FIELD OF THE INVENTION
The present invention relates to channel sections of a structure mill of steel plant. More
particularly, the invention is concerned about a system for controlled cooling of channel to
reduce camber formation in hot rolled channel section.
BACKGROUND OF THE INVENTION
The Heavy structural Mill of Steel Plant produces heavy channels (250x82mm & 300x90mm)
along with other structural like angles, joists etc. These heavy sections after hot rolling and
subsequent cutting to standard lengths at saw are allowed to cool to ambient temperature on
the cooling banks. It has been observed that during cooling the channel section profile gets
cambered, due to differential cooling and the magnitude of camber is as high as 200 to 300
mm in 10 to 12m length. These sections create problem in straightening and sometimes adds
to the percentage rejection and thus reduces the productivity of the finishing line.
JP61132219 discloses that hot leveling rolls are provided to a hot leveling machine and
cooling headers are arranged between the lower rolls. Further, cooling headers are arranged
between table rolls provided to the outlet side of hot rolls. The cladded material side of larger
heat shrinkage of a clad steel sheet is forcibly cooled by the headers during the hot leveling of
sheet. Further, even after the hot leveling, the clad sheet is forcibly cooled by the headers of
rolls so as to reduce the camber of the cladded material-side caused by the sensible heat of
the base material side.; In this way, the production efficiency of composite metallic sheet is
improved, because the camber of the sheet produced in its cooling is reduced..
JP 11104715 discloses that a water spray header 6 extends approximately in parallel with a
rolled steel toward a mill roll and then its end portion is bent toward the water-cutting wiper 5
to be a bend portion 6a. Further, in the wall portion of the bend portion 6a facing the water-
cutting wiper 5, a nozzle hole 9 facing the water-cutting wiper 5 is formed. The base end
portion of the water spraying header 6 is connected to coolant supply source via piping. By
supplying the coolant of a given pressure to the water spray header 6, the coolant is jetted
through a jetting nozzle 8 to cool the rolled steel. From the nozzle hole 9, the coolant is jetted
toward the water-cutting wiper 5 to blow off the sludge.
EP0101224 discloses that a water jet nozzle assembly comprises a hollow cylindrical header
being supplied with cooling water under pressure and formed in its both sides with a series of
apertures, and two elongated curved plates having a substantially quadrantal cross-section
secured to the header with one longitudinal sides of the plates adjacent to lower edges of the
apertures formed in the header and with the other longitudinal sides of the plates upward
extending.; In the other aspect of the invention, a water jet nozzle assembly comprises a U-
shaped trough-like header, an elongated curved plate having a substantially semicircular
cross-section formed in its bottom with a plurality of apertures with substantially equal
intervals and arranged on the trough-like header so as to close an upper open side of the
trough, with longitudinal sides of the curved plate upward extending, and converter plates
arranged above and spaced apart from the respective apertures formed in the curved plate to
turn water flows jetted from the respective apertures into substantially horizontal directions.
The water jet nozzle assembly according to the invention is able to effectively cool
undersides of materials such as steel plates or strips.
The camber formation of channel section and magnitude of camber are problems in the prior
art. Thus, there is a need to overcome the problems of the prior art. Therefore, inventors have
conducted experimental investigation in the laboratory for determination of temperature
distributions between three different zones of channel sections, and optimization of cooling
conditions by simulating the industrial condition. On the basis of the optimization of cooling
parameters on laboratory scale, the inventors have developed an industrial scale controlled
cooling system to reduce camber formation in hot rolled channel section during cooling and
also to increase the productivity of finishing line of the mill.
OBJECTS OF THE INVENTION
An object of the present invention is to overcome the problems/disadvantages of the prior art.
Another object of the present invention is to provide a system for controlled cooling of
Channel to reduce camber formation in hot rolled channel section.
Another object of the present invention is to provide a header assembly in the system.
Yet, another object of the present invention is to provide a fixing arrangement of the header
assembly in the mill.
SUMMARY OF THE INVENTION
According to one aspect of the present invention there is provided a system for controlled
cooling of Channel to reduce camber formation in hot rolled channel section, said system
comprises:
run out roller table means;
plurality of hose pipe means;
floor plate means comprises plurality of slots;
header assembly comprises plurality of headers, wherein each header comprises at least two
series of holes being made at a desired angle on one side of said header; a nipple means
located on other side of said header; the other side of said header being located on a fixture
adapted to be placed on said run out roller table means;
plurality valves means comprises solenoid valve means, valve means, gate valve means
plurality of on/off valve means;
strainer means comprising a substantially basket shape filter means; said strainer being
adapted to connect to an inlet pipe means and an outlet pipe means ;
distributor means comprising pipe means of adequate diameter comprising nipple means,
plurality of adequate size of hole means and said plurality of on/off valve means;
said distributor means both ends being covered with flange arrangement means;
hot saw blade means; and
stopper means;
wherein said strainer and said valves being arranged in such a way that incoming water
reaches said distributor means; said header assembly being connected to said distributor
means through said hose pipe means; said header assembly being adapted to be placed below
the floor plate of said run out roller table means and being adapted to be placed under said
run out roller table means in between said hot saw blade means and said stopper means so as
to cool faster the desired area of the channel.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig 1 illustrates a system for controlled cooling of Channel on the run out roller table of the
Heavy Structural Mill of steel plant.
Fig 2 illustrates header assembly and it's arrangement in the run out roller table.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS
According to the invention there is provided a system for controlled cooling of Channel to
reduce camber formation in hot rolled channel section. Figure 1 shows controlled cooling
system comprises the components such as Spray Headers (1), Hose pipes (2), On/Off valves
(3), Distributor (4), Solenoid Valve (5), Timer (6), Valve (7), Strainer (8), Gate valve (9), and
Deflector (10).
Spray headers (1) are made from seamless pipes. Two series of holes are made at angle on the
top side of the headers. Bottom side of the headers welded with a plate for fixing the header
with the fixture which ultimately welded to the run out roller table structure. A nipple is also
welded in the bottom near middle length of the header for incoming water connection. The
Headers (1) are basically designed to spray calculated amount of water in the targeted area of
the hot rolled channel section coming out of the finishing stand through the series of holes
aligned symmetrically and longitudinally in either side of the central axis of the header (1).
Hose Pipes (2) are high quality rubber hose pipe with end fittings are used to connect each
spray header (1) with distributor (4). Wire breaded flexible hose pipe (2) is used to connect
the individual header (1) with distributor (4). The quality of hose pipe (2) chosen is such that
it will withstand the dust, dirt and environmental temperature which can go as high as 150°C.
On/Off Valves (3) are lever type small valve with on/off facility to isolate header (1) for
maintenance purpose. This is connected in between hose pipe (2) and distributor (4). This is
mainly used to isolate header (1) for maintenance/replacement purpose.
Distributor (4) is basically a large diameter pipe. Inlet water connecting nipple is located at
the middle of the distributor. A number of small outlet holes with nipples and on/off valves
(3) are there in the distributor (4). Both ends of the distributor are closed with flange
arrangement for cleaning purpose. The function of distributor (4) is to supply calculated
amount of inlet water to each individual header (1).
Solenoid valves (5) are basically normally closed, electrically operated solenoid valve. The
valve is open when energized with electrical power and subsequently water flows through it.
This is used to run the cooling spray as and when required. This is actuated by the hot saw
operator (11) when the bar is placed on the headers (1) and it automatically closes by timer
operation. The timer (6) is fitted with the solenoid valve (5). The timer is used to control the
duration of the cooling time. The timer (6) can be set from 0-30 seconds. The timer setting
keeps the solenoid valve (5) open. Depending on channel size, finished rolled temperature of
channel, timer is set to control the solenoid valve.
Valve (7) is located just after the strainer (8). It is basically a globe type of valve (7) and can
isolate the total spray system as and when required.
Strainer (8) is basically a basket type filter and placed in the incoming line of the solenoid
valve (5). Flanged inlet and outlet pipes are connected to ingoing and outgoing side of the
strainer (8).
It ensures the smooth running of the solenoid valve and makes the small spray holes of the
spray headers free from jamming. The wire mesh used in the strainer takes care of unwanted
solid particles of incoming industrial water (containing dirts, debris, mill scales etc.) available
for the spray cooling system
Gate Valve (9) is located just before the strainer (8). It is basically a gate type of valve and
can isolate the total spray system cooling system from strainer (8) onwards as and when
required. The main function of this valve (9) and the other valve (7) placed just after the
strainer (8) is to isolate the strainer (8) for regular maintenance purpose.
Deflector (10) is a fabricated structure placed on the run out roller table just before the spray
headers (1). This is used to place the hot rolled finished channel exactly on the headers centre
line so that the water spray falls on the targeted area of the channel and cools the sprayed area
faster than the rest of the area of the channel.
The operation system is such that the water supply required for the cooling purpose is tapped
from the main supply line outside the mill. Incoming water reaches to distributor passing
through gate valve (9), strainer (8), valve (7) and solenoid valve (5) one after the other. Each
cooling header (1) is connected to the distributor (4) through flexible hose pipe (2). For
isolating each header (1), on/off valve (3) has been provided at the each outlet point from the
distributor (4). Headers are put under the run out roller table in between hot saw blade and
stopper. Headers are put at such location, so that it cools faster the desired area of the channel
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than the rest of area of the channel during hot saw blade operation. This is done to keep cycle
time of each bar rolling unaffected. Slots (15) are cut in the floor plate (13) over each header
for spraying water as per design. For opening and closing of spray headers (1), solenoid
valves (5) are operated with the help of timer (6). The solenoid valve (5) can be put in open
position for a period of 0-30 seconds depending of the cooling requirement.
Figure 2 shows that fixtures (14) are specially designed in the run out roller table (12) for
putting headers (1) on it. Headers (1) are basically welded on the fixture (14) below the top
surface of run out roller table (12) after hot saw for the simple reason that once the headers
are fixed, the location of the headers should not be disturbed. Small slot (15 ) are cut in the
floor plates (13) of the run out roller table (12) for dual purpose - i) To allow the water spray
to fall on the desired area of the channel from below the top surface of the run out roller table,
ii) To accumulate and channelized the used spray cooling water to fall in the trench below the
run out roller table.
As, the spray headers (1) are placed below the floor plate (13) of the run out roller table (12)
and the width of the slots (15) are much less than the width of the structural sections rolled,
so the movement of any rolled section passing on the slot (15) of the floor plates(13) will be
unaffected and uninterrupted. This ensures the continuity of the normal rolling in the mill.
ADVANTAGES OF THE INVENTION
1. Reduction of magnitude of camber from 250-300mm to less than 100mm
2. Facilitating easy handling and feeding of channels in straightening operation
3. Improving productivity of the finishing line of the mill.
The invention has been described in a preferred form only and many variations may be made
in the invention which will still be comprised within its spirit. The invention is not limited to
the details cited above. The spray headers, pipes, valves, strainer, deflector, timer, and
distributor as stated do not limit the scope of the present invention. The structure thus
conceived is susceptible of numerous modifications and variations, all the details may
furthermore be replaced with elements having technical equivalence. In practice the materials
and dimensions may be any according to the requirements, which will still be comprised
within its true spirit.
WE CLAIM
1. A system for controlled cooling of Channel to reduce camber formation in hot rolled
channel section, said system comprises:
run out roller table means;
plurality of hose pipe means;
floor plate means comprises plurality of slots;
header assembly comprises plurality of headers, wherein each header comprises at
least two series of holes being made at a desired angle on one side of said header; a
nipple means located on other side of said header; the other side of said header being
located on a fixture adapted to be placed on said run out roller table means;
plurality valves means comprises solenoid valve means, valve means, gate valve
means plurality of on/off valve means;
strainer means comprising a substantially basket shape filter means; said strainer
being adapted to connect to an inlet pipe means and an outlet pipe means ;
distributor means comprising pipe means of adequate diameter comprising nipple
means, plurality of adequate size of hole means and said plurality of on/off valve
means; said distributor means both ends being covered with flange arrangement
means;
hot saw blade means; and
stopper means;
wherein said strainer and said valves being arranged in such a way that incoming
water reaches said distributor means; said header assembly being connected to said
distributor means through said hose pipe means; said header assembly being adapted
to be placed below the floor plate of said run out roller table means and being adapted
to be placed under said run out roller table means in between said hot saw blade
means and said stopper means so as to cool faster the desired area of the channel.
2. The system as claimed in claim 1 further comprises a deflector means being placed on
said run out roller table means in alignment with centre line of said header assembly.
3. The system as claimed in claim 1 further comprises a timer being set in a range of
about 0-30 seconds.
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4. The system as claimed in claim 1, wherein one side of said header is top side.
5. The system as claimed in claim 1, wherein the other side of said header is bottom
side.
6. The system as claimed in claim 1, wherein said hose pipe means are made up of
rubber and the like materials.
7. The system as claimed in claim 1, wherein said hose pipe means adapted to withstand
about 150°C temperature.
8. The system as claimed in claim 1, wherein said on/off valve means is substantially
lever type valve.
9. The system as claimed in claim 1, wherein said valve means is substantially globe
type valve.
10. The system as claimed in claim 1, wherein said solenoid valve being opened when
said valve is operated with electrical power means.
11. The system as claimed in claim 1, wherein gate valve means is substantially gate type
valve.
12. A system for controlled cooling of Channel to reduce camber formation in hot rolled
channel section as herein substantially described and illustrated with the
accompanying drawings.

The present invention relates to a system for controlled cooling of Channel to reduce camber
formation in hot rolled channel section. The system comprises run out roller table means (12),
plurality of hose pipe means (2), floor plate means (13) comprises plurality of slots (15),
header assembly (1), plurality valves means (3,5,7,9), strainer means (8), distributor means
(4) and stopper means. Each header of the header assembly comprises at least two series of
holes and nipple means located on other side. The system further comprises plurality of
solenoid valves means (5), valve means (7), gate valve means (9) and plurality of on/off
valve means (3).