Experimental study of type 316 stainless steel failure under LCF/TMF loading conditions

A detailed investigation of low cycle fatigue (LCF) and thermo-mechanical fatigue (TMF) of a 316FR type stainless steel is presented in this paper in order to identify the failure mechanism based on the experimental results and the subsequent metallography of the samples. The LCF-TMF servohydraulic testing with a temperature uniformity of less than +/- 5 degrees C within the gauge section of the specimens was employed to conduct the experimental tests. Fully-reversed, strain-controlled isothermal tests were conducted at 650 degrees C for the strain ranges of Delta(epsilon) = +/- 0.4%, +/- 0.8%, +/- 1.0% and +/- 1.2%. Strain-controlled in-phase (IP) thermo-mechanical fatigue tests were conducted on the same material and the temperature was cycled between 500 degrees C and 650 degrees C. Additionally, the creep-fatigue interactions were investigated with the introduction of symmetrical hold time under both LCF-TMF tests. The cyclic behaviour was further studied by performing microstructural investigations using the scanning electron microscope (SEM). (C) 2015 Elsevier Ltd. All rights reserved.