Abstract
In this study, the low cycle fatigue tests of S30408 austenitic stainless steel with a strain ratio of −1 were conducted at 110 K, and the corresponding 110 K cryogenic design fatigue curve (S-N curve) was established. The experimental results demonstrate that within the strain amplitude range of 0.4%-0.8%, the fatigue life of S30408 at 110 K is significantly improved compared to that at 293 K, and the fatigue properties exhibit notable differences.
The cyclic stress response under 0.5% strain amplitude at 110 K exhibits three distinct stages: rapid cyclic hardening, cyclic stabilization, and rapid decline, thus featuring a cyclic stabilization phase and a higher cyclic stress amplitude than that at 293 K. Microscopic analysis reveals that the fatigue fracture at 110 K displays distinct ductile fracture characteristics, while under the high strain amplitude, it further exhibits multiple crack sources, fatigue steps, and secondary cracks in the crack initiation region. Based on the experimental data from this study and relevant literature, the 110 K cryogenic S-N curve for austenitic stainless steels was established with a fatigue life safety factor of 20 and a stress amplitude safety factor of 2.
Compared with the S-N curves specified in ASME VIII-2 and EN 13445–3, the 110 K cryogenic S-N curve exhibits a higher stress amplitude when the number of cycles exceeds 103. Within the typical fatigue life range of pressure vessels (103 to 106 cycles), it can significantly extend the service life of cryogenic pressure vessels.
Visit Us: https://metallurgyaward.com/
Comments
Post a Comment