Title of Invention

A SYSTEM/FURNACE FOR IMPROVED OXIDATION RESISTANCE MEASURING OF CARBON CONTAINING REFRACTORIES

Abstract An improved oxidation resistance measuring furnace and in particular improvement in furnace for comparative evaluation of oxidation resistance of carbon containing refractories. The system /furnace of the invention basically comprises of an enclosed chamber for heating having hearth/plate for placing of the test samples said hearth/plate having at least a portion thereof rotatable under controlled speed and duration of rotation ; means for controlled heating of the chamber; releasable closure means for sample placement/replacement on the rotary hearth/plate ; means for providing controlled atmosphere/air for oxidation in said chamber ; and means for visual inspection of the oxidation process. The furnace provides for determination of oxidation resistance which will generate accurate and reproducible comparative result with more number of samples at a time and adapted for uniform exposure to air/gas (furnace atmosphere) and temperature. The furnace would achieve uniform temperature distribution. The improved oxidation resistance measuring furnace is adapted to test upto six numbers of samples of 40 or 50 mm diameter at a time for comparative evaluation and is directed to provide for an improved oxidation resistance measuring furnace having means for controlled rate of heating, soaking time, cooling rate and duration of rotation.The improved oxidation resistance measuring furnace is further adapted for creating desired gas atmosphere for different heat treatment and kinetic studies.
Full Text The present invention relates to an improved oxidation resistance measuring furnace and in particular improvement in furnace for comparative evaluation of oxidation resistance of carbon containing refractories.
BACKGROUND ART
In Steel Plant different carbon containing refractories e.g. magnesia carbon,
alumina carbon etc. are used in different metallurgical vessels. In BOF MgO-C bricks are used as refractory lining material. MgO-C, AI2O3-C, AI2O3-MgO-C bricks are also finding extensive use in EAF, steel ladles. These bricks contain 5 to 20% carbon. Carbon in MgO-C bricks improves slag corrosion resistance and thermal shock resistance, but the problem with carbon is that it oxidises at high temperature (above 700°C) in oxidising atmosphere. Therefore different additives are used to prevent oxidation.
In order to evaluate oxidation resistance different tests are conducted but there is no standard test method available till date. Generally a 40 or 50 mm cylindrical sample is taken and fired at 1400°C for 2-3 hours and the depth of decarburized layer is measured. But due to changes in furnace size, rate of heating, location of sample inside the furnace, number of samples and their relative positions, distance from the door etc. the results vary considerably. With lot of precautions it is presently done with one test sample along with one standard samples for comparison. Still there is always a chance of error.
OBJECTS OF THE INVENTION
It is therefore the basic object of the present invention to develop a furnace for
determination oxidation resistance which will generate accurate and reproducible 1 ,
comparative result with more number of samples at a time.
Another object of the present invention is to provide an improved oxidation resistance measuring furnace adapted for uniform exposure to air/gas (furnace atmosphere) and temperature.
Another object of the present invention is to provide an oxidation resistance measuring furnace adapted to achieve uniform temperature distribution.

2
Yet another object of the present invention is to provide an improved oxidation resistance measuring furnace adapted to test upto six numbers of samples of 40 or 50 mm diameter at a time for comparative evaluation.
Yet further object of the present invention is directed to provide for an improved oxidation resistance measuring furnace having means for controlled rate of heating, soaking time, cooling rate and duration of rotation.
Yet further object is directed to provide for an improved oxidation resistance measuring furnace adapted for creating desired gas atmosphere for different heat treatment and kinetic studies.
SUMMARY OF THE INVENTION
Thus according to the present invention there is provided a system/furnace for improved oxidation resistance measuring comprising:
an enclosed chamber for heating having hearth/plate for placing of the test
samples said hearth/plate having at least a portion thereof rotatable under
controlled speed and duration of rotation;
means for controlled heating of the chamber;
releasable closure means for sample placement/replacement on the rotary
hearth/plate ;
means for providing controlled atmosphere/air for oxidation in said chamber; and
means for visual inspection of the oxidation process.
Rotation of hearth;
There is a suitable mechanical arrangement and electrical motor for rotating the hearth at the rate of approximately 2 to 15 revolutions per minute (rpm). There is a provision for setting the no. of rotation (count) after which it stops automatically.
Bottom sealing system:
There is a sand sealing arrangement with stainless steel knife system at the rotary hearth bottom to control air infiltration from the bottom.

3
Preferably the furnace is of top loading type with an square opening of about 150mm.
There is a cylindrical hole of about 10 mm with opening and closing arrangement for air circulation. The lid is preferably provided with two handles for easy opening/closing.
In accordance with a preferred aspect of the present invention, the furnace chamber is provided a releasabLe closure means comprising of a top lid for an opening in the top of the chamber adapted for sample placement and replacement on and from the rotary plate/hearth. The lid is preferably provided with two handles for easy opening/closing.
Preferably, the furnace is top loading type with a square opening of about 150mm.
There is a cylindrical hole of about 10mm with opening and closing arrangement for air circulation.
The said means for providing controlled atmosphere/air for oxidation of said chamber comprise means for selectively allowing entry and exit to and from respectively gas or air in and from said chamber for the purpose of oxidation. Preferably, such means comprise pipelines controlling the gas/air source to the chamber inside at the top.
Importantly, to achieve uniform heating, the heating element are provided in all the four side walls of the chamber. Preferably, the furnace is adapted to accommodate upto six samples of 50 mm diameter for uniform testing.
The means for visual inspection of the oxidation process is preferably by way of provision of an inspection hole in the top lid.

4
The details of the invention its objects and advantages are explained hereunder in greater detail in relation to the non-limiting exemplary illustrations as per the accompapying drawings wherein:
Figure 1 is a top plan sectional view of the improved oxidation resistance measuring furnace of the invention.
Fig. 2 is a sectional view of the improved oxidation resistance measuring furnace in accordance with the present invention.
Reference is first invited to Figure 1, which shows in top plan view, an improved oxidation resistance measuring furnace in accordance with the present invention. As shown in said figure, the furnace is basically comprised of the enclosed chamber (CH) having four side walls (SW) and a bottom (BO) and top (TO) which are shown in Figure 2. Substantially, in the middle of the chamber there is provided a rotary plate/hearth (RP) for providing/holding the samples to be tested.
Reference is now invited to Figure 2, which is a sectional view of the improved oxidation resistance measuring furnace in accordance with the present invention. As illustrated in said figure, the said furnace is comprised of the enclosed chamber (CH) with four side walls (SW) and a bottom (BO) and top (TO). At the bottom (BO) thereof is provided a cutout portion (CP) through which the rotatable plate (RP) is operative connected to an arrangement for controlled rotation of the plate. In order to make the chamber air/gas tight, a sand sealing (SS) arrangement is provided there between the rotating arrangement (RA) and the adjacent portions of the cut out portion (CP) of the bottom (BO) of the chamber (CH). Thus the rotatable plate (RP) can be rotated under desired RPM (speed) to thereby expose a test sample to uniform heating and conditions in the chamber. Importantly, in order to facilitate controlled entry of gas/air into the chamber for the purpose of oxidation, a gas entry pipeline (GP) is provided at the bottom is operatively linked to the inside of the chamber while a gas outlet pipeline (GO) at the top is provided communicating with the chamber. Control means (CM) are provided in the pipelines communicating the gas/air into the

chamber and release of gas/air from the chamber to provide for a controlled entry and exit of gas/air into and from the chamber respectively.
To facilitate uniform heating of the chamber heating means/heating elements are uniformly distributed in the chamber preferably in the 4 walls of the chamber.
In order to facilitate placement and replacement of the samples to and from the rotary plate, a releasable lid (LD) is provided on the top of the chamber. With the removal of the lid (LD) by using of the handle means (HM) one can introduce fresh test samples on the rotary plate for testing and there after the lid is closed to effectuate the oxidation process and finally when the oxidation is completed the lid is again opened and the oxidised samples taken out for assessment of its oxidation resistance. Preferably, lid means (LM) is provided with blue glass inspection hole (IH) to favour inspection of the test sample during the oxidation process.
It would be apparent from the above details of the improved oxidation resistance measuring furnace of the invention that the same essentially involves a rotatable hearth used in a chamber having means for programmed heating. By programmed heating it is meant to include the rate of heating, soaking temperature and time as well as the rate of cooling. It is possible to vary the speed of the rotatable plate/hearth as well as the duration of such rotary motion of the plate/hearth depending upon the tests desired to be carried out.
By way of use of the above improved furnace, it is thus possible to carry out the oxidation resistance measuring tests under controlled and simple operating system. Importantly also, reproducibility characteristics of the improved furnace are much better than those of conventional furnaces used of such purposes. The number of test samples, which can be compared with one test sample using the improved furnace of the invention, can extend up to six in numbers and the experimental time required for such comparison of different samples can extend up to one day.

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The number of samples that can be compared using the system can extend up to six and importantly further the furnace provided means for atmosphere control as well as the control of heating soaking temperature, soaking time and the rate of cooling.
Thus it is possible by way of the present invention to not only provide for testing of samples more in numbers under the improved furnace of the invention but even the time for such testing using the improved furnace would be reduced from 5 days to 1 day thereby effecting save of about 4 days of involvement in carrying such steps.
There are wide varieties of different anti-oxidant compounds, which can be used and includes aluminium, silicon, magnesium, aluminium silicon, aluminium magnesium, Ca-Si-Mg, AI-Mg-CaB6, AI-Mg-B4C, AI-CaB6, CaB6, glass, boric compounds and silicates. One or more combination of these compounds can be used as antioxidant depending upon the type of refractory and area of application.
The different process parameters related to the pitch/resin quality and quantity and grain size distribution, pressing pressure/temperature, type of graphite (amorphous, flake) and their amounts, particle size of graphite, type of carbon black and its amount and finally impregnation of bricks with pitch.
It is important to note that while so many advantageous features are included in the improved furnace of the invention it is now possible to test six samples of approximately 50mm diameter and 50mm height on the rotary hearth plate.
Oxidation is a time-temperature phenomenon. Therefore, the rate of heating, soaking time and the cooling rate are to be fixed/controlled from experiment to experiment. Rotation of hearth is essential for uniform oxidation of samples. Variable rpm will help to find out optimum for uniform oxidation. 4-5 rpm is found to be acceptable for uniform oxidation purposes.

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The gas atmosphere for heat treatment and kinetic studies can be any of the following such as argon, nitrogen, carbon mono oxide or air. From the location of the heating element and rotation of the hearth, it is clear that samples are exposed to uniform temperature and gas/air.
Experimental tests were conducted to determine the efficacy of the oxidation resistance measuring furnace of the invention and the results achieved are detailed hereunder:
EXAMPLE-I

Test Temp Soaking Time Rate of heating Rate of cooling Rotation of hearth Duration of hearth rotation Atmosphere Sample size

1400°C
2hr
@ 5°C/min up to 300°C and afterward @ 10°C/min
Natural inside furnace
4 rpm
500 minutes
Air
50 mm dia


Sample No. Description Outer diameter (mm) Core diameter (mm) Oxidised layer
thickness
(mm)
1 Pitch bonded MgO-C of LDBP 50.4 29.0 10.7
2 Pitch bonded MgO-C 50.4 40.4 5.0
3 Resin bonded MgO-C from BSL 50.12 38.8 5.7
4 Resin bonded MgO-C from RSP 50.1 38.9 5.6
5 Resin bonded MgO-C from RSP 50.1 38.7 5.7
6 Tar impregnated burnt magnesia 50.2 16 17.1

8 EXAMPLE-II

Test Temp Soaking Time Rate of heating Rate of cooling Rotation of hearth Duration of hearth rotation Atmosphere Sample size

1400°C
1 hr
8°C/min
Natural inside furnace
5 rpm
400 minutes
Air
50 mm dia


Sample No. Description Outer
diameter
(mm) Core
diameter
(mm) Oxidised layer
thickness (mm) Weight Loss(%)
Drilled from one MgO-C brick 50.1 33.1 8.5 5.7
2 Drilled from the same MgO-C brick 50.1 33.0 8.6 5.3
3 -do- 50.1 33.4 8.4 5.5
4 -do- 50.1 33.0 8.6 5.8
5 -do- 50.1 33.2 8.5 5.6
6 -do- 50.1 33.2 8.5 5.6
EXAMPLE-111

Test Temp Soaking Time Rate of heating Rate of cooling Rotation of hearth Duration of hearth rotation Atmosphere Sample size

1400°C
2hr
8°C/min
Natural inside furnace
5 rpm
400 minutes
Air
40 mm dia

9

Sample Description Outer diameter Core diameter No. (mm) (mm)
Oxidised layer
thickness
(mm)
1L MgO-C with Al alloy 41.0 20.4 10.3
2E MgO-C with Mg alloy 40.6 18.0 11.3
3L MgO-C with Al 40.6 21.7 9.5
4L MgO-C with Al & Si 40.6 23.1 8.8
EXAMPLE-IV
Test Temp : 1450°C
Soaking Time : 2 hr
Rate of heating : @ 10°C/min
Rate of cooling : Natural inside furnace
Rotation of hearth : 4 rpm
Duration of hearth rotation : 500 minutes
Atmosphere : Air
Sample size : 40 mm dia
Sample Description Outer diameter Core diameter Oxidised layer
No. (mm) (mm)
thickness (mm)
R1 Resin bonded MgO-C 40.6 Nil Fully oxidised
R2 Resin bonded MgO-C 40.6 Almost nil 20.3
R3 Resin bonded MgO-C 40.6 Nil Fully oxidised
A1 Resin bonded MgO-C 40.6 15.8 12.4
A2 Resin bonded MgO-C 40.6 24.2 8.2
A3 Resin bonded MgO-C 40.6 27 6.8

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EXAMPLE-V

Test Temp Soaking Time Rate of heating
Rate of cooling Rotation of hearth Duration of hearth rotation Atmosphere Sample size

1400°C
2hr
@ 4°C/min up to 200°C & holding for 5 mins then
@ 5°C/min up to 400°C & holding for 5 mins then
@ 6°C/min up to 700°C & holding for 5 mins then
@ 7°C/min up to 1400°C & holding for 120 mins.
Natural inside furnace
5 rpm
500 minutes
Air
Rectangular cross section

Sample i Description Width (mm) Breadth (mm) Oxidised layer ,
No. thickness
Outer Inner Outer Inner Average (mm)
1 MgO-C (KC-73) 43 26 42 25 8 5
7 2 MgO-C (OCL) 46 34 44 62 6

3 MgO-C(OCL) 45 | 33 44 32 6
4 I" MgO-C (BSCL) 46 37 43 34 45
EXAMPLE-VI
Test Temp : 1450°C
Soaking Time : 1 hr
Rate of heating : @ 5°C/min up to 300°C & holding for 5 mins then
@ 7°C/min up to 1450°C & holding for 60 mins.
Rate of cooling : @ 5°C/min up to 1300°C & holding for 5 mins then
@ 10°C/min up to 1000°C & holding for 5 mins
then natural cooling.

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Rotation of hearth : 5 rpm
* Duration of hearth rotation : 500 minutes
Atmosphere : Air
Sample size : 50 mm dia

Sample No. Description Outer diameter (mm) Core diameter (mm) Oxidised layer
thickness
(mm)
1 Pitch bonded MgO-C 50.2 8.4 10.5
2 Pitch bonded MgO-C 50.2 6.2 22
3 Resin bonded MgO-C from BSL 50.2 18.4 15.9
4 Resin bonded MgO-C 50.2 15.3 17.5
It is seen from Example-II, that there is slight variation of weight loss and the thickness of oxidised layer. This is due to the fact that the distribution of carbon is not exactly the same in all parts of 550x125x150mm refractory bricks and therefore results varied slightly are quite acceptable.
Importantly, as illustrated above, the furnace is electrically heated top loading type, with a part of the hearth circle cross-section adapted to rotate to have uniform heating and oxidation of test pieces.
Preferably, the heating space is approximately 300mm (width) x 300mm (breadth) x 200mm (heights). Operating temperature condition operating from 1450°C (max) for 4 hours run and below 1400°C (max) for continuous run. The heating elements are preferably selected to comprise silicon carbide rods straight in diameter (solid type) with number of elements ranging from 12 or nearest equally distributed in all side walls.
The power feed into the furnace can comprise thyrister power driven.

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The temperature controller is basically a digital programmer controlled microprocessor based PID temperatures controller with ramp facility compatible with different type of thermocouples. The furnace of the invention is thus found to be capable of:
i) controlling the rate of heating from 3 to 7°C/minute.
ii) Temperature control accuracy: within ± 2°C of set point.
iii) Temperature uniformity inside furnace :
within + 0.5% at the set temperature above 100°C. iv) Thermocouples : Pt. - Pt. Rh 13% (R type) or Pt. - Pt. Rh 10% (S type)
Preferably, the constructions of the furnace involve use of welded angle iron frame floor model with separate control panel. Height of the furnace is about 1200 mm for easy loading of samples from the top. There is a peep hole with blue glass for observing the samples during firing. There is an arrangement (with opening and closing system) for sending gas through the lower part of the furnace.
Working face refractories is made of almost zero shrinkage high alumina backed by low heat capacity insulation bricks/and ceramic fibre insulation. There is suitable safety device/blind controller to safe guard against costly heating elements.
It is thus possibly by way of the present invention to achieve the following:
a. An oxidation resistance measuring furnace wherein atleast a part of the
hearth rotates at different speed ranging from 2 to 15 rpm to thereby achieve
uniform exposure to air/gas (furnace atmosphere) and temperature.
b. SiC heating elements located in all the four side walls provide for uniform
temperature distribution.

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c. A top loading type oxidation resistance furnace where up to 6 number of
samples of 40 or 50 mm diameter can be tested at a time for comparative
evaluation.
d. An oxidation resistance furnace where rate of heating, soaking time, cooling
rate and duration of rotation can be controlled.
e. An electrically heated furnace where there is sand sealing arrangement at the
rotating hearth system for closing the entry of air and there is a gas inlet
arrangement for creating desired gas atmosphere for different heat treatment
and kinetic studies.
The above disclosed oxidation resistance measuring furnace of the invention avoids the problems of conventional systems wherein there is always chances of error in evaluating oxidation resistance from experiment to experiment and from furnace to furnace and provide for a system wherein oxidation resistance can be correctly evaluated and compared with different carbon bearing refractories at a time.
Reproducible results can be obtained by fixing furnace operating parameters from experiment to experiment. For more accurate results one standard sample may be incorporated for comparative evaluation of oxidation resistance from experiment to experiment. Considerable research time can be saved by experimenting with more number of smaller diameter samples in one run for the development of oxidation resistance refractories with addition of different antioxidant compounds and process parameter. The developed furnace can also be used for conducting different heat treatment and kinetic studies in different furnace atmosphere, rate of heating and temperature. The system of the invention is also economic in that instead of conducting oxidation test by conventional method for five times, the oxidation test can now be done in the developed furnace in one experiment thereby saving valuable electrical energy and laboratory experimentation time.

WE CLAIM :
1. A system/furnace for improved oxidation resistance measuring of carbon containing
refractories comprising:
an enclosed chamber for heating having hearth/plate for placing of the test samples
said hearth/plate having at least a portion thereof rotatable under controlled speed
and duration of rotation;
means for controlled heating of the chamber;
releasable closure means for sample placement/replacement on the rotarv
hearth/plate ;
means for providing controlled atmosphere/air for oxidation in said chamber; and
means for visual inspection of the oxidation process.
2. A system/furnace as claimed in claim 1 comprising mechanical arrangement and electrical motor for rotating the said hearth/plate.
3. A system/furnace as claimed in anyone of claims 1 or 2 wherein said plate/hearth is adapted for rotation at the rate of approximately 2 to 15 revolutions per minute (rpm).
4. A system/furnace as claimed in anyone of claims 1 to 3 comprising means for setting the duration of rotation (time).
5. A system/furnace as claimed in anyone of claims 1 to 4 comprising a sand sealing arrangement with stainless steel knife system at the rotary hearth bottom to control air infiltration from the bottom.
6. A system/furnace as claimed in anyone of claims 1 to 5 wherein said furnace chamber is of top loading type with a square opening.
7. A system/furnace as claimed in anyone of claims 1 to 6 wherein the lid is comprised of handle means for easy opening/closing.
14

15
8. A system/furnace as claimed in anyone of claims 1 to 7 wherein the releasable closure means comprising of a top lid for an opening in the top of the chamber adapted for sample placement and replacement on and from the rotary plate/hearth.
9. A system/furnace as claimed in anyone of claims 1 to 8 wherein said means for providing controlled atmosphere/air for oxidation of said chamber comprise means for selectively allowing entry and exit to and from respectively gas or air in and from said chamber for the purpose of oxidation.
10. A system/furnace as claimed in anyone of claims 1 to 9 wherein said means comprise pipelines controlling the gas/air source to the chamber inside at the top.
11. A system/furnace as claimed in anyone of claims 1 to 10 comprising means for uniform heating comprising heating element provided in all the four side walls of the chamber.
12. A system/furnace as claimed in anyone of claims 1 to 11 wherein said means for visual inspection of the oxidation process comprise an inspection hole in the top lid.
13. A system/furnace as claimed in anyone of claims 1 to 12 wherein the bottom thereof is provided a cutout portion through which the rotatable plate is operative connected to an arrangement for controlled rotation of the plate.
14. A system/furnace as claimed in anyone of claims 1 to 13 wherein to make the chamber air/gas tight, a sand sealing arrangement is provided there between the rotating arrangement and the adjacent portions of the cut out portion of the bottom of the chamber.
15. A system/furnace as claimed in anyone of claims 1 to 14 comprising means for controlled entry of gas/air into the chamber for the purpose of oxidation

16
comprises a gas entry pipeline is provided at the bottom operatively linked to the inside of the chamber while a gas outlet pipeline at the top provided for communicating with the chamber.
16. A system/furnace as claimed in claim 15 comprising control means provided in the pipelines communicating the gas/air into the chamber and release of gas/air from the chamber to provide for a controlled entry and exit of gas/air into and from the chamber respectively.
17. A system/furnace as claimed in anyone of claims 1 to 16 wherein said means for uniform heating of the chamber comprise heating means/heating elements uniformly distributed in the chamber preferably in the four side walls of the chamber.
18. A system/furnace as claimed in anyone of claims 1 to 17 wherein said lid means is provided with blue glass inspection hole to favour inspection of the test sample during the oxidation process.
19. A system/furnace as claimed in anyone of claims 1 to 18 comprising a rotatable hearth used in a chamber having means for programmed heating.
20. A system/furnace as claimed in anyone of claims 1 to 19 wherein said programmed heating means comprise means for controlled rate of heating, soaking temperature and time as well as the rate of cooling.
21. A system/furnace as claimed in anyone of claims 1 to 20 wherein the gas atmosphere for heat treatment and kinetic studies comprising gases selected from argon, nitrogen, carbon mono oxide or air.
22. A system/furnace as claimed in anyone of claims 1 to 21 wherein the heating space is in the range of 280 to 350 mm (width) preferably 300 mm (width) x 280 to 350 mm preferably 300 mm (breadth) x 170 to 250 mm preferably 200mm (heights).

23. A system/furnace as claimed in anyone of claims 1 to 22 wherein the operating temperature condition are adapted from temperature from 1450°C (max) for 4 hours run and below 1400°C (max) for continuous run.
24. A system/furnace as claimed in anyone of claims 1 to 23 wherein the heating elements are preferably selected to comprise silicon carbide rods straight in diameter (solid type) with number of elements ranging from 12 or nearest equally distributed in all side walls.
25. A system/furnace as claimed in anyone of claims 1 to 24 wherein the power feed
into the furnace can comprise thyrister power driven.
26. A system/furnace as claimed in anyone of claims 1 to 25 wherein the
temperature controller is basically a digital programmer controlled
microprocessor based PID temperatures controller with ramp facility compatible
with different type of thermocouples.
27. A method for carrying out the evaluation of oxidation resistance of carbon
containing refractories, using system/furnace as claimed in claims 1 to 26
comprising :
i) controlling the rate of heating from 3 to 7oC/minute.
ii) temperature control accuracy : within ± 2°C of set point.
iii) temperature uniformity inside furnace:
within ± 0.5% at the set temperature above 100°C.
iv) thermocouples : Pt. - Pt. Rh 13% (R type) or Pt. - Pt. Rh 10% (S type)
28. A system/furnace for improved oxidation resistance measuring and a method for
carrying out the evaluation of oxidation resistance of carbon containing
refractories using such system/furnace substantially such as hereindescribed
with reference to the accompanying figures and examples.
Dated this 21st day of May 2001.
17
An improved oxidation resistance measuring furnace and in particular improvement in furnace for comparative evaluation of oxidation resistance of carbon containing refractories. The system /furnace of the invention basically comprises of an enclosed chamber for heating having hearth/plate for placing of the test samples said hearth/plate having at least a portion thereof rotatable under controlled speed and duration of rotation ; means for controlled heating of the chamber; releasable closure means for sample placement/replacement on the rotary hearth/plate ; means for providing controlled atmosphere/air for oxidation in said chamber ; and means for visual inspection of the oxidation process.
The furnace provides for determination of oxidation resistance which will generate accurate and reproducible comparative result with more number of samples at a time and adapted for uniform exposure to air/gas (furnace atmosphere) and temperature. The furnace would achieve uniform temperature distribution. The improved oxidation resistance measuring furnace is adapted to test upto six numbers of samples of 40 or 50 mm diameter at a time for comparative evaluation and is directed to provide for an improved oxidation resistance measuring furnace having means for controlled rate of heating, soaking time, cooling rate and duration of rotation.The improved oxidation resistance measuring furnace is further adapted for creating desired gas atmosphere for different heat treatment and kinetic studies.

Documents:

00295-cal-2001-abstract.pdf

00295-cal-2001-claims.pdf

00295-cal-2001-correspondence.pdf

00295-cal-2001-description(complete).pdf

00295-cal-2001-drawings.pdf

00295-cal-2001-form-1.pdf

00295-cal-2001-form-18.pdf

00295-cal-2001-form-2.pdf

00295-cal-2001-form-3.pdf

00295-cal-2001-letters patent.pdf

00295-cal-2001-p.a.pdf

295-cal-2001-granted-abstract.pdf

295-cal-2001-granted-claims.pdf

295-cal-2001-granted-description (complete).pdf

295-cal-2001-granted-drawings.pdf

295-cal-2001-granted-form 2.pdf

295-cal-2001-granted-specification.pdf


Patent Number 200689
Indian Patent Application Number 295/CAL/2001
PG Journal Number N/A
Publication Date 26-Jan-2007
Grant Date 25-Jan-2007
Date of Filing 21-May-2001
Name of Patentee STEEL AUTHORITY OF INDIA LIMITED
Applicant Address RESEARCH & DEVELOPMENT CENTRE FOR IRON & STEEL, DORANDA, RANCHI-834002,
Inventors:
# Inventor's Name Inventor's Address
1 GHOSH NIRMAL KANTI RESEARCH & DEVELOPMENT CENTRE FOR IRON & STEEL, DORANDA, RANCHI-834002,
2 DE TAPAS KUMAR RESEARCH & DEVELOPMENT CENTRE FOR IRON & STEEL, DORANDA, RANCHI-834002,
3 BARUA PULAK RESEARCH & DEVELOPMENT CENTRE FOR IRON & STEEL, DORANDA, RANCHI-834002,
4 CHAKRABORTI DEBI PRASAD RESEARCH & DEVELOPMENT CENTRE FOR IRON & STEEL, DORANDA, RANCHI-834002,
5 NANDI SANDIP KUMAR RESEARCH & DEVELOPMENT CENTRE FOR IRON & STEEL, DORANDA, RANCHI-834002,
PCT International Classification Number F 27 B 9/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA