EFFECT OF THERMAL CYCLING ON MECHANICAL BEHAVIOUR OF BIMETALLIC WELDS

Abstract

Fabrication procedures require the application of welding processes in the construction of nuclear power plants and components. It is generally recognized that the mechanical and physical properties of a weldment can differ significantly from those of a base metal with a similar chemical composition. Further, the zones within a weldment (base metal, heat affected zone, and fusion zone) can vary even more significantly than the gross base metal weld ment differences would imply. There is a dearth of design oriented information regarding the behavior of the various zones of a weld ment. The metallurgical and structural complexity of welds tends to deter the behavior of weldments. The used of welded, construction for nuclear plants at elevated . temperatures, where time dependent deformation can occur under possibly novel service condition. Better understanding of the behavior of welds may contribute to confidence in the conservative nature of design practice or tightening of safety factors. The scope of this report is to study of mechanical behavior, microstructural evolution in bimetallic welds undergoing thermal cycling. The effect of temperature range, cycle time and number of cycles would be the varying parameters. We intended to summarize the understanding of weld behavior that may be applicable in the design of welded components for nuclearpower plant systems