Microstructural Features Controlling Ductile-to-Brittle Transition Behavior inHigh-Strength, Martensitic Steel Weld Metals

摘要

An investigation of the transition behavior of high strength steel, martensiticweld metals was conducted. The objective of the investigation was to identify the specific microstructural features that control ductile-brittle transition in these weld metals. The approach systematically combined experimental measurements and observations with the use of analytical expressions. Charpy V-notch (CVN) properties, tensile properties, and cleavage fracture stress (sigma c) were generated over a range of temperatures. The critical tensile stress criterion (CTSC) was applied in the form of a modified Griffith-Orowan expression. To establish the applicability of the CTSC to the transition regime, transition temperatures were predicted from sigma c measurements, and compared to measured CVN transition temperatures.