METHOD AND APPARATUS OF QUICKLY PREDICTING THE DEGREE OF NODULARITY OF SPHEROIDAL GRAPHITE CAST IRON FROM A MOLTEN SAMPLE

摘要

A method of quickly predicting the degree of nodularity of spheroidal graphite cast iron from a molten iron sample is disclosed. The method comprises steps of reading out the lowest temperature TEU due to undercooling and the highest temperature TEM due to recalescence subsequent to the undercooling which occur at the time of eutectic solidification of a number of samples of molten iron for spheroidal graphite cast iron during cooling and solidifying under a predetermined cooling condition; reading out an elapsed time Z from the lowest temperature TEU to the highest temperature TEM; determining constants a, b, c and e in the following formula which shows a relation between the values of the thus read out temperatures and the elapsed time and any of the characteristics DS showing the degree of nodularity of spheroidal graphite cast iron selected from the percentage of spheroidal graphite, the percentage of residual magnesium, the tensile strength of the elongation of the cast iron after solidification; and obtaining the characteristics DS of the iron for spheroidal graphite cast iron, of which the degree of nodularity is unknown, by substituting TEU , TEM and Z read out during cooling and solidifying of a molten sample of said iron under the predetermined cooling condition into the above formula: DS=a+btEM+c DELTA TE+eZ where DELTA TE is a difference between TEM and TEU.