The spheroidizing behavior of cementite in Fe–0.8 C mass% steel during cyclic heat treatment was
investigated.The effect of cyclic numbers on the microstructure and mechanical properties of the
experimental steel was discussed.In the presen twork,each cyclic heat treatment consisted of ashort-
duration(5min) heldat 1043K(above A1 temperature 1003 K)anda short-duration (3min) heldat
953 K.The spheroidizingration of cementite and the average size of particles grow with the in crease of
cyclic numbers. After five cyclic heat treatments, the cementite spheroidizes completely,the average
size of cementite particlesis about 0.49 mm and the larger particles ratio is below 4% .After cyclic heat
treatment, the plastc icity of the experimental steel clearly in creases.The elongation of theas-
transformed specimen is about 8%,the elongation of the1-cycle specimen is 25.4%, and the elongation
of the5-cycle specimen reache sapeak value of 33.9%.The ultimate tensiles trength (UTS)of as-
transformed specimens is about 680 MPa,and the UTS of the1-cycle specimen decreases to about
620 MPa ;however, the UTS ofthe3-cycle specimen in creases to about 650 MPa.The ratio of yield
strength to tensile strength is about 0.70 after cyclic heat treatments