| Austenitic stainless steels are widely used for mobile tanker.304 stainless steel is an austenitic steel extensively used for various applications due to a good combination of strength and ductility and relative low cost.It is predictable to be metastable by way of the austenite phase can transform into martensite under stress.This work reports the low cycle fatigue behavior of a 304 stainless steel under different pre-strain at room temperature Strain reinforcement is a common way to realize the lightweight of austenitic stainless steel pressure vessel.However,the fatigue behavior of austenitic stainless steel after strain reinforcement is not studied systematically.The low cycle fatigue property of strain reinforcement 304 austenitic stainless steel was studied.Pretorsion tests under 0,3%,5%,8%,10%,and 15% for 304 stainless steel were conducted,following strain-controlled fatigue tests under 0.4% strain amplitude.The result showed that different cyclic stress responses were observed for different pretorsions samples.There are cyclic hardening,softening and second hardening during fatigue cyclic loading.Dislocation,martensitic transformation et al.deformation mechanisms accounted for the difference of cyclic stress response among various pretorsions.The influence of fatigue tests on the austenite and martensite content was analyzed.The fatigue life decreased with the increase of pre-torsion degree.Fatigue tests display strong influence of the pre-strains to the fatigue life.However,the effect of pre-strain on fatigue behavior in type 304 stainless steel,which may undergo workhardening and martensitic transformation,is unclear.Not only work hardening but also martensitic transformation due to pre-strain is seen in type 304 stainless steel.In this study,industrial low-temperature Strain control of different Pre-torsional Strain for low cycle fatigue were performed on 304 austenitic stainless steels. |
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