Study on low cycle fatigue of ferritic-martensitic steel at high temperature

Abstract

In 2011, a serious nuclear accident occurred in Fukushima, Japan, and one of the major causes was the destruction of the cladding material mainly made of Zr alloy due to a violent chemical reaction with high-temperature water vapor. Since then, scholars in various countries have been trying to find a better nuclear fuel cladding material. Because of its high temperature strength, ferritic/martensitic(F/M) steel is used in thermal power units. Over the past hundred years, the high temperature performance of ferritic/martensitic steel has developed simultaneously with the operating temperature of thermal power system. F/M steel is widely used in nuclear power system as well as thermal power, The fatigue life of nuclear fuel cladding material is an important parameter to study its service life, due to the special shape of the cladding material, especially for the pipe with a thickness of less than 0.5mm, it is difficult to directly measure its mechanical properties, this paper through special experimental materials and fixtures F/M pipe steel at room temperature and high temperature tensile test, as well as low cycle fatigue performance test, and its fracture port, surface crack analysis. Through the analysis and processing of experimental data, typical stress-cycle life curves, total strain amplitude-life curves, elastic strain amplitude-life curves, hysteresis curves with different strain amplitudes, and fatigue life prediction curves were obtained.