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 present work, each cyclic heat treatment consisted of as hort duration (5min) heldat 1043K (above A1 temperature 1003K)and as hort-duration (3min) heldat
953 K.The spheroidizing ratio of cementite and th eaverage size of particles grow with thein crease of
cyclic numbers. After five cyclic heat treatments, the cementite spheroidizes completely, theaverage
size of cementite particles is about 0.49 mm and the larger particle sratiois below 4%. After cyclic heat
treatment, the plastic city of the experimental steel clearly in creases. The elongation of the as
transformed specimen is about8%, the elongation of the1-cycle specimen is 25.4%, and the elongation
of the5-cycle specimen reache sapeak value of 33.9%. The ultimate tensile strength (UTS) of as-
transformed specimens is about 680 MPa,and the UTS of the 1-cycle specimen decreases to about
620 MPa;however,the UTS of the3-cycle specimen in creases to about 650 MPa.The ratio of yield
strength to tensile strength is about 0.70 after cyclic heat treatments