An apparatus is described that is used to meas ure the heat conduction t hrough ins ulating s upports of storage vessels for cryogenic liquids and presents the data obtained from the cond uc t io n measureme nts. Two types of supports were tested: (1) multiple-contact supports in the form of stacks of thin meta llic p lates or spirally wound strips, a nd (2) nonm etallic spheres. The high t herm al resista nce of the multiple-contact supports ari ses from the numerou s r elatively poor contacts between the individual plates. Some special treatments of the plates were tried, and two of these, p erforating and dusting, Kere found to be effective. Pyrex-glass spheres were also found to be excell ent insulators, but, of course, a re not a s rugged as a stack of m etal plates. Of t he un treated plates tested, t hose of stainless steel (0.0008 in ch thi ck) we re found to be the best insulators per unit length of stack. Th e heat conduction through these p lates, at a load press ure of 1,000 pound s per squ ar e inch , was found to be 2 pe rcent of t he conduction by a solid sample of th e same metal having the sam e dimensions.
Fracture toughness tests over the interval 298 to 4 K and fatigue crack growth rate tests at 298, 111, and 76 K are reported on selected iron-nickel (Fe-Ni) alloys which are commercially available for potential use in storage or transportation of liquefied natural gas (LNG). These alloys include Fe-6Ni and Fe-5Ni in newly developed three-step heat treatments and Fe-9Ni in the quenched and tempered condition. Linear elastic fracture mechanics parameters (KQ, KIC) and J-integral (JIC) test data are presented for 1.25-in.-thick compact specimens. Discussion includes comparisons of fatigue crack growth rate and fracture data between alloys.
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