The Ultrahigh Ductility of an Ultrahigh Carbon Steel Containing 3%Si

Superplastic properties of fine-grained ultrahigh carbon steels (UHCS) have been greatly improved through the addition of 3 wt% Si (UHCS-3Si) and through improved processing conditions. This material showed an elongation to failure of 1300% under optimum superplastic conditions. It is also superplastic at very high strain rates, i.e. 10(-2) s(-1), in the temperature range between 800 and 825 degrees C. An analysis of the effect of silicon additions on the UHCS and the influence of the introduction of temperatures regions in the phase diagram on the superplastic properties is made.