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Abnormal grain growth in M-252 and S-816 alloys

Description: An experimental investigation was carried out on air- and vacuum-melted M-252 and S-816 alloys to find conditions of heating and hot-working which resulted in abnormal grain growth. The experiments were mainly limited to normal conditions of heating for hot-working and heat treatment and normal temperatures of solution treatment were used to allow grain growth after susceptibility to abnormal grain growth was developed by various experimental conditions. Results indicated that small reductions of essentially strain-free metal were the basic cause of such grain growth.
Date: November 1957
Creator: Decker, R F; Rush, A I; Dano, A G & Freeman, J W
Item Type: Report
Partner: UNT Libraries Government Documents Department

Summary of the Spert-I, -II, and -III reactor facilities

Description: Report containing "[a] brief description and design data summary of each of the SPERT Reactor Facilities is presented. Engineering, operating, and physics data are tabulated for use as basic references" (p. 3)
Date: November 1, 1957
Creator: Montgomery, C. R.; Norberg, J. A. & Wilson, T. R.
Item Type: Report
Partner: UNT Libraries Government Documents Department

Surge-Inception Study in a Two-Spool Turbojet Engine, Revised

Description: A two-spool turbojet engine was operated in the Lewis altitude wind tunnel to study the inception of compressor surge. In addition to the usual steady-state pressure and temperature measurements, the compressors were extensively instrumented with fast-response interstage pressure transducers. Thus it was possible to obtain maps for both compressors, pressure oscillations during rotating stall, effects of stall on efficiency, and stage-loading curves. In addition, with the transient measurements, it was possible to record interstage pressures and then compute stage performance during accelerations to the stall limit. Rotating stall was found to exist at low speeds in the outer spool. Although the stall arose from poor flow conditions at the inlet-stage blade tips, the low-energy air moved through the machine from the tip at the inlet to the outer spool to the hub at the inlet to the inner spool. This tip stall ultimately resulted in compressor surge in the mid-speed region, and necessitated inter-compressor air bleed. Interstage pressure measurements during acceleration to the compressor stall limit indicated that rotating stall was not a necessary condition for compressor surge and that, at the critical stall point, the circumferential interstage pressure distribution was uniform. The exit-stage group of the inner spool was first t o stall; then, the stages upstream stalled in succession until the inlet stage of the outer spool was stalled. With a sufficiently high fuel rate, the process repeated with a cycle time of about 0.1 second. It was possible to construct reproducible stage stall lines as a function of compressor speed from the stage stall points of several such compressor surges. This transient stall line was checked by computing the stall line from a steady-state stage-loading curve. Good agreement between the stage stall lines was obtained by these two methods.
Date: November 7, 1957
Creator: Wallner, Lewis E.; Lubick, Robert J. & Saari, Martin J.
Item Type: Report
Partner: UNT Libraries Government Documents Department