The influence of stored energy on crack arrest of BS 4360 50B structural steel

Dynamic crack initiation in BS 4360 50B steel specimens has been achieved by testing the steel with a brittle superimposed Hardex 450 weld bead. The effect of this brittle weld has been shown to move the ductile-brittle transition temperature for the underlying steel from conventional values of approximately −60°C to higher values of the order of −35 to −40°C. The extent by which the transition temperature is raised is shown to be dependent upon the stored energy present in the tested structure. The results confirm that the problem of arresting a running crack in structural steels is not solely a property of the material under test but depends upon the total strain energy stored in the system.