Mechanical and Physical Properties, Fracture Mechanisms, and Residual Strength of 15Kh2GMF Steel for Oil Sucker Rods

The mechanical properties of 15Kh2GMF steel are estimated, and the fracture stages and mechanisms in this steel are studied during static, cyclic, and impact loading in the temperature range from –100°C to 20°C. A direct method is used to measure the real damage of the steel and to determine its physical properties, namely, the velocity and the attenuation coefficient of longitudinal ultrasonic waves, the coercive force, the eddy current parameter, and the self-magnetic field, at various stages of static and cyclic loading. The influence of preliminary cyclic loading on the residual strength and the acoustic emission parameters measured during tensile tests of cyclically deformed specimens and the fracture mechanisms are studied. The stages of damage accumulation characterized by changes in the damage parameters and the physical properties of the steel are distinguished, and informative criteria for the diagnostics of a construction in the initial and late stages of operation are proposed.