PSI - Issue 60

Varsha Florist et al. / Procedia Structural Integrity 60 (2024) 614–630 Varsha Florist, Santhoshkumar R, A. Vamsi, Sajju V, Sarath Mohan, Sanjeev Kumar, Dhanoop A, Venukuttan C, M.K. Sundaresan, SVS Narayana Murty / Structural Integrity Procedia 00 (2024) 000 – 000 7

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predictions of 585 bar pressure. The weld parameters used for realization of sub-scale tank was taken as input for establishing welding procedure specification (WPS) for realization of full scale 15-5 PH pressure vessel. The 15-5 PH pressure vessel comprises of two 4.5mm circumferential butt weld joints between aft end dome to cylindrical shell and cylindrical shell to fore end dome. The pressure vessel also consists of fillet joints of mounting brackets and weld pads on the tank. Gas tungsten arc welding (GTAW) was used to weld 15-5 PH stainless steel and filler wire used was ER630. Both cirseam butt joints in15-5PH tank are classified as Class-I joint, since these joints are subjected to stress due to pressurization and all fillet weld joints are classified as Class-III joint. Finally, the fabricated tank was subjected to aging at 552± 6ºC-4hrs (H1025 condition) as per AMS 5659T standard Aerospace Material Specification, SAE. The precipitation hardened tank was further subjected to, by dipping method, to build a protective oxide layer over the entire surface of the tank. 4. Experimental Results A sub-scale tank of 200mm nominal diameter cylindrical shell was realized with the above flow formed shell and was subject to pressure test Rajan, K. M (2002).

Fig. 6. a) Sub-sized Flow formed shell; b) Sub-scale 15-5 PH pressure vessel with instrumentation plan. The strain gauge instrumentation plan for burst test of subscale version of the pressure vessel is shown in Fig. 6. Specification of maximum expected operating pressure (MEOP), proof and ultimate pressure for sub-scale tank are 32 MPa, 40 MPa and 48 MPa, respectively. The test cycle followed consists of: • 0 – 1 – 0 with hold at 1MPa for 2 min. for carrying out leak checks • 0 – MEOP and hold for 5 min. at MEOP. Repeat this step for 11 more cycles • 0 – proof pressure and hold for 10 min. at proof pressure and repeating this step for 3 more cycles • 0 – ultimate pressure in steps of 1MPa and holding for 1 min. at ultimate pressure and then proceed till burst of the pressure vessel.