Effects of tensile hold time on low cycle fatigue behaviors in AISI 304L stainless steel base metal and weldment at 823K were investigated in Ar and $H_2$ gas atmosphere.
The weldment was prepared by the SMAW process as the welding direction was parallel to the rolling one. Total strain amplitude was controlled to be 1.0-2.5%, hold time at tensile peak strain was controlled to be 10 min.
The microstructures of the base metal and weldment are $\gamma$ phase and $\gamma$/$\delta$ -ferrite, respectively.
The experimental results indicate that there are no significant differences in fatigue behavior between the base metal and weldment under $H_2$ atmosphere whether they are tested under the condition of the continuous cycling or tensile hold time of 10 min.
However, the fatigue life of weldment is significantly decreased, when it is compared with the base metal, with decreasing the plastic strain amplitude. This is considered to be caused by the microstructural differences between the base metal and weldment.
The results of tensile peak strain hold of 10 min show the decreased fatigue life compared with that of continuous cycling. This is considered to be caused by crack growth during tensile hold time.
