Abstract
Effect of temperature and exploitation time on resistance to brittle fracture of welded joint constituents of new and 40 years exploited low-alloyed Cr-Mo steel A-387 Gr. B has been analysed. The plane strain fracture toughness is used as the measure of resistance to brittle fracture of base metal, weld metal and heat affected zone from both new and exploited. The stress-strain curves have been determined as well, to get better inside in welded joint behavior. Comparison of the results indicate detrimental effect of both temperature and exploitation time, both for tensile properties and for the resistance to brittle fracture.