No abstract

AIlo\' 7 18 bolts were ~nicrostri~ctiii.;~Ily examined follo~i,ing thermal exposures of \,arying times at 538°C and 650°C. For an exposuse of 1300 hours at 538°C. the presence of alpha-Cr psecipitatc was obsei-\,ed in the highly worked u e a of the thread root, but \vas not found in the shank body. For an esposure time of 3300 hours at 650cC, the alpha-Cr phase uras obsesved in both the thread root and shank body. Residual strain from cold ~vorli appears to accelerate the fosmation of alpha-Ct-phase. The alpha-Cr phase is found to precipitate at the y-delta phase intesface. at grain boundaries, and in heavily defor~ned areas.

Computer software package routine in another BASIC program could be structured as several "CHAIN" statements, where the appropriate program is chained based on a menu option number and an "ON var GOTO" statement. The following schematized drawing (Fig. I) illustrates a driver program in the software package, including such an operating system.The data structures of the set of values of the operating conditions of the RGA and the set of peak height values were chosen so that the data is uniquely identified and grouped together. One set of peak values in a scan is associated in computer memory with the set of operating conditions of the RGA for that scan, and with the time and date at which the peak data was acquired from the instrument. While in computer memory, the same set of RGA data may be handily referred to by any of the software package's data manipulation routines, mass storage devices, and/or display devices.The virtues in treating the data as a set which then may be identified by an identification number for this data set and may be treated by a variety of devices and programs, is ease of reference, data base compatibility of the data used by any operation and device, and automatic association of a set of peak value data with the RGA conditions under which it was originally acquired.

The threshold fatigue crack gzo-vtrr "e L L havior of Inconel 718 forging was investigated from room temperature to lOOOF. For a fine grain condition (ASTM 10 or finer), the measured thresholds were insensitive to prior forging processing history, For a given florging/heat treat practice, the nec%ured threshold stress intensities increased with increasing temperature. This temperature effect bsceme more prlonounced with decreasing grain size. The measured threshold stress intensities appear to be related to grain site (or strength level); at a given temperature, the largest value of threshold stress intensity was obtained for the coerse grain materiel (ASTM grain size 3). This grain size (or strength level) effect was greatest at low temperature, and dtiinlshed with increasing temperature.