Clearance corrosion test method for metal materials

摘要

PROBLEM TO BE SOLVED: To provide a crevice corrosion test method for preventing corrosion of a portion other than an evaluation target portion in a crevice corrosion test of a metal material. SOLUTION: A crevice corrosion test method in which a non-woven fabric 7 made of an insulator having the characteristics described in the following (1) to (3) is sandwiched in a crevice other than a portion to be evaluated to prevent crevice corrosion in the portion. (1) When the nonwoven fabric 7 is pressed down to a gap other than the evaluation target portion at a pressure of 140 MPa or less, the distance between the metal material test piece and the outer peripheral portion of the contact portion of the member forming the gap is 10 μm or more. Is secured. (2) The non-woven fabric 7 has a Cl-elution amount of 1.0 × 10-8 g / cm2 or less when boiled in pure water for 24 hours. (3) The non-woven fabric 7 retains the characteristics of (1) described above after performing the operation of "inserting this non-woven fabric in a gap other than the evaluation target portion, reducing the pressure at 140 MPa or less, and then releasing the pressure" twice. do. [Selection diagram] Fig. 2