Description:“AUTOMATIC DISCONTINUOUS SPIRAL FIN WELDING IN HIGH FREQUENCY RESISTANCE WELDING MACHINE IN SEAMLESS STEEL TUBE PLANT”

FIELD OF THE INVENTION

The present invention generally relates to Method of automatic discontinuous Spiral Fin Welding in High Frequency Resistance Welding Machine in Seamless Steel Tube manufacturing plant. The present invention in particular relates to a method of automatic discontinuous welding of spiral fin over a seamless steel tube. More particularly, the invention relates to a method of providing welding of FIN at predefined length and at a predefined position over the tube surface.

BACKGROUND OF THE INVENTION

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 art.

In the process of seamless steel tube manufacturing, Solid billet is converted into hollow bloom using Cross Piercing Elongation process. Then Hollow is transferred to next step where mandrel bar is inserted into hollow bloom and Crimping takes place at Crimping Press. Crimped mandrel bar with hollow is fed to Push Bench process for further elongation to make the shell. Secondary re-heating takes place in a furnace called Walking Beam Furnace. Then re-heated shell is fed to Stretch Reducing Mill, where the final reduction process takes place to form a seamless steel tube.

These seamless steel tubes are further subjected to Spiral Fin Welding process for HRSG modules and any special projects that require spiral fin welded tubes.

During SFW process High Frequency Resistance heating method is used to weld the spiral fin over seamless steel tube at required pitch. High frequency (maximum of 400 kHz) heating being used to get benefit from the skin effect. Weld Power can be fed to a maximum of 300 KW.

SFW is equipped with continuous welding facility but there is no discontinuous facility to execute any special requirements, which requires discontinuous fin welding. Hence, the present invention has been introduced.

OBJECTS OF THE INVENTION
Object of the present invention is to implement a method of automatic discontinuous Spiral Fin Welding in High Frequency Resistance Welding Machine in Seamless Steel Tube manufacturing plant.

A further object of the present invention is to modify the welding on/off in such a way that discontinuous welding is executed with sensor based feedback system which enables welder when to on/off.

Another object of the invention is to provide discontinuous fin welding in automatic mode with sensor feedback system.

These and other objects and advantages of the present invention will be apparent to those skilled in the art after a consideration of the following detailed description taken in conjunction with the accompanying drawings in which a preferred form of the present invention is illustrated.

SUMMARY OF THE INVENTION
One or more drawbacks of conventional systems and process are overcome, and additional advantages are provided through the apparatus/composition and a method as claimed in the present disclosure. Additional features and advantages are realized through the technicalities of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered to be part of the claimed disclosure.

Accordingly, sensor feedback system to detect the minimal welding power or Zero welding power zone. Minimal welding power/ zero power signal is transferred to High Frequency Resistance Welder. Welder will then adjust the output power to meet the demand.

By the above disclosed method, the draw backs of the prior art are eliminated and there is a substantial improvement in machine operations to cater the needs of discontinuous welding requirements.

There is provided a method to execute automatic discontinuous Spiral Fin Welding in High Frequency Resistance Welding Machine in Seamless Steel Tube manufacturing plant.

The method comprising the steps of:

- Sensor installation to detect the minimal weld power or zero weld power zone,

- Providing feedback to HF welder,

- Weld power auto adjustment by HF welder;

The inventive features/steps of the invention have been indicated in the principal claim and the subsidiary features have been mentioned in the dependent claims.

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.

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 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 DRAWINGS

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 processes that are consistent with the subject matter as claimed herein, wherein:-
Figure 1 Shows the Existing Spiral Fin Welding (SFW) process flow schematic.
Figure 2 Shows the proposed Spiral Fin Welding (SFW) process flow schematic.
Figure 3 Shows the continuous welded tube with the prior process
Figure 4 Shows the discontinuous welded tube with the proposed process
Figure 5 shows Spiral Fin Welded Tube
Figure 6 Shows the schematic of fin welding over the seamless steel tube
Figure 7 shows Carriage and Spindle

Figure 8 shows Modification for discontinuous fin welding

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 OF A PREFERRED EMBODIMENT OF THE
PRESENT INVENTION

While the embodiments of the disclosure are subject to various modifications and alternative forms, specific embodiment thereof have been shown by way of example in the figures and will be described below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.
High Frequency (maximum of 400kHz) current is delivered through a set of metal contacts (copper bars) placed on fin and seamless steel tube. High frequency current flows mostly on the surface of the conductor (skin effect), with the contacts close together creates uniform heating because of the proximity effect. This is in turn used to weld the fin over the surface of the seamless steel tube to form a Spiral Fin Welded Tube.

SFW is equipped with continuous welding facility but there is no discontinuous facility to execute any special requirements, which requires discontinuous fin welding. Prior to this proposed method, discontinuous welded tube was carried out by stripping the welded fin from the mother tube. It was a laborious job and leads to less productivity.

To cater the discontinuous fin welding process, introduced a sensor based system which enables welder to shift from High Frequency to Low / Zero frequency as desired by the process requirements to achieve no weld area.

Switching operation of welder takes place automatically from High Frequency to Low/Zero Frequency current feeding based on the sensor feedback. This enables the machine to cater the requirements of discontinuous fin welding facility.

The present invention makes a disclosure regarding Automatic discontinuous Spiral Fin Welding in High Frequency Resistance Welding Machine in Seamless Steel Tube manufacturing plant.

Now, the invention can be discussed herein under:

Reference may be made to figure 5 showing the spiral fin welded tube where fin is welded on to the tube surface using high frequency resistance welding. The fin pitch is controlled via spindle and carriage movement.

Referring to figure 6, one end of the tube is held in a chuck. The fin is fed through a feeding unit at required speed based on different input parameters. One of the welding electrodes is in continuous contact with the tube and the other with the fin. The welding occurs when a high frequency(400kHz) current is passed at a required power requirement which can be adjusted.

Reference may be made to figure 7, wherein the spindle starts rotating, rotating along with it the tube and the carriage moves so as to control the fin pitch based on input parameters. As the spindle and carriage move the welding power is pumped to weld the fin to the tube. This is a continuous process and is only stopped after the required number of fins per tube are attained.

Now, reference may be made to figure 8. As part of requirement, the continuous process is needed to be modified to allow for a length of welding free area. The length of the discontinuity is to be adjusted and the length at which discontinuity starts can be set by the user as per the requirement.

To achieve this an actuator is attached to carriage and two position adjustable proximity switches are installed on the railing beside the carriage. The Proximity sensors position is freely adjustable to change the discontinuous interval(D).

As the carriage moves, when the proximity sensor P1 senses the actuator, the welding process is stopped and is again restored only when the proximity sensor P2 senses the actuator, leading to a discontinuous interval of welding free area.

This modification allows for the manufacture of tubes with discontinuous fin welding for different application requirement.

ADVANTAGES OF INVENTION
-Eliminates the manual work to be done to remove the welded fin for dis-continuous requirement which was the practice in prior art;
-Provides for adjustable weld free area as per requirement, wherein both the position and width can be varied as per the specified requirement;
-Reduces time to process a tube over prior art drastically.

WORKING OF INVENTION
As the tube and fin are fed, the fin is welded on to the tube taking into consideration the required fin pitch and the number of fins per tube.
The above process is a continuous process, where fin is welded all along the tube without any dis-continuity.
The present modification is such that the actuator attached to the carriage, when sensed by the proximity sensor P1, sends a signal to the welder to reduce the weld power.
The carriage keeps on moving until the proximity P2 senses when the weld power returns and the fin is welded again leaving a weld free area between the proximity sensors P1 and P2.
The position of P1 and the distance between P1 and P2 can be adjusted to meet the specified requirement.

TEST RESULT
The result of the modification is a new product variety catering to the needs of the customer.
Fig 3 and fig 4 displays the difference between the output of the prior art and the modified version.

Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases, it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.

Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the appended claims.

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 particulars 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 analogues 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, 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”.

The above description does not provide specific details of manufacture or design of the various components. Those of skill in the art are familiar with such details, and unless departures from those techniques are set out, techniques, known, related art or later developed designs and materials should be employed. Those in the art are capable of choosing suitable manufacturing and design details.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be combined into other systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may subsequently be made by those skilled in the art without departing from the scope of the present disclosure as encompassed by the following claims.

The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.

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 by the following claims.
, Claims:We Claim
1. Automatic discontinuous Spiral Fin Welding in High Frequency Resistance Welding Machine in Seamless Steel Tube manufacturing plant comprising steps of:
- welding of fin onto the tube surface by using high frequency resistance welding,
- holding one end of the tube in a chuck,
- feeding the fin through a feeding unit, wherein one of the welding electrodes is in continuous contact with the tube and the other with the fin,
- rotating spindle,
- attachment of an actuator to carriage and installation of two position adjustable proximity switches/sensors on the railing beside carriage.

2. The Automatic discontinuous Spiral Fin Welding as claimed in claim 1, wherein the fin is fed through a feeding unit at required speed based on different input parameters, in which the fin welding machine allows for the fin height in the range of 12.5 to 25mm and the fin thickness in the range of 0.8 to 3.2mm, and the density of the fins can be varied based on the requirement which is fed into the system, wherein the present requirement being 5.5 fins per inch(25.4mm) and the usual allowed range is 40 to 240 fins/mtr.
3. The Automatic discontinuous Spiral Fin Welding as claimed in claim 1 or 2, wherein the spindle rotates along with the tube and the carriage moves so as to control the fin pitch based on input parameters, in which as the spindle and carriage move the welding power is pumped to weld the fin to the tube.

4. The Automatic discontinuous Spiral Fin Welding as claimed in claims 1-3, wherein the fin pitch is controlled via spindle and carriage movement.

5. The Automatic discontinuous Spiral Fin Welding as claimed in claims 1-4, wherein the welding occurs when a high frequency of about 400kHz current is passed at a required power requirement which can be adjusted.
6. The Automatic Discontinuous Spiral Fin Welding as claimed in claims 1-5, wherein the Proximity sensors position is freely adjustable to change the discontinuous interval(D).
7. The Automatic discontinuous Spiral Fin Welding as claimed in claims 1-6, wherein as the carriage moves, when the proximity sensor P1 senses the actuator, the welding is stopped and is again restored when the proximity sensor P2 senses the actuator, leading to a discontinuous interval of welding free area.
8. The Automatic discontinuous Spiral Fin Welding as claimed in claims 1-7, wherein the adjustment of the length of the discontinuity and the length at which discontinuity starts is set by the actuator and two position adjustable proximity switches/sensors, in which the sensors are installed to detect the minimal weld power or zero weld power zone followed by Providing feedback to HF welder and weld power auto adjustment by HF welder.
Dated this 30th day of March, 2024