The chemical composition of the solution used in this test is as follows: 4 percent NaCl + 0.1 percent Fe₂(SO₄)₃+0.01 M HCl. This solution contains 24,300 ppm chlorides and is acidic (pH₂). In both pitting and crevice corrosion testing, the solution temperature was varied in 5 deg. C increments to determine the lowest temperature at which pitting corrosion initiated (observed by examination at a magnification of 40X) after a 24-hour exposure period (Critical Pitting Temperature), and the lowest temperature at which crevice corrosion initiated in a 100-hour exposure period (Critical Crevice-Corrosion Temperature).