Aluminum to Stainless-Steel Joints for Cryogenic Applications

Aluminum to stainless-steel joints are necessary for cryogenic applications such as cryogenic fluid management and combustion devices. Supplemental development in this area was required for a test program at NASA Marshall Space Flight Center (MSFC) of an Al6061-RAM2 additively manufacturing liquid rocket nozzle. The test program identified a risk for installing stainless-steel fluid fittings to aluminum manifolds. To address this, a literature search was completed for various joint designs, and three designs were down selected to be cryogenic pressure cycle tested at MSFC. The test pieces were subsequently burst tested with ambient temperature water. This paper provides an overview of the literature review, down selected designs, test setup, test results, and fractography. The test results informed design decisions for the Al6061-RAM2 nozzle, and the recommended design proved to be a robust option with no notable issues identified during hot-fire testing.