A SYSTEM OF DETERMINING AVERAGE PROFILE OF FUSION ZONE OF WELD BEAD AND METHOD THEREOF
FIELD OF THE INVENTION
[001] The present invention in general relates to the field of joining of
materials by welding and specifically relates to a system and a method of determining the average profile of fusion zone of a weld bead that is deposited on to a base material.
BACKGROUND OF THE INVENTION
[002] Background description includes information that may be useful in
understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior.
[003] Nowadays, a well-known technique called as Finite Element Method
(FEM) is used for product development. The most important reason for the development of this technique is the industrial need to improve productivity and quality of products and to have better understanding of the influence of different process parameters. In addition, the proposed technique plays an important role at various stages of the production of steel parts, such as welding, heat treatment and casting, among others.
[004] Moreover, the importance of this method lies in determining the
evolution of stresses and deformations to predict, for example, susceptibility to cracking and thus prevent failures during manufacturing or even service. Furthermore, this simulation tool can also be used to optimize the time and the cost incurred at various aspects of manufacturing processes.

[005] Furthermore, welding is one of the important step that is performed
during the manufacturing process of the components. Welding is defined by the American Welding Society (AWS) as a localized coalescence of metals or non-metals produced by either heating of the materials to a suitable temperature with or without the application of pressure, or by the application of pressure alone, with or without the use of fille r metal. Welding techniques are one of the most important and most often used methods for joining pieces in industry. In addition, any information about the shape, size and residual stress of a welded piece is of particular interest to improve quality.
[006] Moreover, the analysis of welding processes involves several branches
of physics, and requires the coupling of different models addressed to describe the phenomenological behaviour of a system. Many of these models have been implemented numerically and are being used in an efficient way to solve the problems on an individual basis.
[007] Furthermore, Welding is one of the major fabrication process used in a
variety of industries like power, petrochemical, railways, transportation etc. It involves the joining of two similar (or) dissimilar materials by application of localised heat along the faying surfaces (or) interface regions, with or without the application of pressure, so as to produce a sound joint with a strong metallurgical bond.
[008] The localised heat causes melting of the filler and partially the base
material so as to form a fusion zone, which is referred to as the formation of weld bead. The thin members are generally welded with deposition of a single weld bead, while thicker members are joined by laying multiple weld beads one over the other. The localised melting and deposition of weld beads leads to a non-uniform temperature distribution in the weldment and as a result, the

weldment might end up with warpage and with significant level of residual stress, upon cooling to room temperatures.
[009] Fabrication industries always endeavour to keep such warpages as
minimum as possible, so that there will not be any loss of functionality or assembly related or matching problems. Since warpage control is very essential for weldments, it is a common practice to predict such weld warpages using Finite Element Modelling (FEM) unit. Although the FEM is good computational tool to predict weld warpages, the accuracy of such predictions are dictated by the input parameters assumed, like the weld heat input, geometric profile of fusion zone of weld, the type of mesh in the weldment etc.
[010] Among these factors, the geometric profile of the fusion zone of the
weld is required to be simulated, as there is need to input the data related to geometric profile precisely. Many times, in order to provide an accurate input to FEM with regard to the geometric profile of the weld fusion zone, researchers carry out a real time welding, section the weldment, observe the shape of the weld fusion zone in a stereo microscope, then import the images into an image processing unit and then obtain the shape with (X, Y) coordinates. Using these coordinates, the weld profile can be easily created in the FE modelling unit .
[011] Most of the prior arts have identified a problem and have also identified
a workable alternative for this problem, but fails to solve the same in an effective manner. When the weldments are sectioned to obtain the geometric profile of the weld fusion zone, it is observed that the profile of the weld varies significantly from one place to another along the length of the weld, especially in places where there is a continuous change in the arc gap which could be due to various reasons like welding in a profiled plate or welding in plates which have been pre-set in the form of a bow so as to offset the warpage that would happen finally.
[012] Such weld profile variations are very common wherever welding is
carried out manually. In such cases, the weld profile needs to be taken from

multiple locations along the length of the weld and these have to be averaged
out, so as to have close approximation to the real time condition. While
averaging of numbers can be easily done, averaging of multiple shapes into one
shape is a problem for which there were no readymade solutions available in
the public domain.
[013] Hence, there is need of a system and a method employing an advanced
technique through which the average geometric profile of fusion zone of a weld bead can be accurately determined.
OBJECTS OF THE INVENTION
[014] Some of the objects of the present invention, which at least one
embodiment herein satisfy, are listed herein below.
[015] It is general or primary object of the present invention to provide a
system and a method that helps in accurately determining the average geometric
profile of fusion zone of a weld bead.
[016] It is another object of the present invention to employ an advanced
technique that helps in accurately determining the average geometric profiles
of the fusion zone of the weld beads.
[017] It is yet another object of the present invention to provide the system
and the method that delivers better performance and reliability.
[018] These and other objects and advantages will become more apparent
when reference is made to the following description and accompanying
drawings.
SUMMARY OF THE INVENTION
[019] This summary is provided to introduce concepts related to a system and
a method that helps in accurately determining the average geometric profile of fusion zone of a weld bead. The concepts are further described below in the detailed description. This summary is not intended to identify key features or

essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
[020] In accordance with an embodiment, the present invention defines a
system for determining the average geometrical profile of the fusion zone of a weld bead deposited on a base metal, the system comprising a storage module for importing and storing the digital images of the fusion zones of the weld bead corresponding to each of the weld macro sections from a camera attached; a learning module for tracing the outer profile of the fusion zones of the weld bead imported through the storage module, and forming a closed polygon profiles encompassing various weld bead fusion zones; a learning database for storing the traced outer profile of the weld bead fusion zones received from the learning module; a control module for determining the scale factor and scaling down the closed polygon profiles for determining the actual polygon profile of the weld bead fusion zones; and a processing module determining the average geometrical profile of the fusion zones of the weld bead based on the actual polygon profile determined by the control module.
[021] In an aspect, the processing module is superimposing the actual
polygon profile of the fusion zones of the weld bead to determine the common center of gravity.
[022] In accordance with an embodiment, the present invention provides a
method for determining the average geometrical profile of the fusion zone of a weld bead deposited on a base metal, the method comprising the steps of importing the digital images of the fusion zones of the weld bead corresponding to each of the weld macro sections by a storage module from a camera attached; tracing the outer profile of the fusion zones of the weld bead by a learning module imported through the storage module, and forming a closed polygon profiles encompassing various weld bead fusion zones; storing the traced outer profile of the weld bead fusion zones in a learning database received from the learning module; determining the scale factor and scaling down the closed

polygon profiles for determining the actual polygon profile of the weld bead fusion zones by a control module; and determining the average geometrical profile of the fusion zones of the weld bead by the processing module based on the actual polygon profile determined by the control module.
[023] In an aspect, the processing module is superimposing the actual
polygon profile of the fusion zones of the weld bead to determine the common center of gravity.
[024] 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
[025] The illustrated embodiments of the subject matter will be best
understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and methods that are consistent with the subject matter as claimed herein, wherein:
[026] FIG.1 illustrates a block diagram that shows the interconnection between the components of the system and a camera in accordance with an embodiment of the present invention.
[027] FIG.2 illustrates various views of fusion of weld beads deposited onto a base metal along the multiple locations in the weld in accordance with the embodiment of the present invention.

[028] FIG.3 illustrates the outer profiles of the weld fusion zones traced by an image processing unit of a system proposed in accordance with the embodiment of the present invention.
[029] FIG.4 illustrates various weld profiles superimposed with radial lines drawn over them proposed in accordance with the embodiment of the present invention .
[030] FIG.5 illustrates a method that helps in accurately determining the average geometric profile of fusion zone of a weld bead through a system proposed in accordance with the embodime nt of the present invention.
DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS
[031] The following is a detailed description of embodiments of the invention
depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the invention. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention as defined by the appended claims.
[032] As per the requirement, a system and a method for determining the
average geometric profile of the fusion zone of a weld bead deposited on to a base metal, is introduced. Since FE Modelling of welding requires this as an important input, this invention will be very useful in the field of FE modelling of weldments.

[033] Here, the system 200 comprises a storage module 202, a learning
module 204, a learning database 206, a control module 208, and a processing module 210 that helps in determining the average geometric profile of the fusion zone of a weld bead deposited on to a base metal.
WORKING OF THE INVENTION
[034] Prior to commencing FEM, a welding experiment has to be conducted
wherein the weld bead that is required to be modelled in FEM, is deposited in real time in a base material. Then the weld is sectioned at multiple places and the macro sections of the deposited weld bead so obtained, are observed in a stereo microscope with a magnification level in the range of 5X to 50X. The image of the macro section of the weld bead showing its geometrical profile is obtained from each locations where the specimens were sectioned earlier. These weld macro specimens (cut through the weld cross section) are cut from multiple locations along the weld length.
[035] Then, these specimens are subjected to metallographic specimen
preparation which involves grinding and finely polishing the specimens. The proper preparation of metallographic specimens is a key step to determine the accurate microstructure of a material and it requires sectioning, mounting, course grinding, fine grinding, polishing, etching and microscopic examination.
[036] Then, these specimens are etched using alcoholic base etching reagents.
After etching, the weld macro section specimens are observed in a stereo microscope with the magnification in the range of 5X to 50X. The magnified image of the weld fusion zone of each of the weld macro section specimens are captured as digital images through a camera 100.
[037] Here, the system 200 comprising a storage module 202 for importing all
the digital images of the fusion zones of the weld bead corresponding to each of the weld macro sections from a camera 100 attached either through a

Computer Area Network 102 or hardwired communication line 104 at STEP 502, a learning module 204 for tracing the outer profile of the fusion zones of the weld bead imported through the storage module102 at STEP 504. In each of the weld macro specimen image as shown in FIG.2, the outer boundary of the weld fusion zone is traced by drawing a curvilinear line. The curvilinear line is commonly referred as spline, which will be a polygon drawn encompassing the weld fusion zone and forming a closed polygon profiles encompassing various weld bead fusion zones 1,2,3,4 as shown in FIG.3.
[038] At STEP 506, a learning database 206 of the system stores the traced
outer profile of the weld bead fusion zones 1,2,3,4 received from the learning module 204. At STEP 508, a control module 208 for determining the scale factor and scaling down the closed polygon profiles for determining the actual polygon profile of the weld bead fusion zones1,2,3,4.
[039] Using this scaling factor, the profile of the fusion weld drawn earlier as
a closed polygon is scaled down. After scaling down, the closed polygon now gives the exact profile of the weld with the actual size. The same procedure is repeated for macro section images taken from multiple locations in the weld by a processing module 210. Now, the multiple closed polygons so obtained are superimposed on another in such a way that the Centre of Gravity (CG) of them coincide at one point as shown in FIG.4.
[040] At STEP 510, a processing module 210 determines the average
geometrical profile of the fusion zones of the weld bead 1,2,3,4 based on the actual polygon profile determined by the control module.
[041] Then, multiple radial lines (shown as (6) in FIG.4) with the point C as
their origin are drawn at regular angular intervals so as to cover the entire 360 degrees. The radial lines covering a sector angle of 120° are drawn and indicated as (6) in FIG.4, in a representative manner. It can be observed from FIG.4 that each radial line cuts each of the given weld profile at one point.

[042] For instance, the vertical radial line drawn from C cuts one of the weld
profile at the point marked (7) in FIG.4. Supposing we have ‘n’ numbers of weld profiles, then we will have ‘n’ coordinate points arising from the intersection of a given radial line with each weld profile. The (X,Y) coordinates of each of these ‘n’ points are taken and averaged separately. For instance, if these coordinates are numbered as (X1, Y1), (X2, Y2), (X3, Y3) ……… (Xn, Yn), then the average of all these coordinate points will be (Xa, Ya)
Where,

[043] Once the average coordinate points (determined using the above
method) arising from each radial lines are obtained, then all these points are sequentially connected to form the average geometric profile of the weld fusion zone by the processing module 210 of the system 200. Using this profile, FE modelling of the weld fusion zone can be performed further.
[044] This method is meritorious in terms of determining an average
geometrical weld profile in a simple, reliable and an accurate manner.
TEST RESULTS
[045] Test has been carried out to determine the average geometrical profile
of the weld fusion zone. Here, a sample weld macro section is taken in to

consideration. The weld profile has been traced by a cyan colored polygon. Another cyan colored straight line is drawn on the scale bar which reads 0.6 mm. The length of this straight line is measured as 3.75 mm but, the originally this distance is 0.6 mm only (as indicated in scale bar). Thus magnification factor = 3.75/0.6 = 6.25
[046] This means that the weld profile that is currently seen is magnified by a
factor of 6.25. To bring the weld to actual size, it has to be scaled down by a factor of 6.25 i.e. the image has to be magnified by a factor of 0.16 (=1 /6.25). as shown in FIG.6.
[047] After scaling down, the weld profile is obtained as shown in FIG.7
[048] After that, multiple weld profiles are superimposed so that the CG point
of each of them coincides. Then, multiple radial lines are drawn cutting each of these profiles as shown in FIG.8.
[049] Then the coordinate points of the intersection of each radial line with
each weld profile is obtained. The X-coordinate and Y-coordinate of each of these intersection points are individually averaged. This forms one coordinate point of the average profile as shown in FIG.9. The procedure is repeated for multiple radial lines. A sample calculations have been worked as under. In this trial, 10 radial lines each with an angular interval of 18° have been drawn. Accordingly, the calculations are made.
[050] The coordinate points listed under the ‘average’ column in the above
Table is then plotted in a X-Y space. These are then joined to obtain the fina l weld profile as shown in FIG.10.
TECHNICAL ADVANTAGES
[051] The present invention provides a system and a method that helps in
accurately determining the average geometric profile of fusion zone of a weld bead.

[052] The present invention employs an advanced technique that helps in
accurately determining the average geometric profiles of the fusion zone of the weld beads.
[053] The present invention provides the system and the method that delivers
better performance and reliability.
[054] These and other advantages of the present subject matter would be
described in greater detail with reference to the following figures. It should be noted that the description merely illustrates the principles of the present subject matter. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present subject matter and are included within its scope.
[055] It will be understood by those within the art that, in general, terms used
herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted

to mean “at least one” or “one or more”); the same holds true for the use of
definite articles used to introduce claim recitations. In addition, even if a
specific number of an introduced claim recitation is explicitly recited, those
skilled in the art will recognize that such recitation should typically be
interpreted to mean at least the recited number (e.g., the bare recitation of “two
recitations,” without other modifiers, typically means at least two recitations,
or two or more recitations). It will be further understood by those within the art
that virtually any disjunctive word and/or phrase presenting two or more
alternative terms, whether in the description, claims, or drawings, should be
understood to contemplate the possibilities of including one of the terms, either
of the terms, or both terms. For example, the phrase “A or B” will be understood
to include the possibilities of “A” or “B” or “A and B.”
[056] It will be further appreciated that functions or structures of a plurality
of components or steps may be combined into a single component or step, or the functions or structures of one-step or component may be split among plural steps or components. The present invention contemplates all of these combinations. Unless stated otherwise, dimensions and geometries of the various structures depicted herein are not intended to be restrictive of the invention, and other dimensions or geometries are possible. In addition, while a feature of the present invention may have been described in the context of only one of the illustrated embodiments, such feature may be combined with one or more other features of other embodiments, for any given application. It will also be appreciated from the above that the fabrication of the unique structures herein and the operation thereof also constitute methods in accordance with the present invention. The present invention also encompasses intermediate and end products resulting from the practice of the methods herein. The use of “comprising” or “including” also contemplates embodiments that “consist essentially of” or “consist of” the recited feature.

[057] Although embodiments for the present subject matter have been
described in language specific to structural features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and adaptations of the system/component of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations, which fall within the scope of the present subject matter.

WE CLAIM
1. A system (200) for determining the average geometrical profile of the fusion
zone of a weld bead deposited on a base metal, the system comprising
a storage module (202) for importing the digital images of the fusion zones (1,2,3,4) of the weld bead corresponding to each of the weld macro sections from a camera attached;
a learning module (204) for tracing the outer profile of the fusion zones of the weld bead imported through the storage module (202), and forming a closed polygon profiles encompassing various weld bead fusion zones (1,2,3,4);
a learning database (206) for storing the traced outer profile of the weld bead fusion zones (1,2,3,4) received from the learning module (204);
a control module (208) for determining the scale factor and scaling down the closed polygon profiles for determining the actual polygon profile of the weld bead fusion zones (1,2,3,4); and
a processing module (210) determining the average geometrical profile of the fusion zones (1,2,3,4) of the weld bead based on the actual polygon profile determined by the control module.
2. The system (200) as claimed in claim 1, wherein the processing module (210) is superimposing the actual polygon profile of the fusion zones (1,2,3,4) of the weld bead in such a way that centre of gravity of each polygonal profile coincide at a point.
3. A method (500) for determining the average geometrical profile of the fusion zone of a weld bead deposited on a base metal, the method comprising the steps of

importing the digital images of the fusion zones (1,2,3,4) of the weld bead corresponding to each of the weld macro sections by a storage module (202) from a camera attached;
tracing the outer profile of the fusion zones of the weld bead by a learning module (204) imported through the storage module (202), and forming a closed polygon profiles encompassing various weld bead fusion zones (1,2,3,4);
storing the traced outer profile of the weld bead fusion zones (1,2,3,4) in a learning database (206) received from the learning module (204);
determining the scale factor and scaling down the closed polygon profiles for determining the actual polygon profile of the weld bead fusion zones (1,2,3,4) by a control module (208); and
determining the average geometrical profile of the fusion zones (1,2,3,4) of the weld bead by the processing module (210) based on the actual polygon profile determined by the control module.
4. The method (500) as claimed in claim 3, wherein the processing module (210) is superimposing the actual polygon profile of the fusion zones (1,2,3,4) of the weld bead in such a way that centre of gravity of each polygonal profile coincide at a point.