, Description:A SYSTEM AND METHOD FOR WELDING OF SEAT RING TO VALVE BODY OF A HIGH PRESSURE BY-PASS SAFETY VALVE
FIELD OF INVENTION
[001] The present invention in general relates to a system and a method for welding and cladding of Nickle alloys valve bodies. In particular, the present invention relates to the system and method of welding and cladding of Inconel 617 High Pressure By-Pass Safety Valve.
BACKGROUND OF THE INVENTION
[002] A High Pressure By-Pass Safety Valve is essentially a back pressure regulator. It controls inlet or upstream pressure and functions by opening just enough to relieve excess pressure. High Pressure By-Pass Safety Valves serve to control pressure in a system by diverting a portion of the flow.
[003] High Pressure By-Pass Safety Valves are made of Nickel based alloys like IN 617. The welding of seat ring to valve body in this High Pressure By-pass Safety Valve is challenging because the access to the location of the weld joint is limited and is constrained for manual operation. It is also difficult to ascertain the quality of weld at the location in the current practice. The challenge is to access the location of the fusion line in Deep bore between Valve Body of High Pressure By-Pass Safety Valve and seat ring.
[004] In the present invention a system and method of welding deep bore Nickle alloy that facilitates accessibility to depths of 600mm and more are developed for easy manufacturing and operation.
PRIOR ARTS

[005] China Patent No: CN106239003A relates to an invention Valve body seat ring welding locating tool which provides a valve body seat ring welding locating tool. Through a technology wedge disc, welding of seat rings on the two sides can be completed just by installing the locating tool once. Compared with the prior art that the two sides need clamping and the seat rings are respectively welded, the valve body seat ring welding locating tool is higher in work efficiency. However, it does not talk about the joining of seat ring to valve body welding or welding of valves made with nickel based alloys.
[006] US Patent No: US3508736A is related to a ball type valve plug seat ring construction having an annular elastomeric member bonded to a rigid seat ring and formed with elastically deformable, dual seat to-valve body sealing lips. The lips are so oriented as to respectively resiliently bias the valve plug seat ring radially with respect to fluid flow through the valve and axially toward the plug to establish a seat-to-plug seal.
[007] US patent No: US2887295A relates generally to a novel valve construction and, more particularly, is concerned with a unique design of valve suitable for welding body seat rings' in globe or Y-pattern valves wherein the Weld conveniently applied serves the dual purpose of a fluid seal and also enhances the strength of the valve.
[008] US patent No: US3219311A is a description of Valve assembly having particular head and seat cooperation generally to new and useful improvements and structural refinements in valve constructions and is directed more particularly to the provision of valve means especially suited for controlling the flow of fluids in high temperature and/or high pressure service.
[009] Japan Patent No: JP2005344712A is to provide a cooling type valve seat ring for a cylinder head of an internal combustion engine, having good cooling property and being technically easy to manufacture for protecting a valve seat receiving region in the cylinder head against corrosion. It has at least two ring portions 4, 5, 21, 22 of the valve seat rings 3, 20 are assembled, and both ring portions are firmly joined to each other to form ring flow chambers 6, 23. The flow chambers are pressed into a cylinder head 1 through its press-in face formed. Thereby, they are integrated with a coolant circuit in the internal combustion engine via communication holes 10, 24 formed in at least one of both ring portions.
[0010] US patent No: US5377954A is on Valve with seal ring having edge-welded laminations describing a disc valve with a laminated seal ring secured to the housing which forms a leak-proof seal with a seating surface on the valve disc. The seal ring is made of two or more metal laminates, the outer peripheral edges of which are cold welded together, by WIG welding or laser welding, for example, to prevent any leakage of fluid pass the opposing, abutting surfaces of the laminations. A bolt-tightened pressure ring presses the laminated seal ring in an axial direction against an axially oriented support face of the housing. An axially open groove in support face is covered by the proximate seal ring lamination and is filled with a graphite gasket to prevent leakage behind the seal ring. Alternatively, the laminated seal ring can be mounted on the disc and the cooperating valve seat is formed on the housing.
[0011] European Patent No: E19644356C2 is an invention relating to a seat valve and a method of manufacturing such a seat valves. Seat valves, valve seats, in particular for water, hot water or steam are wear parts. The fixed in a valve housing and the valve seat associated therewith, axially displaceable valve closure member are subject both by the valve actuator as well as by the fluid flowing through relatively strong. In the closed position, the valve closure member is seated firmly on against the valve seat is pressed against a sealing edge or a narrow sealing surface thereof. Deformations of the valve seat or valve closure member would eventually lead to unacceptable leakage rates and thus to failure of the valve. Unlike the rest of the valve body of the valve seat and valve closure member are therefore usually made of a steel size hardness (Brinell hardness (HB)). The valve seat has to be installed in the preparation of the poppet valve, therefore, as a separate part in the valve housing.
[0012] US patent No: US2869221A is an invention relating to a method of producing valve housings. Recently valves have been successfully introduced in practice, the housing of which is composed of two shell shaped, die-forged halves which are welded together along the plane of the die joint which extends through the coaxial mouths of the inlet and outlet passages. Even in the case of larger dimensions, that is the nominal width of the valve, it is possible, by using suitable dies, to forge thin-walled shells provided with the necessary ribs, reinforcements or valve seat parts. Such die-forged housing shells are very strong. The welding of the housing halves is carried out on butt-welding machines by the ash welding process. But other known welding processes might also be used.
[0013] US patent No: US5247960A is for A replacement valve seat device for insertion in a recess of a valve where a valve seat has been removed includes a first ring which provides a valve seat and a cooperating second ring of memory metal which is expandable upon being heated above its transition temperature to fixedly position the first ring in position within the recess.
[0014] US patent No: US5958332A describes a cylinder member for an internal combustion engine such as a valve, piston, cylinder liner or seat portion. The member has a welded high temperature corrosion resistant facing alloy with a hardness increased by use of a precipitation hardening mechanism based on a solid state phase transformation. The facing alloy has a temperature of activation of the precipitation hardening mechanism that is above the operating temperature of the alloy. The participation hardening mechanism acts so slowly that the alloy has not hardened at welding on the cylinder member Hardening occurs during a subsequent heat treatment at a temperature higher than the activation temperature for the participation hardening mechanism.
[0015] US patent No: US9340856B2 is titled Ni—Fe—Cr alloy and engine valve welded with the same alloy and is about a hard-facing alloy having impact resistance, wear resistance and hot corrosion resistance and containing Fe which is a bountiful resource and inexpensive is provided. Provided are: a Ni—Fe—Cr alloy containing 0 to 20.0 mass % of Mo, 8.0 to 40.0 mass % of W, 20.0 to 40.0 mass % of a total amount of Mo and W, 20.0 to 50.0 mass % of Fe, 12.0 to 36.0 mass % of Cr and 1.0 to 2.5 mass % of B, and the remainder being Ni and unavoidable impurities; and an engine valve welded with the same alloy. The above Ni—Fe—Cr alloy can further contain 15 mass % or less of a total amount of elements selected from Co, Mn, Cu, Si and C, in such cases, 15.0 mass % or less of Co, 5.0 mass % or less of each of Mn and Cu, 2.0 mass % or less of Si and 0.5 mass % or less of C are preferred.
[0016] China patent No: CN100575519C is for Nickel base alloy and rustless steel valve possessing nickel base alloy layer seal surface and its preparation method. The invention relates to a nickel-based alloy, a stainless steel valve provided with a seal surface of a nickel-based alloy layer and a preparation method. The components and the contents of the nickel-based alloy used on the seal surface of the nickel-based alloy layer are respectively: 1.0 to 1.5wt percent of C, 17.5 to 19.5wt percent of Cr 7.0 to 9.0wt percent of Mo, 3.5 to 4.5wt percent of W, 1.5 to 2.5wt percent of Nb, 2.0 to 3.0wt percent of Si and the rest is Ni. The stainless steel valve provided with a seal surface of a nickel-based alloy layer is lead the powder of the nickel-based alloy to form a seal surface nickel-based alloy on the stainless steel valve through a laser plating method. The nickel-based alloy layer and a stainless steel matrix are completely metallurgically bonded without the defects like cracks, air holes, and the like. The alloy layer comprises nickel-based solid solution dendrites, the metallic carbides between the dendrites, the metal silicides, and the like. The reinforced layer of the nickel-based alloy has higher rigidity (HRC43-49) and excellent properties for anti-heat and shock and can be used for preparation the alloy reinforced layer on the seal surface of the stainless steel which has strict demands on the alloy components (B and Co are excluded).
[0017] China patent No: CN100344781C is on Build-up wear-resistant copper alloy and valve seat. It is done by welding to provide a wear-resistant copper alloy and the valve seat, while ensuring welding and crack resistance. The wear-resistant copper alloy welding that the valve seat and characterized in having a composition comprising by weight%: Ni: 5.0-24.5%, Fe: 3.0 to 20.0%, Si: 0.5-5.0%, B: 0.05 to 0.5%, Cr: 0.3-5.0%, and selected from molybdenum, tungsten and vanadium of one element or two elements or more than two elements: 3.0 to 20.0%, balance copper and unavoidable impurities.
[0018] US patent No: US4948559A describes the Alloy for building up valve component. An alloy for building up a valve according to the present invention comprises: with respect to the total weight of the alloy taken as 100%, 30 to 40% by weight of chromium; 15 to 31% by weight of nickel; 7 to 20% by weight of molybdenum; 0.7 to 2.2% by weight of carbon; 1.5% or less by weight of silicon; and balance of iron and inevitable impurities. The alloy is superior in hardness at high temperatures, PbO resistance and PbO+PbSO4 resistance. In addition, the alloy is suitable for powder build-up welding.
[0019] Thus from the extent of literature survey, it is reliably learnt that there is no preceding methodology to weld seat ring to valve body HP by pass safety valves for Nickel based alloys.
OBJECTIVE
[0020] A main objective of the present invention is to develop a mechanised Gas Tungsten Arc Welding (GTAW) system and method for welding of seat ring to valve body of High Pressure By-Pass Safety Valve.
[0021] Another objective of the present invention is to provide for a mechanised GTAW to weld seat ring to valve body of High Pressure By-Pass Safety Valve at depth of more than 600mm.
[0022] Yet another objective of the present invention is to provide for a mechanised GTAW to weld U groove of the valve body High Pressure By-Pass Safety Valve and the seat ring.
[0023] Still another objective of the present invention is to provide for custom designed mechanised system and method parameters.

SUMMARY OF THE INVENTION:
[0024] The present subject matter relates to a system and method for welding of a seat ring to valve body of a High Pressure By-Pass Safety Valve. The present system comprises a rotational platform where the High Pressure By-Pass Safety Valve is placed and a X-Y slider having a vertical arm and a horizontal arm. The horizontal arm mounted at upper side of the vertical arm. Further, a Tungsten Inert Gas (TIG) torch is connected with the horizontal arm at one end and other end has a TIG torch nozzle. The TIG torch nozzle positioned at weld joint location of the Nickle alloy valve body to the seat ring. The rotational platform rotates and facilitates welding of the seat ring with the Nickle alloy valve body along circular path.
[0025] In an aspect, length of the TIG torch is in range of 1m to 3m.
[0026] In an aspect, angle of welding by the TIG torch weld is in range of 0o to 45o.
[0027] In an aspect, the TIG torch nozzle is positioned at U groove of the valve body where the welding is to be performed.
[0028] In an aspect, the rotational platform is programmed to rotate at predefined rotational speed.
[0029] In an aspect, Gas Tungsten Arc Welding (GTAW) process is used for the welding.
[0030] In another aspect, the present subject matter relates to a method for welding of a seat ring to a Nickle alloy valve body of a High Pressure By-Pass Safety valve. The method comprises steps of positioning of a Tungsten Inert Gas (TIG) torch inside valve body by moving X-Y slider and positioning a TIG torch nozzle of the TIG torch above fusion line of the Nickle alloy valve body and the seat ring. Further, the valve body of the by-pass safety valve is rotated by rotational platform and the Nickle alloy valve body and the seat ring is welded by the TIG torch nozzle to achieve defect free fusion of the seat ring and Nickle alloy valve body of the High Pressure By-Pass Safety Valve.
[0031] In an aspect, the welding is performed by using mechanised Gas Tungsten Arc Welding (GTAW) process.
[0032] In an aspect, the welding process parameters are welding voltage at 14V, welding current at 160A, hot wire current at 30A and gas flow rate at 16lpm.
[0033] In an aspect, the rotational platform is rotated for at least one complete rotation of 360o.
[0034] The drawings are illustrative only but not used to limit scope of the present subject matter.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0035] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system or methods in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which:
[0036] Fig. 1 illustrates schematic drawing of cross sectional view of a system for welding of a seat ring to valve body of high pressure By-pass Safety Valve in accordance with an embodiment of the present subject matter.
[0037] Fig. 2 illustrates flow chart of steps for method of welding of a seat ring to valve body of High Pressure By-Pass Safety Valve.

DETAILED DESCRIPTION OF THE CURRENT INVESTIGATION
[0038] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.
[0039] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments and detailed in the following description. Descriptions of well-known components and processing techniques are omitted to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0040] It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those skilled in the art that conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those skilled in the art that by devising various arrangements that, although not explicitly described or shown herein, embody the principles of the present subject matter and are included within its spirit and scope. Furthermore, all examples recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. The novel features which are believed to be characteristic of the present subject matter, 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.
[0041] 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.
[0042] Advanced Ultra Supercritical Boilers use Nickel based alloys for operating at rated values of pressure and temperature. One of the most critical component of the circuit is High Pressure By-Pass Safety Valve which is made of Nickel based alloys like IN 617. The component consists of two parts; one being the valve body 8 of the High Pressure By-Pass Safety Valve and the other is seat ring 5. The seat ring 5 is placed inside the valve body 8 and is welded along a 360o circular path of its edges.
[0043] The welding of valve body 8 of High Pressure By-Pass Safety Valve is challenging because the access to the location of the weld joint is limited and is constrained for manual operation. It is also difficult to ascertain the quality of weld at the location using the conventional practice of welding. Hence, it is required to replace the existing practice of manual welding operation with a suitable mechanised system which is unique and is being structured for this particular purpose.
[0044] The present subject matter herein relates to a system and a method of welding of a seat ring 5 to a valve body 8 of a High Pressure By-Pass Safety Valve. The subject matter proposes a mechanised Gas Tungsten Arc Welding system and method for welding of the seat ring 5 to the valve body 8 of the High Pressure By-Pass Safety Valve. The valve body 8 of the High Pressure By-Pass Safety Valve defines a U groove for receiving the seat ring 5. The mechanised GTAW torch is used to access depths of 600mm or more for welding the U groove joint of the valve body 8 of High Pressure By-Pass Safety Valve and the seat ring 5.
[0045] As shown in Fig. 1, the system 10 for welding of the seat ring 5 to the valve body 8 of High Pressure By-Pass Safety Valve, has a X-Y slider (for example, column and boom arrangement) having two arms, such as vertical arm 1 and a horizontal arm 2. On the X-Y slider, the horizontal arm 2 is positioned at upper side of the vertical arm 1. The horizontal arm 2 moves/slides in direction X and Y over the vertical arm 1 according to dimensions of the High Pressure By-Pass Safety Valve. A TIG torch 3 is coupled to the horizontal arm 2 at one end and extends in downward direction. Further, the TIG torch 3 can be angularly positioned with the horizontal arm 2 by means of hinge joint or ball and socket joint. On the other end of the TIG torch 3, a torch nozzle 4 is provided that is positioned in proximity of weld joint or U groove defined by the valve body 8 of High Pressure Safety Valve and the seat ring 5.
[0046] Referring to Fig. 1, the High Pressure By-Pass Safety Valve is positioned over a rotational platform 7. The rotational platform 7 is rotated by means of a motor at a predefined rotational speed. Where the motor is controlled by a programmed logic controller (PLC) which is well known to a person skilled in the art.
[0047] The TIG torch 3 has a length in range of 1m to 3m, preferably 1m. Further, length of the TIG torch 3 depends on depth of the valve body 8 so that the TIG torch 3 can reach the weld joint or U groove defined by the seat ring 5 and the valve body 8. The TIG nozzle 4 is positioned over the fusion line which is U groove defined by the seat ring 5 and the valve body 8 and welding is to be performed along the fusion line in circular path at continuous rate. Further, welding in circular path is achieved by rotating the High Pressure By-Pass Safety Valve over the rotational platform 7.
[0048] For example, the welding process parameters are welding voltages as 14V, the welding current (wire speed) as 160A, Hot wire current as 30A, gas flow rate at 16lpm. The rotational movement of the rotational platform 7 can be programmed for either one pass (for 360o) or continuous passes. The entire valve body 8 of High Pressure By-Pass Safety Valve is held by the rotational platform 7 that allows the rotation of the valve body 8 High Pressure By-Pass Safety Valve to weld the seat ring 5 along the circular profile.
[0049] By ensuring the above methodology, it is possible to achieve a defect free fusion of a Nickel Alloy Valve body 8 of the High Pressure By-Pass Safety Valve with the seat ring 5 and the uniqueness is the application has been successfully completed using the proposed system 10.
[0050] As shown in fig. 2, the method illustrates working steps of welding a seat ring 5 with a valve body 8 of a High Pressure By-Pass Safety Valve.
[0051] At step 101, the seat ring 5 is placed in the valve body 8. The position of the seat ring 5 and the valve body 8 of the High Pressure By-Pass Safety Valve defines a U groove that act as a fusion line or welding joint for welding the seat ring 5 with the valve body 8. Further, a Tungsten Inert Gas (TIG) torch 3 of the system 10 is positioned inside the valve body 8 by moving the X-Y slider. The TIG torch 3 defines a sufficient length to reach the fusion line for welding of the seat ring 5 with the valve body 8.
[0052] At step 102, a TIG torch nozzle 4 of the TIG torch 3 is positioned above the fusion line or U groove defined by the seat ring 5 and the valve body 8 of the High Pressure By-Pass Safety Valve. The TIG torch nozzle 4 is positioned to weld the seat ring 5 with the valve body 8 along the fusion line.
[0053] At step 103, the valve body 8 of the High Pressure By-Pass Safety Valve is positioned over a rotational platform 7 that is rotated by a motor at predefined rotational speed controlled by a programmable control logic.
[0054] At step 104, the TIG torch nozzle 4 welds the seat ring 5 with the valve body 8 of the High Pressure By-Pass Safety Valve along the fusion line in circular path where the welding along circular path is achieved by keeping the TIG torch 3 stationary and rotating the valve body 8 by the rotational platform 7.
[0055] 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.
[0056] Reference numerals:
1. Vertical Arm of the X-Y slider
2. Horizontal arm of the X-Y slider for holding the TIG torch
3. Tungsten Inert Gas (TIG) Torch
4. Tungsten Inert Gas (TIG) torch nozzle
5. Seat ring to be welded to the valve body
6. U groove for making the weld joint.
7. Rotational Platform
8. Valve body of a High Pressure By-Pass Safety Valve
10. TIG torch arrangement or system

Claims:We claim:
1. A system (10) for welding of seat ring to valve body High Pressure By-Pass Safety Valve, the system comprises:
a rotational platform (7) where the High Pressure By-Pass Safety Valve is placed;
a X-Y slider having a vertical arm (1) and a horizontal arm (2), where the horizontal arm (2) mounted at upper side of the vertical arm (1); and
a Tungsten Inert Gas (TIG) torch (3) connected with the horizontal arm (2) at one end and other end has a TIG torch nozzle (4), wherein the TIG torch nozzle (4) positioned at weld joint location of the Nickle alloy valve body (8) to the seat ring (5),
wherein the rotational platform (7) rotates and facilitates welding of the seat ring (5) with the Nickle alloy valve body (8) along circular path.
2. The system (10) as claimed in claim 1, wherein length of the TIG torch (3) is in range of 1m to 3m.
3. The system (10) as claimed in claim 1, wherein angle of welding by the TIG torch (3) weld is in range of 0o to 45o.
4. The system (10) as claimed in claim 1, wherein the TIG torch nozzle (4) is positioned at U groove of the valve body where the welding is to be performed.
5. The system (10) as claimed in claim 1, wherein the rotational platform (7) is programmed to rotate at predefined rotational speed.
6. The system (10) as claimed in claim 1, wherein Gas Tungsten Arc Welding (GTAW) process is used for the welding.
7. A method for welding of Nickle alloy valve body to seat ring of by-pass safety valve, the method comprises:
(101) positioning of a Tungsten Inert Gas (TIG) torch (3) inside valve body by moving X-Y slider;
(102) positioning a TIG torch nozzle (4) of the TIG torch (3) above fusion line of the Nickle alloy valve body (8) and the seat ring (5);
(103) rotating the valve body of the by-pass safety valve by rotational platform (7); and
(104) welding of the Nickle alloy valve body (8) and the seat ring (5) by the TIG torch nozzle (4) to achieve defect free fusion of the Nickle alloy valve body (8) and the seat ring (5).
8. The method as claimed in claim 7, wherein the welding (104) is performed by using mechanised Gas Tungsten Arc Welding (GTAW) process.
9. The method as claimed in claim 7, wherein the welding (104) process parameters are welding voltage at 14V, welding current at 160A, hot wire current at 30A and gas flow rate at 16lpm.
10. The method as claimed in claim 7, wherein the rotational platform (7) is rotated (103) for at least one complete rotation of 360o.