A Study On Rachetting And Fatigue Performance Of 16MnR Steel And Its Welding Joint

A series of uniaxial tensile tests and uniaxial cyclic tests were conducted on 16MnR steel. Comparisons of the uniaxial tensile stress strain curve and stress-strain hysteresis loop under different cyclic strain amplitude show that an obviously strain hardening effect occurs when 16MnR steel is subjected to cyclic loading.Uniaxial ratcheting characteristics of 16MnR at room temperature were studied experimentally. The effects of stress amplitude, mean stress, and loading history on the ratcheting behavior of 16MnR were analyzed, respectively. It can be concluded that the ratcheting strain amplitude and ratcheting strain rate of 16MnR steel increases with increasing stress amplitude or mean stress correspondingly. At the meantime, the loading history and loading sequence were found having significant influence on ratcheting strain.In addition, the low cycle fatigue behavior of 16MnR steel and its weld joints were also investigated under strain controlled uniaxial loading. A continuous load drop was observed during the test. A fatigue criterion of Coffin-Manson formula was adapted here to predict the fatigue life of 16MnR steel. Comparing strain controlled fatigue test and the ratcheting test with the same strain amplitude, it can be concluded that the cyclic accumulation of plastic strain will accelerate damage accumulation and significantly reduce the fatigue life of 16MnR steel.