Seven Years of Uranium Alloy Development at Weldon Spring, 1959/1966. Page: 23 of 47
This report is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided to Digital Library by the UNT Libraries Government Documents Department.
The following text was automatically extracted from the image on this page using optical character recognition software:
* . . .. . **. .. 0t S
beta-quenched sample at 1000*F. and then beta heat treating once more no matter
what the structure was prior to the first beta treatment quoted in this -sequence.
Similarly, a coarse grained structure could always be obtained by a high alpha
anneal and then beta treating once more, again entirely independently of the
heat treating history and grain size in earlier cycles.
This concept of grain size control gave rise to very interesting speculations
concerning the possibility of refinement of a coarse grain structure derived
from cooling from the gamma phase. This was a possibility of specific interest
at Weldon Spring since the addition of alloys to uranium had been observed to
stiffen the metal to the degree where some alloys desired by the reactor sites
could no longer be extruded in the alpha phase in the Weldon Spring press. By
going to the gamma phase, however, with its much softer condition, extrusion
would be possible at any contemplated alloy level provided the structure could
later be suitably refined. This was explored with a quantity of gamma-extruded
rods which were subsequently alpha annealed at 950*F. for four hours and then
given a standard beta heat treatment.l1,13 Included in-the array of specimens
were both alloyed and unalloyed dingot uranium. In the as-extruded condition,
both the alloyed and the pure uranium had similar coarse grained structures.
Samples given a standard beta heat treatment following gamma extrusion showed a
much finer grain size for the alloyed uranium. The addition of the intervening
anneal at 950*F. - 1000 F. resulted in a very fine grain size for the alloyed
uranium, confirming the basic effectiveness of the precipitate system introduced
by an appropriate additive.
These data immediately suggested the possibility of controlled refinement of
as-cast uranium structures in massive shapes such as extrusion billets. Hereto-
fore, billets for the Hanford N-Reactor fuel had been cast ,as U1-inch-diameter
ingots which were alpha extruded to approximately 7-inch-diameter bar stock for
subsequent machining and co-extrusion to clad N-fuel sizes. The primary alpha
extrusion had offered a modicum of grain refinement but, since the reduction
ratio was small and the amount of mechanical working in extrusion varies
considerably between the lead end, the middle, and the-tail, it had been less
effective than might be desired.
Billets cast for extrusion to Savannah River tubes (such as Mark VB-OF)-had
been subjected to a triple beta heat treatment in an effort to refine the as-cast
structure. This was successful in eliminating the as-cast grain size, but the
beta-quenched structure was not necessarily so fine as would be wished
To test the effectiveness of a precipitate system on heavy section, a'dingot
containing 140 ppm Fe and 100 ppm Si was gamma-extruded to 7-inch-O.D. bar
stock and machined to a simulated billet for N-outer fuel, 6-3/4-inches O .D by
2-3/4-inches I.D.12 Sections of this shape were alpha annealed at 9500Fo for
both 20 and 100 hours and then beta heat treated at temperatures such as 1350
and 1400"F. Portions of the billets were quenched into brine at 650 to 8o0F.i
and the remainder were quenched in oil at 80*F. The micrographs revealed that
Here’s what’s next.
This report can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Report.
Fellows, J. A. Seven Years of Uranium Alloy Development at Weldon Spring, 1959/1966., report, January 1, 1966; Weldon Spring, Missouri. (https://digital.library.unt.edu/ark:/67531/metadc1033773/m1/23/: accessed March 24, 2019), University of North Texas Libraries, Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.