FIELD OF INVENTION
The present invention relates to a process to produce tailored microstructure
blank to generate localized strength and formability in automotive grade steel for
manufacturing automotive component.
BACKGROUND OF THE INVENTION
The current invention relates to the production of tailor made blanks using
localized heat treatment technique to create differential microstructure and
strength within the blanks (Fig.2 and Fig.4). Therefore, complex auto
components can be produced with differential strength without welding and
joining process of dissimilar materials, which is very much advantageous with
compared to the existing TWB (tailor welded blank) technology. Consequently,
the inherent problems of welding and joining process will be solved.
In the past three decades, the automotive industry has seen constricting
government regulations concerning fuel conservation and safety mandates along
with the environmental concerns. These concerns have prompted the
automakers to come up with innovative solutions to develop lighter cars for

reduced fuel consumption, while improving the overall structure of the vehicles
for occupant safety. The weight reduction can be met by using high strength
steel. Research and development of steel industries are continuously working to
develop new grades of high strength steel. However, the application of advanced
high strength steel (AHSS) in vehicle components are not so easy as its
formability is comparatively poor. To overcome this situation, Tailor made blanks
together with the Advanced High Strength Steels (AHSS) offer a great potential
to increase safety and/or decrease the weight of cars while at the same time
reducing their cost.
The tailor made blanks are sheet assemblies that are joined or machined prior to
the forming process. The applied process can be welding, adhesive bonding, or
machining. However, the welding has received much more attention compared to
the other processing methods, and that is why tailor-made blanks are also
known as Tailor-Welded Blanks (TWBs). Tailor-welded blank (TWB) technology is
to form sheet blanks welded from tailored sheet blanks different in thickness,
grade and coating system to meet the best properties of materials were located
precisely within the part where they were needed.
The benefits of TWB technology are obvious and can be summarized as (1) cost
reduction by requiring less forming dies; (2) weight reduction by welding sheet
material with different thickness or strength for performance requirements; (3)
part dimensional consistency improvement by removing inaccurate spot welding
processes; (4) corrosion resistance enhancement by eliminating of lap joints; (5)
strength improvement by substituting traditional spot welds with laser and mash

seam welds (AS Partnership, 2001); (6) cost reduction by reducing process
steps.
Since 1980s, TWB industry continues to experience steady growth at an
approximate rate from 25 to 30% per year in North America, Europe and Japan.
Research has been conducted along with the industrial practice. ArcelorMittal has
successfully made TW blanks using two ultra high strength steels named USIBOR
1500 and DUCTIBOR 500.
Furthermore, the development of Ultra High Strength Steel (UHSS), was more
advantageous for automakers to reduce the sheet thickness (weight saving) or
even improving the crash behaviour (safety). The idea of this work is to develop
a structure by local heat treatment to improve plastic flow in regions where high
deformation degrees are essential. The rest of the sheet is unaffected and in the
heat treated regions the high strength is regained by work hardening,
martensite, ferrite, retained austenite and in some cases carbide. In ULSAB
study, nearly half of ULSAB's mass consists of tailored blanks promoting smooth
load flow, reduction of structural discontinuity and a combination of thicker and a
higher strength materials within the same part. For instance, use of such steels
reduced 933kg weight with fuel consumption of 4.41/100 km.
However, the poor formability of UHSS with compared to typical deep drawing
steels results in a reduced deformation degree, increased spring back and tool
wear. Although, a suitable heat treatment of the whole sheet will improve the
formability but the high strength will be lost. To achieve both (high strength as
well as formability) at the same time, to develop a suitable heat treatment

technique is a thrust area of research for steel industries as well as automakers.
Sametime, it has to be cheaper and faster compared to current industrial
practice. In addition, complex auto components require differential strength level
at its different region and these are often manufactured from tailor rolled or
tailor welded, blanks (TRB or TWB) however both welding and/or rolling is time
and resource intensive. Welding is defect so it will definitely weaken the
structure.
A mega project has been done by European Research Commission from 2003 to
2007 [1] on local heat treatment of Ulta-High Strength Steel (UHSS) with an
overall aim of the project is to increase the applicability of ultra high strength
steel in European automotive industry. Induction heating method was adopted as
a local heat treatment technique for the improvement of formability property by
making such steels an option for new areas of applications.
Similarly, Tailor Annealed Strip (TAS) project idea was generated under Next
Generation High-Strength Steel (NGHSS) Thrust area project at TSE, RD&T,
Ijmuiden. TAS generates whole coils using a bespoke continuous annealing
process using induction heating method, which will fit into the traditional steel
production process (coils). The target of TAS is to produce a strip (coil) of
material with varying mechanical properties across the strip width.
The current invention, TMB technology will replace TWB (Tailor Welded Blank)
technology, considering the fact that it will be more cost effective and will give
better localized mechanical properties during forming of single components. At
the same time, role of steel companies in making TRB or TWB are very limited.

Therefore, the present invention will be the first step to be a "complete solution
provider" for automotive industries. In turn, manufacturing cost can be lowered
and complex auto-parts can be manufactured with greater flexibility.
The US patent application US20080178970, assigned to Aga AB., discloses a
method for the heat treatment of extended steel products while they are in
motion. During heat treatment extended products cannot be heated evenly and
rapidly along their entire length. In this invention extended steel products are
heated using direct flame impingement (DFI) such that one set of burners
essentially covers the circumference of the products. The material is divided into
even multiple lengths, for it to be possible to heat-treat simply and evenly. The
use of direct heating ensures that the heating in a holding furnace can deal with
different lengths of material. This entails an increased yield not only in the rolling
process but also in subsequent processes. The method finds use in the treatment
of extended steel products such as rod, pipe, work piece, etc.
The Japanese patent application JP2007332415, assigned to JFE Steel, KK,
discloses a method for the manufacturing of a high-tensile-strength, hot-dip
galvanized steel sheet. The manufacturing method comprises of: heating the
steel sheet from room temperature to 850°C; galvanizing it at 480°C using the
galvanizing bath containing 0.135% of Al (and saturation amount of Fe) and is
kept into the temperature of 460°C. This method reduces the surface of the steel
sheet by using the direct flame burner and prevents oxides from forming on the
surface. This process can be used for manufacturing of steel plates that are used
in motor vehicle, household appliance, and building materials, etc.

The Japanese patent application JP2004027286, assigned to Sumitomo Electric
Industries Ltd., provides a direct heat treatment method for hot-rolled wire rod
with which the high strength steel wire can be obtained. Iii this the steel wire
having low amount of alloy element is hot rolled. Then the wire is cooled by
immersing it in cooling channel of warm water or stream mixed coolant at a
cooling rate of 5°C/sec or more. The wire pulled out from the cooling channel at
a wire temperature of 150-450°C is further cooled with air to obtain hot-rolled
wire. The hot rolled wires thus prepared have excellent strength, bending
property and weldability and are effectively used for reinforcements.
The European patent EP2009127, assigned to Arcelormittal, France, discloses
an invention that deals with a process for manufacturing a hot-dip galvanized or
galvannealed steel sheet having a TRIP microstructure. The process comprises
following steps: first step involves oxidizing steel sheet in a direct flame furnace
where the atmosphere comprises air and fuel with an air-to-fuel ratio between
0.80 and 0.95. This forms a layer of iron oxide having a thickness from 0.05 to
0.2 urn on the surface of the steel sheet. At this stage an internal oxide of Si
and/or Mn and/or Al is formed. The second step involves reducing oxidized steel
sheet in order to achieve a reduction of the layer of iron oxide. Next step is hot-
dip galvanizing of reduced steel sheet to form a zinc-coated steel sheet. The
optional step involves subjecting hot-dip coated steel sheet to an alloying
treatment to form a galvannealed steel sheet.
The US patent US6218642, assigned to J. F. Helmold & Bro., Inc., discloses a
method of surface hardening of steel workpieces using laser beams so as to
obtain equivalent or superior ductility properties with superior wear resistance.

The selected surface areas of steel workpieces are heat treated using the laser
beam to increase the hardness of the area. Laser beam of less intensity is
subsequently applied, for relieving stress. Application of laser beam reduces
processing time without weakening metal section and its durability. The method
can be used for the cutting rules, knife blades etc.
The European patent EP2161095, assigned to Alstom Technology Ltd.,
discloses method of surface treatment of turbine component using laser or
electron radiation. In this method the surface of the steam turbine is remelted by
laser radiation or electron radiation and then surface-alloying is done to increase
the mechanical stability and the corrosion resistance of the surface of the steam
turbine. The method gives steam turbine part with good smoothness, high
strength and high corrosion resistance thus improves the efficiency of the turbine
blade. This method can be used for treating surface of a steam turbine made of
austenitic or ferritic-martensitic steel.
The European patent EP0893192, assigned to Timken Co, discloses the method
of imparting residual compressive stresses to steel machine components by
inducing martensite formation in a microstructure. In this invention the steel
component, such as a bearing race, is locally melted using laser beam along its
surface so that the thickness of the melted region is substantially less than the
thickness of the component. The molten steel is rapidly solidified to transform
some of the austenite into martensite. After tempering most of the surface is
martensite and the solidified steel acquires a residual compressive stress due to
the increased volume occupied by the martensite. This process improves fatigue

performance and crack resistance of the component and can be used to improve
physical characteristics of machine.
The Chinese patent CN101225464, assigned to Xi An Thermal Power Res.
Inst., discloses an invention that relates to a method to improve the anti-
oxidation performance in high temperature steam atmosphere of
ferrite/martensite refractory steel. The properties of quick heating and quick
cooling of laser phase transition heat treatment is utilized to form the steel
surface into a fine-grain region. This improves chromium element diffusion from
basal body to oxygenation level, thereby improving high temperature and steam
oxidation resisting properties of ferrite/ferrite refractory steel. Thus this method
can be used for improving the properties of ferrite/ferrite refractory steel.
3.3 Other heat treatments of AHSS
The PCT application WO20090451 46, assigned to Aktiebolaget Skf et Al,
discloses a process for inducing a compressive residual stress in a surface region
of a steel component. In the process of heat treatment a portion of steel
composition is subjected to induction heating and quenching, such that the
hardness in the surface region of component is increased and the microstructure
comprising martensite and/or bainite is formed in the component. The method
efficiently improves the mechanical properties of steel components and can be
used for forming bar, rod, tube and rings.
The US granted patent US6277214, assigned to Powertech Labs Inc., reveals a
process for the heat treatment of iron-based alloys such as carbon steels and low

alloy steels, in a controlled oxidative environment. Treatment of an iron-based
alloy material involves: heating the material at high temperature in an electric
resistance furnace in the presence of oxygen to form austenite in the material
and wustite outside the material; cooling the material to form martensite or
bainite in the material; and heating the material at a lower temperature to
transform a surface of the scale. The process provides objects of desired
mechanical properties, high strength and ductility. The process can be used for
coating iron-oxide surfaces and useful products such as natural gas cylinders to
protect thenrrfrom corrosion, erosion and abrasion.
The US granted patent US6228188, assigned to N.V. Bekaert S.A., discloses
heat treatment of a steel wire with a diameter less than 2.8 mm. The methods
for heat treatment of smaller diameter wires are very expensive. In this patent a
low cost process for heat treatment of wire is provided in which the wire is
heated in a furnace to 1000°C and then cooled using air and water cooling
methods. The numbers of the water cooling periods, the numbers of the air
cooling periods, the length of each water cooling period are so chosen so as to
avoid the formation of martensite or bainite. The invention allows small diameter
wires to be made by a cheaper method.
The first four patents uses direct heat treatment method in which, the US patent
application US20080178970 discloses an invention about the even and rapid heat
treatment of extended steel having different length. On the other hand the
Japnese patent JP2007332415 reveals a method in which a steel sheet is heat
treated directly and then galvanized at certain temperature. This process finds
use in the manufacturing of steel plates that are used in vehicles and other

appliances. An European patent EP2009127 discloses a method of hot-dip-
galvanization of steel sheet having TRIP microstructure using direct heat
treatment method. High strength steel wire can be effectively manufactured
using the method given in Japnese patent JP2004027286.
The patetns disclosing laser based heat treatment methods are found in 4
documents. These documents related to methods of either hardening or
improving the compressive stress of steel. In these methods the steel with
austenite as a microstructure is heated using laser to transform it to martensite
thus improving its properties. The major advantage of laser surface treatment is
high processing speeds with precise case depths.
The third category of heat treatment include induction heating or furnace
heating. The induction heating is used to impart compressive residual stress to
the surface, thus improving the mechanical properties of steel. The furnace
heating method is used for coating surface of the steel or hardening the steel
wires. This method seems to be cheaper than the previously discussed method.
OBJECTS OF THE INVENTION
It is therefore, an object of the present invention to propose a process to
produce tailored microstructure blank to generate localized strength and
formability in automotive grade steel which manufactures complex auto-ports
with greater flexibility.

Another object of the present invention is to propose a process to produce
tailored microstructure blank to generate localized strength and formability in
automotive grade steel which generates better localized mechanical properties
during forming of single component.
A further object of the present invention is to propose a .process to produce
tailored microstructure blank to generate localized strength and formability in
automotive grade steel which lowers the manufacturing cost.
A yet further, object of the present invention is to propose a process to produce
tailored microstructure blank to generate localized strength and formability in
automotive grade steel which enables to manufacture the complex auto-parts
with greater flexibility.
SUMMAARY OF THE INVENTION
The current TMB technology will deal with the localized heat treatment of single
blank at different regions within the blank to create differential microstructure
and strength. Therefore, complex auto components can be produced with
differential strength without welding and joining process of dissimilar materials,
which is very much advantageous with compared to the existing TWB
technology. Consequently, the inherent problems of welding and joining
processed will be solved.

Flame hardening apparatus was build based on direct flame method to develop
an online heat treatment process to produce tailored microstructure blanks
(TMB).
Automotive grade steel (CMn440) was chosen as work material because of its
good hardenability and it is already in use in the automotive industry. Laboratory
heat treatment results evidenced that this steel can be hardened to achieve
desired properties with dual phase microstructure. Direct Flame method was
chosen as heating method because of low manufacturing cost.
To prove the TMB technology concept, B-pillar was identified as the first auto-
component for press forming, because it requires differential strength level along
its length. A scale down (1:4) B-pillar die was designed and manufactured locally
at Jamshedpur. Press forming was done for the TMB sheets and successfully
formed the B-pillar auto-component with differential properties along the length.
A numerical simulation work was done to understand the forming behavior of
the tailored microstructure blank using explicit solver PamStamp 2G. FEM
analysis suggests that prototype of B-Pillar can be formed out of TM blanks and
its limiting strain was within the safe zone in FLD curves.
Variables •
An experimental apparatus was build for localized heat treatment experiments to
develop the TMB concept; where, direct flame method was chosen as a heating
technique.

In the TMB technology, to obtain a tailored microstructure blank, one need to
heat treat the steel sheet at austenitising temperature followed by rapid
quenching to form martensite to improve the strength level of the selective area.
After the heat treatment, the blanks will be formed to produce auto components
(B pillar in our case). Metallurgical characterizations of these blanks are also
done to see whether it meets the strength and ductility combination. To obtain
the temperature to heat treat the samples, lab scale heat treatment and
metallurgical characterization are also done. The important variables of the TMB
technology are as follows
a) Heat Treatment concept
The following points have to be considered during flame heating
• The heat treatment has to be uniform throughout the thickness of the
sheet.
• Temperature profile needs to be developed during heating of the sheet.
• Heat treatment temperatures need to be scheduled.
• Whether transformation temperature is achieved for developing dual
phase microstructure.
• CCT curve needs to be developed for the steel grade
• Quenching should be fast enough to form martensite phase to achieve
dual phase structure.

b) Heating Sources
For localized heat treatment the following methods are available:
1. Heating with LPG flames.
2. Heating with electrical induction.
3. Heating with electron beam.
4. Heating with laser.
Hardening by formation of martensite is one the oldest heat treatment process
for the improvement of surface hardness, wear resistance, fatigue strength and
the resistance for impact or compressive forces. Formation of martensite is
basically followed by quenching in a suitable medium in conditions enables
transformation of austenite as much as possible. Depending upon sources to
generating heat for austenization we can differentiate the methods of flame
hardening, induction hardening, laser beam hardening or electron beam
hardening etc.
Among these techniques, flame hardening route was chosen in our case because
of its low production cost, flexibility and mobility.
In case of flame hardening the surface of work piece was heated with a flame
burner supplied with a mixture of fuel gas and technically pure oxygen. Flame
hardening involves several different operating methods depending upon the
relative

movement of work piece and the burner. Specific hardening variants are
stationary method, spin method and progressive method etc. With the stationary
method both the burner and the work piece is stationary for the whole duration
of heating immediate followed by quenching. This method primarily used for
small work piece and very much ideal for series of productions. The other
methods generally used for surface hardening for round surface by rotation both
the work piece and burner.
c) Chemical composition
The composition of the alloy lends the steel its mechanical strength. The
composition of the steel should be such that it has higher hardenability.
d) Microstructure
Dual phase microstructure needs to be developed for optimum strength and
ductility.
e) Strength distribution on the tailor made blank
Strength distribution of the auto components determine the localized heat
treatment schedule.

f) Formability analysis
Formability of the heat treated region should be as good as the un treated
region, so that complex shape can be formed.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
Fig.l: Schematic representation of TMB process concept (TM: Tailored
Microstructure, TMB: Tailored Microstructure Blank).
Fig.2: Schematic illustration of the tailored microstructure blank after localized
heat treatment.
Fig.3: Schematic view of the heat treatment line.
Fig.4: Plan view of CMn440 grade steel sheet for localized heat treatment to
produce a prototype auto-component (B-pillar) using TMB process
concept.
Fig.5: Die design for forming a prototype auto-component (B-Pillar, scale: 1:4).
Fig.6: a) TMB sheet of CMn440 grade steel b) Press forming of prototype B-pillar
from TMB sheet (Scale: 1:4).
Fig.7: a) FLC Contour for formed component, b) FLC curve for the formed
component

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
TMB (Tailored Microstructure Blank) comprises was started parallel to develop a
new technology which will enable us to produce high and advanced high
strength steel blanks with an intension to replace TWB (Tailor Welded Blank)
technology, considering the fact that it will be more cost effective and will give
better localized mechanical properties during forming of single components.
In TMB technology, the discrete blanks already cut or stamped out from strip,
are modified to achieve varying mechanical properties along the length and/or
width of the blank (Fig. 2 and Fig.4). As the blanks are processed individually,
this new technology allows complex shaped heat treated zones and processing
can be done with a relatively simple and compact line concept (low CAPEX). A
semi-continuous, automated TMB process line can be considered to realize
higher volumes. Dependent on application, the TMB material should have a cold-
rolled surface, preferably of full-finish quality, whereas hot rolled surface finish
can also be considered for chassis parts.
The TMB line consists of a heating and cooling head that partially heat-treats a
single piece of blank at a time (Fig. 3). The heating and cooling head can scan
locally along length/width direction of the blank, so complex heat treated
sections can be produced, which makes this process more flexible and easy and
complete solution provider. The heating and cooling cycle will be done point by
point. However such scanning cycle may take time and simple processing cycle is
more reliable. An increased processing rate can be achieved by implementing

multiple heads and or further automated line. Since production is by single
blanks, the production time will be influenced by loading and" unloading individual
blanks into the processing station; however this can be rectified by introducing
automated production line and can be make it continuous process.
General Layout
The process flow diagram is shown in Fig. 1. To obtain a tailored microstructure
blank, one need to heat treat the steel sheet at austenitising or intercritical
temperature followed by rapid quenching to form martensite and/or dual phase
microstructure. After the heat treatment, the blanks will be formed to produce
auto components (B pillar in our case). Metallurgical characterizations of these
blanks are incorporated to see whether it meets the strength and ductility
combination.
The flame hardening is one of the oldest method for heat treatment. The source
of heat is the burner ignited in the air and if this flame applied to metallic surface
it will heat up the surface very fast and if that surface immediately quenched,
the surface may get hardened due to formation of harder phase like martensite.
The current project demands for heat treatment of a blank in a defined area or
in complex shape by local heating method. For local heating by direct flame, a
pilot line was designed and fabricated for the current project.
The overall schematic diagram of the flame heating system is shown in Fig. 3.
The design contains a rectangular frame (1) where burner nozzle (2) will move in
X-Y directions on a working table (3). The movement can be controlled by a

computer interface. This movement can be automatically controlled for heating
the defined area. Along with burner nozzle (2), water spray nozzle (4) is
connected in such a way that it can move with the burner (2) synchronized way.
The water spray nozzle (4) always will be behind the burner (2) so that water (5)
can be sprayed on the heating zone (6) immediately. An infrared (7) system for
temperature measurement is also attached with burner head (2) in such an
angle, that it'can measure the live temperature of hot zone (6) of the work piece
(3) during heating by flame.
The burner nozzle (2) is connected with gas cylinders (8) followed by a gas flow
meter. The current gas mixture was used as LPG and Oxygen in right proportion
to make suitable flame for heating. The water nozzle (4) was also connected
with water tank through water inlet (9) and water outlet pipe (10) and controlled
by the computer program.
The main object of the apparatus is to provide an improved flame heating and
cooling mechanism for heat treatment in the local area of the steel blank.
The materials used for this experiment was C-Mn440 grade steel of CRCA
conditions with a thickness level of 1.18 mm. The partial heat treatment of the
steel blanks were planned according to the Fig.4 with an intention to produce
tailored microstructure blank according to the required dimensions of auto
component, which will be cold formed after the tailored blank is ready. The heat
treatment process was performed point by point using one burner at particular
target temperature. The heat treatment temperature was selected based on the
previous laboratory experiments. The target microstructure (dual phase

structure, ferrite and martensite) was achieved based on laboratory experiments
for good combination of strength and formability.
The heat treated blanks are shown in Fig.6a. The temperatures were measured
from the Infrared system. The heat treatment experiment was performed at two
different temperatures (770°C & 800°C). The microstructural and mechanical
characterization were done after fabricating samples from both untreated and
from heat treated regions of the blank and shown in table 1.

Formability analysis of Tailored Microstructure Blank during forming of
B-Pillar (prototype) auto component:
B-pillar was identified as the first auto-component for press forming, because it
requires differential strength level along its length. A scale down (1:4) B-pillar die
was designed and manufactured locally at Jamshedpur (Fig.5). Press forming
was done fpr the TMB sheets and successfully formed the B-pillar auto-
component with differential properties along the length (Fig.6b). A numerical
simulation work was done to understand the forming behavior of the tailored
microstructure blank using explicit solver PamStamp 2G. An input property for
the FEA was evaluated by performing uniaxial tension tests on the base as well
as the heat treated blanks. The simulations were performed in three stages -
gravity, holding and drawing. FEM analysis suggests that prototype of B-Pillar
can be formed out of Tailored Microstructure Blanks and its limiting strain was
within the safe zone in FLD curves (Fig.7).

WE CLAIM
1. A process to produce tailored microstructure blank for automotive
component to generate localized strength and formability in automotive
grade steel comprises the steps of:-
- flame heating the steel in a definite area from a burner nozzle;
- measuring the temperature of steel with an infrared temperature
'measuring unit attached with the burner head;
- cooling the heated area of steel by water spraying having
synchronized with the burner head;
2. The device to produce tailored microstructure blank as claimed in claim 1
comprises.
- a rectangular shaped frame having a guide rod disposed on the top
of the frame;
- "a movable dual attachment of a burner nozzle and a spray nozzle,
slideable on a guide rod means of a servo motor;
- a table is provided on which the steel is place for heating disposed
at bottom of the burner nozzle;
- an infrared temperature measuring unit attached with the burner
nozzle;

3. The device as claimed in claim 2 wherein the burner nozzle is connected
with one DA inlet pipe and one oxygen inlet pipe.
4. The device as claimed in claim 2 wherein the burner nozzle is connected
with one water inlet pipe and one water outlet pipe.
5. The device as claimed in claim 2 wherein the burner nozzle is movable in
X-Y direction.
6. The device as claimed in claim 2 wherein the dual attachment (burner
nozzle and spray nozzle) is slideable along the guide rod by a servo motor.
7. The device as claimed in claim 2 wherein the spray nozzle is connected to
a coolant pipe.
8. The process of produce tailored microstructure blank wherein tensile
strength of at least YS 300 MPa and UTS 550 MPa or more in achieved in
the tailored regiow of the blank after cooling.

ABSTRACT
The present invention is provided with a process to produce tailored
microstructure blank to enhance localized strength and formability in
commercially automotive grade steel comprises the steps of, flame heating the
steel in a definite area from a burner nozzle; and measuring the temperature of
steel with an infrared temperature measuring unit attached with the burner
head; and cooling the heated area of steel by water spraying having
synchronized with the burner bead; The device to produce tailored
microstructure blank as claimed in claim 1 comprises a rectangular shaped frame
having a guide rod disposed on the top of the frame; and a movable dual
attachment of a burner nozzle and a spray nozzle, slideable on a guide rod
means of a servo motor; and a table is provided on which the steel is place for
heating disposed be health the burner nozzle; and an infrared temperature
measuring unit attached with the burner nozzle;