PSI - Issue 14

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Santosh Kumar et al. / Procedia Structural Integrity 14 (2019) 872–882 Santosh / Structural Integrity Procedia 00 (2018) 000–000

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Fig. 8. Fracture toughness results for A) Hardness level (48-50 HRc) and B) Hardness level (44-46 HRc)

Results indicate that K IC value of SF route material is approximately 19.5% and 33.3% lower than that of CR in LS and TS orientations, respectively at higher hardness range (48~50 HRc). But, the same at lower hardness range (44~46 HRc), is approximately 28.7% and 24.8% lower for SF route as compared to that of CR in LS and TS orientations, respectively. For both route material, fracture toughness value increases with decrease in hardness. 4. Microstructural analysis Microstructural analysis of both route materials was carried out. Tempered martensitic microstructure was observed for both route materials as shown in Fig. 9.

B

A

Fig. 9. Microstructure of (A) SF and (B) CR material

Fig. 10. Carbide distribution at lower hardness level A) CR B) SF