Title of Invention	A DEVICE FOR DETERMINING THE SECONDARY WORKING EMBRITTLEMENT PROPERTY OF SHEET-METAL
Abstract	Accordingly, there is provided a device for determining the SWE property of sheet metals, which allows conducting a destructive testing of a deep drawn specimen, in order to evaluate if the material is ductile or brittle at a certain temperature. The test specimen is immersed in a liquid bath, which allows conducting tests at various temperatures as per requirement. The invention involves designing of an anvil including a suitable hydraulic powerpack operable by an electric source. The test-specimen is reconfigured so as to be accommodated on the anvil. The invention further provides a method for determining the SWE property of sheet-metals adapting the innovative device.

Title of Invention

A DEVICE FOR DETERMINING THE SECONDARY WORKING EMBRITTLEMENT PROPERTY OF SHEET-METAL

Abstract

Accordingly, there is provided a device for determining the SWE property of sheet metals, which allows conducting a destructive testing of a deep drawn specimen, in order to evaluate if the material is ductile or brittle at a certain temperature. The test specimen is immersed in a liquid bath, which allows conducting tests at various temperatures as per requirement. The invention involves designing of an anvil including a suitable hydraulic powerpack operable by an electric source. The test-specimen is reconfigured so as to be accommodated on the anvil. The invention further provides a method for determining the SWE property of sheet-metals adapting the innovative device.

Full Text	2 FIELD OF THE INVENTION The present invention relates to a device for determining the secondary working embritlement (SWE) property of sheet-metals. The invention further relates to a method of determining SWE property of sheet metals adapting the innovative device. BACKGROUND OF THE INVENTION Cold rolled annealed sheet steels are used for making various automobile components. These components are fabricated by various kinds of forming operations. After forming, these components may be subjected to further deformation, by following ways: • The fabrication requirement of the particular component may necessitate multiple forming treatments. • The formed component, during actual service, may be subjected to some kind of loading, e.g. when a car experiences an accidental impact. In either case, an already formed component may be subjected to a secondary forming. This is known as 'Secondary Working'. During secondary working, the material may behave like a brittle material, especially at low temperatures, and this phenomenon is known as 'Secondary Work Embritlement', or SWE in short. 3 It is therefore important to determine the duclite-brittle transition temperature for those materials, which are prone to SWE problem, for example high strength interstitial free steels. The determination of SWE property requires developing a suitable device. Presently, there is no known device, which can determine in a single set-up the duetile-brittle transition temperature for such materials / components for example, high strength interstitial steels which are susceptible to secondary work embrittlement. The property of SWE is basically characterized by the parameter called as ductile-brittle transition temperature, which provides data to evaluate whether or not a material is duetile or brittle at a certain temperature. OBJECTS OF THE INVENTION It is therefore an object of the invention to propose a device for determining the SWE property of sheet metals. Another object of the invention is to propose a device for determining the SWE property of sheet metals, which evaluates a duetile-brittle transition temperature. A still another object of the invention is to propose a method of determining the SWE property of sheet metals. 4 SUMMARY OF THE INVENTION Accordingly, there is provided a device for determining the SWE property of sheet metals, which allows conducting a destructive testing of a deep drawn specimen, in order to evaluate if the material is ductile or brittle at a certain temperature. The test specimen is immersed in a liquid bath, which allows conducting tests at various temperatures as per requirement. The invention involves designing of an anvil including a suitable hydraulic powerpack operable by an electric source. The test-specimen is reconfigured so as to be accommodated on the anvil. The invention further provides a method for determining the SWE property of sheet-metals adapting the innovative device. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Fig. 1 - shows a hydraulic power pack in a schematic view, which constitutes a feature of the device of the invention. Fig. 2 - shows a line diagram of the device of the invention. Fig. 3 - shows an anvil configured according to the invention. 5 DETAILED DESCRIPTION OF A PREFFERED EMBODIMENT OF THE INVENTION Fig. 1. shows a hydraulically-operated pressing means (1) having a vertically- movable piston element (19). The pressing means (1) is energized by an external electrical source (2). The pressing means (1) is operable in such a manner that an incremental pressure-cum-load can slowly be exerted on a deep- drawn specimen of sheet-metal. As shown in Fig - 2, the pressing means (1) is releasably disposed on a hollow chamber means (3) accommodating a liquid which can absorb incremental and decremental temperature when created therein. An anvil (4) having a conically- shaped head to detachably attached by a deep-drawn cup-shaped specimen (5) of sheet-metal. A static load when slowly applied on the specimen (5) held on the anvil (4) by the piston element (la), a propagatable crack is formed on the specimen (5) if the cup (5) constitutes a brittle material. On the other hand, if the material of the cup (5) is non-brittle, the open bore of the cup (5) gets enlarged / deformed, without forming any crack. The activity of slow-loading is repeated for number of times, at different temperatures with different specimen, and the observations are tabulated. The minimum temperature, at which none of the specimens fail, is determined as the duetile-brittle tension temperate. 6 The method of the invention can be performed by carrying-out the following sequential steps :- 1. A steel sheet sample is drawn into a cup having for example, 50 mm diameter, with a drawing ratio of approximately 2.0. 2. The drawn cup is placed on a conical anvil, and the entire system is immersed in a cold bath. 3. A piston slowly applies a static load on the cup. • If it is a brittle material, a crack is formed and it gets propagated immediately. • If the material is not brittle, the open bore of the cup gets enlarged/deformed, but no cracking takes place. • This test is carried out for a certain number of times (with as many samples) at a certain temperature. • A chart is made, based on the observations. • The minimum temperature at which none of the three cups fail, is considered as the ductile-brittle transition temperature. 7 Fig. 3 shows an embodiment of an anvil designed according to the invention. The two parallel arms (pa) of the trapezodical-shaped anvil (4) can be designed between 10 to 20mm, the top and bottom bases (tb, bb) respectively should be 40 and 100 mm, the height between the top and bottom bases (tb, bb) shall be between 60 to 70 mm, the two trapezodical arms (ta) shall be intersecting at an apex making an angle of 60°. Example of the set of data Temperature Test observation 0°C OK OK OK -10°C OK OK OK -20°C OK OK OK -30°C OK OK OK -40°C OK Failed OK -50°C Failed OK Failed Conclusion DBTT = -30°C 8 WE CLAIM 1. A device for determining secondary working embrittlement (SWE) property of sheet-metals, comprising : - a hollow chamber means (3) accommodating a liquid susceptible to absorb varying temperature, the chamber means (3) having a top- opening (3a) to allow ingress and egress of a piston element (la); - a hydraulically-operated pressing means (1) incorporated with said piston element (la) detachably attached on the chamber means (3), the pressing means (1) being energized by an external electrical source (2); - an anvil (4) fixed to a bottom portion (3b) of the chamber means (3) being submearged in said liquid, the anvil having a concically- shaped head portion (3c); and - a specimen (5) of the sheet-metal deeply drawn and being correspondingly configured for fixing on the anvil (4), an incremental static load via the pressing means (1) being applied on the specimen (5) at different temperature to collect data on formation or otherwise of a crack-development, which being propagatable through the liquid for collection of repetitive data with several specimens (5) thereby determining the SWE of the sheet- metal. 9 2. A method of determining secondary working embrittlement (SWE) property of sheet-metals in a device as claimed in claim 1, the method comprising the steps of: - preparing a specimen by drawing a sheet-metal into a cup (5); - placing the cup (5) in a inverted manner (open bore at the bottom), on a conical head of an anvil (4); - disposing the anvil (4) with the cup (5) in a chamber means (3) which is filled with a liquid; - slowly applying a static load on the cup (5) at different temperature of the liquid via a hydraulically-operated pressing means (1), the pressing means (1) being detachably placed on the chamber means (3); - collecting repetitive data on crack-development on the cup (5) and/or on a several number of replaced cups (5) to determine the minimum temperature at which the cups (5) sustain the load, thereby evaluating the SWE property of the sheet-metal. 3. A device for determining secondary working embritlement (SWE) property of sheet-metals, as substantially described herein with reference to the accompanying drawings. 10 4. A method of determining secondary working embrittlement (SWE) property of sheet-metals in a device as substantially described herein with reference to the accompanying drawings. Accordingly, there is provided a device for determining the SWE property of sheet metals, which allows conducting a destructive testing of a deep drawn specimen, in order to evaluate if the material is ductile or brittle at a certain temperature. The test specimen is immersed in a liquid bath, which allows conducting tests at various temperatures as per requirement. The invention involves designing of an anvil including a suitable hydraulic powerpack operable by an electric source. The test-specimen is reconfigured so as to be accommodated on the anvil. The invention further provides a method for determining the SWE property of sheet-metals adapting the innovative device.

Full Text

2
FIELD OF THE INVENTION
The present invention relates to a device for determining the secondary working
embritlement (SWE) property of sheet-metals. The invention further relates to a
method of determining SWE property of sheet metals adapting the innovative
device.
BACKGROUND OF THE INVENTION
Cold rolled annealed sheet steels are used for making various automobile
components. These components are fabricated by various kinds of forming
operations. After forming, these components may be subjected to further
deformation, by following ways:
• The fabrication requirement of the particular component may necessitate
multiple forming treatments.
• The formed component, during actual service, may be subjected to some
kind of loading, e.g. when a car experiences an accidental impact.
In either case, an already formed component may be subjected to a secondary
forming. This is known as 'Secondary Working'. During secondary working, the
material may behave like a brittle material, especially at low temperatures, and
this phenomenon is known as 'Secondary Work Embritlement', or SWE in short.

3
It is therefore important to determine the duclite-brittle transition temperature
for those materials, which are prone to SWE problem, for example high strength
interstitial free steels. The determination of SWE property requires developing a
suitable device.
Presently, there is no known device, which can determine in a single set-up the
duetile-brittle transition temperature for such materials / components for
example, high strength interstitial steels which are susceptible to secondary work
embrittlement. The property of SWE is basically characterized by the parameter
called as ductile-brittle transition temperature, which provides data to evaluate
whether or not a material is duetile or brittle at a certain temperature.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to propose a device for determining the
SWE property of sheet metals.
Another object of the invention is to propose a device for determining the SWE
property of sheet metals, which evaluates a duetile-brittle transition temperature.
A still another object of the invention is to propose a method of determining the
SWE property of sheet metals.

4
SUMMARY OF THE INVENTION
Accordingly, there is provided a device for determining the SWE property of
sheet metals, which allows conducting a destructive testing of a deep drawn
specimen, in order to evaluate if the material is ductile or brittle at a certain
temperature. The test specimen is immersed in a liquid bath, which allows
conducting tests at various temperatures as per requirement. The invention
involves designing of an anvil including a suitable hydraulic powerpack operable
by an electric source. The test-specimen is reconfigured so as to be
accommodated on the anvil.
The invention further provides a method for determining the SWE property of
sheet-metals adapting the innovative device.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig. 1 - shows a hydraulic power pack in a schematic view, which constitutes a
feature of the device of the invention.
Fig. 2 - shows a line diagram of the device of the invention.
Fig. 3 - shows an anvil configured according to the invention.

5
DETAILED DESCRIPTION OF A PREFFERED EMBODIMENT OF THE
INVENTION
Fig. 1. shows a hydraulically-operated pressing means (1) having a vertically-
movable piston element (19). The pressing means (1) is energized by an
external electrical source (2). The pressing means (1) is operable in such a
manner that an incremental pressure-cum-load can slowly be exerted on a deep-
drawn specimen of sheet-metal.
As shown in Fig - 2, the pressing means (1) is releasably disposed on a hollow
chamber means (3) accommodating a liquid which can absorb incremental and
decremental temperature when created therein. An anvil (4) having a conically-
shaped head to detachably attached by a deep-drawn cup-shaped specimen (5)
of sheet-metal.
A static load when slowly applied on the specimen (5) held on the anvil (4) by
the piston element (la), a propagatable crack is formed on the specimen (5) if
the cup (5) constitutes a brittle material. On the other hand, if the material of
the cup (5) is non-brittle, the open bore of the cup (5) gets enlarged / deformed,
without forming any crack. The activity of slow-loading is repeated for number of
times, at different temperatures with different specimen, and the observations
are tabulated. The minimum temperature, at which none of the specimens fail, is
determined as the duetile-brittle tension temperate.

6
The method of the invention can be performed by carrying-out the following
sequential steps :-
1. A steel sheet sample is drawn into a cup having for example, 50 mm
diameter, with a drawing ratio of approximately 2.0.
2. The drawn cup is placed on a conical anvil, and the entire system is
immersed in a cold bath.
3. A piston slowly applies a static load on the cup.

• If it is a brittle material, a crack is formed and it gets propagated
immediately.
• If the material is not brittle, the open bore of the cup gets
enlarged/deformed, but no cracking takes place.
• This test is carried out for a certain number of times (with as many
samples) at a certain temperature.
• A chart is made, based on the observations.
• The minimum temperature at which none of the three cups fail, is
considered as the ductile-brittle transition temperature.

7
Fig. 3 shows an embodiment of an anvil designed according to the invention. The
two parallel arms (pa) of the trapezodical-shaped anvil (4) can be designed
between 10 to 20mm, the top and bottom bases (tb, bb) respectively should be
40 and 100 mm, the height between the top and bottom bases (tb, bb) shall be
between 60 to 70 mm, the two trapezodical arms (ta) shall be intersecting at an
apex making an angle of 60°.
Example of the set of data

Temperature Test observation
0°C OK OK OK
-10°C OK OK OK
-20°C OK OK OK
-30°C OK OK OK
-40°C OK Failed OK
-50°C Failed OK Failed
Conclusion DBTT = -30°C

8
WE CLAIM
1. A device for determining secondary working embrittlement (SWE)
property of sheet-metals, comprising :
- a hollow chamber means (3) accommodating a liquid susceptible to
absorb varying temperature, the chamber means (3) having a top-
opening (3a) to allow ingress and egress of a piston element (la);
- a hydraulically-operated pressing means (1) incorporated with said
piston element (la) detachably attached on the chamber means
(3), the pressing means (1) being energized by an external
electrical source (2);
- an anvil (4) fixed to a bottom portion (3b) of the chamber means
(3) being submearged in said liquid, the anvil having a concically-
shaped head portion (3c); and
- a specimen (5) of the sheet-metal deeply drawn and being
correspondingly configured for fixing on the anvil (4), an
incremental static load via the pressing means (1) being applied on
the specimen (5) at different temperature to collect data on
formation or otherwise of a crack-development, which being
propagatable through the liquid for collection of repetitive data with
several specimens (5) thereby determining the SWE of the sheet-
metal.

9
2. A method of determining secondary working embrittlement (SWE)
property of sheet-metals in a device as claimed in claim 1, the method
comprising the steps of:
- preparing a specimen by drawing a sheet-metal into a cup (5);
- placing the cup (5) in a inverted manner (open bore at the
bottom), on a conical head of an anvil (4);
- disposing the anvil (4) with the cup (5) in a chamber means (3)
which is filled with a liquid;
- slowly applying a static load on the cup (5) at different temperature
of the liquid via a hydraulically-operated pressing means (1), the
pressing means (1) being detachably placed on the chamber means
(3);
- collecting repetitive data on crack-development on the cup (5)
and/or on a several number of replaced cups (5) to determine the
minimum temperature at which the cups (5) sustain the load,
thereby evaluating the SWE property of the sheet-metal.
3. A device for determining secondary working embritlement (SWE) property
of sheet-metals, as substantially described herein with reference to the
accompanying drawings.

10
4. A method of determining secondary working embrittlement (SWE)
property of sheet-metals in a device as substantially described herein with
reference to the accompanying drawings.

Accordingly, there is provided a device for determining the SWE property of
sheet metals, which allows conducting a destructive testing of a deep drawn
specimen, in order to evaluate if the material is ductile or brittle at a certain
temperature. The test specimen is immersed in a liquid bath, which allows
conducting tests at various temperatures as per requirement. The invention
involves designing of an anvil including a suitable hydraulic powerpack operable
by an electric source. The test-specimen is reconfigured so as to be
accommodated on the anvil.
The invention further provides a method for determining the SWE property of
sheet-metals adapting the innovative device.

Documents:

00960-kol-2007-abstract.pdf

00960-kol-2007-claims.pdf

00960-kol-2007-correspondence others 1.1.pdf

00960-kol-2007-correspondence others 1.2.pdf

00960-kol-2007-correspondence others.pdf

00960-kol-2007-description complete.pdf

00960-kol-2007-drawings.pdf

00960-kol-2007-form 1 1.1.pdf

00960-kol-2007-form 1.pdf

00960-kol-2007-form 18.pdf

00960-kol-2007-form 2.pdf

00960-kol-2007-form 3.pdf

00960-kol-2007-gpa.pdf

960-KOL-2007-(24-07-2012)-CORRESPONDENCE.pdf

960-KOL-2007-CORRESPONDENCE 1.1.pdf

960-KOL-2007-CORRESPONDENCE.pdf

960-KOL-2007-EXAMINATION REPORT.pdf

960-KOL-2007-FORM 18.pdf

960-KOL-2007-FORM 3.pdf

960-KOL-2007-GPA.pdf

960-KOL-2007-GRANTED-ABSTRACT.pdf

960-KOL-2007-GRANTED-CLAIMS.pdf

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

960-KOL-2007-GRANTED-DRAWINGS.pdf

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

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

960-KOL-2007-GRANTED-LETTER PATENT.pdf

960-KOL-2007-GRANTED-SPECIFICATION.pdf

960-KOL-2007-OTHERS.pdf

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

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Patent Number

254166

Indian Patent Application Number

960/KOL/2007

PG Journal Number

39/2012

Publication Date

28-Sep-2012

Grant Date

25-Sep-2012

Date of Filing

04-Jul-2007

Name of Patentee

TATA STEEL LIMITED

Applicant Address

JAMSHEDPUR

Inventors:

#	Inventor's Name	Inventor's Address
1	BASUDEV BHATTACHARYA	TATA STEEL LIMITED, JAMSHEDPUR-831001
2	VIJAYANT KUMAR	TATA STEEL LIMITED, JAMSHEDPUR 831001

PCT International Classification Number

C 21 D 8/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA