Investigation of Creep Properties and Fracture Mechanism of 430 Ferritic Stainless Steel at Elevated Temperature

During the continuous casting of 430 ferritic stainless steel, the broadening phenomenon and bulging deformation are considered a high-temperature creep. This study investigates 430 ferritic stainless steel by conducting high-temperature uniaxial creep experiments under the temperatures of 0.4-0.5 T_m and stresses of 32.5-85 MPa. After creep deformation, the microstructure is analyzed by scanning electron microscopy, energy-dispersive spectroscopy, electron backscatter diffraction, and transmission electron microscopy. The creep curves show the “Normal type.” The creep stress exponent is 3.6-6.7. The creep activation energy is 476.533 kJ/mol. The dislocations climbed over the (Fe, Cr)₂₃C₆ are observed. The creep mechanism is dislocations climbing, and the precipitation strengthening contributes to the creep deformation. The recovery and recrystallization are confirmed during the creep deformation. Temperature, not stress, is the main factor in recovery and recrystallization. Numerous voids are observed around the precipitates. There are many dimples on the fracture surface. The creep fracture mechanism belongs to the Transgranular ductile fracture.