WO2022201014A1

WO2022201014A1 - An apparatus for thickening a tube at its intermediate portion

Info

Publication number: WO2022201014A1
Application number: PCT/IB2022/052595
Authority: WO
Inventors: Vinay Sanjay Gujre; Pala LAKSHMIKANT; Vishal KALUBHAI BHARODIYA; Rahul KUMAR VERMA
Original assignee: Tata Steel Limited
Priority date: 2021-03-24
Filing date: 2022-03-22
Publication date: 2022-09-29
Also published as: JP2024514292A; CO2023013425A2; BR112023019384A2; EP4313438A1

Abstract

Present disclosure relates to an apparatus for thickening a tube at its intermediate portion along an inner surface. The apparatus includes a first support member for supporting outer surface of the tube and a mandrel assembly for supporting inner surface of the tube, where the mandrel assembly is supported by a second support member. The mandrel assembly may be defined with a profile, which corresponds to the profile of the intermediate section to be thickened. Further, the apparatus includes a punch configured to contact an end of the tube and exert axial force on to the tube to plastically deform the tube for thickening the tube at its intermediate portion. The apparatus facilitates in facilitate gradual thickening by inducing only necessary material localization. Also, the apparatus aids in easy and quick removal of the thickened tube resulting in reducing cycle time and, thus improving productivity.

Description

TECHNICAL FIELD:

Present disclosure relates to a field of manufacturing technology. Particularly, but not exclusively, the present disclosure relates to an apparatus for forming or thickening a tube. Further embodiments of the present disclosure disclose the apparatus and a process for thickening the tube at its intermediate portion along an inner surface.

BACKGROUND OF THE DISCLOSURE:

A tube is a long hollow cylinder made of materials such as metal, plastic, or composites. The tubes may be used in various applications including domestic, medical, fuel gas distributions, automotive and other applications including air conditioning and refrigeration. For example, in the automotive applications such as two-wheelers, bikes, bi-cycles, tubes may be used to form frames, seating systems, fuel delivery components and automotive link arms require tubes, and in all such applications tubes to be welded in series to create an integrated frame. Automotive assembly lines need tubes with extra thickness at its intermediate portion for various applications. This can be achieved by using tube with extra thickness for thorough length or through intermediate thickening of tube. The latter approach ensures overall weight reduction of the entire assembly.

Conventionally, there are known prior arts that disclose various process of producing variable thickness tubes. For instance, flexible rolling is disclosed in the prior art US7107682B2 which iterates about a rolling technique to produce flat sheets of varying thickness and using them for tube production which at end will lead to variable wall thickness tubes. Other processes include swage auto-frettage, wherein the thick-walled tubes are provided with desired internal profile by inserting a mandrel with slightly higher diameter into the tube. Other processes include tube drawing using position-controlled mandrel method, a specially designed mandrel is used in this case for producing tubes with variable thickness along longitudinal direction. Yet another patent US6807837B1 discloses about use of reducing die along with no internal mandrel. An axial force of tensile nature on one side and that of compressive nature on the other side of the die is applied. Variation of relative magnitude of these forces lead to production of variable wall thickness. In brief, the conventional process known in art for producing variable thickness tubes are flexible rolling, swage auto-frettage process, tube drawing using position-controlled mandrel methods, extrusion with special die setup and also internally and externally upsetting ends of the tube. Deployment of the processes mentioned above are limited either due to economic constraints such as higher investment in tooling and/or low productivity due to increased cycle time. Also, tube may buckle due to compressive forces involved.

The present disclosure is directed to overcome one or more limitations stated above.

SUMMARY OF THE DISCLOSURE

One or more shortcomings of the conventional process are overcome by process as claimed and additional advantages are provided through the provision of apparatus and process as claimed in the present disclosure.

Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.

In one non-limiting embodiment of the disclosure, an apparatus for thickening a tube at its intermediate portion is disclosed. The apparatus includes a first support member, configured to support an outer surface of the tube and a mandrel assembly, configured to support an inner surface of the tube. At least a portion of the mandrel assembly is defined with a profile corresponding to a profile of the intermediate portion of the tube to be thickened. Further, the apparatus includes a second support member, configured to support an end of the mandrel assembly. Furthermore, the apparatus includes a punch structured to abut an end of the tube between a free end of the mandrel assembly and the first support member. The punch is configured to exert axial force on to the tube, where application of axial force by the punch plastically deforms the tube, resulting in thickening of the tube at the intermediate portion.

In an embodiment of the disclosure, the mandrel assembly comprises a first mandrel section and a second mandrel section, removably connected to each other and defining with the profile corresponding to the profile of the intermediate portion of the tube to be thickened.

In an embodiment of the disclosure, the first support member is configured to exert radial force on to the outer surface of the tube for clamping the tube from its outer surface. In an embodiment of the disclosure, plastically deforming the tube, results in accumulation of material in the profile defined by the mandrel assembly, thereby thickening the intermediate portion of the tube along the inner surface.

In an embodiment of the disclosure, the apparatus includes a retractor structured to abut another end of the tube between a fixed end of the mandrel assembly and the first support member. The retractor is configured to exert axial force in a direction opposite to the direction of axial force exerted by the punch.

In an embodiment of the disclosure, the punch is coupled to an actuator to exert axial force on to the tube.

In an embodiment, the retractor is coupled to the actuator to exert axial force on to the tube.

In an embodiment of the disclosure, the actuator is either one of an electric , pneumatic or a hydraulic actuator.

In another non-limiting embodiment, a tube is disclosed. The tube includes a body portion defined with an inner surface and an outer surface. The body portion is configured such that, thickness at an intermediate portion of tube along the inner surface is greater than thickness of other longitudinal portions of the inner surface.

In an embodiment, the outer surface of the tube is of uniform diameter.

In yet another non-limiting embodiment of the disclosure, a process of thickening a tube at its intermediate portion is disclosed. The process includes positioning a mandrel assembly contacting an inner surface of the tube, where an end of the mandrel is supported by a second support member. Further, the process includes positioning a first support member on an outer surface of the tube. Furthermore, the process includes exerting an axial force by a punch on to the tube to plastically deform the tube for thickening of the tube at the intermediate portion.

In an embodiment of the disclosure, the process includes exerting the axial force by a retractor in a direction opposite to the axial force exerted by the punch which plastically deforms the intermediate portion of the inner surface of the tube. It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined together to form a further embodiment of the disclosure.

The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES

The novel features and characteristic of the disclosure are set forth in the appended claims. The disclosure itself, however, as well as a preferred mode of use, further objectives, and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:

Figure. 1 illustrates a schematic view of an apparatus used for thickening a tube at its intermediate portion, in accordance with an embodiment of the present disclosure.

Figure. 2 illustrates a sectional view of a tube that is to be thickened.

Figures. 3a and 3b illustrates a perspective view of a first mandrel section and a second mandrel section of a mandrel assembly, respectively, in accordance with an embodiment of the present disclosure.

Figure. 4 illustrates a perspective view of a first support member of the apparatus of Figure. 1, in accordance with an embodiment of present disclosure.

Figure. 5 illustrates a sectional view of a thickened tube by the apparatus of Figure. 1, in accordance with an embodiment of the present disclosure.

Figures. 6a to 6f illustrates a step-by-step operating condition of the apparatus, in accordance with an embodiment of the present disclosure. The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION

The foregoing has broadly outlined the features and technical advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter which form the subject of the claims of the disclosure. It should be appreciated by those skilled in the art that the conception and specific embodiments disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that such equivalent processes do not depart from the spirit and scope of the disclosure as set forth in the appended claims. The novel features which are believed to be characteristic of the disclosure, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated and make part of this disclosure.

Embodiments of the present disclosure discloses an apparatus for thickening a tube at its intermediate portion along an inner surface. The apparatus may be used to thicken intermediate section of the components adapted in automobile sector. Conventional process for producing variable thickness tubes are flexible rolling, swage auto-frettage process, tube drawing using position-controlled mandrel methods, extrusion with special die setup and also internally and externally upsetting ends of the tube. Deployment of the processes mentioned above are limited either due to economic constraints such as higher investment in tooling and/or low productivity due to increased cycle time. Also, tube may buckle due to compressive forces involved. Accordingly, an apparatus to thicken intermediate section of the tube along its inner surface is disclosed. The apparatus facilitates in gradual thickening, thus avoiding stress raising zones. Further, the apparatus aids in thickening the intermediate section of the tube, without buckling the tube. The term “intermediate portion” may be inferred as any portion between ends of the tube.

The apparatus includes a first support member, configured to support an outer surface of the tube, and exert radial force on to the outer surface for clamping the tube. Further, the apparatus may include a mandrel assembly, which may be include a first mandrel section and a second mandrel section, removably connected to each other. At least a portion of the mandrel assembly is defined with a profile corresponding to a profile of the intermediate portion of the tube to be thickened. Furthermore, the apparatus includes a second support member, configured to support an end of the mandrel assembly. Additionally, the apparatus includes a punch and a retractor, which are configured to abut an end of the tube between a free end of the mandrel assembly and the first support member and abut the other end of the tube between a fixed end of the mandrel and the first support member, respectively. The punch may be configured to exert an axial force on to the tube and the retractor may be configured to exert axial force in a direction opposite to the direction of axial force exerted by the punch. Due to application of axial forces, the tube may plastically deform resulting in thickening of the tube at the intermediate portion.

The terms “comprises...a”, “comprising”, or any other variations thereof used in the specification, are intended to cover non-exclusive inclusions, such that an assembly that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or method. In other words, one or more elements in an assembly proceeded by “comprises... a” does not, without more constraints, preclude the existence of other elements or additional elements in the assembly.

Henceforth, the present disclosure is explained with the help of one or more figures of exemplary embodiments. However, such exemplary embodiments should not be construed as limitation of the present disclosure.

The following paragraphs describe the present disclosure with reference to Figures. 1 to 6f. In the figures, the same element or elements which have similar functions are indicated by the same reference signs. For the purposes of promoting an understanding of the principles of the disclosure, reference will now be made to specific embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended, such alterations and further modifications in the illustrated methods, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention pertains.

The following detailed description is merely exemplary in nature and is not intended to limit application and uses. Furthermore, there is no intention to be bound by any theory presented in the preceding background or summary or the following detailed description. It is to be understood that the disclosure may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices or components illustrated in the attached drawings and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hereinafter, preferred embodiments of the present disclosure will be described referring to the accompanying drawings. While some specific terms of “substantially”, “between”, “along”, “free end” and other terms containing these specific terms and directed to a specific direction will be used, the purpose of usage of these terms or words is merely to facilitate understanding of the present invention referring to the drawings. Accordingly, it should be noted that the meanings of these terms or words should not improperly limit the technical scope of the present invention.

Figure. 1 is an exemplary embodiment of the present disclosure, illustrating a schematic view of an apparatus (100) used for thickening intermediate portion (115) of a tube (111) [as seen in Figure. 2]. The tube (111) may include a body portion (112), defined with an inner surface (113) and an outer surface (114). The tube (111), before subjected to thickening may include uniform thickness and diameter along the body portion (112) (thus, the inner surface (113) and the outer surface (114) of the body portion (112)]. Now, as seen in Figure. 1, the apparatus (100) may include a first support member (101), which may be configured to support and clamp an outer surface (114) of the tube (111). In an illustrated embodiment, as seen in Figure. 4 the first support member (101) includes a pair of semi-cylindrical members, which may surround and clamp the outer surface (114) of the tube (111), thus supporting the outer surface (114) of the tube (111). That is, the first support member (101) may exert radially inward force on to the outer surface (114) of the tube (111), to firmly clamp the outer surface (114) of the tube (111). In an embodiment, inner diameter of the semi-cylindrical members may be slightly greater than outer diameter of the tube (111), for receiving, supporting, and clamping the outer surface (114) of the tube (111). In some embodiment, the semi-cylindrical members are coupled to each other through a suitable joining technique such as spline locking or a fastening.

Further, the apparatus (100) may include a mandrel assembly (102), which may be configured to radially support an inner surface (113) of the tube (111). That is, the mandrel assembly (102) may extend through a hollow cavity of the tube (111) and thus supports the inner surface (113) of the tube (111). In an embodiment, outer diameter of the mandrel assembly (102) may be slightly less than inner diameter of the tube (111). Furthermore, the apparatus (100) may include a second support member (104), which may be configured to support an end of the mandrel assembly (102). In an embodiment, the end of the mandrel assembly (102) may be either rigidly or removably supported by the second support member (104).

Referring further to Figure. 1 in conjunction with Figures. 3a and 3b, the mandrel assembly (102) may include a first mandrel section (103a) [as seen in Figure. 3a] and a second mandrel section (103b) [as seen in Figure. 3b], which are removably connected to each other, and the first mandrel section (103a) may be either rigidly or removably connected to the second supporting member (104). In an embodiment, one end of the first mandrel section (103 a) may be defined with a groove (105) of predefined diameter and, which extends into the first mandrel section (103a) for a predefined distance. Further, a key slot (106) may be defined at a periphery of the groove (105), which may extend along a length of the groove (105). As apparent from Figure. 3a, a portion [i.e., a certain length] of an outer surface of the first mandrel section (103a) may defined with a tapered profile, which extends till the end [i.e., the end at which the groove (105) is defined]. Further, an end of the second mandrel section (103b) may be defined with a protrusion (107), which may extend for a predefined length away from the end. A key (108) may be defined on a periphery of the protrusion (107), which may extend along a length of the protrusion (107). As apparent from Figure. 3b, an outer surface of the second mandrel section (103b) may be defined with a tapered portion at a substantially central portion and the portion ahead of the tapered portion includes diameter lesser than diameter of the portion behind the taper portion.

In an embodiment, the protrusion (107) and the key (108) defined at the end of the second mandrel section (103b) may be received by the groove (105) and the key slot (106) defined at the end of the first mandrel section (103a), respectively, such that the first mandrel section (103a) and the second mandrel section (103b) may mate each other (i.e., removably connect to each other) forming a mandrel assembly (102). Further, upon coupling the tapered portions in each of the first mandrel section (103a) and the second mandrel section (103b), a profile corresponding to a profile of the intermediate portion (115) of the tube (111) to be thickened is defined. This profile of the mandrel assembly (102) may facilitate gradual thickening, thus avoiding stress raising zones and also aids in inducing only necessary material localization.

In an embodiment, the end of the first mandrel section (103a), which is supported by the second support member (104) may be defined with suitable provisions for rigidly or removably supporting by the second support member (104). As an example, threaded or snap fit provisions may be provided for removably supporting the first mandrel section (103 a) and the end of the first mandrel section (103 a) may be welded or brazed for rigidly supporting the first mandrel section (103a).

Turning back to Figure. 1, the apparatus (100) may include a punch (110) which may be structured to abut the tube (111). In an embodiment, the punch (110) may abut an end of the tube (111), between a free end of the mandrel assembly (102) [thus, the second mandrel section (103b) of the mandrel assembly (102)] and the first support member (101). The punch (110) may be configured to displace axially, to exert axial force on to the tube (111) to plastically deform the tube (111), for thickening the intermediate portion (115) of the tube (111). Further, the apparatus (100) may include a retractor (109), which may be movably disposed on a second support member (104). The retractor (109) may be structured to about the other end of the tube (111) [i.e., the end opposite to the end to which the punch (110) abuts]. The retractor (109) may be configured to exert axial force in a direction opposite to direction in which the punch (110) exerts the axial forces.

In an embodiment, the retractor (109) may be configured to facilitate retraction of the formed tube [i.e., tube with intermediate portion thickened] from the apparatus (100). That is, the retractor (109) may exert axial force to move the formed tube away from the mandrel assembly (102) for retracting the formed tube from the apparatus (100).

In an embodiment, each of the punch (110) and the retractor (109) may be coupled to a linear actuator for exerting axial force on to the tube (111). As an example, the linear actuator may be but not limiting to hydraulic, electric, pneumatic actuator and any other components, which is intended to perform similar function. Hereinafter, an operation of the apparatus (100) to thicken the intermediate portion (115) of the tube (111) is described. As seen in Figure. 6a, the second mandrel section (103b) may be co-axially connected with the first mandrel section (103a) to form a mandrel assembly (102), which may define a profile on its outer portion, which corresponds to profile of the intermediate portion (115) of the tube (111) to be thickened. In an embodiment, connecting the second mandrel section (103b) with the first mandrel section (103 a) may not be construed as a limitation, as the first mandrel section (103 a) may be connected with the second mandrel section (103b). Upon connecting the first mandrel section (103 a) and the second mandrel section (103b) with each other, the tube (111) may be positioned on the mandrel assembly (102) [as seen in Figure. 6b]. That is, the tube (111) may be concentrically positioned on the mandrel assembly (102), such that the mandrel assembly (102) supports the inner surface (113) of the tube (111), and the punch (110) and the retractor (109) abuts ends of the tube (111). Further, the first support member (101) may be operated to support the outer surface (114) of the tube (111). The first support member (101) may exert radially inward force on to the outer surface (114) of the tube (111), for clamping the tube (111) [as seen in Figure. 6c].

Upon, positioning the tube (111), as seen in Figure. 6d the punch (110) may be operated to exert axial force to the end of the tube (111) and the retractor (109) may be operated to exert the axial force in a direction opposite to the direction of application of punch force. In an embodiment, the axial forces exerted by the punch (110) and the retractor (109) along with the radial inward forces by the first support member (101) may induce compressive stresses in the tube (111), causing the tube (111) to plastically deform. This plastic deformation of the tube (111), may result accumulation of material of the tube (111) in the profile defined on the outer surface of the mandrel assembly (102), thereby thickening a substantially intermediate portion (115) along the inner surface (113) [as seen in Figure. 5]. The intermediate portion (115) along the inner surface (113) may have a thickness greater than thickness of remaining portion of the inner surface (113). In some embodiments, the thickness of the intermediate portion (115) of the tube (111) may be maximum of 30% greater than the thickness of the body portion (112). The outer surface (114) includes constant diameter.

After, forming [thus, thickening intermediate portion (115) along the inner surface (113)], as seen in Figure. 6e the first support member (101) may be operated to release the clamping force on the tube (111), and similarly the punch (110) and the retractor (109) may be operated to release the axial forces. Once, the first support member (101) is released, as seen in Figure. 6f, the second mandrel section (103b) may be disconnected from the first mandrel section (103 a) and the retractor (109) may be operated to exert axial force, such that the formed tube moves away from the mandrel assembly (102), for retracting the formed tube from the apparatus (100).

In an embodiment, the apparatus (100) aids thickening of the intermediate portion (115) of the tube (111) along the inner surface (113), without buckling the tube (111).

In an embodiment, the apparatus (100) aids in easy and quick removal of the thickened tube (111), resulting in reducing cycle time and, thus improving productivity,

In an embodiment, the apparatus (100) includes less tonnage equipment and hence results in low manufacturing costs. Also, the apparatus (100) aids the tubes undergo strain hardening during thickening process, which contributes to increasing strength of the tube (111).

Equivalents

With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.

It will be understood by those within the art that, in general, terms used herein, 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 description 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). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to "at least one of A, B, or C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). 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, 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."

While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated in the description.

Referral Numerals:

Claims

We Claim:

1. An apparatus (100) for thickening a tube (111) at its intermediate portion (115), the apparatus (100) comprising: a first support member (101), configured to support an outer surface (114) of the tube (111); a mandrel assembly (102), configured to support an inner surface (113) of the tube (111), wherein, at least a portion of the mandrel assembly (102) is defined with a profile corresponding to a profile of the intermediate portion (115) of the tube (111) to be thickened; a second support member (104), configured to support an end of the mandrel assembly (102); and a punch (110) structured to abut an end of the tube (111) between a free end of the mandrel assembly (102) and the first support member (101), wherein the punch (110) is configured to exert axial force on to the tube (111); wherein, application of axial force by the punch (110) plastically deforms the tube (111) resulting in thickening of the tube (111) at the intermediate portion (115).

2. The apparatus (100) as claimed in claim 1, wherein the mandrel assembly (102) comprises a first mandrel section (103a) and a second mandrel section (103b), removably connected to each other and defining the profile corresponding to the profile of the intermediate portion (115) of the tube (111) to be thickened.

3. The apparatus (100) as claimed in claim 1, wherein the first support member (101) is configured to exert radial force on to the outer surface (114) of the tube (111) for clamping the tube (111) from its outer surface (114).

4. The apparatus (100) as claimed in claim 1, wherein plastically deforming the tube (111), results in accumulation of material in the profile defined by the mandrel assembly (102), thereby thickening the intermediate portion (115) of the tube (111) along the inner surface (113).

5. The apparatus (100) as claimed in claim 1, comprises a retractor (109) structured to abut another end of the tube (111) between a fixed end of the mandrel assembly (102) and the first support member (101), wherein the retractor (109) is configured to exert axial force in a direction opposite to the direction of axial force exerted by the punch (110).

6. The apparatus (100) as claimed in claim 1, wherein the punch (110) is coupled to an actuator to exert axial force on to the tube (111).

7. The apparatus (100) as claimed in claim 5, wherein the retractor (109) is coupled to the actuator to exert axial force on to the tube (111).

8. The apparatus (100) as claimed in claimed in claims 6 and 7, wherein the actuator is either one of an electric, pneumatic or a hydraulic actuator.

9. A metallic tube (111) formed using the apparatus (100) as claimed in claim 1.

10. A tube (111) comprising: a body portion (112) defined with an inner surface (113) and an outer surface

(114); wherein, the body portion (112) is configured such that, thickness at an intermediate portion (115) of tube (111) along the inner surface (113) is greater than thickness of other longitudinal portions of the inner surface (113).

11. The tube (111) as claimed in claim 10, wherein the outer surface (114) of the tube (111) is of uniform diameter.

12. A process of thickening a tube (111) at its intermediate portion (115), the process comprising: positioning, a mandrel assembly (102) within an inner surface (113) of the tube (111); positioning, a first support member (101) on an outer surface (114) of the tube (111); supporting by a second support member (104) at an end of the mandrel assembly

(102); exerting, an axial force on to the tube (111) by a punch (110) to plastically deform the tube (111) resulting in thickening of the tube (111) at the intermediate portion (115); and exerting the axial force by a retractor (109) in a direction opposite to the axial force exerted by the punch (110).