Correlation of Energy, Deformation and Fractographic Parameters of Microalloyed Steel Welded Joint Fracture

Toughness is a complex material characteristic that is viewed from multiple aspects and is influenced by numerous factors. It is very important to have ability to assess toughness, i.e. to determine ductile or brittle material behaviour at any specific time. Beside total impact energy obtained at Charpy instrumented pendulum, the use of additional parameters such as lateral extension measurements and fractographic evaluation of fractured specimens reveals more information of the fracture mechanisms. In this paper, microalloyed steel is welded by MMA process and Charpy specimens were cut from base metal, HAZ and weld metal. The total impact energy at room and lower temperatures, lateral extension of specimens after fracture and fractography of fracture surface were estimeted. The comparasion of all considered parameters enables assessment of welded joint susceptibility to brittle fracture and potential sites of fracture occurrence.