Static and dynamic microstructure evolution and fracture behavior of the 06Cr25Ni20 austenitic heat-resistant steel at different high temperature tensile temperatures were analyzed by means of optical microscope,scanning electron microscope,transmission electron microscope and high temperature laser confocal microscope.The results show that the yield strength of the tested steel decreases from 180 MPa to 40 MPa,the tensile strength decreases from 450 MPa to 50 MPa,and the elongation after fracture increases from 44％to 56％with the increase of tensile test temperature in the rang of 600-1000 ℃.The fracture is ductile.The number of dimples gradually decreases with the increase of temperature,and the size and depth gradually increase.The recrystallization phenomenon occurs in the microstructure,and the secondary phase black carbide and intragranular substructure decrease or even disappear with the temperature increasing.The formation of cracks and fracture are mainly generated at the interface between austenite and ferrite and high energy grain boundaries when the tested steel is stretched at high temperature.
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