WELDING OF TUBE-TO-TUBE JOINTS BETWEEN MARTENSITIC AND AUSTENITIC STAINLESS-STEELS FOR REACTOR APPLICATIONS

Studies of the welding of tube-to-tube joints between dissimilar steels are described. The material combination was martensitic F6NM (0Cr13Ni4Mo) and austenitic AISI 347 stainless steels. Such joints are important parts in the primary circuit of a pressurized water reactor. A welding procedure was developed based on a series of weldability tests. The joints were subjected to various mechanical property tests including tensile test, bending test and impact test at various temperatures. A prototype product was made and subjected to pressure testing. Results of various tests indicated that the quality of the tube-to-tube joints is satisfactory for meeting all the design requirements. The joints can be used in the primary circuit of a pressurized water reactor.