Abstract: A new spheroidizing process of ultra-high carbon steel (UHCS) containing C 1. 55%. Cr 1. 45%, and Al 1. 5% in mass percent has been proposed. The effect of processing parameters on the microstructure was analyzed. The UHCS produced by this new process has a microstructure with recrystallized ferrite matrix and fine anduniform carbide particles. After this spheroidizing, the UHCS exhibits good mechanical properties at ambient temperature,
for example ab=1 100 MPa, 0,=915 MPa, S=S% and high ratio of a,/ub.
Key words: ultra-high carbon steel; spheroidizing technique; proeutectoid carbide; equalization