The solution chemistry in cuneiform crevice of 316L stainless steel was studied in 3.5%NaCl at room temperature.The Cl
-was concentrated and PH value decreased in the cuneiform crevice with two sizes of crevice opening. When the crevice opening is 1.36mm,the Cl
-concentration increased and PH value decreased with time and the distrance from the opening. The highest Cl
-concentration is 1.6mol/l and the lowest PH value is 5.01.When the opening is 0.22mm, the highest Cl
- is 1.1 mol/l and the lowest PH value is 3.1.The very low PH value in the crevice was formed by the hydrolysis of dissolving metal ions and Cl
-. The chloride can be very concentrated in the crevice. even be saturated.