PSI - Issue 60

Md Rakim et al. / Procedia Structural Integrity 60 (2024) 136–148

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Md Rakim et al. / Structural Integrity Procedia 00 (2023) 000 – 000

as well as crack propagation seem to be different and the investigation of welded joints concerning fatigue damage has to be confirmed. Herein, the investigation is drawn on the comparative study of FCG behaviour for both base and weld forms of alloy 617M during cyclic loading conditions. The current work aims in characterizing FCG behaviour of alloy 617M at different test temperatures (27 °C, 650 °C, 710 °C and 750 °C). Through this paper, an effort has been made in the investigation of for alloy 617M base under aged treatment at 710 °C for various durations up to 20000 hours. Whereas for welded form of the alloy, investigation of has been carried out under aged treatment at 710 °C for various durations up to 5000 hours. The microstructural investigation under the particular aged period and its coordination with the have also been presented. 2. Material and Experimental Description Alloy 617M is a Ni-based super-alloy made in tube forms that has been used in the production of one-quarter compact tension (CT) specimens. CT specimen is prepared via wire-cut electro-discharge machining (EDM) which is used for fatigue crack growth (FCG) test. Despite several specimens recommended through ASTM E 647-15, CT specimens of dimensions 25 mm width ( W ) and 6.25 mm thickness ( B ) need to be selected to reduce the wastage of material happens during the machining process as shown in Fig. 1. The above-mentioned CT specimen has been accepted from IGCAR, Kalpakkam, India in conditions of as-received along with different aged durations up to 20000 hours at 710 °C for alloy 617M. The chemical constituents of alloy 617M are depicted in Table 1.

Fig.1: Compact tension (CT) specimen used for FCG test.

Table 1. Chemical constituents of alloy 617M. Elements Ni Cr Co

Mo

Al

Ti

Fe

Si

C

Weight %

Balance

22.10

12.28

8.32

1.20

0.43

0.38

0.11

0.07