PSI - Issue 60

Rohan Nair et al. / Procedia Structural Integrity 60 (2024) 93–114 Rohan Nair / StructuralIntegrity Procedia 00 (2023) 000–000

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There are four of longitudinal (long-seam or L_S) weld joints between two half shells and four circumferential (cir-seam or C_S) weld joints between shells, IC rings and flanges. Two additional circumferential seam weld joints are from the two adaptors to shell. AA4043 filler wire of Ø2.4 mm was used for welding and Ø1.6 mm AA4043 filler wire was used for repair welding to the study the effect of weld repair on the mechanical properties. Dye-penetrant (DP) test [8] and X-ray radiographic (RT) non-destructive testing (NDT) was carried out on weld joints to evaluate the soundness of weld joints. To confirm the strength of the both weld joints and qualify the welders, tensile testing of weld specimens was carried out. To simulate long-seam weld joints, flat heat treated coupons were welded and specimens were extracted for tensile testing. To simulate cir-seam weld joints, welding was carried out between shell and forging in 1:1 scale. Final Assembly: The ends of the flanges were bolted by closure plates, 20mm thick which were machined out of AISI 304 forgings with provision for ‘O’ ring for containing the medium during pressure test. The test article was thoroughly buffed to remove any scratches or slight dent marks and it is cleaned with IPA thereafter. The test article was stored with application of SAE 30 oil and wrapped under bubble sheet for preservation. Weld rework in the fabrication of the test article: The test article realization did not account for any intentional rework welding at any of the weld joints. However the need to implement reworks, like rework 1 (RW1) and rework 2 (RW2) at certain locations on both long seam and cir-seam joints was intended to obtain confidence in the strength of the joints post rework welding and simulate the behaviour of the same, in case a need arises in the acceptance of flight hardware. Towards this, certain rework locations were identified on the test article which shall simulate the joint subjected to maximum stress during pressure testing and at the same time take care of ease of fabrication without distorting the hardware. The rework locations for cir-seam joints were identified based on the fact that inner side of the toroidal shell will be subjected to maximum stresses and thus RW2 can be included on the inner diameter (ID) side and RW1 on the outer diameter (OD) side. The rework locations on long-seam and cir-seam welds is shown in fig. 7 and 8 respectively. 2.1.5. 2.1.6.

Fig. 7: Test article with long seam reworks RW1 and RW2