Suppose you have a 4340 steel plate in fully reversed axial loading . The plate is 1⁄4” thick, 2” high, and 5” long. The bar is machined, with factor a = 2.70 ksi and exponent b = -0.265. The bar is operating at 600 degrees F. The program required reliability is 99.99.

What is the fully adjusted endurance limit of this bar?