EFFECT OF PRESTRESSING ON THE STRESS-CORROSION RESISTANCE OF TWO HIGH- STRENGTH STEELS
BOEING CO RENTON WA COMMERCIAL AIRPLANE GROUP
Pagination or Media Count:
Precracked, single-edge-notched specimens of 4340 steel 194-ksi yield strength and 18 Ni maraging 300 steel were prestressed in laboratory air to various percentages 0 to 90 of K sub Ic and then unloaded. The times to failure were subsequently determined in 3.5 aqueous NaCl solution as a function of initial stress intensity. Prestressing increased the threshold stress intensity K sub Iscc of the 4340 steel, but had only a slight effect on the K sub Iscc of the maraging steel. The times to failure of both steels at initial stress-intensity levels above K sub Iscc were unaffected by prestress. The prestressing effects are attributed to the presence of compressive stresses at the crack tip.
- Properties of Metals and Alloys