The results of experimental tests of 10MgNi2MoV steel samples for low-cycle fatigue at various deformation rates in air and in distilled water at a temperature of 280 °C in a rigid loading mode with a symmetrical change in the range of elastic-plastic deformations are presented.
Since it is technically difficult to create real operating conditions for the material of a nuclear reactor vessel and a steam generator in laboratory conditions, the authors of the article created testing equipment. The results of experimental tests have shown that high-temperature distilled water significantly reduces the durability of steel than air.
The composition of the water has a great influence; it has been found that neutral water is less damaging than water with high acidity. Distilled water of these parameters, along with a decrease in the cyclic strength of steel, significantly affects its plastic properties. It has been established that during low-cycle deformation in high-temperature water, the plasticity of steel is significantly affected by the rate of elastic-plastic deformation of the material. Plasticity decreases at a certain critical range of deformation rates.
A mathematical model of the change in the ductility of steel in high-temperature water from the rate of deformation of the material is presented.
It has been established that the operating mode of the equipment must be organized so that the deformation rates of the bearing elements are far from the critical deformation rates obtained experimentally.