FRICTION WELDING OF 20MnMoNi55 RPV STEEL - SS 304 BIMETALLIC WELD JOINTS FOR NUCLEAR APPLICATIONS

摘要

The use of Reactor Pressure Vessel (RPV) steel 20MnMoNi55 and Stainless Steel 304 bimetallic weld joint is inevitable in pressurized water reactor systems. This bimetallic weld joint is a critical component from the safety point of view in the nuclear power plant. The joining of RPV steel-Stainless steel is usually carried out using conventional arc welding processes. Arc welding processes generally used are Submerged arc welding, Manual metal arc welding, Tungsten inert gas welding and Metal inert gas welding. Friction welding provides a new and unique solid state approach for joining without adding any external filler metal. This approach is particularly useful in joining of dissimilar welds. The reason for increased utility being the absence of any external filler material which may otherwise add to the heterogeneity of the weld structure. This research paper discusses the fabrication and mechanical-micro structural characterization of bimetallic weld joints fabricated using friction welding approach. The effect of friction welding parameters on the strength of the bimetallic weld joints has been investigated. An attempt has been made to relate the micro-structural and macro-scopic behavior of the friction welded bimetallic weld joints with the variation in friction welding process parameters.