Inconel 690 is an alloy mainly used for heat transfer tube materials of steam generators in pressurized water reactor nuclear power plants. It is the core technology of steam generators.

Alloy 690 has excellent resistance to intergranular corrosion and intergranular stress corrosion cracking, and is mainly used as a heat transfer tube material for steam generators in pressurized water reactor nuclear power plants.

The materials used for the heat transfer tube of the steam generator of the PWR nuclear power plant have gone through a development process, including 304 austenitic stainless steel, 600 alloy, 800 alloy and 690 alloy.

Research on corrosion failure of 600 alloy in service shows that intergranular corrosion and intergranular stress corrosion cracking are the main problems.

Alloy 690 is used as the heat transfer tube material of the steam generator of the PWR nuclear power plant. Since it was put into use in the 1990s, no damage has been reported.

Chemical Composition %
     Ni           Cr        Fe        C        Al       Ti       Mn     Si       Cu        P           S
Balance    30.39    8.88    0.023   0.22   0.26   0.23   0.07   0.02   0.006    0.002

The physical and mechanical properties of annealed 690 alloy.

Density            Melting      Young's modulus    Poisson's ratio     Yield strength    Tensile strength   Elongation
8.19g/cm    1343-1377°C           211GPa              0.289                  350MPa              700MPa               45%