, the float plate glass was scratched by the roll. In particular, in the case of a glass substrate for display, since high-quality glass without scratches or the like is required, the generation of scratches by the roll has a great influence on the yield.

  In order to solve the above-mentioned problems, the present inventor has intensively studied and a float sheet glass transporting roll having a specific alloy film in which specific ceramic particles are dispersed solves the above problems. As a result, the present invention has been completed.

The present invention includes the following (1) to (8).
(1) A float plate glass transporting roll having a coating on at least a portion of the surface of the roll body contacting the glass, wherein the coating is a carbide or boron of at least one element selected from the group consisting of Va group and VIa group A float plate glass transporting roll, wherein the ceramic particles containing a compound are dispersed in an alloy containing Co and Cr.
(2) The alloy contains 50% or more of Co, 15% or more of Cr, and 80% or more in total of Co and Cr in terms of mass percentage, and the ceramic particles are expressed in terms of mass percentage, including group Va and The float sheet glass carrying roll according to (1) above, containing 70% or more of a carbide or boride of at least one element selected from the group consisting of Group VIa.
(3) The float glass transport roll according to (1) or (2), wherein the coating includes 2 to 30% of the ceramic particles in terms of mass percentage.
(4) The float glass transport roll according to (1) or (2), wherein the coating includes 40 to 90% of the ceramic particles in terms of mass percentage.
(5) The float glass transport roll according to any one of (1) to (4), wherein the ceramic particles are made of tungsten carbide and / or molybdenum carbide.
(6) The roll for glass sheet conveyance according to any one of (1) to (5), wherein the roll body portion has a flange and the coating is provided at least on a portion of the surface of the flange that contacts the glass.
(7) A method for producing a float plate glass, comprising a step of slowly cooling a float plate glass at 600 ° C. or lower while transporting it using the float plate glass transport roll according to any one of (1) to (6) above.
(8) A step of forming a film by HVOF spraying on at least a portion of the surface of the roll body that is in contact with the glass, to obtain the float sheet glass transport roll according to any one of (1) to (6) above. A method for producing a roll for conveying float plate glass.

  If the roll for transporting the float plate glass of the present invention is used in the slow cooling step, even if the plate glass is broken during the slow cooling, the broken glass cullet (glass fragments) may cause burrs and scratches on the roll surface, It is prevented that the surface of the roll is damaged by being stuck in the surface of the roll. Therefore, it is prevented that the sheet glass is scratched due to a defect on the roll surface, and stable glass quality can be ensured. It is particularly effective for the production of glass for display substrates.

FIG. 1 is a schematic side view of a preferred embodiment of the roll of the present invention. FIG. 2 is a schematic cross-sectional view of a preferred embodiment of the roll of the present invention. FIG. 3 is a schematic diagram for explaining an oxidation resistance / sulfuration resistance evaluation test. FIG. 4 is a schematic diagram for explaining a cullet sticking / adhesion evaluation test. FIG. 5 is a schematic diagram for explaining a friction property-glass scratching property evaluation test for glass. FIG. 6 is a graph showing the number of cullets per unit area in a cullet sticking / adhesion evaluation test. FIG. 7 is a graph showing measurement results of Vickers hardness. FIG. 8 is a graph showing the average friction coefficient measurement results.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Roll body part 12 Collar 13 Coating 15 Shaft 16 Tubular furnace 17 Porous brick 18 Test piece 19 Gas 21 units 23 Plate made of alumina 25 Calette 27 Thermal spray coating 29 Base material 31 Presser 40 Wire 42 Holder 44 Test piece 45 Coating surface 46 Alumina plate 48 Non-alkali glass plate

The present invention will be described in detail.
The present invention is a roll for conveying a float plate glass having a coating on at least a part of the surface of a roll body, wherein the coating is a carbide or boride of at least one element selected from the group consisting of Va group and VIa group This is a roll for conveying a float plate glass, which is a film in which ceramic particles containing are dispersed in an alloy containing Co and Cr.
Hereinafter, such a roll for conveying a float sheet glass is also referred to as “roll of the present invention”.

First, the coating film of the roll of the present invention will be described.
In the roll of the present invention, the coating film is a coating film in which specific ceramic particles are dispersed in an alloy containing Co and Cr (hereinafter also referred to as “Co—Cr alloy”).

In the Co—Cr alloy, the content of Co and Cr is not particularly limited, but in terms of mass percentage, it may contain 50% or more of Co and 15% or more of Cr, and may contain 80% or more of Co and Cr in total. (Hereinafter, simply “%” means mass percentage display (mass%) unless otherwise specified). This is because high corrosion resistance can be maintained, and adhesion with the base material is enhanced, so that peeling of the film can be suppressed.
Here, the total of Co and Cr is more preferably 85% or more, and further preferably 90% or more.
Further, Co is more preferably 60% or more, and further preferably 65% or more.
Further, Cr is more preferably 20% or more, and further preferably 25% or more.

  The remaining components other than Co and Cr in the Co—Cr alloy are not particularly limited, but may be Fe, Ti, Ni, for example.

  In the roll of the present invention, the coating is a coating in which specific ceramic particles described below are dispersed in such a Co—Cr alloy.

The ceramic particles include a carbide or boride of at least one element selected from the group consisting of Va group and VIa group. That is, vanadium carbide, niobium carbide, tantalum carbide, dubnium carbide, chromium carbide, molybdenum carbide, tungsten carbide (tungsten carbide, etc.), carbonized carbide, vanadium boride, niobium boride, tantalum boride, dobnium boride, chromium boride Ceramic particles containing at least one selected from the group consisting of molybdenum boride, tungsten boride, and sea bogium boride. Since such ceramic particles are firmly bonded to the Co—Cr alloy and the coating properties such as hardness and sinterability are improved, the broken glass cullet may cause burrs and scratches on the surface of the roll body. Further, it is less likely to pierce the surface of the roll body.
Among these, tungsten carbide and / or molybdenum carbide are preferable. Examples of tungsten carbide include WC and W ₂ C.

  The content of carbide or boride of at least one element selected from the group consisting of Group Va and Group VIa in the ceramic particles is preferably 70% or more, more preferably 85% or more, and 95%. More preferably, it is more preferable that it is substantially 100%, that is, other than unavoidable impurities.

  The remaining components other than carbide or boride of at least one element selected from the group consisting of Group Va and Group VIa in the ceramic particles are not particularly limited. For example, Co and / or inevitable impurities, and their C, O And at least one compound selected from the group consisting of B and B.

  The particle size of the ceramic particles in the coating is not particularly limited, but the average particle size is preferably 0.2 to 20 μm, and more preferably 0.5 to 10 μm.

  It is preferable that the ceramic particles are uniformly dispersed in the coating. This is because the strength is further increased.

  In the roll of the present invention, the coating preferably contains 2 to 90% of the ceramic particles in the Co—Cr alloy. This content is more preferably 2 to 30% or 40 to 90%, more preferably 3 to 15% or 60 to 90%, and further preferably 4 to 10% or 80 to 88%. preferable. When it is 2 to 30%, the surface smoothness and the peel resistance are excellent, and it is suitable when the surface smoothness is particularly required for a glass product. When it is 40 to 90%, the wear resistance is excellent, and it is suitable when the durability of the coating is particularly required.

  Among such coatings, ceramic particles having an average particle size of 0.5 to 10 μm made of tungsten carbide and / or molybdenum carbide, preferably tungsten carbide substantially, that is, other than inevitable impurities, are included. 4-10%, the Co—Cr alloy is substantially composed of Co and Cr, the Co content in the Co—Cr alloy is 65 to 75%, and the ceramic particles and the Co—Cr alloy The coating is preferably a dispersion strengthened alloy (such a coating is hereinafter also referred to as “coating α”).

Although the thickness of the film in the roll of the present invention is not particularly limited, it is preferably 0.05 to 1 mm, and more preferably 0.1 to 0.5 mm. This is because if the film is too thin, the coating properties cannot be sufficiently exhibited, and if it is too thick, the adhesion is lowered.
The thickness of the coating means a value calculated from the difference by measuring the thickness of the substrate before spraying and the thickness after spraying / polishing using a micrometer or a caliper. .

  Moreover, although the film in the roll of this invention can be formed by the method mentioned later, it is preferable that it was formed on the surface of the roll trunk | drum by the HVOF thermal spraying method (high-speed flame spraying method). More preferably, the coating contains 2 to 30% or 40 to 90% of the ceramic particles in a Co—Cr alloy and is formed by HVOF spraying. Further, it is more preferable that the coating film is the above-described coating film α and is formed by the HVOF spraying method.

The roll of the present invention has such a coating on at least a portion of the surface of the roll body that is in contact with the glass.
It is preferable that the roll of this invention has the said film in all the parts which contact the plate glass of the surface of a roll trunk | drum. When the roll of the present invention has a flange in the roll body as described below, the flange comes into contact with the plate glass, and therefore it is preferable to have a coating on the surface of the flange.

Next, parts other than the film in the roll of the present invention will be described.
Parts other than the said film in the roll of this invention are not specifically limited, For example, you may be the same as that of the roll for the conventional float plate glass conveyance. The size, material, shape and the like are not particularly limited, and may be the same as a conventional one such as stainless steel. For example, the shaft may be attached to a roll body portion that is a cylindrical body made of alloy steel such as stainless steel, but it is preferable that the surface of the roll body portion of the cylindrical body has a flange. This is because by reducing the number of contact points, it is possible to reduce the generation source of scratches and to obtain effects such as stress relaxation by reducing heat absorption from the glass.
The preferred embodiment of the roll of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic side view of a roll for conveying a float sheet glass having a flange on the surface of a roll body, and FIG. 2 is a schematic cross-sectional view thereof.
1 and 2, 11 is a roll body portion that is a metal substrate, 12 is a flange on the surface of the roll body portion 11, 13 is the coating formed on the surface of the surface of the flange 12 that is in contact with the float plate glass, 15 is A shaft attached to the roll body 11.

The length of each part, the number of brims, etc. are not specifically limited. For example, the length L1 in the longitudinal direction (axial direction) of the roll body 11 is 4000 to 6000 mm, the diameter L2 of the cross section in the direction perpendicular to the longitudinal direction is 200 to 400 mm, and the height from the surface of the roll body 11 of the flange 12 is high. The length L3 is 4 to 10 mm, the width L4 of the flange 12 in a direction parallel to the longitudinal direction of the roll body 11 is 20 to 60 mm, and the pitch L5 of the flange 12 is 100 to 300 mm.
Here, L3 is preferably 5 to 7 mm. L4 is preferably 30 to 50 mm. L5 is preferably 150 to 250 mm. This is because even if the sheet glass to be transported is thin, there is little deflection of the sheet glass between the collars, and the formation of scratches on the sheet glass due to contact with the collars can be suppressed.

  1 and 2 exemplify those in which the shaft 15 is attached to the cylindrical roll body 11, the roll body and the shaft may be integrally cast. Further, the flange and the roll body may be integrally cast.

Next, the manufacturing method of the roll of this invention is demonstrated.
The manufacturing method of the roll of this invention is not specifically limited. For example, a cylindrical body obtained by machining a centrifugal cast pipe is used as a body portion, and when it has a flange, the flange is welded to the surface thereof. And after forming a film by flame spraying (such as HVOF), explosion spraying, arc spraying, plasma spraying, and line explosion spraying at least on the surface in contact with the glass, the surface shape of the coating is adjusted by mechanical polishing or the like as necessary. . Then, the shaft is inserted from the opening at the end in the longitudinal direction of the cylindrical body and attached.

Here, the body portion may be formed by other methods as long as it is a cylindrical body.
Moreover, the material of the collar may be the same as that of the body portion or may be different.
Further, the manufacturing method and material of the shaft are not particularly limited. It may be of a conventionally known material formed by a conventionally known method.

  Thus, the roll of this invention can be manufactured.

  According to the method for producing a float plate glass comprising the step of gradually cooling while carrying the roll of the present invention for carrying a float plate glass of 600 ° C. or lower, a float plate glass having very few scratches can be obtained. Therefore, it is preferable. Here, the float plate glass is more preferably 500 ° C. or less, and further preferably 430 ° C. or less. This is because a plate glass with less scratches can be obtained. Although the roll of this invention can be used also by conveyance at normal temperature, it is preferable to use it for conveyance of 150 degreeC or more float plate glass which becomes difficult to use a resin roll.

Such a method for producing a float plate glass may be the same as the conventional method for producing a float plate glass except that the roll of the present invention is used to convey float plate glass at 600 ° C. or lower.
For example, after supplying a glass raw material to a melting furnace set at about 1600 ° C. to obtain molten glass, the molten glass is poured into a float bath filled with molten tin to form a plate glass, and discharged from the float bath. The manufacturing method which cools slowly, conveying the plate glass supplied to 1 by the roll of this invention is mentioned. The temperature of the plate glass in the vicinity of the inlet of the slow cooling furnace is usually about 700 ° C. You may convey plate glass using the roll of this invention only in the area | region where the temperature of plate glass will be 600 degrees C or less. It is preferable to use a roll having the above-described brim as the roll of the present invention.

  The type, size, thickness and the like of the plate glass to which the method for producing a float plate glass using the roll of the present invention can be applied are not particularly limited, but the thickness is 0.3 to 3 mm, preferably 0.8. It can be suitably applied to produce an alkali-free glass plate for a display having a thickness of 3 to 0.8 mm, preferably for a liquid crystal display. By carrying and slow cooling using the roll of the present invention, scratches on the glass can be suppressed. The effect becomes more remarkable when the roll of the present invention has the above-described brim.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail with reference to an Example, this invention is not limited to these Examples.

  Five types of thermal spraying raw materials shown in Table 1 were prepared. Symbols “A” to “E” were attached to the raw materials. For example, in the case of “Co-28% Cr-4% W-1% C” in Example 1, the thermal spraying raw material types listed in Table 1 are 28% Cr, 4% W, and 1 C. % And the balance means Co.

Each of these raw materials was sprayed onto a flat plate made of SUS316L (hereinafter also referred to as “base material”) to prepare a test piece. And these test pieces and those that do not spray the raw material (flat plate made of SUS329J1) (Comparative Example 3), the following oxidation resistance / sulfuration resistance evaluation test, cullet sticking / adhesion evaluation test, friction against glass It was subjected to four types of tests: a property / scratch property evaluation test on glass, and a burr ease / scratch property evaluation test.
Table 1 shows the thermal spraying method applied when spraying each raw material onto the base material. These thermal spraying methods will be described.

  “APS” in Table 1 means “atmospheric plasma spraying method”. The thermal spraying apparatus manufactured by Meteco was used under normal conditions.

  Further, when spraying the thermal spray raw materials B, C and E by the HVOF thermal spraying method, JP5000 (manufactured by Plax) was used as a thermal spraying apparatus under normal conditions.

<1. Oxidation resistance / sulfuration resistance evaluation test>
Each raw material shown in Table 1 was sprayed by one of the thermal spraying methods shown in Table 1 on one main surface of a SUS316L base material having a thickness of 25 mm × 25 mm × 6 mm. The sprayed surface was polished with water-resistant abrasive paper (# 80 to # 1200).
The test pieces sprayed with the thermal spray raw materials A to E obtained here are referred to as test pieces A1 to E1. Moreover, let the flat plate made from SUS329J1 which has not sprayed the thermal spray raw material be the test piece F1.

The test shown next was done using test piece A1-E1.
FIG. 3 shows a schematic diagram of this test.
Each test piece 18 was placed on a porous brick 17 installed in a tubular furnace 16 and a gas containing oxygen, sulfurous acid gas and water vapor was introduced to perform a test for evaluating the corrosion resistance in a high temperature environment.
Specifically, each test piece 18 is placed on an alumina porous brick 17 (length 100 mm, width 50 mm, height 10 mm) inside a tubular furnace 16 (total length: 1200 mm, cross section is circular with a diameter of 100 mm). After that, the temperature of the tubular furnace 16 was increased at 5 ° C./min. When the temperature inside the tubular furnace 16 reaches 200 ° C., the gas 19 containing oxygen, sulfurous acid gas and water vapor starts to be introduced. When the temperature inside the tubular furnace 16 reaches 450 ° C., the temperature inside the tubular furnace 16 increases. And held at this temperature for 100 hours. Thereafter, the temperature was lowered at 5 ° C./min. When the temperature in the tubular furnace 16 reached 200 ° C., the introduction of the gas 19 containing oxygen, sulfurous acid gas and water vapor was stopped, and the temperature was lowered at the same rate until the temperature reached room temperature. did.

Here, in this test, a gas 19 containing oxygen, sulfurous acid gas and water vapor was 765 cc / min of a gas containing 13% O ₂ , 0.1% SO ₂ , 4% H ₂ O and the balance N _2. Introduced in.

And the cross-sectional observation of the film of each obtained test piece 18 and the elemental analysis of the cross section were performed.
<1-1> Section Observation After cutting the test piece with a blade-type cutting machine, the section was observed using a scanning electron microscope (trade name: S-3000H, manufactured by Hitachi, Ltd.).
Elemental analysis of <1-2> cross section It performed about three places, the surface part in a film, the film thickness direction center part, and the interface part with the base material in a film. As an analyzer, EDS (trade name: INCA Energy, manufactured by Oxford Instruments) was used.

<2. Caret sticking / adhesion evaluation test>
Above 1. Test pieces were prepared by the same method as the oxidation resistance / sulfuration resistance evaluation test. The obtained test piece was made into test piece A2-F2 according to the kind of spraying raw material. Here, the same spraying material type as A1 is designated as A2. The same applies to B2 to F2, A3 to F3, and A4 to F4 described later.
First, after the plate glass is crushed using a mortar, the particles are adjusted to 250 to 500 μm by repeating the operation of collecting 250 to 500 μm using a sieve of 250 μm and 500 μm and crushing more than 500 μm again. Got cullet.

Next, the test was performed by the method shown in FIG. 4 using the obtained cullet. The entire apparatus shown in FIG. 4 is installed in a heating furnace (not shown). This test was performed using a portal type Tensilon universal testing machine (model: Tensilon, manufactured by A & D). As shown in FIG. 4, an alumina plate 23 is placed almost horizontally on a table 21, and 0.05 g of cullet 25 is laid on the plate 21 so that the cullets do not overlap each other. The sprayed coating 27 was arranged substantially horizontally so as to contact the cullet 25. And it heats up so that the temperature of a test piece may become 450 degreeC in 1 hour, and after it becomes 450 degreeC, it hold | maintains for 15 minutes, Then, the surface of the base material 29 of a test piece is downward through the presser 31. Pressurized. The pressurization speed was 0.35 mm / min, and when the pressure reached 1 kg / cm ² , the pressure was maintained for 10 seconds and then unloaded. Then, after 45 minutes had elapsed from the start of pressurization, the temperature was lowered to room temperature in 1 hour.

  Then, the number of cullets per unit area was calculated by counting the number of cullets stuck on the surface of each test piece that had been cooled to room temperature. Moreover, the Vickers hardness of the surface of each test piece after temperature-fall was measured. The measuring method was based on JIS Z2244.

<3. Friction characteristics for glass and scratching characteristics evaluation test for glass>
<3-1> Abrasion characteristic test for glass After spraying each spraying raw material by each spraying method shown in Table 1 on a disk-shaped SUS316L base material having a thickness of 10 mm and a diameter of 28 mm, the sprayed surface is water-resistant. Polishing was performed using abrasive paper so that the surface roughness (Ra) of all the test pieces was almost the same and the masses were almost the same. The obtained specimens after polishing were designated as specimens A3 to F3 according to the kind of the thermal spray raw material.
Table 2 shows the surface roughness and mass of each test piece, and the total mass of the holder and the test piece.

Next, a test for evaluating the frictional properties against the glass and the scratching properties to the glass was carried out by the method shown in FIG. The entire apparatus shown in FIG. 5 is installed in a heating furnace (not shown).
A test piece 44 was fitted into a stainless steel holder 42 connected to the wire 40. As shown in FIG. 5, the test piece 44 was placed on the alumina plate 46 so that the coating surface 45 was below and in contact with the alumina plate 46.
And the whole temperature of the apparatus shown in FIG. 5 was heated so that it might become 450 degreeC in 1.5 hours, after becoming 450 degreeC, it hold | maintained for 15 minutes, and was connected to the holder 42 in the state of 450 degreeC after that. The wire 40 was pulled and slid on the alkali-free glass plate 48 installed at the same height as the alumina plate 46. And the average friction coefficient was calculated | required by measuring the average load concerning the wire 40. FIG.

<3-2 Scratch characteristic evaluation test for glass>
After the temperature was lowered to room temperature, the surface of each glass plate 48 after sliding each test piece was visually observed.

<4. Evaluation test for burr ease and scratches>
The test pieces A4 to F4 were scratched on the coating surface with a load of 200 g with a sapphire pin at 450 ° C. using a surface property measuring instrument (trade name: 14 FW, manufactured by Shinto Kagaku Co., Ltd.). And the shape of the surface was observed using the laser microscope.

  Next, the result of each test is shown.

<1. Oxidation resistance / sulfuration resistance evaluation test results>
<1-1 Cross-sectional observation>
The test piece D1 after the test had a crack between the coating and the substrate.
There was no change in other test pieces before and after the test.

<1-2 Elemental analysis>
As a result of elemental analysis of the cross section of each test piece, sulfur was detected at the interface between the film and the substrate at D1. This is presumably because hollows having a diameter of about 0.1 mm or less and holes communicating with the base material are relatively scattered on the surface of the coating. Therefore, it is considered that D1 is easily corroded by the base material and easily peeled due to the interface crack.

<2. Results of cullet stab / adhesion evaluation test>
A graph showing the number of cullets per unit area is shown in FIG. The test pieces A2, D2 and F2 were pierced with cullet, but the test pieces B2, C2 and E2 were not pierced.

FIG. 7 shows the measurement results of Vickers hardness. Specimens C2 and E2 had high Vickers hardness, whereas specimens A2 and F2 were low. From these results, it is considered that the material having low Vickers hardness is relatively easy to pierce the cullet.
However, the specimen D2 had a high Vickers hardness to some extent, but the amount of cullet stabbed was also large. This is presumably because hollows having a diameter of about 0.1 mm or less are relatively scattered on the surface of the coating.

<3. Friction characteristics for glass and scratching characteristics evaluation test results for glass>
<3-1 Measurement result of friction force on glass>
The average coefficient of friction is shown in FIG. It can be seen that the friction coefficients of the test pieces A3, C3 and E3 are as low as 0.3 or less.

<3-2 Results of evaluation test for scratching properties on glass>
Table 3 shows the result of confirming the surface of the glass on which each test piece was slid.
Factors that cause the degree of scratch formation to differ depending on the material of the film include the difference in fine surface shape depending on the material, the shape of the fallen particles (particles dropped from the film), the behavior of the fallen particles, and the surface shape after the fallen particles fall off This is presumed to be due to characteristics peculiar to the coating material such as.

<4. Evaluation test results for ease of burr appearance and scratching>
As a result of observing the surface after scratching the surface of the coating using a sapphire pin, the specimens A4 and F4 were deeply scratched and large burrs were generated. On the other hand, in the test pieces B4, C4, D4 and E4, scars and burrs were hardly generated.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on Japanese Patent Application No. 2007-288548 filed on Nov. 6, 2007, the contents of which are incorporated herein by reference.

  The roll for transporting the float glass sheet of the present invention is less likely to cause burrs and scratches on the surface of the roll body due to the cullet of the plate glass broken during slow cooling, and the cullet is less likely to pierce the surface of the roll body. It is possible to prevent the plate glass from being scratched. Particularly in the case of a glass substrate for display, the yield is greatly improved as the generation of scratches is reduced.

Claims (8)

A float plate glass transporting roll having a coating on at least a part of the surface of the roll body in contact with the glass,
Float plate glass conveyance, wherein the coating is a coating in which ceramic particles containing a carbide or boride of at least one element selected from the group consisting of Group Va and Group VIa are dispersed in an alloy containing Co and Cr Rolls. The alloy contains, by mass percentage, 50% or more of Co, 15% or more of Cr, and 80% or more in total of Co and Cr,
2. The roll for conveying a float sheet glass according to claim 1, wherein the ceramic particles contain 70% or more of a carbide or boride of at least one element selected from the group consisting of Va group and VIa group in terms of mass percentage.   The float glass roll according to claim 1 or 2, wherein the coating contains 2 to 30% of the ceramic particles in terms of mass percentage.   The float glass roll according to claim 1 or 2, wherein the coating contains 40 to 90% of the ceramic particles in terms of mass percentage.   The float sheet glass conveyance roll according to any one of claims 1 to 4, wherein the ceramic particles are made of tungsten carbide and / or molybdenum carbide.   The float plate glass conveyance roll according to any one of claims 1 to 5, wherein the roll body portion has a flange and the coating is provided on a portion of the surface of the flange that is in contact with the glass.   The manufacturing method of float plate glass which comprises the process of gradually cooling float plate glass of 600 degrees C or less using the roll for float plate glass conveyance in any one of Claims 1-6.   A roll plate glass transport roll comprising a step of forming a film by HVOF thermal spraying on at least a portion of the surface of the roll body in contact with glass, and obtaining the float plate glass transport roll according to claim 1. Production method.

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