Low cycle fatigue behavior of high strength gun steels

Maoqiu Wang;Han Dong;Qi Wang;Changgang Fan Division of Structural Materials, Central Iron & Steel Research Institute, Beijing 100081, China

摘 要：<正> The low cycle fatigue （LCF） behavior of two high strength steels, with norminal chemical compositions （mass fraction, %）of 0.40C- 1.5Cr-3Ni-0.4Mo-0.2V （PCrNi3MoV） and 0.25C -3Cr- 3Mo-0.8Ni -0.1Nb （25Cr3Mo3NiNb）, was investigated by using thesmooth bar specimens subjected to strained-controlled push-pull loading. It is found that both steels show cyclic softening, but25Cr3Mo3NiNb steel has a lower tendency to cyclic softening. 25Cr3Mo3NiNb steel has higher fatigue ductility, and its transitionfatigue life is almost three times that of PCrNi3MoV. 25Cr3Mo3NiNb steel also shows higher LCF life either at a given total strainamplitude above 0.5% or at any given plastic strain amplitude, despite its lower monotonic tensile strength than that of PCrNi3MoV.It also means that 25Cr3Mo3NiNb steel can endure higher total strain amplitude and plastic strain amplitude at a given number ofreversals to failure within 10⁴. 25Cr3Mo3NiNb steel is expected to be a good gun steel with high LCF properties because only sever-

关键词：