Volume 19, Issue 4 (July 1991)
Electrical Resistance Measurements on Type 304 Stainless Steel with Different Degrees of Sensitization
Most of the test methods commonly used to evaluate the susceptibility of austenitic stainless steels to intergranular attack are qualitative and destructive in nature. Practice A of ASTM Standard A 262 and the EPR tests are nondestructive but are less discriminating for higher degrees of sensitization. Because the sensitized material contains chromium-rich carbides at grain boundaries and chromium depletion zones at and adjacent to the grain boundaries compared with uniform structure in the solution annealed material, there is a need for a nondestructive test method using electrical resistance, eddy current, ultrasonic testing, or magnetic susceptibility. Testing methods based on eddy currents and ultrasonics are reported to be insensitive to the degree of sensitization. In this study an attempt is made to measure the electrical resistance for Type 304 stainless steel (SS) with various degrees of sensitization. The results indicated no correlation between the electrical resistance measurements and the degree of sensitization for Type 304 SS.