PSI - Issue 54

Paulo Mendes et al. / Procedia Structural Integrity 54 (2024) 340–353 Mendes et al. / Structural Integrity Procedia 00 (2023) 000–000

348

9

10 µm

10 µm

a)

b)

25 µm

50 µm

c) d) Fig. 9. Microstructure from the: a) Heat-a ff ected zone close to the fusion zone (100 × ); b) Intermediate heat-a ff ected zone (100 × ); c) Heat-a ff ected zone farther of the fusion zone (50 × ); d) Base material (20 × ).

Base material

Weld

HAZ heated to intercritical temperatures

4

3

2

T max = 900 ºC T max = 700 ºC T max = 600 ºC Coarse-grained HAZ Fine-grained HAZ

1

Fusion line T max = 1150 ºC

Fig. 10. Schematic representation of the heat-a ff ected sub-zones, adapted from Ferreira et al. (2018).

the literature. It is expected that the hardness increases with a more refined grain size. The results of the microhardness tests performed across the sub-zones are presented in Figure 11. The morphology and grain size have a significant impact on hardness, as evident from Figure 11. The hardness values of martensite with a coarser grain size (zone 1) are clearly lower than those of martensite with a finer grain