Material Constants of Ferritic Spheroidal Cast Iron during Hot Deformation

摘要

The hot deformation behaviors of a ferritic spheroidal cast iron (FSCI) have been investigated by compression testing on a Gleeble 3500 machine of the DSI-YSU Joint Laboratory. The temperature rang was from 1073K to 1273K and strain rate from 10~(-3) to 1 s~(-1). The total true stain was 0.7. The result shows that the flow curves obtained are typical of dynamic recrystallization processes. The plots of either the natural logarithms of the corresponding temperature or the natural logarithms of strain rate against the hyperbolic of flow stresses satisfy straight line relationships over the experimental data, indicating that the hot compression of the FSCI is thermally activated. The material constants, including activation energy ΔH as 240.8 kJ/mol, stress-level coefficient a as 1.352×10~(-8) Pa~(-1), stress exponential n as 3.9937, structural factor A as 5.64×10~8 s~(-1), are derived .