OPTIMIZING THE ROOT GAP FOR ORBITAL WELDED SS321 PIPE by IRJET Journal

International Research Journal of Engineering and Technology (IRJET)

e-ISSN: 2395-0056

Volume: 11 Issue: 11 | Nov 2024

p-ISSN: 2395-0072

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OPTIMIZING THE ROOT GAP FOR ORBITAL WELDED SS321 PIPE SREERAM SAI1, Dr. L. SREE VARDHAN2 1SRF, CAS-DRDO 2SC- ‘F’, Technology Director (R&QA), CAS-DRDO.

---------------------------------------------------------------------***--------------------------------------------------------------------1.1 Material Properties (SS321 or ER347) pipes is done with root gap of 0.05mm ,0.10mm, 0.15mm,

Abstract – In this work Orbital welding of nine SS321

0.20mm,0.30mm. Filler gauge is used to maintain the gap between workpieces. After the welding done, now welded samples are investigated for Radio Grapy Test to check weld defects if any. After the RT test done, weld samples are tested for tensile strength using universal Testing Machine. We now examine the behavior of weld samples at various root gaps as mentioned above.

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Key Words: Orbital welding, SS 321,UTM, Radio Graphy Test, Tensile test.

1. INTRODUCTION Orbital welding is a specialized arc welding process whereby tubes or pipes are secured as the electrode rotates (or orbits) around the object to form the weld. Orbital welding is a specialized area of welding whereby the arc is rotated mechanically through 360° (180 degrees in double up welding) around a static workpiece, an object such as a pipe, in a continuous process. The process was developed to address the issue of operator error in gas tungsten arc welding processes (GTAW), to support uniform welding around a pipe that would be significantly more difficult using a manual welding process, and to ensure high quality repeatable welds that would meet more stringent weld criteria set by ASME. In orbital welding, computer-controlled process runs with little intervention from the operator.[1]

Density : 8027 gm/cm3 ID : 6mm OD : 8mm Thickness : 1mm Temperature Range: 538 to 870 degree C Tensile Strength: 515 Mpa Yield Strength : 205 Mpa Elongation : 40% Rockwell Hardness : 95 HRB

Fig 3. SS321 Pipes ready for welding process

1.2 Weld parameters:  Pre purging : 30secs  Post purging : 30secs  Purging gas : Inert gas  Overlap : 10 degrees  Gas flow force : 15 lit/min(initially given)  Gas flow force : 12 lit/min(intake)  Rotor start delay : 5secs  Down slope time : 5 secs  Gas Flow force time : 10secs(at the end of the weld)  Final current : 5 amps(at the end of the weld)

History: The orbital welding process was invented by Rodrick Rohrberg of North American Aviation to address fuel and hydraulic fluids leaking in and around the plumbing of the X-15 Rocket Research plane.

2. WELDING METHODOLOGY 6/8 SS321 Pipe is used for welding. Orbital welding is done on the 9 specimens of SS321 pipe by the following root gaps.Filler gauge is used to put the root gap between the pipes to be welded after one pipe is clamped.

Fig 1.Chucks holding ss pipes Fig 2.Orbital Welding Machine

Impact Factor value: 8.315

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