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

Abstract

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 σmax = 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.

Influence of Overheating on High-Cycle Fatigue Characteristics of the Base Metal and Weld Metal of Low-Carbon Steel Welded Joints

“…This is especially true for CC vessel construction conducted in areas with increased seismic hazards. The fatigue characteristics of lowcarbon steels have been extensively studied [14][15][16][17][18][19][20][21]. In particular, the mechanisms of fatigue crack propagation [22], the relationship between the fatigue groove spacing and the fatigue crack propagation rate [23], and the effect of the chemical composition [24] have been studied.…”

Determination of Two-Stage Heat Treatment Parameters in Industrial Conditions in Order to Obtain a TRIP Structure in Low-Alloy Carbon Steel Wires

“…The high mechanical properties (strength and plasticity) of TRIP steel are obtained thanks to the phenomenon of additional plasticity during the transformation of metastable retained austenite into martensite during plastic deformation (Umwandlungsplastizit in Wassermann, 1937 [7], or Transformation-Induced Plasticity (TRIP) in Zackay, 1969 [8]) [9]. The TRIP effect occurs in three types of steel: austenitic stainless steels, nickel steels for cryogenic operation and low-alloy carbon steels with the addition of manganese, aluminium and/or silicon or phosphorus [10][11][12][13][14][15][16][17][18][19]. A TRIP-type structure in low alloy carbon steels can be obtained using a two-stage heat treatment process.…”