Impact of temperature and exploitation time on plane strain fracture toughness, k-ic, in a welded joint

Abstract

This paper presents the analysis of the impact of temperature and exploitation time on the tendency toward brittle fracture of welded joint constituents of new and exploited low-alloyed Cr-Mo steel A-387 Gr. B, by using fracture mechanics parameters. The exploited parent metal is a part of the reactor mantle which has been in service for over 40 years and is in the damage repair stage, i.e. in the stage where a part of the mantle is being replaced with new material. Testing of the fracture toughness at plane strain is done in order to determine critical value of stress intensity factor, K-Ic, i.e. evaluation of behaviour of new and exploited parent metal (PM), weld metal (WM) and heat affected zone (HAZ). Based on the testing results, the analysis of tendency to brittle fracture represents the comparison of the obtained values for characteristic areas of the welded joint and the justification of selected welding technology.