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.

The effects of interrelated factors such as microstructure and composition on the mechanical properties of as-deposited and stress-relieved weld metals are described in this report. Factors such as welding procedures, welding processes and positions, and post weld heat treatments that also influence weld properties are discussed. Descriptive and tabulated information about current pressure vessel steel and weld metal properties are presented, along with a discussion of weld metal problems that limit the potential uses of pressure vessel steels. Recommendations for work needed to resolve these problem areas are outlined.