Peculiarities of deformation of thin-sheet TRIP steel under static and fatigue loading

The features of the deformation of austenitic-martensitic thin-sheet TRIP steel under static and fatigue loading with varying parameters of the breaking rate as well as the maximum cycle stress under cyclic loading were studied. The ten-fold increase in the tensile rate led to the decrease in the ultimate strength by ≈ 6% and the relative elongation δ from 32% to 21%, which is due to a decrease in the intensity of the formation of deformation martensite. The nature of hardening during deformation of steel under static and repeated tension is almost the same. The effect of the greatest TRIP - strengthening under loading to the yield-point stress level and physical fatigue limit were found. Preliminary fatigue loading up to σ_max = 1550 MPa with N = 3000 led to the increase in the yield strength and ultimate strength by ≈200 MPa and ≈100 MPa, respectively; the relative elongation decreased by a factor of 2.