HEAT RESISTANT SEPARATION FABRIC

Abstract

A heat resistant separation fabric for use as tool covering in the production of glass products at temperatures over 580° C., wherein the heat resistant separation fabric comprises fiber yarns, and wherein said fiber yarns comprise metal fibers out of first material containing: 18 to 21 weight percent Cr, 23 to 26 weight percent Ni, 5.5 to 7 weight percent Mo, and 40 to 50 weight percent Fe.

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Claims

1. A heat resistant separation fabric for use as tool covering in the production of glass products at temperatures over 580° C., wherein the heat resistant separation fabric is made of fiber yarns, and wherein said fiber yarns comprise metal fibers out of a first material consisting of: 18 to 21 weight percent chromium, 23 to 26 weight percent nickel, 5.5 to 7 weight percent molybdenum, 40 to 50 weight percent iron, optionally one or more than one of silicon, manganese, and copper, each in a range between 0.2 weight percent to 2 weight percent, and optionally one or more than one of carbon, nitrogen, cobalt, magnesium, neodymium, phosphorus, sulphur, tin, titanium, vanadium and tungsten, each less than 0.15 weight percent.

2. The heat resistant separation fabric as in claim 1, wherein said first material contains 40 to 46 weight percent iron.

3. The heat resistant separation fabric as in claim 1, wherein said fiber yarns comprise carbon fibers or silica fibers.

4. The heat resistant separation fabric as in claim 1, wherein said heat resistant separation fabric consists out of fiber yarns out of said first material.

5. The heat resistant separation fabric as in claim 1, wherein said fiber yarns comprise fibers out of a second material.

6. The heat resistant separation fabric as in claim 5, wherein said second material is a stainless steel alloy of the 300 series according to ASTM A313 including 316, 316L and 347, glass, ceramic and/or basalt.

7. The heat resistant separation fabric as in claim 1, wherein the equivalent diameter of said fiber yarns is 12 μm.

8. The heat resistant separation fabric as in claim 1, wherein said fiber yarns are spun yarns.

9. The heat resistant separation fabric as in claim 1, wherein said heat resistant separation fabric is a sleeve for covering a roller.

10. The heat resistant separation fabric as in claim 1, wherein said heat resistant separation fabric is a knitted, a woven or a braided fabric.

11. The heat resistant separation fabric as in claim 1, wherein said heat resistant separation fabric is a felt or a tape, e.g. quench tape.

12. The heat resistant separation fabric as in claim 1, wherein the Limited Oxygen Index according to ISO 4589-2 of said heat resistant separation fabric is more than 45 vol % oxygen.

13. A spun fiber yarn, comprising fibers out of alloy consisting of: 18 to 21 weight percent chromium, 23 to 26 weight percent nickel, 5.5 to 7 weight percent molybdenum, 40 to 50 weight percent iron, and optionally one or more than one of silicon, manganese, and copper, each in a range between 0.2 weight percent to 2 weight percent, and optionally one or more than one of carbon, nitrogen, cobalt, magnesium, neodymium, phosphorus, sulphur, tin, titanium, vanadium and tungsten, each less than 0.15 weight percent.

14. A method of using a heat resistant separation fabric as in claim 1, comprising the step of covering tooling in glass production with the heat resistant separation fabric; wherein in use the temperature of the heat resistant separation fabric is higher than 580° C.; and wherein the tooling covered with the heat resistant separation fabric is brought in contact with glass panels.

15. The heat resistant separation fabric as in claim 2, wherein said fiber yarns comprise carbon fibers or silica fibers.

16. The heat resistant separation fabric as in claim 2, wherein said heat resistant separation fabric consists out of fiber yarns out of said first material.

Description

MODE(S) FOR CARRYING OUT THE INVENTION

[0039] A metal fiber yarn that has been spun out of 100% by weight out of a first material. The first material has the following composition:

[0040] 18 to 21 wt % Cr, e.g. 18.5 wt %, 19.6 wt %, or from 18.5 wt % to 19.6 wt %;

[0041] 23 to 26 wt % Ni, e.g. 23.3 wt %, 24.7 wt % or from 23.3 wt % to 24.7 wt %;

[0042] 5.5 to 7 wt % Mo, e.g. 5.7 wt %, 6.0 wt % or from 5.7 wt % to 6.0 wt %;

[0043] Si, Mn, and Cu in a range between 0.2 weight percent to 2 weight percent, e.g. 0.35 wt %, 0.37 wt %, or from 0.35 wt % to 0.37 wt % Si; 0.76 wt %, 0.81 wt %, or from 0.76 wt % to 0.81 wt % Mn; and 1.25 wt %, 1.33 wt %, or from 1.25 wt % to 1.33 wt % Cu;

[0044] 40 to 50 wt % Fe, e.g. 44.5 wt %, 47.1 wt % or from 44.5 wt % to 47.1 wt %.

[0045] In addition, the material may contain one or more than one of the following elements, e.g. carbon (C), nitrogen (N), cobalt (Co), magnesium (Mg), neodymium (Nb), phosphorus (P), sulphur (S), tin (Sn), titanium (Ti), vanadium (V) and tungsten (W), each less than 0.15 wt %.

[0046] The metal fibers have an equivalent diameter of about 12 μm. The metal fibers have been made by means of bundled drawing. The bundles of fibers of continuous length made via bundled drawing have been transformed into staple fibers by means of stretch breaking. The yarns have been spun by means of ring spinning, on a long staple type ring spinning frame. The yarns have been ply twisted into a two ply yarn of count 1½ Nm (90*2 tex). The plied yarn has been knitted into a single jersey fabric of 1050 g/m.sup.2 that has been tested. This is sample A for the comparative testing.

[0047] The behavior of sample A has been compared with a sample of the same fabric construction but where the spun yarns consisted for 100% out of 12 pm equivalent diameter fibers out of 316L-related alloy (sample B for the comparison). The 316L-related alloy has the same specification as alloy 313L (according to ASTM A 313) but with a modified nickel content (between 12 and 15% by weight), a modified chromium content (between 17 and 18% by weight) and a modified molybdenum content (between 2 and 2.5% by weight).

[0048] Both metal fiber types of sample A and sample B have been made by means of bundled drawing, as is e.g. described in U.S. Pat. No. 2,050,298.

[0049] Inventive sample A showed the benefit that it can be removed from a tooling after use in hot glass processing, and be put on again and re-used for multiple times. A comparison was made at 680° C. Sample B showed much less lifetime in multiple use than sample A.

[0050] Limiting Oxygen Index (LOI) is measured for sample A and B. Sample B has a measured LOI of 39 vol % oxygen and flame time of 20 seconds. Sample A showed significantly better flame retardant property than sample B: there was no ignition at sample A at 55 vol % oxygen, which is the maximum oxygen volume that can be applied safely in the test.

[0051] Sample A showed excellent heat resistant properties at high temperature. After keeping the sample during 24 hours at 750° C., the sample still showed a good appearance and good performance characteristics, such as strength and elongation of the sample in tensile loading. Sample A and sample B have been tested in cyclic impact loading mode at a temperature of 680° C. Inventive sample A showed a comparable wear and less damage in the cyclic impact loading test than sample B.

[0052] Sagging is the heat resistant separation fabric coming somewhat loose from the surface of the tooling when the tooling is brought in use at high temperature. Sagging is believed to be caused by creep phenomena in the fibers. Sagging can cause quality problems in glass that is contacted by a sagging fabric. In sagging simulation, a fabric is clamped in a ring. The ring with the clamped sample is put in an oven at high temperature (here 680° C.), a plunger is pushed into the fabric until a specific force is attained, after which the plunger is withdrawn. This is repeated 500 times. Sagging is expressed as the increase in distance the plunger has to travel before it touches the fabric and force is build up. In the sagging test, sample A behaviors lightly better than sample B: Sample B showed a result of 30.6 mm, whereas sample A showed a result of 30.1 mm.

[0053] Sample A has been analyzed via Scanning Electron Microscopy (SEM) after heating it to 780° C. in air. Surprisingly, it was observed that the fibers out of the first material had not been much attacked by the heating in air.

[0054] The above examples have been made with fibers of 12 μm equivalent diameter. The invention is not limited to fibers of this equivalent diameter. The use of the invention is not limited to the metal alloys of the specific examples described in the section Mode(s) for Carrying Out the Invention. Also other yarn counts can be made besides the yarn counts of the specific examples.