Fracture Toughness of Welded Low Alloy Steels

Investigation of the fracture toughness, expressed as the J-integral, of the heat-affected zone of three welded low alloy steels show that the addition of niobium increases toughness. However for an alloy containing niobium and molybdenum, there is a marked decrease in toughness. Electron microscopy of replicas of the heat affected zone reveals a decrease in the number of carbide precipitates for the Nb + Mo steel. Fracture toughness is related …