Issue 35

X.C. Arnoult et alii, Frattura ed Integrità Strutturale, 35 (2016) 509-522; DOI: 10.3221/IGF-ESIS.35.57 513 shown that delamination cracks may have positive effect on the impact toughness properties if their number is relatively low. Fracture surface of specimens from plate of HSLA steels which underwent a tempering step [6] and were tested at room temperature did not display any delamination cracks, unlike those tested at -30°C (cf. Table 2 and Figure 5). Tempering Temperature, °C CVN Impact Energy, J Delamination cracks As-rolled 56 No 200 60 No 300 50 No 400 51 Small and Local 500 47 Large and Global 550 45 Large and Global 575 49 Large and Global 600 50 Large and Global 625 53 Large and Global 650 49 Large and Global 700 55 Small and Local Table 2 : Charpy Impact Toughness of tempered specimens and tested at -30°C [6]. Figure 5 : SEM picture of fracture surface of Charpy specimens tempered at 200°C a) , 400°C b) , 500°C c) , 600°C d) and tested at - 30°C.