The spheroidizing behavior of cementite in Fe–0.8C 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) held at 1043K (above A1 temperature 1003K) and a short-duration (3min) held at
953 K.The spheroidizingration of cementite and the average size of particles grow with the increase of
cyclic numbers.After five cyclic heat treatments ,the cementite spheroidizes completely,the average
size of cementite particles is about 0.49 mm and the larger particles ratio is below 4%. After cyclic heat
treatment,the plasticity of the experimenta lsteel clearly increases.The elongation of theas-
transformedspecimenisabout8%,theelongationofthe1-cyclespecimenis25.4%,andtheelongation
of the5-cycle specimen reache sapeak value of 33.9%.The ultimate tensile strength (UTS)of as-
transformed specimens is about 680MPa ,and the UTS of the1-cycle specimen decreases to about
620 MPa;however,the UTS of the3-cycle specimen increases to about 650 MPa.The ratio of yield
strength to tensile strength is about 0.70 after cyclic heat treatments