Fatigue Strength of Structural Steel DAN400 Plate Produced by Thermomechanical Treatment Technology with Accelerated Cooling

Fatigue properties of contemporary low-carbon micro-alloyed structural steel grades have not been studied sufficiently in spite of a large amount of available reference information. This slows down and hinders introduction of the latest generation of structural steel grades into production chains for manufacturers of heavy machinery and structures. According to multicycle fatigue test results for plate steel grade DAN400 36 mm thick with σ_y = 450 MPa, C_equ = 0.27%, and P_wi = 0.12% produced by thermomechanical treatment technology with accelerated cooling (TMTT + AC) the fatigue strength (σ_–1, MPa) on a base of two million cycles, the index of the left-hand branch of the fatigue curve m = 1/α, and coefficients C and α in the equation for the left-hand branch of the fatigue curve σ_–1 = С·N^–α are determined. An experimental fatigue curve is constructed on double logarithmic coordinates for the test steel.