Title of Invention

"A PROCESS AND SYSTEM FOR MANUFACTURING OF CARBON MANGANESE GRADE STRUCTURAL STEEL PLATE USING ACCELERATED COOLING"

Abstract A process for manufacture of hot rolled carbon manganese grade structural plates wherein the step of improving mechanical properties without normalising operations comprise subjecting the plates after hot rolling to a step of controlled accelerated cooling such that the finalising temperature after hot rolling is selectively maintained in the range of 860-900°C. The process achieves providing stimulated plates with improved mechanical properties without using the conventional complex and energy intensive normalising operation. The process is specifically directed to provide carbon manganese grade structural plates of 14-28 mm thickness with improved mechanical properties. The process is simple and also cost-effective.
Full Text The present invention relates to a process for manufacturing hot rolled carbon manganese grade structural steel plates using accelerated cooling and in particular, relates to the step of improving mechanical properties without normalising operations but using accelerated controlled cooling in manufacture of such grade of structured plates. The invention also relates to a system for use in achieving the controlled accelerated cooling and improving of mechanical properties of such steel plates.
Usually, plates after being hot rolled in the finishing stand are generally cooled in air. These plates are subjected to surface and ultrasonic soundness testing on inspection beds and after trimming operation cut into sizes. The sized plates are then normalised in the continuous normalising furnace at around 900°C to improve the mechanical properties. Conventionally the temperature in the last finishing pass is in the range of 950-1050°C depending upon the thickness of plate. The required temperature range is brought by controlling the reheating temperature and by oscillating the plate between roughing and finishing stand. The normalising operation involves not only an additional process but also consumes a lot of thermal energy (440 Mcal / Tonne). Thus there is a need to develop a suitable process such that normalising process can be eliminated and the required mechanical properties are achieved by the developed process.
It is thus the basic object of the present invention to provide a process for manufacture of hot rolled carbon manganese grade structural steel plates with improved mechanical properties without use of the conventional complex and energy intensive normalising operations.
Another object of the present invention is to provide a process for manufacture of hot rolled carbon manganese grade structural steel plates with improved mechanical properties following a controlled accelerated cooling of the hot rolled plates.
Yet another object of the present invention is specifically directed to provide carbon manganese grade structural plates of 14-28 mm thickness with improved mechanical properties by controlled accelerated cooling of the hot rolled plates.
Yet further object of the present invention is directed to provide for a system for use in controlled accelerated cooling of carbon manganese structural grade plates with improved mechanical properties which would be simple to operate and would be cost-effective.

Yet further object is directed to provide for an auto mode operative system for accelerated cooling of hot rolled carbon manganese plates using a spray cooling device which would be automatically operative based upon the speed of flow of hot plates, the characteristics of the hot plates to be cooled and related operating conditions.
Thus according to one aspect of the present invention there is provided in the process for manufacture of hot rolled carbon manganese grade structural plates the step of improving mechanical properties without normalising operations comprising :
subjecting the plates after conventional hot rolling in the temperature range of 860 - 900 °C to a step of controlled accelerated cooling such that the stop cooling temperature of plates are achieved in the temperature range of 660 - 710°C. /
Cold Slabs are heated in the reheating furnace to make these soft for processing in roughing and finishing stands. As the temperature of stock is increased the resistance to deformation is greatly decreased. There are three zones in the reheating furnace, namely preheating zone, heating zone and finally soaking zone. In the pushing type reheating furnace, slabs are continuously pushed in the furnace. The temperature of soaking zone is in the range of 123020°C. Slabs are kept for sufficient time here such) that the temperature between the surface and centre of slabs become equal. So far the relevance of reheating to the hot rolling controlled accelerated cooling is concerned, if the soaking temperature is not sufficiently high, it will not be possible to roll these slabs into final plate thickness as the mill has limitations with regard to load, torque etc. Secondly, the finishing temperature achieved is lower than the transformation temperature of steel (Ar3), then the beneficial effect of accelerated cooling will not be realized. The beneficial effect of accelerated cooling is grain refinement. Due to grain refinement, the mechanical properties are improved.
In the above disclosed process manufacturing of hot rolled carbon manganese grade structural plates with high strength properties of the invention is achieved under accelerated cooling conditions. The finishing temperature is however, controlled within the narrow range. In controlled rolling the material should be deformed below the recrystallisation stop temperature at the finishing stand. The recrystallisation stop temperature for the above carbon manganese grade structural plates is around 800°C and the finishing temperature in process of this invention is in the range of 880 ± 20°C. The process of the invention provides for selective finishing temperature and controlled cooling regime. Controlled finishing temperature and cooling regime is based on the mathematical modelling and validation of the model by plant experiments.
In accordance with a first aspect, the mathematical model based cooling regimes was established for production of plates of different thickness with desired

mechanical properties without following the post rolling heat treatment (normalising) route after finish rolling. A mathematical model was developed to predict the temperature profile of the plate on the run out table and its dependence on the finishing temperature of the plates, the heat transfer coefficient and the speed and thickness of plate. The heat released as a result of phase change was also included while ascertaining the temperature profile.
The implicit finite difference method was adopted to solve the heat transfer equations taking into account the boundary conditions. The heat transfer coefficient between the plate surface and cooling water was estimated by comparing the plate surface temperature measured during plant experiments with those predicted by the model and retrofitting the values so arrived at.
For achieving the desired cooling regime optimisation of water management (flow rate of water) and rate of material flow.is very important.
Thus in accordance with another aspect the present invention provides a system for use in accelerated cooling of hot rolled carbon manganese grade structural plates comprising :
spray cooling device having a top cooling means and a bottom cooling means ; means for monitoring the temperature of the plate exiting from the hot rolling finishing stand and entering the cooling zone and also means fcr monitoring the stop cooling temperature after the accelerated cooling ;
said spray cooling system adapted to be operative based upon the plate characteristics and relevant operating parameters for the cooling regime such that the,temperature in the last finishing'pass'is in the range of 860-900oC
The above system of the invention utilises a distributed control system (DCS) based automation scheme and the water delivery system was modified/changed to suit the automatic conditions. The main aim of the automated coolin system is to carry out the following functions


(i) Auto mode operation of the cooling system. (ii) Process monitoring (iii) Report generation.
The spray cooling device (SCD) used in our invention was not the conventional SCD. The conventional SCD did not have any instrument for measuring and controlling the process parameters. For producing accelerated cooled plates of consistent and uniform properties a distributed control system (DCS) based automation scheme is developed and implemented.
Water quantity is one of the main parameters of the process. Flow control system
for each section is provided. For achieving steady pressure in the main line a
pressure control loop with an autpmated bypass and pressure transmitter is
provided. The bypass is adapted for a maximum discharge of 1200 m3/hr.

For flow control system, orifice type flow meter is provided since the main purpose
of the loop was to control the flow, not to stop and start the flow, a butterfly valve
was used. Eleven such loops were designed and installed between the first gate
valve and the branching point of the top and bottom collectors. The new-scheme
was aimed at operating the SCD in flow control mode. Due to this, the pressors
measurement in collectors is not found necessary. However, pressure switches
were mounted on each collector for giving an alarm in case of pressure increase
in the collectors. The flow control system was aimed at controlling the flow in auto
mode not to start or step the flow through the collectors.
The details of the invention, its objects and advantages are explained in greater detail in relation to non-limiting exemplary embodiments of the method and system of the invention discussed in relation to the accompanying figures wherein
Fig. 1 is a schematic diagram of cooling arrangement of run out table. Fig. 2 illustrates the effect of roller table speed on temperature profile. Fig. 3 illustrates the automation scheme for the spray cooling and Fig. 4 is an illustration of the upgraded spray cooling device.

Fig. 1 shows a schematic diagram of the cooling arrangement on the run out table in accordance with the invention. The total length of the run out table is about 83 m the distance between the exit from the finishing stand and the start of the first water bank is about 41.5 m. Each water bank is about 2.4 m long and consists of four top laminar water headers. The gap between two adjacent headers is about 0.8 m. the distance between the first bank and the pyrometer 1 is about 7.0 m whereas that between last bank and pyrometer 2 is about 7.1 m.
Bottom cooling is carried out through spray jets. There are eleven water banks each having four headers. The maximum water flow rate for each header on the top cooling system is 70 m3h1 while that in the bottom is 50 m3 h1. The water pressure of the top headers is 0.02 - 0.03 MPa whereas that of the bottom headers is 0.01 - 0.015 Mpa.
In the present case roll table speed indicates the speed of plate under cooling conditions. The effect of roller table speed on the temperature profile of the hot plate when other parameters like thickness, heat transfer coefficient and finishing temperatures are kept constant is important in arriving at optimum cooling rate. The temperature profile of the hot rolled plate at different roller table speeds, when other parameters are constant has been shown in (Fig. 2) for 25 mm plate thickness as an example. It is observed that for speeds 1, 1.5 and 2 ms'1 the stop cooling temperature is about 652, 690 and 708°C respectively. Similar values for 16 and 20 mm plate thickness are 530, 650, 695°C and 613, 681 and 704°C respectively. To maintain uniformity in microstructure in the through thickness direction, the temperature difference between the surface and mid thickness should be as low as possible. To ensure the minimum difference, the proper selection of heat transfer coefficient,and roller table speed is important.,
To achieve the desired stop cooling temperature at a particular cooling rate, an accurate estimation of heat transfer coefficient between the plate and the water banks from top and bottom is of paramount importance. This is primarily because a single value of heat transfer coefficient describes the cooling conditions of the hot,plate under the laminar water banks from top and bottom in the modelling exercise The stop cooling temperature was chosen as the single parameter to

test the accuracy of the model as this can be measured experimentally through plant experiments.
Balancing of water from top and bottom is very important, as uneven cooling of plates leads to warpage of the plates.
The distributed control system (DCS) used in the system was adapted to access the following signals for executing the control strategy :
S. NO. Devices Number l/O's Number
1. Pyrometer 02 Analogue input 4-20 mA
2. Pressure transmitter 01 Analogue input 4-20 mA
3. Flow transmitter 11 Analogue input 4-20 mA
4. Roll table speed 01 Analogue input 0-24 VDC indication
5. Pressure switches 22 Analogue input contact
6. Valve position control 13 Analogue input 4-20 mA
7. Pneumatic ON/OFF 22 Digital output contact valves
8. Roll table speed control 01 Analogue output 0-24 VDC
All together 73 l/O's were available in the field equipments and 12 PID loops were to be executed using 26 l/O's.
For this job, a DCS (CIE-1000) from Toshiba was used. This DCS is configured around a PC which works as an operator interface station (OIS). This communication between OIS and MCS is executed through a thin ether-net. The DCS has two components. One is tile panelrcoritaining MCS and associated hardware and the other one is the operator interface station containing PC and Auto/manual stations.An exemplary preferred technical configuration of the DCS is given hereunder:

Hardware IBM Compatible PC
CPU Pentium (133 MHz)
RAM 48 MB
HDD 1.2 GB
FDD 1.44 MB
Cache 256 KB
Monitor 19" high resolution CRT
Communication Ethernet
Operator key board Membrane type water & dust proof
Engineering key board 101 key
Operating system Windows NT 3.51
GUI FX DMACS
TAG number 1024 max.
TAG length 16 max.
Real time trend 64 pts
Historical trend 256 pts
Graphic screen 32 max.
Secutiry Password and level set for each screen
Control Station MCS 1000
CPU Non redendant 32-bit
Programme memory Total 150 pages 1280 bytes/page
Serial I/O
AI module 8 pts/module
DO module 32 pts/module
Dl module 32 pts/module
Function : -
PID controller 32 Loops/MCS
Indicator 96 Loops/MCS
Counter 32
Timer 64

Transmission speed
Serial bus 1 Mbps
I/O bus 19.2 Kbps
Power supply 170-264 VAC
Frequency 47-63 Hz
Operating temperature 0-55°C
Humidity 30-90% RH (non condensing)
Cooling Natural air cooling.
The MCS panel of the DCS contains microprocessor based control station with its l/O's, all hardware required for inter facing l/O's with field equipments and power supplies for field equipments and OIS. The OIS desk houses the PC which supervises the total operation of the system. This PC is equipped with two key boards e.g. engineering key board and operator's key board. Engineering key board is used only for modifying the software and some base data and is not available to the operator. The total operation is carried out using operator's key board which is always connected to the PC. All auto manual stations are also mounted on the desk along with the processor of the entry side pyrometer.
For executing the cooling regime for different thickness a look up table is incorporated in the software.
As already mentioned, achievement of stop cooling temperature at a particular cooling rate is of paramount importance for the required microstructure and therefore, the mechanical properties in plates. Process variables such as heat transfer coefficient, finishing temperature, speed and thickness of plate have great influence on the stop cooling temperature of the plate on the run out table.
Keeping finishing temperature, speed and stop cooling temperature constant, the accurate estimation of heat transfer coefficient becomes important for a particular thickness of plate. However, for fixed value of heat transfer coefficient, speed and finishing temperature, the required stop cooling temperature is controlled by varying the speed of the plate as the thickness of the plate varies.

it is definitely possible to have a range for the operating parameters relative to the thickness which can cover all varieties of the process Operating parameters for each thickness can be selected and the accelerated cooling determined accordingly.
Industrial trials were conducted at 3600 mm plate mill with plates of grade IS:2062 and thickness 14-28 mm. To obtain the desired microstructures in plates, a cooling regime was worked out and implemented at plate mill. The cooling regime followed consisting of thickness of plate finish rolling temperature, water flow between top and bottom cooling sections, total flow rate, material speed and stop cooling temperature are illustrated in Table-I hereunder:
TABLE -l
Thickness Temp, of Roller Section to Temp. Total flow
(mm) plate in table be used after spray rate m3/hr
the last speed cooling
finishing m/s. (°C)
pass fC) Top ( Bottom
14 860-900 2 7 10 660-710 2500
16 860-900 2 7 10 660-710 2500
18 860-900 175.1.5 7 10 660-710 3000-4000
20 860-900 175.1.5 7 10 660-710 3000-4000
22 860-900 1.5-125 7 10 660-710 3000-4000
25 860-900 1.5-125 7 10 660-710 3000-4000
28 860-900 1.25-1 7 10 660-710 3000-4000
Typical mechanical properties achieved by accelerated cooling have been indicated in Table-I I hereunder:
.


TABLE - II
Thickness Carbon I Mechanical Properties Charpy Cooling
Impact Rate
(mm) Equivalent YS UTS El Value (J) C/S
(Mpa) (Mpa) (%) -20°C
14 0.25 343 483 30 73 9.4
16 025 330 466 30 66 8.8
20 0.20 322 457 28 63 80
25 028 320 442 28 52 7.4
28 028 320 434 26 43 6.3
As per 230 410 23 27
standard
IS : 2062-
94
Carbon manganese grade structural steel of the invention comes in the category of Bureau of Indian Standard 2062-94. Specified mechanical properties mentioned in the standard can be obtained by the novel technique such as accelerated cooling of the' invention. It is needless to emphasise that mechanical properties obtained by accelerated cooling technique is equivalent / better to those achieved by the conventional normalising process.
Accelerated cooled plates are ideally suited for structural applications including buildings, bridges, ships, offshore structure, railway wagons, pipes etc. accelerated cooling results in huge saving of thermal energy due to elimination of normalising route It also involves an elimination of additional process Due to this process there is a reduction in secondary scale loss by 1-2%.


WE CLAIM :

1. A process for manufacture of hot rolled carbon manganese grade structural steel
plates for improving mechanical properties without normalising operations comprising:
subjecting the plates after conventional hot rolling in the temperature range of 860 -900 °C to a step of controlled accelerated cooling such that the stop cooling temperature of plates are achieved in the temperature range of 660 - 710°C.
2. A process as claimed in claim 1 wherein the carbon manganese grade structural steel
plates are of 14-28 mm thickness.
• 13. A process as claimed in anyone of claims 1 or 2 wherein the soaking temperature in the reheating furnace is maintained in the range of 1180-1240°C.
4. A process as claimed in anyone of claims 1 to 3 wherein said accelerated cooling is achieved by passing the plates obtained after hot rolling through a spray cooling device having top cooling means and bottom cooling means.
5. A process as claimed in claim 4 wherein said top cooling means comprise water banks with water heads and said bottom cooling means comprise spray jets.
6. A process as claimed in claim 5 wherein there is provided plurality of water banks each said water bank having plurality of top laminar water heads, the maximum flow rate of each said header on the top cooling means being 70 m3/hr while that of the bottom spray header being 50 m3/hr, the water pressure at the top header being adjusted at 0.2 - 0.3 Kg/cm2 and at the bottom header being adjusted at 0.1 - 0.2 Kg/cm2.
7. A process as claimed in anyone of claims 1 to 6 wherein said finishing temperature of 860-900°C is brought by controlling the reheating temperature and by oscillating the plate between roughing and finishing stand.

8. A process as claimed in anyone of claims 1 to 7 wherein the finishing temperature is
selected based upon the heat transfer co-efficient, the speed, the thickness of the
plates during accelerated cooling.
9. A process as claimed in anyone of claims 1 to 8 wherein said water flow on to said
plate is adjusted by optimisation of the required water flow rate based on the rate of
material flow through the spray cooling device and the characteristics of the material.
10. A process as claimed in anyone of claims 1 to 9 wherein for uniformity in micro
structure the temperature difference between the surface and the mid thickness of
plate is maintained as low as possible.
11. A process as claimed in claim 10 wherein to ensure minimum difference between the
surface and the mid thickness temperature proper selection is made of the heat
transfer coefficient and the roller table speed.
12. A process as claimed in anyone of claims 1 to 11 wherein the flow of water from the
top and the bottom cooling means of the spray cooling device is selected to avoid
uneven cooling of plates.
13. A system for carrying out the process of accelerating cooling of hot rolled carbon
manganese structural plates as claimed in claim 1 comprising:
spray cooling device having a top cooling means and a bottom cooling means:
means for monitoring the temperature of the plate exiting from the hot rolling finishing
stand and entering the cooling zone and also means for monitoring the stop coolin temperature after the accelerated cooling ;



said spray cooling system adapted to be operative based upon the plate characteristics and relevant operating parameters for the cooling regime such that the temperature in the last finishing pass is in the range of 860-900°C
14.A system as claimed in claim 13 comprising auto mode operation of the cooling device means for process monitoring, and means for generating process status report for the controlled accelerated cooling depending upon the end characteristics desired.
15. A system as claimed in anyone of claims 1 to 14 wherein said spray cooling device comprise a top cooling-means;having plurality of water brinks each said water bank having top ,laminar water heads and a bottom cooling system comprising of spray jets.
16.A system as claimed in anyone of claims 13 to 15 wherein said means for mdnitofing the temperature of the plate exiting from the hot rolling pass and that of the finishing temperature after the accelerated cooling comprise pyrometer means.
17. A system as claimed in any one of claims 13 to 16 wherein the total length of the run out table carrying the hot rolled plates for the accelerated cooling extend to 82.8 to 83.2 meters and the distance from the exit of the hot rolling finishing stand and the first water bank of said cooling device is in the range of 41.4 to 41.6 meter, the distance between the first (bank and a first pyrometer is in the range of 6.9 to 7.1 mets. and the distance between trie last bank and a second pyrometer is between 7 to 7.2 m.
18. A system as-claimed in anyone of -claims 13 to 17 wherein the saidtdp cooling means comprising said water head is adapted to generate a maximum flow rate of 70 m3/hr while the bottom cooling system is adapted to generate a flow rate of 50 m3/hr.
19. A system as claimed in anyone of claims 13 to 18 wherein said cooling device is adapted for auto mode of operation for optimised water flow based upon the


rate of material flow and material characteristics passing through said cooling system in particular the recrystallization stop temperature for the plates
20. A system as claimed in anyone of claims 13 to 19 wherein the water pressure
in the top header is adapted to be in the erange of 0.02 to 0 03 MPa while in the
bottom header it is adapted to be in the erange of 0.01 to 0 015 MPa.
21. A system as claimed in anyone of claims 13 to 20 comprising means for
generating optimum cooling rate based on the effect of the roller table speed
on the temperature profile of the hot plate the other parameters remaining
constant and the temperature profile of trie hot rolled plate at different roller
table speed with other parameters rema'mang constant.
22 A system as claimed in anyone of claims 13 to 21 comprising means for maintaining uniformity in micro structure by minimising the temperature difference between the surface and the mid thickness of the plate by selection of heat transfer coefficient and roller table speed
23. A system as claimed in any one of claims 13 to 22 comprising means for generating the stop cooling temperature at a particular cooling rate by estimation of heat tronsfer coefficient-between the plate and water'banks from top and bottom.
24. A system as claimed in anyone of claims 13 to 23 comprising means for balancing the water flow from the top and bottom cooling means.
25. A system as claimed in anyone of claims 13 to 24 comprising distributed control system based on automation scheme for producing accelerated cooling of plates.
26. A system as claimed in anyone of claims 13 to 25 wherein the water quantity in the cooling system is monitored and controlled by flow control system

27. A system as claimed in anyone of claims 13 to 26 wherein for achieving steady
pressure in the main line there'is provided a pressure control loop with an
automated by-pass and pressure transmitter said bypass having a maximum
discharge of 1200 m3/hr.
28. A system as claimed in anyone of claims 26 to 27 wherein said flow control
system comprises orifice type flow meter and butterfly valves.
29. A system as claimed in anyone of claims 27 to 28 wherein said loops are
provided between a first gate valve and branching point of the top and bottom
collectors.
30.A system as claimed in claim; 29 comprising pressure switches mounted on each collector for generations alarm in case of pressure increase in the collectors.
31. A system as claimed in anyone of claims 13 to 30 wherein the flow control system is adapted to control the flow in an auto mode.
32.A system as claimed in anyone of claims 25 to 31 wherein the distributed control system is operatively connected to access the signals generated by said pyrometer means, pressure transmeter means, flow transmitter means, roller table speed indication means-, pressure switch means, valve position control means, pneumatic on off valves and roller table speed control means.
33. A systerp as claimed in anyone of claims 13 to 32 wherein the said distributed control system is configured around a PC adapted to work as an operator interface station, said communication between the operator interface station and the MCS being executed through a thin ether net.
34. A system as claimed in anyone of claims 13 to 33 wherein said distributed control system comprises of:
a panel containing MCS and ass.pciated hardware , and operator interface station containing PC and auto/manual stations.


35. A system as claimed in anyone of claims 13 to 34 wherein said MCS panel comprise micro processor based control station with its input/output, all hardware for interfacing input/output with field equipments and power supplies for the field equipment and the OIS.
36. A system as claimed in claim 35 wherein the said OIS houses the PC.
37. A System as claimed in anyone of claims 33 to 36 wherein said PC is equipped with an engineering key board adapted for modification of software and data bases and an operating key board.
38.A system as claimed in anyone of claims 13 to 27 wherein all auto/manual stations are mounted on the desk alongwith the processor of the entry side pyrometer.
39.A system as claimed in anyone of claims 13 to 38 wherein for executing the cooling regime for different thickness a look up table is incorporated in the operating system.
40.A system as claimed in anyone of claims 13 to 39 comprising software adapted to generate signals for operation of the flow control means of said spray cooling device based on process variables including heat transfer coefficient, finishing temperature speed and thickness of plate, the stop cooling temperature of the plate.
41. A process for manufacture of hot rolled carbon manganese grade structural plates and as system of accelerated cooling for use in such methods substantially as herein described and illustrated with reference to the accompanying figures.
Dated this 8th day of March 2000
ANJAN SEN
Of S. MAJUMDAR & CO.
Applicants' Agent

A process for manufacture of hot rolled carbon manganese grade structural plates wherein the step of improving mechanical properties without normalising operations comprise subjecting the plates after hot rolling to a step of controlled accelerated cooling such that the finalising temperature after hot rolling is selectively maintained in the range of 860-900°C. The process achieves providing stimulated plates with improved mechanical properties without using the conventional complex and energy intensive normalising operation. The process is specifically directed to provide carbon manganese grade structural plates of 14-28 mm thickness with improved mechanical properties. The process is simple and also cost-effective.

Documents:

00145-cal-2000-abstract.pdf

00145-cal-2000-claims.pdf

00145-cal-2000-correspondence.pdf

00145-cal-2000-description(complete).pdf

00145-cal-2000-drawings.pdf

00145-cal-2000-form-1.pdf

00145-cal-2000-form-18.pdf

00145-cal-2000-form-2.pdf

00145-cal-2000-form-3.pdf

00145-cal-2000-letters patent.pdf

00145-cal-2000-p.a.pdf

00145-cal-2000-reply examination report.pdf


Patent Number 203277
Indian Patent Application Number 145/CAL/2000
PG Journal Number 10/2007
Publication Date 09-Mar-2007
Grant Date 09-Mar-2007
Date of Filing 08-Mar-2000
Name of Patentee STEEL AUTHORITY OF INDIA LIMITED
Applicant Address DORANDA , RANCHI-834 002, STATES OF BIHAR, INDIA A GOVT.OF INDIA ENTERPRISE.
Inventors:
# Inventor's Name Inventor's Address
1 SINGH ARJUN PRASAD RESEARCH AND DEVELOPMENT CENTRE FOR IRON & STEEL STEEL AUTHORITY OF INDIA LIMITED.DORANDA , RANCHI-834 002, STATES OF BIHAR, INDIA AN INDIAN NATIONAL
2 PRASAD ARUN RESEARCH AND DEVELOPMENT CENTRE FOR IRON & STEEL, STEEL AUTHORITY OF INDIA LIMITED.DORANDA , RANCHI-834 002, STATES OF BIHAR, INDIA AN INDIAN NATIONAL
3 SENGUPTA DIPANKAR RESEARCH AND DEVELOPMENT CENTRE FOR IRON & STEEL, STEEL AUTHORITY OF INDIA LIMITED.DORANDA , RANCHI-834 002, STATES OF BIHAR, INDIA AN INDIAN NATIONAL
4 THAKUR RAMESH CHANDRA RESEARCH AND DEVELOPMENT CENTRE FOR IRON & STEEL, STEEL AUTHORITY OF INDIA LIMITED.DORANDA , RANCHI-834 002, STATES OF BIHAR, INDIA AN INDIAN NATIONAL
5 PRAKASH KUNDAN RESEARCH AND DEVELOPMENT CENTRE FOR IRON & STEEL, STEEL AUTHORITY OF INDIA LIMITED.DORANDA , RANCHI-834 002, STATES OF BIHAR, INDIA AN INDIAN NATIONAL
6 GANTI MAHAPATRUNI RESEARCH AND DEVELOPMENT CENTRE FOR IRON & STEEL, STEEL AUTHORITY OF INDIA LIMITED.DORANDA , RANCHI-834 002, STATES OF BIHAR, INDIA AN INDIAN NATIONAL
7 JHA SUDHAKAR RESEARCH AND DEVELOPMENT CENTRE FOR IRON & STEEL, STEEL AUTHORITY OF INDIA LIMITED.DORANDA , RANCHI-834 002, STATES OF BIHAR, INDIA AN INDIAN NATIONAL
PCT International Classification Number B 21B 37/10
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA