GB2371560A

GB2371560A - Wire for reinforcing glass

Info

Publication number: GB2371560A
Application number: GB0129975A
Authority: GB
Inventors: Junichi Nishida; Minoru Takuwa; Tadashi Abe; Shinichi Harada; Daisuke Hasegawa
Original assignee: Asahi Glass Co Ltd; Hitachi Metals Ltd
Current assignee: AGC Inc; Proterial Ltd
Priority date: 2000-12-15
Filing date: 2001-12-14
Publication date: 2002-07-31
Anticipated expiration: 2021-12-14
Also published as: GB0129975D0; GB2371560B

Description

WIRE FOR REINFORCING GLASS, GLASS SEALING THE SAME AND GLASS PLATE HAVING STAINLESS STEEL WIRE SEALED The present invention relates to a stainless steel wire used for reinforcing a building'glass, a glass sealing the same and a glass plate having a stainless steel wire sealed therein.

Heretofore, wires sealed in a glass for reinforcing a glass are knitted wire nets or single line wires sealed in parallel in a glass. Examples of a wire used for reinforcing a glass include an iron wire, a stainless steel wire and the like, but the iron wire produces a rust such as a corrosion product non-uniformly formed on the iron wire due to dew condensation or invasion of rain water, and the glass is sometimes cracked by volume expansion caused at that time.

The stainless steel can prevent production of a rust to a certain extent, but cracks or bubbles are produced in a glass surrounding a stainless steel wire at the time of sealing the wire in the glass, and the glass sometimes cracks at that point during heat-processing the glass

into a final product or during using the glass.

Generally, a wire for reinforcing a glass is required to have the following properties that: (1) cracks and bubbles are not produced at the time of sealing a wire into a glass; (2) it is possible to carry out electromagnetic separation (to have a ferromagnetic property); (3) a property transformation of a wire is not caused at the time of reheating (800-3000C) ; (4) a Ni content is small for a glass recycling property.

It is preferable to'have all of the above properties.

A stainless steel wire used for this purpose is generally a stainless steel (mainly JIS Standard SUS410 or SUS430) containing Cr as Fe-Cr (about 13 to 18 wt%).

Also, a stainless steel having other elements added can be used. For example, JP-A-57-73169 proposes a stainless steel wire containing 14 to 20% of Cr, 1 to 3% of Mo for improving corrosion resistance, and 0.5 to 2% of Ni for reducing a metallic gloss on a wire surface. JP-A-55136136 proposes a wire containing 12 to 24% of Cr and a free-cutting element such as Pb, S or Se for reducing a cutting resistance.

The alloy disclosed in the above JP-A-57-73169 is improved in respect of corrosion resistance, but is not satisfactorily improved in respect of preventing crack

occurrence at the time of sealing the wire into a glass. JP-A-55-136136 provides a wire having an improved cutting property but having a poor corrosion resistance because of containing a free-cutting element.

An aim of the present invention is to provide a stainless steel wire for reinforcing a glass, which has an excellent corrosion resistance after being sealed in a glass and can prevent production of cracks or bubbles at the time of being sealed in a glass and also can prevent production of cracks during re-heating the glass or during using the glass, and also provides a glass sealing the stainless steel wire and a glass plate having the stainless steel wire sealed.

Further, a glass plate having a Ni-plated stainless steel wire sealed in parallel (a conventional wire-sealed glass plate) has been widely used, but there was a problem of requiring many production steps. That is, the Ni plating of a stainless steel wire is carried out for preventing crack occurrence at a cut section end face at the time of cutting a wire-sealed glass plate. Thus, the Ni plating step was therefore necessary for a conventional wire-sealed glass plate.

From other viewpoints, an aim of the present invention is to provide a glass plate sealing a stainless steel wire having no plating, which does not produce cracks at a cut section end face at the time of cutting.

It is an essential condition for preventing a glass

from cracking during re-heating or during using to prevent crack occurrence at the time of sealing a stainless steel wire in the glass. The present inventors have intensively studied about these problems and have discovered that crack occurrence is closely connected with an adhesion strength between a glass and a wire.

Further, the present inventors have studied an influence of elements added to a wire for reinforcing a glass on an adhesion strength between the glass and the wire, and have studied further to research for optimum amounts of the elements to be added to the wire. The present invention is based on these studies.

Still further, the present inventors have studied about a corrosion resistance of a wire.

That is, the first feature of the present invention resides in a wire for reinforcing a glass, which comprises a stainless steel wire containing B in an amount of from 1 to 100 ppm.

Preferably, the wire contains at most 0.1 mass% of C, at most 1 mass% of Si, at most 1 mass% of Mn and from 12 to 24 mass% of Cr.

More preferably, the wire contains at most 3 mass% of Mo.

Preferable examples of satisfying the above conditions include a wire for reinforcing a glass, which comprises B in an amount of from 30 to 80 ppm, Cr in an amount of from 16 to 18 mass%, Si in an amount of larger

than 0% to at most 1 mass%, Mn in an a mount of larger than 0% to at most 1 mass%, and the remainder being substantially Fe, and C in an amount of at most 0.03 mass% as an unavoidable impurity, or a wire for reinforcing a glass, which comprises B in an amount of from 30 to 80 ppm, Cr in an amount of from 16 to 18 mass%, Si in an amount of larger than 0% to at most 1 mass%, Mn in an amount of larger than 0% to at most 1 mass%, Mo in an amount of from 1 to 3 mass%, and the remainder being substantially Fe, and C in an amount of at most 0. 03 mass% as an unavoidable impurity.

A more preferable example of a wire for reinforcing a glass, comprises Cu in an amount of at most 2 mass% and one or at least two elements selected from the group consisting of Zr, V, Nb, Ti and Ta in a total amount of at most 2 mass%, in addition to the above-mentioned components.

Further, since a surface roughness of a wire surface has an influence on an adhesion strength to a glass, the wire surface preferably has a roughness of Ra (JIS B0601) of at most 0.5 urn.

A glass having the above wires sealed hardly produces cracks during re-heating or during using. The above wires may be knitted or may not be knitted.

It is preferable that there is no stress at the interface between a glass and a wire, but if an adhesion strength between the glass and the wire is too high after

solidification, a heat shrinkage difference between the glass and the wire is hardly released at the time of solidification and cooling. As this result, a heat stress occurs at the interface between the two materials at the time of cooling, and a heat stress crack easily occurs on the glass side at the interface. Particularly, if there is a dispersion or variation in an adhesion strength on the wire, there is also a dispersion or variation in the release of the heat shrinkage difference. Accordingly, a heat stress is concentrated at the boundary and a heat stress crack easily occurs.

Further, if the adhesion strength between a glass and a wire is too high, cracks are liable to occur when separating the glass and the sealed wire at a cut section end face at the time of cutting the glass.

Since breaking mechanisms of a glass and a metal are essentially different from each other, the sealed wire tends to cause a phenomenon of being separated from the glass in the vicinity of the cut section end face when cutting the glass. At this time, if the adhesion strength between the glass and the wire is too high, fine minute reverse circular cone-like cracks occur from the wire-separated boundary into the glass.

As mentioned above, it is effective for preventing occurrence of cracks to control an adhesion strength between a glass and a wire as low as possible and as uniform as possible.

According to the study of the present inventors, the adhesion strength between the glass and the wire varies depending on the state of an oxide film on the wire surface and the surface skin conditions. From this point of view, the present inventors have studied about an influence of various minor elements contained in the wire on the adhesion strength, and it has been discovered that B and Cu, particularly B, have an effect of reducing the adhesion strength.

Also, the present inventors have studied about an influence of minor elements on a corrosion resistance, and it has been discovered that an addition of B in a minor amount improves the corrosion resistance.

If a rust is formed on a wire surface before being sealed in a glass, an outer appearance is degraded after being sealed in the glass and the rust becomes a site of producing bubbles which cause cracks of the glass, but the present inventors have discovered that this problem can be overcome by reducing an affected layer such as an oxide layer formed on the outermost surface of the wire.

The second feature of the present invention is based on this discovery. That is, the second feature of the present invention resides in a wire for reinforcing a glass, wherein a detected amount of Fe at a depth of 10 nm from the outermost surface of the wire is at least 10 atom% when measured by a photoelectronic spectrum device.

This second feature of the present invention can be

combined with the first feature of the present invention in order to achieve the aimed effect of the present invention.

Further, as mentioned above, the present inventors have considered that the above adhesion strength between a glass and a wire is an important factor of producing cracks at a cut section end face at the time of cutting a glass plate having a stainless steel wire sealed, and the third feature of the present invention is based on this consideration.

That is, the third feature of the present invention is to provide a glass plate having a plurality of stainless steel wires sealed, characterized in that a Po value measured by the following method is at most 0.30

2 N/mm2. The stainless steel wire used herein is a stainless steel wire which is not plated, i. e. a stainless steel raw wire.

(Method for measuring a Po value) A single wire line-sealed glass plate having one stainless steel wire sealed is cut off from a glass plate having the above-mentioned a plurality of stainless steel wires sealed, and the glass of the single wire linesealed glass plate is divided into two parts without cutting the stainless steel wire in such a manner as to cross the center of the stainless steel wire sealed in the single wire line-sealed glass plate, and the divided two glass parts are respectively drawn. When the glass

and the stainless steel wire are separated by applying a drawing force of F, a Po value is a value obtained by dividing the drawing force F by a surface area S of the separated stainless steel wire.

Further, the present inventors have discovered that the above-mentioned surface roughness Ra of the stainless steel wire is an important factor to control the above Po value, and the fourth feature of the present invention is based on this discovery. Thus, the fourth feature of the present invention is to provide a glass plate sealing a stainless steel wire having a surface roughness Ra of at most 0.25 pm.

As mentioned above, the most important feature of the present invention is to prevent cracks from occurring at the time of sealing a wire in a glass by employing a stainless steel wire containing B in an amount of from 1 to 100 ppm. The stainless steel wire used in the present invention is an iron-based alloy wire containing Cr in an amount of at least 10 mass%.

A detailed function of an effect of reducing an adhesion strength by adding B in the present invention is not clear but is considered to be as mentioned below.

When sealing an ordinary wire in a glass, the wire is exposed to a high temperature of at least 700oC.

Therefore, an oxide scale having a form different from a rust formed at room temperature, is formed on the entire surface of the wire. In a case of an ordinary stainless

steel wire containing no B, an oxide scale formed on the wire surface at the time of being sealed in a glass mainly comprises oxides of Cr and Fe, and when the alloy contains Mn, Si and the like, a scale containing their oxides is formed. When the alloy contains B as in the present invention, B is oxidized, and this is considered to have a large influence on an action of a surface oxide film in a crack-forming process.

B can be solid-dissolved in an alloy only in a small amount of ppm order, but its diffusion rate is high and it is densified on the surface, and is oxidized in an oxidizing atmosphere to form B203 in a uniformly mixed state in an oxide scale. When B203 is mixed in the scale, the scale itself becomes brittle, and as this result, provides an effect of reducing an adhesion strength to a glass at the time of being sealed in the glass. Further, B203 has a low melting point of about 500oC, and it is considered to provide an effect of reducing an adhesion strength to a glass since B203 is melted at a temperature higher than the melting point. As this result, it is considered to release a heat stress occurred at the time of being sealed in a glass, thereby preventing crack occurrence. Further, this is also effective for preventing crack occurrence at the time of cutting the glass.

Further, after sealing a wire in a glass, B provides an effect of improving a corrosion resistance to prevent

a rust from ununiformly forming on the wire surface at room temperature when using the glass. As mentioned above, B has a high diffusion rate and is liable to be densified at a grain boundary, and when B is densified at the grain boundary, it is considered to achieve a function of preventing grain boundary precipitation of Cr carbide having a negative influence on a corrosion resistance at room temperature.

These effects can be achieved even in such a small amount as 1 ppm, but these effects are hardly observed when B is used in an amount of less than 1 ppm. On the other hand, if the amount of B exceeds 100 ppm, B forms a eutectic crystal (Fe, Cr) 2B having a low melting point, and hot processibility and ductility are lowered at the time of forming a wire. Accordingly, the upper limit of an amount of B is 100 ppm, and a preferable amount of B is from 30 ppm to 80 ppm.

As mentioned above, it is preferable that the wire for reinforcing a glass in the present invention contains C in an amount of at most 0.1 mass%, Si in an amount of at most 1 mass%, Mn in an amount of at most 1 mass% and Cr in an amount of from 12 to 24 mass%, in addition to B.

Also, it is preferable that the wire contains Mo in an amount of at most 3 mass%, Cu in an amount of at most 2 mass%, and one or two or more elements selected from the group consisting of Zr, V, Nb, Ti and Ta in a total amount of at most 2 mass%. Reasons for adding the above

elements are explained hereinafter.

C : At most 0. 1 mass% C is not an essential component but is contained unavoidably. If the amount of C exceeds 0.1 mass%, a work-hardening tendency is increased at the time of drawing a wire, and bubbles are liable to be caused at the time of sealing the wire, and glass cracks tend to be caused at the site of wire during re-heating or during using. Accordingly, a content of C is preferably at most 0.1 mass%, more preferably at most 0.03 mass%.

Si: At most 1 mass% Si is a deoxidizing element at the time of producing a wire, and improves an oxidation resistance. However, if si is contained too much, a wire drawing property is degraded. Accordingly, a preferable amount of Si is at most 1 mass%.

Mn: At most 1 mass% Mn is a deoxidizing element and achieves an effect of preventing embrittlement at a high temperature by combining with S present as an unavoidable impurity.

However, if the amount of Mn is too much, a spinel type oxide is formed, and an oxidation resistance is degraded and a wire-drawing property is also lowered.

Accordingly, the content of Mn is preferably at most 1 mass%.

Cr: From 12 to 24 mass% Cr imparts a basic corrosion resistance to a wire

when it is contained in an amount of at least 10 mass%, and it is essential for producing a stainless steel to add Cr. Also, the addition of Cr achieves an effect of making a thermal expansion coefficient of a stainless steel close to that of a glass. In order to satisfactorily achieve these effects, it is preferable to use Cr in an amount of at least 12 mass%. However, if the amount of Cr is too much, a wire-drawing property is degraded and a surface skin at the time of drawing becomes bad. Accordingly, it is preferable to use Cr in an amount of at most 24 mass%. A more preferable content of Cr is from 16 to 18 mass%.

Mo : At most 3 mass% Mo achieves an effect of improving a corrosion resistance and a hot strength. However, if the amount of Mo is too much, a wire-drawing property and a ductility are degraded. Accordingly, it is preferable to use Mo in an amount of at most 3 mass%. A more preferable content of Mo is from 1 to 3 mass%.

Zr, V, Nb, Ti and Ta: 1 or 2 or more elements in a total amount of at most 2 mass% These elements improve an oxidation resistance of a wire by adding in a small amount, and also achieve an effect of minimizing crystal grains by forming a carbide or a nitride. However, if these elements are contained too much, such a carbonitride as Ti (C, N), V (C, N) or the like becomes large and coarse grains, and a wire-drawing

property is lowered. Accordingly, it is preferable to use these elements in a total amount of at most 2 mass%.

Cu: At most 2 mass% In a stainless steel wire having B added, Cu achieves an effect of making an oxide scale brittle, which is formed at the time of sealing a wire in a glass, and also achieves an effect of lowering an adhesion strength between the wire and the glass. This is probably because solid-insoluble Cu precipitates in the scale since a solid solubility limit of Cu is lowered due to selective oxidation of Fe on the alloy surface. If the content of Cu is too much, hot processibility at the time of forming a wire becomes poor. Accordingly, the content of Cu is preferably at most 2 mass%.

In the present invention, Ni is not an essential component in a stainless steel wire, and it is preferable to make the content of Ni at most 1 mass%. If Ni is admixed when recycling a glass, the glass is expanded and causes cracks. The expansion of the glass when recycling the glass can be prevented by making the content of Ni in the wire at most 1 mass%. Also, if the content of Ni is at most 1 mass%, the stainless steel wire easily provides the above-mentioned general properties (1) to (4) required for a wire for reinforcing a glass since a ferromagnetic ferrite phase in the stainless steel wire becomes stable.

In addition to the above-mentioned compositions, it

is preferable for a wire for reinforcing a glass in the present invention to control a surface state condition of the wire before being sealed in the glass. Concretely preferable surface states are explained hereinafter.

Surface roughness Ra (JIS B0601): at most 0. 5 urn If a wire surface has a large concavo-convex part, a surface area in contact with a glass is increased and an adhesion strength to the glass is increased. If the surface roughness Ra exceeds 0.5 urn, cracks are liable to easily occur at the time of sealing the wire in the glass or during using.

Accordingly, the surface roughness Ra should be preferably at most 0. 5 urn.

The surface roughness Ra is defined in JIS B0601 (3.

Arithmetic mean roughness (Ra) definition and indication). Thus, the surface roughness Ra is determined by taking a standard length (L) from a roughness curve in its average line direction, taking an X-axis in the average line direction of the above taken part, taking a Y-axis in the longitudinal magnification direction, expressing the roughness curve as y=f (x), integrating If (x) I from 0 to L and dividing the integrated value by L.

The roughness curve is a curve obtained by removing a surface waviness component longer than a predetermined wavelength from a profile curve by a phase compensating type high-pass filter, and the profile curve is a profile

appearing at the cut section obtained by cutting an object plane by a plane rectangular to the object plane.

The surface roughness Ra in the present invention has values of a cut off value of 0.8 mm and an evaluation length of 2.4 mm.

Hereinafter, the second feature of the present invention is explained.

If a rust is ununiformly formed on a wire surface before being sealed in the glass, an outer appearance after being sealed in the glass is spoiled and the rust provides a site producing bubbles which cause glass cracks. Therefore, it is preferable not to form a rust on the wire before being sealed in the glass. According to the study by the present inventors, it is possible to improve a corrosion resistance of a wire before being sealed in the glass and to prevent rust formation before being sealed in the glass by reducing a degraded layer such as an oxidized layer formed on the outermost surface of the wire by controlling an atmosphere of annealing heat treatment at the time of producing the wire or removing an oxide formed.

On the outermost surface of a stainless steel, easily oxidizable elements such as Cr, Mn or Si are densified on the outermost surface of the stainless steel and an Fe element is detected only in a very small amount. The present inventors discovered that a corrosion resistance becomes poor if oxides of these

alloy elements are formed on the outermost surface of a wire and are present to a deeper zone in the radius direction of the wire, and that the corrosion resistance of the wire can be improved and the rust formation can be prevented by reducing the amounts of the oxides on the surface.

Concretely, when measuring each element amount at a depth of 10 nm from the outermost surface of a wire by means of a photoelectronic spectrum device referred to as ESCA or XPS, a corrosion resistance is improved when the surface is made clean to such an extent as to detect at least 10 atom% of Fe.

Since a dry etching rate varies depending on the composition of an alloy, the depth of 10 nm measured by the photoelectronic spectrum device is made by etching for the time taken to etch a standard test piece of Si02 to a depth of 10 nm.

Hereinafter, the third feature of the present invention is explained.

In the stainless steel wire-sealed glass plate of the present invention, a plurality of stainless steel wires may be sealed in parallel or a plurality of stainless steel wires may be knitted to prepare a stainless steel net (a typical size of each mesh is 25 mm) and the stainless steel net may be sealed in a glass plate. The former product corresponds to a wire-sealed glass plate (a distance between wires is typically 50

mm), and the latter product corresponds to a rhombic mesh wire net-sealed glass plate or a rectangular mesh wire net-sealed glass plate.

The above-mentioned Po value depends on an adhesion strength between the glass and the wire, and the Po value of the stainless steel wire-sealed glass plate of the

2 present invention is at most 0. 30 N/mm, and therefore cracks rarely occur at the cut section at the time of cutting. The Po value is preferably at most 0. 29 N/mm2, more preferably 0. 28 N/mm, most preferably at most 0. 27 N/mm2.

Hereinafter, the method for measuring a Po value is explained by referring to FIG. 1. FIG. l (a) illustrates a single wire line-sealed glass plate 1 before dividing the glass, and FIG. l (b) illustrates the state of the glass of the single wire line-sealed glass plate 1 divided into two parts. C shows a cutting line, and la and Ib show the divided two glass parts of the single wire line-sealed glass plate 1.

The single wire line-sealed glass plate 1 containing only one stainless steel wire is cut off from a glass plate having a plurality of stainless steel wires sealed. The wire for reinforcing a glass of the present invention is typically a stainless steel wire.

A typical size of the single wire line-sealed glass plate 1 is 100 mm in length along the stainless steel wire and 50 mm in width in the case of a linear wire

sealed glass plate, and a typical size of a wire netsealed glass plate is from 20 to 25 mm square.

The glass part of the single wire line-sealed glass plate 1 is divided into two parts la and lb by cutting the glass only along the cutting line C across the central part of a stainless steel wire line 2. The stainless steel wire line 2 is not cut when cutting the glass part.

Thereafter, the glass parts la and Ib are respectively drawn so as to separate the stainless steel wire 2 from the glass parts la and Ib, i. e. to withdraw the stainless steel wire 2 from the glass parts la and lob : The Po value is defined as a value obtained by dividing a withdrawing force F at the time when the stainless steel wire 2 is separated from the glass parts la and Ib, by a surface area S of the stainless steel wire 2 (i. e. a surface area S of the stainless steel wire 2 in contact with the glass part of the single line wiresealed glass plate 1).

A typical diameter of the stainless steel wire is from 0.3 to 0.5 mm.

Also, its surface roughness Ra is preferably at most 0. 25 urn. If the surface roughness Ra exceeds 0. 25 urn, it

2 becomes difficult to make a Po value at most 0. 28 N/mrn.

The surface roughness Ra is more preferably at most 0. 2 um.

In order to make the Po value smaller, it is preferable to employ a stainless steel wire containing B in an amount of 1 to 100 ppm. The content of B is more preferably from 30 to 60 ppm.

Hereinafter, the fourth feature of the present invention is explained.

In the fourth feature of the present invention, in order to make the Po value small, the surface roughness Ra is controlled to at most 0. 25 um. The surface roughness Ra is preferably at most 0.2 um.

EXAMPLES Hereinafter, the present invention is further illustrated with reference to Examples and Comparative Examples, but should not be limited thereto.

EXAMPLE 1 Billets of 100 mm square were prepared by subjecting the components expressed by mass% in the following Table 1 to vacuum-dissolving and blooming. The billets thus prepared were hot-rolled to produce a bar steel of (P5 mm, and the bar steel was subjected to cold drawing and annealing to produce a wire of (DO. 35 mm. With regard to all samples, the annealing was carried out at 8000C in hydrogen atmosphere. Ten wires thus produced were sealed at a wire distance of 50 mm between two soda lime glasses heated at a high temperature, and immediately after sealing, the sealed product was roll-molded (glass thickness 10 mm), cooled and cut into a sample, and crack

occurrence rates respectively at the time of sealing in the glass and at the time of cutting and a corrosion resistance of the wire after sealed in the glass were evaluated. Also, an oxidized state of the wire of this example after annealing was evaluated by measuring a detected amount of Fe at a depth of 10 nm from the outermost surface of the wire by means of a photoelectronic spectrum device (ESCA), and the detected amount of Fe ranged from 30 to 50 atom%. The measurement by the photoelectronic spectrum analyzing device was carried out by preparing 10 samples by cutting wires in respective oxidized states to a length of 10 mm and the 10 samples were properly arranged and subjected to sputtering to a depth of 10 nm to analyze their components.

Table 1

(mass%) g.

No. c si Mn Ni Cr B Others Fe roughness Note Ra 1 0. 023 0. 15 0. 16 0. 15 18. 10 < 0. 0001-Remainder 0. 37 Comparative Example 2 0. 012 0. 14 0. 17 0. 16 18. 06 0. 0015-f 0. 35 Present invention 3 0. 008 0. 15 0. 17 0. 16 18. 02 0. 0046-0. 73 Present . invention 4 T T T-0. 41 Present invention 5 0. 25 Present invention 6 0. 007 0. 24 0. 14 0. 14 18. 08 0. 0074-1'0. 36 Present .... invention 7 0. 035 0. 22 0. 34 0. 15 17. 58 0. 0122-T 0. 38 Comparative Example 8 0. 009 0. 22 0. 25 0. 12 18. 12 0. 0035 Mo/1. 97 T 0. 37 Present ... invention 9 0. 015 0. 12 0. 16 0. 13 18. 04 0. 0037 Cu/0. 49 i 0. 32 Present .... invention 10 0. 024 0. 17 0. 17 0. 15 18. 09 0. 0038 Nb/0. 28 i 0. 27 Present inventlon 11 0. 017 0. 14 0. 74 0. 15 18. 00 0. 0039 Ti/0. 32 ? 0. 38 Present . lnventlon 12 0. 044 0. 61 0. 52 0. 12 20. 17 0. 0027 Zr/0. 18 t 0. 34 Present invention 13 0. 064 0. 27 0. 31 0. 11 16. 21 0. 0045 Ta/0. 33 ? 0. 33 Present invention

Crack occurrence rates at the time of sealing in a glass and at the time of cutting were respectively evaluated by cutting off a sample so as to make one wire length 1m and then observing cracks produced in the surrounding of the sealed wire and cracks produced at the cut section end face with naked eyes. With regard to the cracks in the surrounding of the wire, by observing one wire, a sample wherein no crack was observed was evaluated as a mark 0 and a sample wherein cracks were observed was evaluated as a mark X. With regard to the cracks at the cut section face, by observing cut section faces of 100 wires, crack occurrence rates were measured.

The evaluation results are shown in the following Table 2.

The evaluation of a corrosion resistance of a wire after sealed in the glass was carried out by cutting off a sample of 200 x 150 mm from a wire-sealed glass plate, dipping the sample in 5% NaCl solution (liquid temperature 35OC) and measuring a time of producing a rust. The evaluation results are shown in the following Table 2.

Table 2

Section crack Glass Corrosion No. occurrence Corrosion crack resistance rate Comparative Example Example pressent 2 O 0% 72h Example 3 0596h Example ., Present 4 0 0% 96h Example pressent 5 O 0% 96h Example .... Present Example Example 7 0 0% 96h Comparative Example 8 0 0% > 168h Example 9 00% 96h Present Example 10 0 0% 96h Present Example 11 00% 96h Example 12 00% 96h Example 13 0 0% 96h ' Example

Sample No. 1 is a Comparative Example containing no B, and a large amount of cracks were produced at the time of sealing the wire in the glass and a crack occurrence rate at the cut section face was also large. Further, a corrosion resistance was unsatisfactory, and a rust was produced in a short time. Samples No. 2 to No. 6 are materials containing B, and an adhesion strength to a

glass was reduced, and no crack was produced at the time of sealing. Further, a corrosion resistance was also remarkably improved.

Samples No. 3 to No. 5 were checked with regard to an influence by a surface roughness, and a crack occurrence rate at a cut section face was liable to become larger as a surface roughness becomes larger, and a smaller surface roughness was more preferable for preventing crack occurrence.

Sample No. 7 contains B in a little excessive amount, and no glass crack was produced and a corrosion resistance was also satisfactory. However, since B was added in an excessive amount, a eutectic crystal (Fe, Cr) 2B having a low melting point was formed along a grain boundary and cracks were developed along the grain boundary, and therefore hot processibility was very poor and there were many defects during hot processing.

Sample No. 8 contained Mo, and its corrosion resistance was remarkably improved.

Samples No. 9 to No. 13 were the products of the present invention, and a crack resistance and a corrosion resistance were improved as compared with Comparative Example No. 1.

EXAMPLE 2 In the same manner as in Example 1, a bar steel of (D 5 mm was produced by using the components as shown in sample No. 3 in Table 1, and was produced into a wire of

00. 4 mm by combining cold drawing and annealing. By adjusting the annealing atmosphere at 800oC, wires in three kinds of surface-oxidized states were prepared.

These wires were cut to a length of 200 mm, and were dipped in 5% NaCl (liquid temperature 35OC) to measure a time taken for producing a rust.

Also, the measurement of the oxidized states of the wires after annealing was carried out by a photoelectronic spectrum analyzing device (ESCA) in the same manner as in Example 1.

The following Table 3 shows the corrosion resistance evaluation results and the analytical results by ESCA.

Sample No. 16 had a detected amount of Fe of at most 10 atom% at a depth of 10 nm from the outermost surface, and produced a rust by dipping for 24 hours. On the other hand, samples No. 14 and No. 15 had a detected amount of Fe of at least 10 atoms% at a depth of 10 nu from the outermost surface, and produced no rust even after dipping for 216 hours, thus proving an excellent corrosion resistance.

Table 3

Fe detected amount (atom%) after Corrosion Corrosion No. sputtering 10 nm from outermost resistance surface surface 1429. 3 > 216h 1538. 5 > 216h 167. 824h

EXAMPLE 3 A stainless steel wire (diameter : 0. 4 mm) having a

composition (mass%) of Fe : 82. 07%, C : 0. 01%, Si : 0. 63%, Mn : 0. 81%, P : 0. 011%, S : 0. 004%, Cr : 16. 46% and B : 0. 005% and having a surface roughness Ra in a range of from 0.15 to 0.2 pm, was sealed into the inside of a ribbon-like glass of melted state by a well-known method to prepare a linear wire-sealed glass plate Al.

A Po value of the linear wire-sealed glass plate Al was measured to be 0.265 N/mm. A single line wiresealed glass plate used had a width of 50 mm and the sealed stainless steel wire had a length of 100 mm. The withdrawing force F was measured by Autograph AG-5000D manufactured by Shimadzu Corporation (crosshead speed: 10 mm/min.).

By using a rhombic mesh net prepared from the above stainless steel wire, a wire net-sealed glass plate B having a thickness of 6.8 mm and a width of 2.7m was prepared in the same manner as in the linear wire-sealed glass plate Al. It is estimated from the measurement result of the linear wire-sealed glass plate Al that the wire net-sealed glass plate B has a Po value of 0.265 N/mm.

Not only a glass part but also a wire net part of the wire net-sealed glass plate B were cut, and cracks were observed at 1,360 points of the wire net cut part of the cut section face. That is, cracks were observed at a glass face surrounding the wire net cut part and at 10 mm inner side glass from the wire net cut part. As this

result, no crack was recognized at each of 1, 360 points.

Further, a stainless steel wire (diameter : 0. 4 mm) having a composition (mass%) of Fe: 82.075%, C: 0.01%, Si: 0.63%, Mn: 0. 81%, P: 0.011%, S: 0.004% and Cr: 16.46% and having a surface roughness Ra in a range of from 0.15 to 0. 2 urn, was sealed into the inside of a ribbon-like glass in melted state by a well-known method to prepare a linear wire-sealed glass plate A2. The linear wiresealed glass plate A2 had a Po value of 0.285 N/mrn2. In the same manner as above, cracks were observed at three points of a linear wire cut part of a cut section face, but no crack was recognized at any of the observed points.

For comparison, a linear wire-sealed glass plate A3 was prepared by using the same stainless steel wire as used in the preparation of the linear wire-sealed glass plate A2, except for having a surface roughness Ra in a range of from 0.3 to 0.35 um.

The linear wire-sealed glass plate A3 had a Po value

2 of from 0. 4 to 0. 6 N/mm2, and cracks were observed in the same manner as above at 55 points of a linear wire cut part of a cut section face, and as this result, cracks were recognized at 28 points.

According to the present invention, a stainless steel wire-sealed glass plate of the present invention has an excellent corrosion resistance after being sealed in a glass and prevents generation of bubbles and cracks

at the time of being sealed in the glass, and also prevent generation of cracks during pre-heating the glass and during using. Also, the present invention provides a stainless steel wire-sealed glass plate having a nonplated stainless steel wire sealed, which rarely causes cracks at a cut section face.

The entire disclosure of Japanese Patent Application No. 2000-381306 filed on December 15,2000 including specification, claims, drawings and summary are incorporated herein by reference in its entirety.

Claims

CLAIMS : 1. A wire for reinforcing a glass, which comprises a stainless steel wire containing B in an amount of from 1 to 100 ppm.
2. The wire for reinforcing a glass according to Claim 1, wherein the stainless steel wire further contains Si in an amount of at most 1 mass%, Mn in an amount of at most 1 mass% and Cr in an amount of from 12 to 24 mass%, in addition to C which may be present as an unavoidable component in an amount of at most 0.1 mass%.
3. The wire for reinforcing a glass according to Claim 2, wherein the stainless steel wire further contains Mo in an amount of at most 3 mass%.
4. The wire for reinforcing a glass according to Claim 2 or 3, wherein the stainless steel wire further contains Cu in an amount of at most 2 mass%.
5. The wire for reinforcing a glass according to any one of Claims 2 to 4, wherein the stainless steel wire further contains one or at least two elements selected from the group consisting of Zr, V, Nb, Ti and Ta in a total amount of at most 2 mass%.
6. The wire for reinforcing a glass according to any one of Claims 1 to 5, wherein the wire has a surface roughness Ra (JIS B0601) of at most 0.5 pm.
7. The wire for reinforcing a glass according to any one of Claims 1 to 6, wherein a detected amount of Fe at a depth of 10 nm from the outermost surface of the wire is

at least 10 atom% when measured by a photoelectronic spectrum device.
8. A wire for reinforcing a glass, wherein a detected amount of Fe at a depth of 10 nm from the outermost surface of the wire is at least 10 atom% when measured by a photoelectronic spectrum device.
9. A glass having a wire for reinforcing a glass as defined in any one of Claims 1 to 8 sealed.
10. A glass plate having a plurality of stainless steel wires sealed, wherein a Po value measured by the following method is at most 0.30 N ! mm2, said method comprises cutting off a single wire linesealed glass plate having one stainless steel wire sealed from the glass plate having a plurality of stainless steel wires sealed, dividing the glass only of the single wire line-sealed glass plate into two parts without cutting the stainless steel wire in such a manner as to cross the center of the stainless steel wire sealed in the single wire line-sealed glass plate, drawing the divided two glass parts respectively and applying a drawing force F to separate the glass and the stainless steel wire, said Po value being a value obtained by dividing the drawing force F by a surface area S of the separated stainless steel wire.
11. A glass plate having a stainless steel wire sealed, wherein the wire has a surface roughness Ra (JIS B0601) of at most 0.25 urn.
12. A wire for reinforcing a glass substantially as hereinbefore described in any one of the Examples.
13. A glass having a wire for reinforcing a glass substantially as hereinbefore described in any one of the Examples.
14. A glass plate having a plurality of stainless steel wires sealed substantially as hereinbefore described in any one of the Examples.