Historically, the properties of some weld metals have been inferior to those of the steels that they joined.The problem still exists for certain pressure vessel weldments currently being fabricated.As a result, it has not been possible to use some pressure vessel steels for certain desirable applications.Numerous technical and economic factors influence weld metal properties, but these factors are often less appreciated and understood than those associated with the behavior of their base plates.The Fabrication Division of the Pressure Vessel Research Committee recognized the need for more clarification of factors that control weld properties.Further, the Division expressed interest in a current definition of the weld metal problems that restrict the full applicability of pressure vessel steels.This report was written to satisfy these needs.