Application of Koistinen and Marburger’s athermal equation for volume fraction of martensite to diffusional transformations obtained on continuous cooling 0·13C high strength low alloy steel

摘要

Koistinen and Marburger?s (KM) equation for the variation of volume fraction of athermal martensite y with temperature Tbelow the Ms has been applied to continuous cooling diffusional data. The data consisted of dilatometer curves obtained on continuous cooling of a 0?13%C high strength low alloy steel. The KM equation takes the form, ln(1 - y) = ?(Ms - T ). Plots of -ln (1 - y) against temperature for what are thought to be grain boundary ferrite, intragranular ferrite, proeutectoid ferrite, and pearlite give a series of straight lines of increasing slope ?. Intersections of these lines give the temperature of transformation points in good agreement with those on the dilatometry curves. Values of ? obtained for each transformation are compared with those previously obtained for martensite in plain carbon and alloy steels and ferrite in Fe?9%Ni.Koistinen and Marburger?s (KM) equation for the variation of volume fraction of athermal martensite y with temperature Tbelow the Ms has been applied to continuous cooling diffusional data. The data consisted of dilatometer curves obtained on continuous cooling of a 0?13%C high strength low alloy steel. The KM equation takes the form, ln(1 - y) = ?(Ms - T ). Plots of -ln (1 - y) against temperature for what are thought to be grain boundary ferrite, intragranular ferrite, proeutectoid ferrite, and pearlite give a series of straight lines of increasing slope ?. Intersections of these lines give the temperature of transformation points in good agreement with those on the dilatometry curves. Values of ? obtained for each transformation are compared with those previously obtained for martensite in plain carbon and alloy steels and ferrite in Fe?9%Ni.