Accession Number : AD0683061

Title :   DETERMINATION OF RESIDUAL STRESS PROFILES BY X-RAY DIFFRACTION AND STRAIN GAGE METHODS FOR BRAKE-PRESS FORMED Ti-6Al-4V,

Corporate Author : BOEING CO RENTON WASH COMMERCIAL AIRPLANE DIV

Personal Author(s) : Esquivel,A. L.

Report Date : 09 DEC 1968

Pagination or Media Count : 41

Abstract : The residual stress profiles (stress versus depth) from brake-press formed Ti-6Al-4V (annealed) right angle bends were determined by the two-exposure X-ray diffraction method and a stress relaxation strain gage method using either continuous or stepwise (incremental) chem-milling. Results from the strain gage method were tested on four available stress formulations. The Haigh equation (computer program: NORS) was found most suitable and is recommended for future use. A reasonable correspondence was found between the residual stresses calculated from X-ray peak shift data and those from strain gage data. Residual stresses obtained by the strain gage method utilizing chem-milling were found reproducible to within 3 to 5 ksi. Residual stress profiles of the brake-press formed bends indicate compressive stress (-30 ksi) near the outside bend surface and tensile stresses (40 to 50 ksi) on the inside bend surface. Depth of the compressive stresses varied from 0.008 to 0.012 inch. No significant differences were found between the residual stress profiles of bends 0.045-inch thick and those 0.050-inch thick. (Author)

Descriptors :   (*TITANIUM ALLOYS, STRESSES), (*NONDESTRUCTIVE TESTING, TITANIUM ALLOYS), X RAY DIFFRACTION, STRAIN GAGES, COLD WORKING, STRESS RELIEVING, CHEMICAL MILLING, METAL FORMING BRAKES

Subject Categories : Metallurgy and Metallography
      Fabrication Metallurgy

Distribution Statement : APPROVED FOR PUBLIC RELEASE