Indian Patents. 255487:METHOD OF ENHANCING WATER SPRAY COOLING OF STEEL

Title of Invention	METHOD OF ENHANCING WATER SPRAY COOLING OF STEEL
Abstract	A method of enhancing water spray cooling of finished steel comprising of controlled cooling of steel rolls and hot rolled steel products such as strips and rods with an aqueous solution of DuPont™ ZonyI® FSH, a nonionic surfactant in predetermined concentration and under pressure, the steel products being in the respective temperature ranges of interest.

Full Text	Field of invention: The invention relates to enhanced heat transfer in general and to rapid controlled cooing of finished steel products in particular. This invention relates to a controlled cooling process for rapid cooling, which is applicable to a number of applications such as roll cooling, Run-Out-Table cooling, continuous casting of steel strip and cooling, continuous casting of steel strip and cooling of steel rods. Background and prior art: Cooling of steel products is very important stage in the manufacturing of such products. Cooling has to be as fast as possible in order to reduce the total time for manufacturing . At the same time, cooling must be controlled to ensure that the end product meets the standards of metallurgical and mechanical properties and the desired surface finish. The cooling process must also ensure that it is cost effective and poses least threat to the environment. The best available choice is water and water sprays are common for cooling of materials at high temperature. There is therefore continuous effort in this field to achieve controlled cooling methods with higher heat transfer rates which have industrial applicability from perspectives of water conservation and improvements in its cooling efficiency In describing the prior art, the following documents have been referred to: 1. GLEEBLE 1500 Operation Manual, Duffers Scientific, Inc., 1989. 2. Wasekar, V.M.,2007, 'Accelerated cooling approaches for Run Out table applications', TATA Search, pp. 256-265 Chen, S.J. and Tseng, A.A., 1992, "Spray and jet cooling in steel rolling", Int. J. Heat and Fluid Flow, Vol.13, No.4, pp.358-369. Spray cooling is known in the art, which is typically used for rapid rates of controlled cooling of hot surfaces, such as rolls having surface temperatures in the range of 80°C to 200°C and strips, which have surface temperature range of 400°C to 1000°C (Chen and Tseng, 1991). In general, two types of spray cooling approaches are employed viz., atomized sprays and pressure sprays. While atomized sprays use high pressure gas to break up the liquid, pressure is applied to liquid in pressure sprays to deliver a jet of fluid through orifices. Schone, J.W. and Williams, R., 2003, "Method of continuously casting electrical steel strip with controlled spray cooling", WO03/023074 A1. International Publication Number WO 03/023074 A1 (Schone and Williams, 2003) discloses controlled spray cooling to cool continuously cast electrical steel strip to the end temperatures in the range of 600°C to 100°C. The spray duration based on end temperatures varied from 8 seconds to more than 20 seconds, respectively. These are water sprays without any additives in water. For fast cooling applications, the disadvantage of water sprays is that they provide limitation from the point of view of larger flow rates and corresponding strip deformation issues are possible due to impacting sprays. Conklin, M.T. and Mowry, C.F., 1984, "Cooling heated metal surfaces", US Patent Number 4476687. A method is disclosed in US 4476687 (Conklin and Mowry, 1984), which uses comparatively low flow rates for rapidly cooling heated surfaces by water having one or more of nonionic surfactants sprayed without foam to cool faster than conventionally used water systems. However, it has disadvantage in terms of the cooling efficiency not being quantified with respect to the improvement in cooling time or cooling rate over that of water system. Further disadvantage of this cooling process is the total time it takes for cooling of a plate or sheet from 1100°C to 80°C, which is of the order of few minutes. The controlled water spray cooling system disclosed in WO 03/023074 A1 (Schoen and Roberts, 2003) typically cools a steel sheet having thickness of about 2.9 mm and width of about 80 mm by water spraying both surfaces in a total time, which is of the order of 10 to 20 seconds. Both these total for cooling are comparatively much higher than the time desired by the manufacturing processes of today's facilities, which are of the order of few seconds for thin strips of around 1 mm thickness. The other disadvantage of the invention disclosed in 4476687 is the limiting range of surfactant additive(s) cloud point from 68°F - 212°F, beyond which the cooling efficiency goes down drastically. DuPont, 2001, "DuPont™ Zinyl@ FSH Fluorosurfactant" (Information on technical data). For the same flow rates of water an improvement over the cooling spray duration values can be achieved using the invention disclosed in this description, which uses DuPont™ Zonyl@ FSH (a nonionic surfactant) in water. It may be mentioned here that the current trend in the steel industry is to produce thinner strips, their thickness starting from 0.7 mm. These strips are very sensitive to surface distortion due to high pressure water spray during cooling. At the same time, very high cooling rates in the range of 700°C/ second are demanded by the manufacturing process. The invention as disclosed in this description is suited for such types of controlled rapid cooling of thin strips. This rapid cooling method of the present invention disclosed herein has further advantage over that disclosed inUS4476687 with respect to the cloud point of the surfactant additive(s). While a single nonionic surfactant or combinations of these surfactants should have cloud point in the range of 68°F - 212°F as per the invention disclosed in US 4476687 the nonionic surfactant DuPont™ Zonyl@ FSH used in the present invention has no cloud point in the temperature range of 68°F - 212°F (DuPont,2001). Furthermore the referred US patent states that a nonionic surfactant with a cloud point above 212°F loses its cooling capability for rapidly cooling heated surfaces by spraying without foam. Present invention disproves this temperature limit based on the cloud point characteristic of the nonionic surfactant DuPont™ Zonyl@ FSH. Objects of the invention: An object of this invention, is to propose a cooling process for the rapid cooling of steel, especially for applications such as roll cooling, Run-Out-Table cooling, continuous casting of steel strip and cooling of steel rods. Yet another object of this invention, is to propose a cooling process that employs spray cooling using pressure sprays. Still another object of this invention, is to propose a cooling process that provides much more efficient cooling than water for cooling of steel in the temperature range of interest from 950°C to 840°C. A further object of this invention, is to propose a cooling process, which uses Dupont™ Zonyl@ FSH surfactant as an additive to water. A still further object of this invention, is to propose a cooling process, which uses surfactant additive(s) having no could point in the range of 68°F -212°F. Description of the invention: According to this invention there is provided a method of controlled cooling process for rapid cooling of steel wherein the process comprises of spray cooling using Dupont™ Zonyl@ FSH surfactant (nonionic) as an additive to water at volumetric concentration levels of less than 2% more specifically in the range of 0.01% to 0-0,4%. DuPont™ Zonyl@ FSH is a nonionic fluorosurfactant having structure as R1CH2 CH2O(CH2CH2O)xH, where Rf = F(CF2CF2)y (DuPont, 2001). It gives exceptionally low surface tension in its aqueous solutions, the values of which are of the order of 17 to 22 dyn/cm for the surfactant concentration range of 0.1 to 0.001% and provides better wetting and spreading characteristics. Even at very low concentrations, it delivers much improved wetting power. Additionally, the surfactant concentration is small, which changes only the surface tension of water and the other properties of water remain same. Moreover, DuPont™ Zonyl@ FSH is nonhazardous, nonflammable thus making it an appropriate choice as safe and economically useful additive. Aqueous solutions of DuPont™ Zonyl@ FSH have been investigated for rapidly cooling heated surfaces, more specifically, hot steel surface from temperatures of around 800°C to temperatures of around 100°C. This is carried out using Gleeble Quench System, which uses spray cooling that allows to investigate cooling using horizontal pressure sprays impacting vertical steel strip (GLEEBLE 1500 Operation Manual, 1989). The nature of the invention, objective and further advantage residing in the same will be apparent from the following description made with reference to non limiting exemplary embodiment of the invention represented in the accompanying drawing. Fig.l is a graphical representation of the cooling efficiency of DuPont™ Zonyl@ FSH in the temperature range of interest. In this invention, the temperature range of interest is from 800°C to 100°C. Figure 1 shows the drop in heated steel surface temperature over cooling time period. With DuPont™ Zonyl@ FSH, cooling time reduction is more than 40%. Higher cooling rates are observed with higher pressure. For lower pressure flow condition, both water cylinders were used, whereas single water cylinder was used for higher pressure flow condition. Moreover, maximum temperature drop is more than two times that for water. Additionally, for all the operating conditions employed in this investigation, the cooling performance of DuPont™ Zonyl@ FSH with respect to the total cooing time is consistent for various of its concentrations in water. As already mentioned, the present invention relates to the process of employing rapid cooling using spray cooling approach in the cooling of hot steel surface on the Run-Out-Table or steel rods or steel rolls. Primarily two possibilities for rapid cooling for ROT application exist: early UFC (Ultra Fast Cooling) located just after the finishing mill to refine grain and to improve the properties of high strength low alloy (HSLA) steels and late UFC located at the Run-Out-Table exit, before the down-coiler to generate multiphase microstructures and improved mechanical properties (Wasekar, 2007). The present invention envisages useful possibility of "late UFC" application with very high temperature drops near the exit of ROT for the processing of dual phase and multiphase high strength steels. The high rates of cooling achieved with this rapid cooling approach as disclosed in this invention cover the range of temperatures up to martensitic transformation and beyond. The conventional rapid cooling water system requires turbulent flow conditions to achieve high secondary cooling rates of around 1000°C/s (Wasekar,2007).The maximum cooling rates as achieved in this invention are comparable to those achieved for these systems. Aqueous solutions of DuPont™ Zonyl@ FSH have also been investigated for rapidly cooling heated surfaces, more specifically, hot steel surface from temperatures of around 950°C- 930°C to temperatures of around 880°C-840°C. This is carried out for 5.5 mm wire rod at mill speed of 55m/s by injecting surfactant in water stream, which is supplied to cool the wire rod in a water box through nozzles under pressure of 4 bars. Fig.2 is schematic of experimental facility showing the injection system for the DuPont™ ZonylR FSH in water stream for cooling of 5.5 mm wire rod. The facility was first calibrated with water. The surfactant is allowed to drain with water and is not recirculated. The enhancement as observed in above embodiments is presented in Fig. 3 schematically. The are exemplary embodiments presenting a cooling process employing spray cooling and using aqueous solution of DuPont™ ZonylR FSH that provide efficient cooling than water for cooling of steel in the temperature ranges of interest shown in Fig.3 and the dynamic condition of steel surface to be cooled. The invention described hereinabove is in relation to a non limiting embodiment and is exemplary. Any other embodiment employing the same inventive concept is deemed to be included in this description. We claim 1. An method of enhancing water spray cooling of finished steel comprising of controlled cooling of steel rolls and hot rolled steel products such as strips and rods with an aqueous solution of nonionic surfactant in predetermined concentration and under pressure, the steel products being in the respective temperature ranges of interest. 2. A method as claimed in claim 1, wherein the said nonionic surfactant is used in volumetric concentration of less than 2%, more specifically in the range of 0.01% to 0.4%, 3. A method as claimed in claims 1 and 2, wherein the said surfactant has no dould point in the temperature range of 68°F - 212°F. 4. A method as claimed in claims 1 and 2, wherein one of the said temperature range of interest is 800°C - 100°C. 5. A method as claimed in claims 1 and 2, wherein one of the said temperature range of interest is 950°C - 840°C. 6. A method as claimed in claims 1 and 2, wherein the maximum temperature drop is more than two times that for water. Abstract Title: Method of enhancing water spray cooling of steel A method of enhancing water spray cooling of finished steel comprising of controlled cooling of steel rolls and hot rolled steel products such as strips and rods with an aqueous solution of DuPont™ ZonyI® FSH, a nonionic surfactant in predetermined concentration and under pressure, the steel products being in the respective temperature ranges of interest.

Full Text

Field of invention:
The invention relates to enhanced heat transfer in general and to
rapid controlled cooing of finished steel products in particular.
This invention relates to a controlled cooling process for rapid
cooling, which is applicable to a number of applications such as roll
cooling, Run-Out-Table cooling, continuous casting of steel strip and
cooling, continuous casting of steel strip and cooling of steel rods.
Background and prior art:
Cooling of steel products is very important stage in the
manufacturing of such products. Cooling has to be as fast as possible
in order to reduce the total time for manufacturing . At the same
time, cooling must be controlled to ensure that the end product
meets the standards of metallurgical and mechanical properties and
the desired surface finish. The cooling process must also ensure that
it is cost effective and poses least threat to the environment. The
best available choice is water and water sprays are common for
cooling of materials at high temperature. There is therefore

continuous effort in this field to achieve controlled cooling methods with
higher heat transfer rates which have industrial applicability from
perspectives of water conservation and improvements in its cooling
efficiency
In describing the prior art, the following documents have been referred
to:
1. GLEEBLE 1500 Operation Manual, Duffers Scientific, Inc., 1989.
2. Wasekar, V.M.,2007, 'Accelerated cooling approaches for Run Out
table applications', TATA Search, pp. 256-265
Chen, S.J. and Tseng, A.A., 1992, "Spray and jet cooling in steel
rolling", Int. J. Heat and Fluid Flow, Vol.13, No.4, pp.358-369.
Spray cooling is known in the art, which is typically used for rapid
rates of controlled cooling of hot surfaces, such as rolls having
surface temperatures in the range of 80°C to 200°C and strips, which
have surface temperature range of 400°C to 1000°C (Chen and
Tseng, 1991). In general, two types of spray cooling approaches are
employed viz., atomized sprays and pressure sprays. While atomized
sprays use high pressure gas to break up the liquid, pressure is
applied to liquid in pressure sprays to deliver a jet of fluid through
orifices.

Schone, J.W. and Williams, R., 2003, "Method of continuously
casting electrical steel strip with controlled spray cooling",
WO03/023074 A1.
International Publication Number WO 03/023074 A1 (Schone and
Williams, 2003) discloses controlled spray cooling to cool
continuously cast electrical steel strip to the end temperatures in the
range of 600°C to 100°C. The spray duration based on end
temperatures varied from 8 seconds to more than 20 seconds,
respectively. These are water sprays without any additives in water.
For fast cooling applications, the disadvantage of water sprays is
that they provide limitation from the point of view of larger flow
rates and corresponding strip deformation issues are possible due to
impacting sprays.
Conklin, M.T. and Mowry, C.F., 1984, "Cooling heated metal
surfaces", US Patent Number 4476687.
A method is disclosed in US 4476687 (Conklin and Mowry, 1984),
which uses comparatively low flow rates for rapidly cooling heated
surfaces by water having one or more of nonionic surfactants sprayed
without foam to cool faster than conventionally used water systems.
However, it has disadvantage in terms of the cooling efficiency not

being quantified with respect to the improvement in cooling time or
cooling rate over that of water system. Further disadvantage of this
cooling process is the total time it takes for cooling of a plate or sheet
from 1100°C to 80°C, which is of the order of few minutes. The
controlled water spray cooling system disclosed in WO 03/023074 A1
(Schoen and Roberts, 2003) typically cools a steel sheet having
thickness of about 2.9 mm and width of about 80 mm by water
spraying both surfaces in a total time, which is of the order of 10 to 20
seconds. Both these total for cooling are comparatively much higher
than the time desired by the manufacturing processes of today's
facilities, which are of the order of few seconds for thin strips of around
1 mm thickness. The other disadvantage of the invention disclosed in
4476687 is the limiting range of surfactant additive(s) cloud point from
68°F - 212°F, beyond which the cooling efficiency goes down
drastically.
DuPont, 2001, "DuPont™ Zinyl@ FSH Fluorosurfactant" (Information on
technical data).
For the same flow rates of water an improvement over the cooling
spray duration values can be achieved using the invention disclosed in
this description, which uses DuPont™ Zonyl@ FSH (a nonionic
surfactant) in water.

It may be mentioned here that the current trend in the steel industry is
to produce thinner strips, their thickness starting from 0.7 mm. These
strips are very sensitive to surface distortion due to high pressure water
spray during cooling. At the same time, very high cooling rates in the
range of 700°C/ second are demanded by the manufacturing process.
The invention as disclosed in this description is suited for such types of
controlled rapid cooling of thin strips.
This rapid cooling method of the present invention disclosed herein has
further advantage over that disclosed inUS4476687 with respect to the
cloud point of the surfactant additive(s). While a single nonionic
surfactant or combinations of these surfactants should have cloud point
in the range of 68°F - 212°F as per the invention

disclosed in US 4476687 the nonionic surfactant DuPont™ Zonyl@
FSH used in the present invention has no cloud point in the
temperature range of 68°F - 212°F (DuPont,2001).
Furthermore the referred US patent states that a nonionic
surfactant with a cloud point above 212°F loses its cooling capability
for rapidly cooling heated surfaces by spraying without foam. Present
invention disproves this temperature limit based on the cloud point
characteristic of the nonionic surfactant DuPont™ Zonyl@ FSH.
Objects of the invention:
An object of this invention, is to propose a cooling process for the
rapid cooling of steel, especially for applications such as roll cooling,
Run-Out-Table cooling, continuous casting of steel strip and cooling
of steel rods.
Yet another object of this invention, is to propose a cooling
process that employs spray cooling using pressure sprays.
Still another object of this invention, is to propose a cooling
process that provides much more efficient cooling than water for
cooling of steel in the temperature range of interest from 950°C to
840°C.

A further object of this invention, is to propose a cooling process,
which uses Dupont™ Zonyl@ FSH surfactant as an additive to water.
A still further object of this invention, is to propose a cooling
process, which uses surfactant additive(s) having no could point in
the range of 68°F -212°F.
Description of the invention:
According to this invention there is provided a method of
controlled cooling process for rapid cooling of steel wherein the
process comprises of spray cooling using Dupont™ Zonyl@ FSH
surfactant (nonionic) as an additive to water at volumetric
concentration levels of less than 2% more specifically in the range of
0.01% to 0-0,4%.
DuPont™ Zonyl@ FSH is a nonionic fluorosurfactant having structure
as R1CH2 CH2O(CH2CH2O)xH, where Rf = F(CF2CF2)y (DuPont, 2001).
It gives exceptionally low surface tension in its aqueous solutions, the
values of which are of the order of 17 to 22 dyn/cm for the
surfactant concentration range of 0.1 to 0.001% and provides better
wetting and spreading characteristics. Even at very low
concentrations, it delivers much improved wetting power.
Additionally, the surfactant concentration is small, which changes

only the surface tension of water and the other properties of water
remain same. Moreover, DuPont™ Zonyl@ FSH is nonhazardous,
nonflammable thus making it an appropriate choice as safe and
economically useful additive. Aqueous solutions of DuPont™ Zonyl@
FSH have been investigated for rapidly cooling heated surfaces, more
specifically, hot steel surface from temperatures of around 800°C to
temperatures of around 100°C. This is carried out using Gleeble
Quench System, which uses spray cooling that allows to investigate
cooling using horizontal pressure sprays impacting vertical steel strip
(GLEEBLE 1500 Operation Manual, 1989).
The nature of the invention, objective and further advantage
residing in the same will be apparent from the following description
made with reference to non limiting exemplary embodiment of the
invention represented in the accompanying drawing.
Fig.l is a graphical representation of the cooling efficiency of
DuPont™ Zonyl@ FSH in the temperature range of interest. In this
invention, the temperature range of interest is from 800°C to 100°C.

Figure 1 shows the drop in heated steel surface temperature over
cooling time period. With DuPont™ Zonyl@ FSH, cooling time
reduction is more than 40%. Higher cooling rates are observed with
higher pressure. For lower pressure flow condition, both water

cylinders were used, whereas single water cylinder was used for
higher pressure flow condition. Moreover, maximum temperature
drop is more than two times that for water. Additionally, for all the
operating conditions employed in this investigation, the cooling
performance of DuPont™ Zonyl@ FSH with respect to the total
cooing time is consistent for various of its concentrations in water.
As already mentioned, the present invention relates to the process of
employing rapid cooling using spray cooling approach in the cooling
of hot steel surface on the Run-Out-Table or steel rods or steel rolls.
Primarily two possibilities for rapid cooling for ROT application exist:
early UFC (Ultra Fast Cooling) located just after the finishing mill to
refine grain and to improve the properties of high strength low alloy
(HSLA) steels and late UFC located at the Run-Out-Table exit, before
the down-coiler to generate multiphase microstructures and improved
mechanical properties (Wasekar, 2007).
The present invention envisages useful possibility of "late UFC"
application with very high temperature drops near the exit of ROT for
the processing of dual phase and multiphase high strength steels.
The high rates of cooling achieved with this rapid cooling approach
as disclosed in this invention cover the range of temperatures up to

martensitic transformation and beyond. The conventional rapid cooling water
system requires turbulent flow conditions to achieve high secondary cooling rates
of around 1000°C/s (Wasekar,2007).The maximum cooling rates as achieved in
this invention are comparable to those achieved for these systems.
Aqueous solutions of DuPont™ Zonyl@ FSH have also been investigated for
rapidly cooling heated surfaces, more specifically, hot steel surface from
temperatures of around 950°C- 930°C to temperatures of around 880°C-840°C.
This is carried out for 5.5 mm wire rod at mill speed of 55m/s by injecting
surfactant in water stream, which is supplied to cool the wire rod in a water box
through nozzles under pressure of 4 bars.
Fig.2 is schematic of experimental facility showing the injection system for the
DuPont™ ZonylR FSH in water stream for cooling of 5.5 mm wire rod. The facility
was first calibrated with water. The surfactant is allowed to drain with water and
is not recirculated.
The enhancement as observed in above embodiments is presented in Fig. 3
schematically. The are exemplary embodiments presenting a cooling process
employing spray cooling and using aqueous solution of DuPont™ ZonylR FSH that
provide efficient cooling than water for cooling of steel in the temperature ranges
of interest shown in Fig.3 and the dynamic condition of steel surface to be
cooled.
The invention described hereinabove is in relation to a non limiting
embodiment and is exemplary. Any other embodiment employing the same
inventive concept is deemed to be included in this description.

We claim
1. An method of enhancing water spray cooling of finished steel comprising of
controlled cooling of steel rolls and hot rolled steel products such as strips
and rods with an aqueous solution of nonionic surfactant in predetermined
concentration and under pressure, the steel products being in the respective
temperature ranges of interest.
2. A method as claimed in claim 1, wherein the said nonionic surfactant is used
in volumetric concentration of less than 2%, more specifically in the range of
0.01% to 0.4%,
3. A method as claimed in claims 1 and 2, wherein the said surfactant has no
dould point in the temperature range of 68°F - 212°F.
4. A method as claimed in claims 1 and 2, wherein one of the said temperature
range of interest is 800°C - 100°C.
5. A method as claimed in claims 1 and 2, wherein one of the said temperature
range of interest is 950°C - 840°C.
6. A method as claimed in claims 1 and 2, wherein the maximum temperature
drop is more than two times that for water.

Abstract

Title: Method of enhancing water spray cooling of steel
A method of enhancing water spray cooling of finished steel
comprising of controlled cooling of steel rolls and hot rolled steel
products such as strips and rods with an aqueous solution of
DuPont™ ZonyI® FSH, a nonionic surfactant in predetermined
concentration and under pressure, the steel products being in the
respective temperature ranges of interest.

Documents:

00880-kol-2007-abstract.pdf

00880-kol-2007-claims.pdf

00880-kol-2007-correspondence others 1.1.pdf

00880-kol-2007-correspondence others.pdf

00880-kol-2007-description complete.pdf

00880-kol-2007-drawings.pdf

00880-kol-2007-form 1.pdf

00880-kol-2007-form 18.pdf

00880-kol-2007-form 2.pdf

00880-kol-2007-form 3.pdf

00880-kol-2007-gpa.pdf

880-KOL-2007-(24-05-2012)-AMANDED CLAIMS.pdf

880-KOL-2007-(24-05-2012)-AMANDED PAGES OF SPECIFICATION.pdf

880-KOL-2007-(24-05-2012)-DESCRIPTION (COMPLETE).pdf

880-KOL-2007-(24-05-2012)-DRAWINGS.pdf

880-KOL-2007-(24-05-2012)-EXAMINATION REPORT REPLY RECEIVED.pdf

880-KOL-2007-(24-05-2012)-FORM-1.pdf

880-KOL-2007-(24-05-2012)-FORM-2.pdf

880-KOL-2007-(24-05-2012)-OTHERS.pdf

880-KOL-2007-(28-05-2012)-PETITION UNDER RULE 137.pdf

880-KOL-2007-(28-08-2012)CORRESPONDENCE.pdf

880-KOL-2007-CORRESPONDENCE-1.1.pdf

880-KOL-2007-CORRESPONDENCE.pdf

880-KOL-2007-EXAMINATION REPORT.pdf

880-KOL-2007-FORM 13-1.1.pdf

880-KOL-2007-FORM 18.pdf

880-KOL-2007-FORM 3.pdf

880-kol-2007-form-13.pdf

880-KOL-2007-GPA.pdf

880-KOL-2007-GRANTED-ABSTRACT.pdf

880-KOL-2007-GRANTED-CLAIMS.pdf

880-KOL-2007-GRANTED-DESCRIPTION (COMPLETE).pdf

880-KOL-2007-GRANTED-FORM 1.pdf

880-KOL-2007-GRANTED-FORM 2.pdf

880-KOL-2007-GRANTED-SPECIFICATION.pdf

880-KOL-2007-OTHERS.pdf

880-KOL-2007-REPLY TO EXAMINATION REPORT.pdf

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Patent Number

255487

Indian Patent Application Number

880/KOL/2007

PG Journal Number

09/2013

Publication Date

01-Mar-2013

Grant Date

26-Feb-2013

Date of Filing

18-Jun-2007

Name of Patentee

TATA STEEL LIMITED

Applicant Address

JAMSHEDPUR

Inventors:

#	Inventor's Name	Inventor's Address
1	DR. VIVEK M. WASEKAR	RESEARCH AND DEVELOPMENT DEPARTMENT OF TATA STEEL LIMITED, JAMSHEDPUR 831001

PCT International Classification Number

B22D11/04

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA