STS 316L의 sub-zero 및 역변태 온도에 따르는 탄성파 특성

Abstract

This study investigated the mechanical properties and excellent elastic wave frequencies of STS316L at different sub-zero temperatures and reverse transformation temperatures. As the rolling degree increased, austenite decreased and martensite increased. The martensite volume fraction increased as the temperature decreased, but rapidly increased at a rolling degree of 50%. The tensile strength increased rapidly as the rolling degree increased, and the increase was greater at lower temperatures. The elongation decreased sharply until the rolling degree was 33%, but decreased slowely thereafter. The dominant frequency appeared higher with an increase in rolling degree at each rolling temperature, and the dominant frequency at the low-temperature rolling temperature was higher than that at the high-temperature rolling temperature. The dominant frequency appeared higher as the martensite volume fraction increased, but a higher dominant frequency appeared at low roling temperatures. The dominant frequency was higher at each rolling degree as the sub-zero temperature was lower and the sub-zero time was longer. The dominant frequency decreased and then increased as the reverse transformation temperature and time increased. This is because during cold rolling, the grains have different directions at low temperatures, and have the same direction at high temperatures.