Cyclic Deformation Behavior of Type 316LN Stainless Steel under Low Cycle Fatigue Loading in 310°C Low Oxygen Water

摘要

Low cycle fatigue tests of type 316LN stainless steel were carried out with various strain amplitudes and stain rates in 310 °C low oxygen water. The material underwent a primary hardening, and a moderate softening for all strain rates. The hardening was associated with the dynamic strain aging. At the strain amplitude of 0.4 %, secondary hardening was observed at the strain rate range from 0.04 to 0.4 %/s. The secondary hardening can be related to the development of tangled dislocation substructure. On the other hand, the fatigue life of the material in 310 °C low oxygen water was shorter than that of the ANL statistical model in air. The reduction of fatigue life was more pronounced as strain rates decreased from 0.4 to 0.008 %/s. The shorter fatigue life was interpreted in terms of the dynamic strain aging and low oxygen in the water.