This study by Gourav Rao investigates the tensile properties of dissimilar metal weld joints (DMWJ) between modified 9Cr-1Mo ferritic steel (P91) and 316LN stainless steel (SS 316LN), which are used in liquid metal-cooled fast breeder reactors (LMFBR).

Material Selection and Joint:

• P91 steel is preferred in steam generators due to its creep resistance and resistance to stress corrosion cracking.
• SS 316LN is used in piping systems due to its excellent oxidation resistance and superior creep strength.
• The joint between these two materials is made using nickel-based filler materials such as Alloy 82 and Alloy 182.

Temperature and Mechanical Properties:

• The mechanical properties of the DMWJ were evaluated at room temperature (RT) and 550°C.
• Tensile tests showed heterogeneous mechanical properties across the DMWJ. Specifically, the tensile properties at high temperature (550°C) were significantly lower compared to the values at RT.

Microstructural Effects:

• The complex microstructures developed in the joint regions contributed to changes in mechanical properties.
• Microstructure and microhardness analyses provided a detailed understanding of these changes.

This study provides valuable insights into the reliability and integrity of DMWJ connections operating at high temperatures.

For a detailed review, you can access the related study here.