Abstract:
A creep testing system has been designed, fabricated, installed and validated for carrying out creep tests
in flowing liquid sodium. The testing system consists of two sections namely creep testing machine and
an environmental chamber. The testing system has the ability of (i) applying tensile load to the test
specimen through a lever, (ii) monitoring continuously the creep elongation and (iii) allowing sodium
to flow around the creep specimen at constant velocity. The annular space between the creep specimen
and the environmental chamber has been suitably designed to maintain constant sodium flow velocity.
Primary and secondary bellows are employed in the environmental chamber to (i) mechanically isolate
the creep specimen, (ii) prevent the flowing sodium in contact with air and (iii) maintain an argon gas
cover to the leaking sodium if any from primary bellow, with a provision to an alarm get activated by
a spark plug. The lever-horizontality during creep test has been maintained by automatically lifting up
the fulcrum instead of lowering down the pull rod as conventionally used. A mini lever mechanism has
been incorporated in the load train to counter balance the load reduction on specimen from the changing
stiffness of the bellows. The validation of the testing system has been established by carrying out creep
tests on 316L(N) stainless steel at 873 K over a wide stress range and comparing the results with those
obtained in air by employing the developed and conventional creep testing machines.
