Claims:We Claim:
1. Composition of filler rod for joining Cu-Ni pipe to a Gunmetal flange using TIG welding methodology, comprising:
97 to 98 weight percentage of non-ferrous material; and
2 to 3 weight percentage of silver, thereby joining the Cu-Ni pipe to a gunmetal flange.
2. The composition of filler rod for joining Cu-Ni pipe to a Gunmetal flange using TIG welding methodology as claimed in claim 1, wherein said non-ferrous filler rod include alloys, metals or any other material other than iron (ferrite).
3. The composition of filler rod for joining Cu-Ni pipe to a Gunmetal flange using TIG welding methodology as claimed in claim 1, wherein said non-ferrous metal/material may include aluminum, copper, lead, nickel, tin, alloys such as brass and any other alloy without ferrous content and can act as filler material and precious metals such as gold, platinum and thereof.
4. A method for joining Cu-Ni pipe to Gunmetal flange, comprising:
holding Cu-Ni pipe and Gunmetal flange nearby;
selecting a filler material containing of a non-ferrous alloy with silver content; and
welding said Cu-Ni pipe and Gunmetal flange using said filler material using TIG welding thereby protecting Cu-Ni pipe and Gunmetal from oxidation.
5. The method for joining Cu-Ni pipe to Gunmetal flange as claimed in claim 4, wherein said Cu-Ni (Cupro nickel) acts as corrosion resistant piping which is used in highly corrosive flow systems and the Gunmetal (GM) flange aids in joining the pipes together.
6. The method for joining Cu-Ni pipe to Gunmetal flange as claimed in claim 4, wherein said Tungsten Inert Gas (TIG) welding process uses a high melting point non-ferrous alloy filler rod with 2 to 3 weight percentage of silver content in the said filler rod to join Cu-Ni pipe to Gunmetal flange thereby preventing oxidation of joining or welding parts and with low cost. , Description:DESCRIPTION:
Field of invention:
[0001] The present disclosure generally relates to the field of welding technologies, and more particularly relates to a method for joining Cu-Ni (Cupro Nickel) pipe to Gunmetal (GM) flange using Tungsten Inert Gas (TIG) welding using a non-ferrous alloy filler rod with silver content.
Background of the invention:
[0002] Shipbuilding is the construction of ships and other floating vessels. It normally takes place in a specialized facility known as a shipyard. Shipbuilders are also named as shipwrights who follow a specialized occupation that traces its roots to before recorded history. Shipbuilding and ship repairs, both commercial and military are referred to as naval engineering. The construction of boats is a similar activity named as boat building. These shipbuilding industries is suitable for panels for decks, sides, bulkheads and floors, aluminium extrusions, hulls and superstructures, helicopter landing platforms, offshore accommodation, marine and transport structures, masts and booms in sailing boats and thereof.

[0003] The utilization of steel in the shipbuilding industry started way back in the year 1859 and the first welded hull ship HMS Titanic was launched in the year 31 May 1911. The welding in shipbuilding starts from welding plates to form the blocks which are in turn erected and assembled to give the shape of the hull. The water tight spaces, accommodation spaces, machinery spaces, piping and thereof form major part of the hull and systems required for shipbuilding. Currently, the welds run for hundreds of kilometres per ship in the shipbuilding.

[0004] Welding is one of the most widely used hot-work processes used in the shipbuilding industry. The development in welding technology has enabled the industry to produce perfectly watertight and oil-tight joints. Welded joints as compared to riveted joints are much easier to produce and they reduce the cycle time of the project. Welded joints have also resulted in reducing steel weight and require minimal maintenance compared to rivet joints. The major contribution of welding technology to the shipbuilding industry is the possibility of producing smooth hull surfaces, therefore reducing the bare hull resistance and power requirements considerably. The three main welding techniques that are usually used in a shipyard are arc welding, gas welding and resistance welding.

[0005] Conventionally, the corrosion resistant Cu-Ni (Cupro nickel) piping and the GM (gunmetal) flanges are used in joining the pipes together in shipbuilding industry. The weld seam between the GM flange and the pipe is usually a fillet weld. Conventionally, welding procedure for joining the Cu-Ni pipe to LG4C GM Flange involves a brazing process with silver bearing electrode grade BaCuAg 16A. The bearing electrode grade BaCuAg 16A comprises of high percentage (i.e. 43%) of silver (Ag) metal. However, the silver brazing rod is expensive and the brazing process used for joining the pipes is time consuming and requires immense concentration.

[0006] Gas tungsten arc welding (GTAW) is also well-known as Tungsten Inert Gas (TIG) welding is an arc welding process that uses a non-consumable tungsten electrode to produce the weld. The weld area and electrode is protected from oxidation or other atmospheric contamination by an inert shielding gas (argon or helium), and a filler metal is normally used, though some welds, known as auto genous welds. A constant-current welding power supply produces electrical energy, which is conducted across the arc through a column of highly ionized gas and metal vapours known as a plasma. Tungsten Inert Gas (TIG) welding is most commonly used to weld thin sections of stainless steel and non-ferrous metals such as aluminium, magnesium, and copper alloys.

[0007] In updated technology, the joining of Cu-Ni (Cupro nickel) pipes to the GM flanges in the shipbuilding industry is done through a Tungsten Inert Gas (TIG) welding process using an A302/A512 (stainless steel) welding rods. Iron mixed with carbon to produce steel is the main component of stainless steel. However, welding of stainless steel is challenging due to its fast dissipation of heat producing ruined pieces or high scrap cost and difficult metal to handle.

[0008] Conventionally, argon arc (TIG) welding method is used for joining of Cupro pipe to the metal plate. During the welding process the electrodes heat continuously to melt the end of the Cupro Nickel and the metal of the seam thereby increasing the welding speed, strength and toughness of the weld metal between the Cupro Nickel pipe and steel plate. However, joining of Cu-Ni pipe to the GM flange using a filler rod with minimum silver content is not found.

[0009] Therefore, there is a need to address the above shortcomings of the traditional methods, generate a method for joining Cu-Ni (Cupro Nickel) pipe to Gunmetal (GM) flange using Tungsten Inert Gas (TIG) welding. In the past, various welding methods have been made to join Cu-Ni (Cupro Nickel) pipe to Gunmetal (GM) flange in shipbuilding industry, but those efforts are expensive, time consuming and requires immense concentration. There is a need to develop a new Tungsten Inert Gas (TIG) welding process for joining Cu-Ni pipe to Gunmetal (GM) flange using a high melting point non-ferrous alloy filler rod with minimum silver content which is economic and time saving.

Objectives of the invention:
[0010] The primary objective of the invention is to provide a method for joining Cu-Ni (Cupro Nickel) pipe to Gunmetal (GM) flange using TIG welding.

[0011] Another objective of the invention is to weld Tungsten Inert Gas (TIG) process using a high melting point non-ferrous alloy filler rod with silver content.

[0012] Further objective of the invention is to provide a filler rod with 2 to 3 weight percentage of silver composition thereby protecting Cu-Ni pipe and Gunmetal flange from oxidation.

[0013] Further objective of the invention is develop a new TIG welding process for joining Cu-Ni pipe to Gunmetal flange which is economic and time saving.

[0014] Yet another objective of the invention is to provide a TIG welding process which will withstand higher pressures.

[0015] The other objective of the invention is to reduce the poisonous gases during welding process.

Summary of the invention:
[0016] The disclosure proposes a method for joining Cu-Ni pipe to Gunmetal (GM) flange using TIG welding. The following presents a simplified summary in order to provide a basic understanding of some aspects of the claimed subject matter. This summary is not an extensive overview. It is not intended to identify key/critical elements or to delineate the scope of the claimed subject matter. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.

[0017] In order to overcome the above deficiencies of the prior art, the present disclosure is to solve the technical problem to provide a method for joining Cu-Ni (Cupro Nickel) pipe to Gunmetal (GM) flange using Tungsten Inert Gas (TIG) welding process.

[0018] According to an aspect, the disclosure proposes a composition of filler rod for joining Cu-Ni pipe to a Gunmetal flange using TIG welding methodology. The composition of filler rod comprises of 97 to 98 weight percentage of non-ferrous material with 2 to 3 weight percentage of silver content.

[0019] The selected non-ferrous filler rod includes alloys, metals or any other material other than iron (ferrite). The non-ferrous metal/material may include aluminium, copper, lead, nickel, tin, alloys such as brass and any other alloy without ferrous content and can act as filler material and precious metals such as gold, platinum and thereof.

[0020] According to another aspect of the disclosure, the method for joining Cu-Ni pipe to Gunmetal flange includes the steps comprising of holding Cu-Ni pipe and Gunmetal flange nearby. The Cu-Ni (Cupro nickel) acts as corrosion resistant piping which is used in highly corrosive flow systems and the Gunmetal (GM) flange aids in joining the pipes together. Later, selecting a filler material containing of a non-ferrous alloy with silver content and welding the Cu-Ni pipe and Gunmetal (GM) flange using the filler material using TIG welding process. In specific, the Tungsten Inert Gas (TIG) welding process uses a high melting point non-ferrous alloy filler rod with 2 to 3 weight percentage of silver content in the filler rod to join Cu-Ni pipe to Gunmetal flange thereby preventing oxidation of joining or welding parts and with low cost.

[0021] Further, objects and advantages of the present invention will be apparent from a study of the following portion of the specification, the claims, and the attached drawings.

Detailed description of Drawings:
[0022] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention, and, together with the description, serve to explain the principles of the invention.

[0023] FIG. 1 illustrates an exemplary method for joining Cu-Ni pipe to Gunmetal (GM) flange using TIG welding in accordance to an embodiment of the invention.

[0024] FIG. 2 illustrates a specimen of TIG welding process in accordance to an embodiment of the invention.

Detailed invention disclosure:
[0025] Various exemplary embodiments of the present disclosure will be described in reference to the accompanying drawings. Wherever possible, same or similar reference numerals are used in the drawings and the description to refer to the same or like parts or steps.

[0026] The present disclosure has been made with a view towards solving the problem with the prior art described above, and it is an object of the present disclosure to provide a method for joining Cu-Ni (Cupro Nickel) pipe to Gunmetal (GM) flange using Tungsten Inert Gas (TIG) welding process.

[0027] In accordance to an embodiment, the disclosure proposes a composition of filler rod for joining Cu-Ni pipe to a Gunmetal (GM) flange using TIG welding methodology. The composition of filler rod comprises of 97 to 98 weight percentage of non-ferrous material with 2 to 3 weight percentage of silver content.

[0028] The selected non-ferrous filler rod includes alloys, metals or any other material other than iron (ferrite). The non-ferrous metal/material may include aluminium, copper, lead, nickel, tin, alloys such as brass and any other alloy without ferrous content and can act as filler material and precious metals such as gold, platinum and thereof.

[0029] Referring to Fig.1, a method 100 for joining Cu-Ni pipe to Gunmetal flange includes the steps comprising of holding Cu-Ni pipe and Gunmetal flange nearby 101. The Cu-Ni (Cupro nickel) acts as corrosion resistant piping which is used in highly corrosive flow systems and the Gunmetal (GM) flange aids in joining the pipes together. Later at step 102, a filler material containing of a non-ferrous alloy with silver content is selected and welds the Cu-Ni pipe and Gunmetal (GM) flange using the filler material using TIG welding process at step 103. In specific, the Tungsten Inert Gas (TIG) welding process uses a high melting point non-ferrous alloy filler rod with 2 to 3 weight percentage of silver content in the filler rod to join Cu-Ni pipe to Gunmetal flange thereby preventing oxidation of joining or welding parts and with low cost.

[0030] According to an exemplary embodiment of the invention, FIG. 2 illustrates a specimen of TIG welding process 200.

[0031] Different experimental studies are conducted to show the strength of the proposed novel method to join Cu-Ni pipe to GM flange using Tungsten Inert Gas (TIG) welding using a high melting point non-ferrous alloy filler rod with minimum silver content in the filler rod have been tested to attain best results when compared to conventional filler rods.

[0032] Example 1: The Cu-Ni pipe to GM flange fillet welded plates comprises of 8nos. The size of Cu-Ni pipe consisting of outside diameter 18mm, 75mm long and the Gunmetal (GM) Flange consisting of 10mm thick. The material specification of Cu-Ni is ASTM B 111 to Gunmetal (GM) flange is BS 1400 LG4C. The test method used to test is ASME Sec-IX-2010 Addenda 2011.

[0033] Below table 1 represents type of filler materials with different positions of materials of the filler rod composition.
Table 1:

Sl.
Filler Metal WPS/ PQR Number
Position
Result
1 AWS A 5.8 B cup6 68-1 2F L&T (ewac) Satisfactory
2 Silver – 2 (GM) Spl B-Cup 6 68-2 2F Saru Silver Satisfactory
3 AWS A 5.8 B cup6 68-3 3F L&T (ewac) Satisfactory
4 Silver – 2 (GM) Spl B-Cup 6 68-4 3F Saru Silver Satisfactory

[0034] But with above observation, the cost of newly inducted filler material is economical when compared to the earlier filler material. The cost benefit that was envisaged by adopting the new TIG welding process instead of the existing brazing process was to the tune of more than Rs 3.5 to 4.0 Cr. based on the consumption pattern for the project VC 11184 in addition to the savings on 3nos. 25 ton tugs (VC11175-77) constructed and 6no. 10 tons tugs (VC 11178-83) being constructed which would be to the range or Rs 1.0 to 1.5Cr.

[0035] The new innovated process of Tungsten Inert Gas (TIG) welding is much stronger, superior and of higher quality, economy of scale than the existing brazing process. This is established by the strength of the weld being stronger than the parent metal itself. Another quality of this welding technology is it was proven over time that this type of welding for joining Cu-Ni pipe to Gunmetal flange reduces time consuming which was evident by the ease of welding.

[0036] Thus, the disclosure proposes a method for joining Cu-Ni (Cupro Nickel) pipe to Gunmetal (GM) flange through Tungsten Inert Gas (TIG) welding process. The Tungsten Inert Gas (TIG) welding process uses a high melting point non-ferrous alloy filler rod with 2 to 3 weight percentage of silver content in the filler rod to join Cu-Ni pipe to Gunmetal flange thereby preventing oxidation of joining or welding parts and with low cost. The other objective is to reduce the poisonous gases during welding process.

[0037] It will readily be apparent that numerous modifications and alterations can be made to the processes described in the foregoing examples without departing from the principles underlying the invention, and all such modifications and alterations are intended to be embraced by this application.