FIELD OF THE INVENTION
The present invention generally relates to an automated system for gas carburizing
furnace (GCF), more particularly, relates to an automated system for gas carburization
of metal components in gas carburizing furnace (GCF). The present invention further
relates to a method for controlling and monitoring essential parameters of metallurgical
components in gas carburizing furnace (GCF).
BACKGROUND OF THE INVENTION :
Gas Carburizing Process is a process, which improves the case depth hardness of a
component by diffusing carbon into the surface layer to improve wear and fatigue
resistance. In order to achieve specific properties and the desired surface quality of an
object, during the heat treatment, numerous process parameters need to be monitored
and controlled. Out of various parameters, a most critical parameter is the fuel
composition, function and control of the furnace atmosphere. In Gas Carburizing
furnace one of the main function is to maintain carbon content through gaseous
atmosphere around components in closed chamber. This gas is controlled through CP
controller whose feedback is given by oxygen probe based upon carbon content
requirement in the chamber.
The carbon content of the heat-treated object determines the final properties of the
carburized object. Therefore, it is important to ensure supply of a reliable blend of
process gas, including precision control of furnace atmosphere during the heat
treatment operation, to ultimately achieve the desired product specifications of heattreated
steels. The first part of the heat-treatment process focuses on basic parameters
of the hardness and carbon content of steels, and the remaining part of the process
focuses on the types of furnaces used including the associated equipment.
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The prior art gas carburising furnace (GCF) system, generally include a gas carburising
furnace, at least one each probe for temperature control of heater zone-1, and heater
zone-2 as shown in the figure- 1. An oxygen (O2) probe is also provided to feeding the
data to a controller, for controlling carbon content during the heat treatment process.
The every type of component, treated during the prior art heat treatment process, are
substantially monitored manually. This process was human dependent as operator
follows recipe by feeding temperature and monitoring time through clock, which is one
of the major drawbacks of the existing system. The gas carbon furnace is consisting of
at least two heater zones, where the first heater zone is located above the second
heater zone. Both the heater zone includes at least one each probe as (probe 1 and
probe 2) which are connected to separate controllers for monitoring the temperature of
both the zones of the furnace separately.
A continuous reference air is provided to O2 probe which calculates the required carbon
content and provide feedback to the CP controller for controlling gas to maintain carbon
content.
In the existing gas carburising furnace system, a few problems arise on quality of the
surface properties of the heat treated objects, wherein lead to rejection and rework.
Mostly, because of high manual intervention during heat treatment process, such
defects on the object generated. The design of the existing GCF contribute to many
disadvantages, such as high work at GC furnace, human error, complex controlling
system and manual controlled of process. The drawbacks of conventional system are
encountered as:
 the conventional system is used manual process which involves high chance of
human errors.
 there are four types of controllers used for a single furnace
 there is no option of data recording for analysis.
 the manual process involve rework and rejection of metal objects in GCF.
 the conventional system has economical disadvantages.
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The root cause of the problems are identified in GCF by 4M condition analysis.
The problems due to Manual process are listed in below,
 Furnace is not operated according to the prescribed process stipulated operation
manual.
 Operating parameters of the furnace are not monitored and maintained suitably.
 Wrong process selection is occasionally done due to human intervention.
The problems due to Machine are listed in below,
 Furnace thermocouple becomes faulty after repeated use.
 Furnace brick lining is not retaining heat.
 Heater is not replaced based on the standard life of heater.
The problems due to Material are listed in below,
 Material composition is not as per standard.
 Metallurgical requirements is incorrect.
 Material weight is more than required.
The problem due to known Method are listed in below,
 there is Furnace loading delays.
 the method is manually controlled furnace.
The analysis shows the following disadvantages as given below:-
The effect due to the cause of Manual Process:
1. There is a chance of variations in actual parameters against required due to
manual errors in controlling the furnace operation.
The effect due to the cause of Machine:
1. Slight variation in skin temperature and amperage of heaters inside the furnace.
2. It is also observed that observed skin temp 75 degree, but it should be 80 degree.
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3. The effect is caused due to furnace thermocouple faulty.
4. The effect is due to unchanging of heater as per life of heater.
The effect due to the cause of Material:
1. Material gross weight is reduced to 710 kg according to specification the gross
weight of the furnace is 750 kg
The prior art EP3324255 patent disclosed for achieving superior bending fatigue
strength and pitting fatigue life by using carbonitriding treatment and hard shot penning
process. However the prior art patent fails to provide automation process for online
monitoring of various parameters of metal object during heat treatment process to
enhance the product quality.
Another prior art EP1516940 patent described about the controller and all its functions
with parameters and set values. However the prior art patent literature fails to provide
the enhancement process using a controller and making whole system interlocked with
different recipes.
Still another prior art US4288062A describes apparatus for control and monitoring of
the carbon potential of an atmosphere in a heat-processing furnace.
Therefore, there is also need to modify the gas carburising furnace system in such a
manner, that, the above mentioned drawbacks of conventional GCF system are
addressed. There is a need of an improved system and a method performed for a GCF
to overcome all the above problems, inter alia the 4M problem. Further, the problem in
the prior art, includes rework and rejection on GCF because of that the cost of the
conventional system is much higher and it also include multiple controllers for
controlling various parameters of metal objects during heat treatment process in the
furnace.
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OBJECTS OF THE INVENTION:
1. It is therefore an object of the present invention to overcome the aforementioned
and other drawbacks existing in prior art process along with an improved Gas
carburising furnace.
2. The primary object of present invention is to modify existing manual process with
a developed automated process for monitoring and controlling the process
parameters in real-time during heat treatment of an object by the furnace with
feasible cost.
3. Another object of the present invention is to monitor and control of vital
parameter such as carbon potential and temperature in a GCF system during the
process of heat treatment.
4. Still another object of the present invention is to provide an automatic process
for monitoring and controlling the parameters in a heat treatment process
performed in a GCF using a single controller.
5. A further object of the present invention is to provide an online monitoring
system connected with the controller which is continuously monitor the essential
parameters of heat treated object during the heat treatment process.
6. Yet another object of the present invention is to provide the essential parameter
details using paperless recorder connected in any network OR (LAN-local area
network) to take necessary action.
7. A further object of the present invention is to provide graphical representation
of essential parameters using online digitized system for tracking different vital
parameter live on screen connected in Ethernet network or LAN (local area
network).
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SUMMARY OF THE INVENTION:
One or more drawbacks of conventional arts for measuring and controlling the essential
parameters of heat treated objects in GCF are overcome, and additional advantages are
provided through the present invention as disclosed. Additional feature and advantages
are realized through the technicalities of the present disclosure. Other embodiments
and aspects of the disclosure are described in detail herein and are considered to be
part of the claimed disclosure.
This excludes the need for the manual interface to deal with vague and indirect methods
of adjustment, instead entering values into the controller that has real and apparent
physical meaning. In the present invention, the prior art “the normal GCF system”, is
coupled with multiple controllers for separate unit to control various parameter
separately, and are replaced by a master controller which is used to monitor and control
essential parameters of heat treated metallurgical component during heat treatment
process in the furnace. The monitoring system includes both paperless recorder and
also online monitoring computer apparatuses connected in a network. The present
invention discloses that the automated system which reduces the chance of user error
as well as huge wastage of materials caused due to inaccurate proportion of parameters
inside the metal objects, so that, the present invention reduces the rework and rejection
of the whole process in the furnace.
In an embodiment, an automated system for gas carburization of metal components
comprising: a master controller (2) configured to receive and transmit data signal from
and to the constituent components of the system, the system having a plurality of gas
carburizing furnaces; at least two heater zones (Z1,Z2) for heating up the metallurgical
component to its melting point; one each thermocouple (Z1 T/C,Z2 T/C) fitted to each
of said two heater zones (Z1,Z2); and one each probe (P1,P2) connected to said
thermocouples (Z1T/C,Z2T/C) respectively, and a third probe (P3) to allow the
referenced air supply to said heater zones (Z1,Z2), and a fourth probe (P4) connected
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to the master thermocouple, all the other end of said probes (P1,P2,P3,P4) are
connected to said master controller (2) for transmitting parametric data, wherein the
master controller (2) and a monitoring and control device are connected via a network
to ensure desired properties of the metallurgical component during the gas carburizing
process. Further, the present invention relates to a method for controlling and
monitoring essential parameters in a gas carburizing furnace.
In an embodiment, a method for controlling and monitoring essential parameters of
metallurgical components in a gas carburizing furnace, comprising the steps of: heating
the metallurgical component to its melting point on the heater zones (Z1, Z2)
demarcated in carburizing furnace; measuring the temperature of each of the heater
zones (Z1, Z2) by using at least two thermocouples (Z1 T/C, Z2T/C) fitted to each of
said heater zones (Z1, Z2); transmitting the measured temperature data to the master
controller (2) by using at least two probes (P1, P2); controlling the temperature by
heating operation in the heater zones (Z1, Z2) by using retort safety contactors (RC1,
RC2) through a master controller(2); measuring the overall temperature of the furnace
by using a fourth probe (P4) and feeding to the master controller (2); providing
reference air to the oxygen probe (P3) for controlling the Carbon content of the
metallurgical component; and transmitting the temperature and carbon potential data
from the master controller to computer apparatuses (PC1, PC2) for monitoring and
paperless recorder (5) via a network switch in a network .
In the present invention, the proposed system includes a furnace and a master
controller coupled in such a manner, the proposed system is used for monitoring the
temperature of the furnace and carbon content information which is the vital
information to check in the heat-treated metal object in the furnace during heattreatment
process.
Further, in the present invention, the automated system includes a gas carburising
furnace, a master controller, at least a pump for supply and purge of atmospheric air,
oxygen (O2) probe for controlling the carbon content of the metal objects, and a
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plurality of probes for monitoring and controlling the process parameters during heat
treatment process, and a Ethernet network connected to a paperless recorder and
computer apparatuses through a single network switch.
Further, the Gas Carburising Furnace includes two heater zones (zone 1 and zone 2).
The two probes are connected to both heater zones along with two thermocouples for
measuring the temperature of both the heater zones and further those temperature
data are inputted into the master controller for monitoring and controlling purpose. The
master thermocouple is used to measure overall furnace temperature and by using
probe 4, and the temperature information is send to the master controller via probe 4.
Probe 3(Oxygen (O2) probe) is used to provide feedback, for carbon potential data of
heat treated metallurgical components to the master controller for precise control of
carbon potential and recording the parameters of the heat treated objects. Depending
on the carbon content, O2 probe continuous supplies reference air through pump.
The master controller stores the essential parameters and compare with the
predetermined stored parameters values. The essential parameters of the heat treated
objects are carbon content in the heat-treated metal objects and the temperature of
the furnace during heat treatment process. If the temperature is not maintained in the
desired level, the retort safety contactor will open to control the temperature of the
furnace zones during the heat-treatment process. Depending on the carbon content of
the gaseous atmosphere, O2 probes passes signal to master controller for controlling
Carbon Potential by supplying desired amount of carburizing fluid.
The master controller show the data as temperature of the furnace and carbon content
of the processed metal object by using a plurality of monitoring apparatuses. Further
for online monitoring purpose, the output of the controller is connected to a plurality of
monitoring apparatuses via an Ethernet network through a network switch which
comprises at least a paperless recorder and at least two computer apparatuses for
showing live data of processed metal object during heat treatment process in the
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furnace. The output of the computer apparatuses and paperless recorder are shown
carbon information and temperature trend.
A paperless recorder is used to show the information about temperature trend and
carbon content which are the major factor during the heat-treatment process of the
metallurgical component in the GC furnace. The paperless recorder is connected via an
Ethernet network (i.e. Local area network) through a single network switch along with
other computer apparatuses.
Various objects, features, aspects and advantages of the inventive subject matter will
become more apparent from the following detailed description of preferred
embodiments, along with the accompanying drawing figures in which like numerals
represent like components.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
The illustrated embodiments of the subject matter will be best understood by reference
to the drawings, wherein like parts are designed by like numerals throughout. The
following description is intended only by way of example, and simply illustrates. Certain
selected embodiments of improved Gas carburising furnace system that are consistent
with the subject matter as claimed herein, wherein:
Figure 1: illustrates Gas Carburising Furnace coupled with four controllers along with
manual reference air process according to prior art.
Figure 2a: illustrates an improved Gas Carburising Furnace system for automatic
monitoring and controlling various essential parameters in the furnace according to
present invention.
Figure 2b: illustrates the output of the improved system which include graph and the
essential parameters of metal object during heat treatment in the furnace according to
present invention.
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Figure 3: illustrates the proposed system coupled with a paperless recorder and
computer apparatus via a network for online monitoring and trend print of essential
parameters of at least four automated GCF system according to present invention.
The figures depict embodiments of the disclosure for purposes of illustration only. One
skilled in the art will readily recognize from the following description that alternative
embodiments of the structures illustrated herein may be employed without departing
from the principles of the disclosure described herein.
DETAILED DESCRIPTION OF THE INVENTION:
While the embodiments of the disclosure are subject to various modifications and
alternative forms, specific embodiment thereof have been shown in the figures and will
be described below. It should be understood, however, that it is not intended to limit
the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to
cover all modifications, equivalents, and alternative falling within the scope of the
disclosure.
The figures illustrate only those specific details that are pertinent to understand the
embodiments of the present disclosure, so as not to obscure the disclosure with details
that will be clear to those of ordinary skill in the art having benefit of the description
herein.
The present invention is directed towards an automated system for gas carburization
of metal components. Further, the present invention relates to a method for controlling
and monitoring essential parameters in a gas carburizing furnace.
Fig (2a) illustrates an exemplary embodiment of an automated system for gas
carburization of metal components, to avoid above mentioned drawbacks which is in
case with the prior art system as shown in fig (1). In the present invention, the improved
system as showed in fig (2a) includes a gas carburizing furnace (GCF) (1), a master
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controller (2), at least a pump for supply and purge of atmospheric air (3), a plurality
of probes such as probe (P1) and probe (P2), Oxygen (O2) probe (P3) and a probe
(P4).
Fig (2a) also illustrates, the gas carburizing furnace (1) which includes two heater zones
(Z1 and Z2) having at least one probe for each zone (P1 and P2) connected to each
heater zones (Z1 and Z2). The temperature of both the heater zones (Z1, Z2) are
measured by using the thermocouples (Z1 T/C, Z2 T/C) which is then transmitted to
the master controller (2) through the probes (P1, P2) respectively for monitoring
purpose. The overall temperature of the furnace is measured by using a master
thermocouple (MT/C) and is fed to the master controller through probe (P4). Retort
safety contactors (RC1 and RC2) are connected to both the heater zones (Z1, Z2) to
control the heater zones at the desired temperature. Reference air is provided by the
pump (3) for oxygen sensors (P3) which generates signals of carbon potential value of
metallurgical component inside furnace and transmitted the signals to the master
controller (2), thereby allowing the master controller (2) monitoring and controlling of
reference air supply in order to maintain carbon content of the metallurgical component
in the gas carburizing furnace.
Further, fig (2a) illustrating, that the master controller (2) stores and evaluates the
essential parameters by comparing with the predetermined stored parameters values.
The essential parameters of the heat treatment process are carbon content in the heattreated
metal objects and the temperature of the furnace. Depending on the desired
temperature, the master controller (2) sends signal to control the temperature of the
heater zones through retort safety contactors (RC1 and RC2). Depending on the desired
carbon content during the heat treatment of the metallurgical component, the controller
sends signal to allow the carburizing fluid to pass in furnace which increases carbon
potential content inside furnace.
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In the present invention, Fig (2b) illustrates that the master controller (2) shows the
graph of temperature trend and carbon potential information of heat treated
metallurgical component in the gas carburizing furnace (1).
In the present invention, fig (3) illustrates an exemplary embodiments about online
monitoring of the essential parameter of the metal object during heat treatment process
in the furnace which includes the master controller (MC) (2) is connected to a plurality
of monitoring apparatuses comprise a paperless recorder (5) and at least two computer
apparatuses (PC1 and PC2) via a Ethernet network through a network switch (4).
Moreover, fig (3) also illustrates, a paperless recorder (5) is used to record the
information about the carbon content and temperature which are the essential factors
during the heat-treatment process in the gas carburizing furnace. The paperless
recorder (5) is connected with other four improved gas carburising furnaces to record
the essential parameters of the processed metal object during the heat treatment
process.
Further fig (3) illustrating, that the computer apparatuses (PC1 and PC2) are connected
in an Ethernet network used for online monitoring and it can be adapted to take print
of the parametric data for quality inspection of the heat treated objects in the gas
carburizing furnace.
Further, a method for controlling and monitoring essential parameters of metallurgical
components in a gas carburizing furnace, the method comprising the steps of : heating
the metallurgical component to its melting point on the heater zones (Z1, Z2)
demarcated in each gas carburizing furnace; measuring the temperature of the heater
zones (Z1,Z2) by using at least two thermocouples (Z1 T/C, Z2T/C) fitted to each of
said heater zones (Z1,Z2); transmitting the measured temperature data to the master
controller (2) by using at least two probes (P1, P2); controlling the heating operation in
the heater zones (Z1, Z2) by using retort safety contactors (RC1, RC2) through a master
controller(2); measuring the overall temperature of the furnace by a overall master
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thermocouple (MT/C) through the fourth probe (P4) and feeding to the master
controller (2); a continuous reference air is provided to O2 probe which calculates the
required carbon content and provide feedback to the controller for controlling gas to
maintain carbon content; as shown in fig (2) and feeding the temperature and carbon
potential data from the master controller (2) to computer apparatuses (PC1, PC2) via a
network to display and also recording the parameter data for analysis as shown in the
fig (3).
The advantages of the present improved system are listed in below,
1. Automated system is provided with the facility to monitor and control the
essential parameters during the heat treatment process in the gas carburising
furnace.
2. Single master controller is used with better user interface.
3. Paperless recorder is provided for recording parameter data for analysis.
4. Online digitized system is provided for tracking all parameters live on screen.
5. The system cycle time is controlled to exact value as per process defined.
6. The quality of the product subjected to this improved GCF system is enhanced
as per the metallurgical data discloses about the product quality in terms of core
hardness, case depth and surface hardness and micro-structure and because of
this improvement, there is no rejection of metal objects during the heat
treatment process.

WE CLAIM :
1. An automated system for gas carburization of metal components comprising:
a) a master controller (2) configured to receive and transmit data signal from and
to the constituent components of the system, the system having a plurality of
gas carburizing furnaces;
b) at least two heater zones (Z1,Z2) for heating up the metallurgical component to
its melting point;
c) one each two thermocouple (Z1 T/C,Z2 T/C) fitted to each of said two heater
zones (Z1,Z2); and
d) one each probe (P1,P2) connected to said thermocouples (Z1T/C,Z2T/C)
respectively, and a third probe (P3) to allow the referenced air supply to said
heater zones (Z1,Z2), thereby measuring the carbon potential of the
components, and a fourth probe (P4) connected to the master thermocouple,
whereas all said probes (P1,P2,P3,P4) are connected to said master controller
for transmitting parametric data,
 wherein the master controller (2) and a monitoring and control device are
connected via a network to ensure desired properties of the metallurgical
component during the gas carburizing process.
2. An automated system for gas carburization of metal components comprising:
a) a master controller (2) configured to receive and transmit data signal from and
to the constituent components of the system, the system having a plurality of
gas carburizing furnaces;
b) at least two heater zones (Z1,Z2) for heating up the metallurgical component to
its melting point;
c) one each two thermocouple (Z1 T/C,Z2 T/C) fitted to each of said two heater
zones (Z1,Z2); and
d) one each probe (P1,P2) connected to said thermocouples (Z1T/C,Z2T/C)
respectively, and a third probe (P3) to allow the referenced air supply to said
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heater zones (Z1,Z2), thereby measuring the carbon potential of the
components, and a fourth probe (P4) connected to the master thermocouple,
whereas all said probes (P1,P2,P3,P4) are connected to said master controller
for transmitting parametric data,
 wherein the master controller (2) and a monitoring and control device are
connected via a network to ensure desired properties of the metallurgical
component during the gas carburizing process,
 wherein at least one paperless recorder (5) is provided for each of the
plurality of gas carburizing furnaces (GCF-1,GCF-2, GCF-3, GCF-4) to record
the parametric data which is connected to each of at least one said master
controller (MC-1, MC-2, MC-3, MC-4) for analysis of the metallurgical
component during gas carburizing process.
3. The automated system for gas carburization as claimed in claim 1 or claim 2, further
comprising at least two retort safety contactors (RC1, RC2) interconnected to said
heater zones (Z1, Z2) respectively and an overall retort safety contactor (RC), which is
then connected to said single master controller (2) which controls the temperature of
the said heater zones of the system.
4. The automated system for gas carburization as claimed in claim 1 or claim 2, wherein
said monitoring device is at least two computer apparatuses (PC1, PC2) connected to
said network via at least one network switch (4).
5. A method for controlling and monitoring essential parameters of metallurgical
components in a gas carburizing furnace (1), comprising the steps of:
- heating the metallurgical component to its melting point on the heater zones (Z1, Z2)
demarcated in carburizing furnace;
-measuring the temperature of each of the heater zones (Z1, Z2) by using at least two
thermocouples (Z1 T/C, Z2T/C) fitted to each of said heater zones (Z1, Z2);
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-transmitting the acquired temperature data to the master controller (2) by using at
least two probes (P1, P2);
-controlling the temperature by heating operation in the heater zones (Z1, Z2) by using
retort safety contactors (RC1, RC2) through a master controller(2);
-measuring the overall temperature of the furnace by using a fourth probe (P4) and
feeding to the master controller (2);
-providing reference air to the oxygen probe (P3) for measuring carbon potential of the
metallurgical component and transmitting the acquired carbon potential data to the
master controller (2); and
-transmitting the temperature and carbon potential data from the master controller (2)
to computer apparatuses (PC1, PC2) for monitoring via a network.
6. The method as claimed in claim 5, wherein the temperature and carbon potential
data are inputted to a paperless recorder (5), and further those data are remotely
transmitted through a network to the computer apparatuses (PC1, PC2) via a network
switch (4).
7. The method as claimed in claim 5, wherein carbon potential is measured through
oxygen sensors which calculates the required carbon content and provide feedback to
the controller (2) for controlling reference air supply to maintain carbon content.