질소를 첨가한 316L 스테인리스 강의 고온 저주기 피로균열 생성 = Mechanical Behavior:Nueleation of Low Cycle Fatigue Crack at High Temperature in Nitrogen Alloyed Type 316L Stainless Steel

다국어 초록 (Multilingual Abstract)

The effect of nitrogen on the nucleation of a low cycle fatigue (LCF) crack was studied at high temperature using type 316L stainless steel with different nitrogen contents (0.04-0.15%). Strain-controlled LCF tests were conducted in the temperature range of R.T. ∼600℃ and in air. The waveform of LCF was a symmetrical triangular with a total strain amplitude of 1.0% and in a constant strain rate of 2×10^(-3)/s for all tests. The sites for crack nucleation, crack population, and crack depth from the surface of the specimens were measured after LCF testing up to 40% of fatigue life. The preferred sites for crack nucleation were grain boundaries, but some of cracks also nucleated at twin boundaries and slip bands. Crack population on the surface of the specimen decreased but the maximum depth of the crack from the surface of the specimen did not change with the addition of nitrogen at high temperatures. The cycles for the nucleation (100㎛) of LCF crack increased with the addition of nitrogen. So, the increase of LCF life with the addition of nitrogen at high temperatures may be explained by the fact that nitrogen increases the resistance of crack nucleation.

목차 (Table of Contents)

• 1. 서론
• 2. 실험방법
• 3. 실험결과 및 고찰
• 피로균열의 생성장소
• 피로균열의 크기분포
• 균열의 깊이변화
• 4. 결론
• 후기