Title of Invention

AN APPARATUS FOR DETERMINING QUALITY OF MAGNETIC PARTICLE TESTING IN A SINGLE SET-UP

Abstract The apparatus comprising a single piece plate formed of a ferromagnetic material having several grooves (5) with continuously varying width, a plurality of said several grooves (5) being configured at different depths, the plate (1) is disposed on the test piece such that the grooves (5) facing the top-surface of the test-piece remain mutually synchronized white being magnetized with selected parameters. A grooved direction is maintained substantially perpendicularly to a desired direction (4) of the magnetic flux.
Full Text 2
FIELD OF INVENTION
The invention relates to an apparatus for identifying in a single set - up, the
capability of a magnetic particle testing device, applicability of a magnetizing
technique and selecting a magnetic medium including useable parameters in a
MPI testing method.
BACKGROUND OF THE INVENTION
Magnetic particle testing is a well - established non - destructive testing method
for evaluating the surface and sub surface quality of raw material, semi -
finished and finished products.
An MPI procedure involves magnetizing a test - piece to be tested and then
spraying small magnetic particles on the test piece. The basis behind performing
MPI procedures is to have a magnetic field of sufficient strength oriented in the
proper direction to detect the flaws. MPI procedure successfully functions
because the magnetic field (or flux) in the test part is disrupted if the flaws and
discontinuities exist on the surface of the test - piece. This disruption in the field
results in flux leakage out of the surface of the test - piece across the flaw or
discontinuity, trapping thereon very small magnetic particles that are sprayed on
the surface. Thus, MPI requires that the test piece under inspection should be
magnetic and that the piece should be magnetized to a level that allows
sufficient flux leakage around the actual flaws and discontinuity but not around

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the false indications; if any. The accepted parameter for such detection is field
strength. Field strength must be sufficient to fully magnetize the piece, in order
to allow for leakage around the flaws, without magnetically saturating any
unflawed areas.
Field strength is critical to MPI in that if it is too weak, indications will not be
shown and if it is too strong, false indications will result. Field direction is also
important in that it needs to be orientated approximately perpendicular to the
direction of the flaws. Accordingly, the magnetic field strength and direction are
checked with a field strength indicator prior to MPI inspections.
One of the drawbacks to the pie - type field strength indicator of prior art, is that
the points between the carbon steel pieces are relatively wide, being in the order
of 0.010 to 0.030 inches. These wide artificial flaws although are easy to
magnetize and show; however, they are not representative of real flaws. This is
because the field strengths even though are sufficient to show the pie
indications, they are not adequate to show the real service - induced flaws and
cracks. Because of the problems associated with the standard pie field strength
indicators, there is a need to develop a field strength indicator which is capable
of representing more closely, the surface flaws including sub - surface quality of
a test - piece.
Another drawback of the prior art including the pie indicators, is that the material
from which they are manufactured. They are generally made from carbon steel,
which has significantly different magnetic properties than many of raw materials,
such as alloy steels, for which testing is necessary owing to their large - scale
industrial use.

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A field strength indicator is disclosed in patent document CA 2024573 which
enables a magnetic particle inspection process to determine field strength and
direction sufficient to identify real flaws in a test piece. The field strength
indicator of the reference, is substantially a flat shim having at least one series of
artificial flaws formed therein by electric discharge machining. The artificial flaws
have a geometry, which render them compatible with real flaws' and thus enable
the magnetic field strength and direction to be properly set for conducting a
magnetic particle inspection procedure. The surface containing the artificial flaws
must be covered with a thin inert and non - magnetic coating for proper
operation.
This invention provides a configuration, which has grooves with smallest possible
width and varying lengths and depths. However, it is not possible to identify the
width of the defect at a specific depth by application of a method of
magnetization in a specific device by using a magnetic medium in a single shot.
Further, it is necessary for better result that the device is used during testing
such that the groove is in direct contact with the surface of the test piece. The
cited reference however teaches that the device is made applicable keeping the
groove on the top without direct contact.
The method of manufacture and use of a magnetic field sensitivity indicator is
disclosed in US patent US 4172315. The invention provides a method and
apparatus for evaluating magnetic fields applied to ferromagnetic material parts
during magnetic particle inspection utilizing known defect indicators to establish
the strength and direction of magnetic fields in the parts under test.

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However, the indicator of this invention simulates cracks only with very narrow
groove.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to propose an apparatus for identifying
in a single set - up, the capability of a magnetic particle testing device,
applicability of a magnetizing technique and selecting a magnetic medium
including useable parameters in a MPI testing method.
Another object of the invention is to propose an apparatus for identifying in a
single set - up, the capability of a magnetic particle testing device, applicability
of a magnetizing technique and selecting a magnetic medium including useable
parameters in a MPI testing method, which provides indications in respect of the
depth and the width of the detected to be revealed by the device including the
magnetic medium and the test parameters employed.
A further object of the invention is to propose an apparatus for identifying in a
single set - up, the capability of a magnetic particle testing device, applicability
of a magnetizing technique and selecting a magnetic medium including useable
parameters in a MPI testing method which is economical and easy to
manufacture.
A still further object of the invention is to propose an apparatus for identifying in
a single set - up, the capability of a magnetic particle testing device, applicability
of a magnetizing technique and selecting a magnetic medium including useable

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parameters in a MPI testing method which can be configured for all typed of
materials including alloy steel.
At the outset of the description, which follows, it is to be understood that the
ensuing description only illustrates a particular form of this invention. However,
such a particular form is only an exemplary embodiment and the teachings of the
invention are not intended to be taken restrictively
SUMMARY OF THE INVENTION
Accordingly, there is provided an apparatus for identifying in a single set - up
the capability of a magnetic particle testing device, applicability of a magnetizing
technique, and selecting a magnetic medium including useable parameters in a
MPI testing method, the apparatus comprising: a single piece plate formed of a
ferromagnetic material having several grooves with continuously varying width, a
plurality of said several grooves being configured at different depths, wherein the
plate is disposed on the test piece such that the grooves facing the top - surface
of the test - piece remain mutually synchronized while being magnetized with
selected parameters, and wherein a grooved direction being maintained
substantially perpendicularly to a desired direction of the magnetic flux.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 - Shows an embodiment of the apparatus.
Figure 2 - Shows the invented apparatus during its operation.

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DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF
THE INVENTION
According to the invention the apparatus consists of a single piece of a
ferromagnetic material with artificial grooves (5) with continuous varying width.
A number of grooves are made with different depths. The thickness of the plate
is such that the depth of the groove from the surface varies in steps such that
the remaining thickness available is around 1, 2, 3, 4, 5 mm. The exact thickness
can be varied based on the thickness desired for the actual test. The size of the
device could be 75 x 50 x 6 mm but can be altered according to requirements.
The location of groove, orientation of groove and dimensions of ferromagnetic
material of the apparatus can be varied according to the test specimen
requirements.
The apparatus is placed on the job under test such that the same has direct
contact with the groves facing the top surface of test piece and magnetized with
selected parameters, and the grooved direction (5) is perpendicular to the
desired magnetic flux direction (4).
The set magnetizing current is passed through the job as in the regular testing.
The magnetizing medium is sprayed on the apparatus (1). The indications are
formed on the surface of the apparatus indicating the level of the magnetizing
effect. The indications are formed on the surface of the apparatus indicating the
level of the magnetizing effect. The indication will reveal the depth of the slot,
width of the slot which is appropriate for the parameters or vice versa.

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Firstly, this indicates the suitability of the apparatus (1) for the test of the job
(2). Secondly, this confirms whether the magnetic medium, its size and
composition is suited for the job. ( 3 ) Thirdly, it confirms the suitability of the
parameters for testing a specific component. ( 4 )Fourthly, it confirms the
suitability of magnetizing technique.
The main advantage is that the suitability of these aspects for MPI testing is
confirmed in a single test.

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We Claim
1. An apparatus for identifying in a single set - up the capability of a
magnetic particle testing device, applicability of a magnetizing technique,
and selecting a magnetic medium including useable parameters in a MPI
testing method, the apparatus comprising:
- a single piece plate formed of a ferromagnetic material having
several grooves (5) with continuously varying width, a plurality of
said several grooves (5) being configured at different depths,
wherein the plate (1) is disposed on the test piece such that
the grooves (5) facing the top - surface of the test - piece remain
mutually synchronized while being magnetized with selected
parameters, and wherein a grooved direction being maintained
substantially perpendicularly to a desired direction (4) of the
magnetic flux.
2. The apparatus as claimed in claim 1, wherein the thickness of the plate
(1) is selected between 5 to 8 mm.
3. The apparatus as claimed in claim 1, wherein the grooves (5) are
preferably designed in a triangular shape.

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4. The apparatus as claimed in claim 1 or 3, wherein the depth of the
grooves (5) is configured at 1 to 5 mm.
5. The apparatus as claimed in claim 1, wherein the dimension of the plate
(1) is configurable preferably at 75 x 50 x 6 mm.
6. An apparatus for identifying in a single set - up, the capability of a
magnetic particle testing device, applicability of a magnetizing technique
and selecting a magnetic medium including useable parameters in a MPI
testing method as substantially described herein with reference to the
accompanying drawings.
Dated this 26th day of AUGUST 2005.


The apparatus comprising a single piece plate formed of a ferromagnetic material having several grooves (5) with continuously varying width, a plurality of said several grooves (5) being configured at different depths, the plate (1) is disposed on the test piece such that the grooves (5) facing the top-surface of the test-piece remain mutually synchronized white being magnetized with selected parameters. A grooved direction is maintained substantially perpendicularly to a desired direction (4) of the magnetic flux.

Documents:

00780-kol-2005-claims.pdf

00780-kol-2005-description complete.pdf

00780-kol-2005-drawings.pdf

00780-kol-2005-form 1.pdf

00780-kol-2005-form 2.pdf

00780-kol-2005-form 3.pdf

780-KOL-2005-ABSTRACT.pdf

780-KOL-2005-AMENDED CLAIMS.pdf

780-KOL-2005-CANCELLED PGES.pdf

780-KOL-2005-CLAIMS-1.1.pdf

780-KOL-2005-CORRESPONDENCE-1.1.pdf

780-kol-2005-correspondence.pdf

780-KOL-2005-DESCRIPTION (COMPLETE)-1.1.pdf

780-KOL-2005-DRAWINGS-1.1.pdf

780-kol-2005-examination report.pdf

780-KOL-2005-FORM 1-1.1.pdf

780-kol-2005-form 13.pdf

780-kol-2005-form 18.pdf

780-KOL-2005-FORM 2-1.1.pdf

780-kol-2005-form 3.pdf

780-KOL-2005-FORM 5.pdf

780-KOL-2005-FORM-27.pdf

780-kol-2005-gpa.pdf

780-kol-2005-granted-abstract.pdf

780-kol-2005-granted-claims.pdf

780-kol-2005-granted-description (complete).pdf

780-kol-2005-granted-drawings.pdf

780-kol-2005-granted-form 1.pdf

780-kol-2005-granted-form 2.pdf

780-kol-2005-granted-letter patent.pdf

780-kol-2005-granted-specification.pdf

780-kol-2005-reply to examination report.pdf


Patent Number 246726
Indian Patent Application Number 780/KOL/2005
PG Journal Number 11/2011
Publication Date 18-Mar-2011
Grant Date 14-Mar-2011
Date of Filing 26-Aug-2005
Name of Patentee BHARAT HEAVY ELECTRICALS LIMITED
Applicant Address REGIONAL OPERATIONS DIVISION(ROD), PLOT NO : 9/1 DJBLOCK ,3RD FLOOR, KARUNAMOYEE, SALT LAKE CITY, KOLKATA-700091 BHEL HOUSE, SIRI FORT, NEW DELHI- 110049, INDIA
Inventors:
# Inventor's Name Inventor's Address
1 GANAPATHY UMASHANKER WELDING RESEARCH INSTITUTE, BHEL, TIRUCHIRAPPALLI 620014
2 NAGAMUTHU DHANASEKARAN WELDING RESEARCH INSTITUTE, BHEL, TIRUCHIRAPPALLI 620014
3 SETHURAMA SRINIVASA ANANTHAN WELDING RESEARCH INSTITUTE, BHEL, TIRUCHIRAPPALLI 620014
PCT International Classification Number G01R 3/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA