The Ms temperature increases as the cooling rate decreases down to the VC-B and then lowers gradually as the bainite transformation proceeds.
In 1273 K austenitization, the Ms temperature is 475K to 495K in the low C cast iron and 375K to 380K in the high C cast iron.
The Ms temperature rise because the alloy concentration in matrix decreases due to an increase in the precipitation of secondary carbides.
The Ms temperature is lower because the enrichment of C in austenite takes place due to the discharge of C by the proceeding of bainite transformation.ing elements increases at high T, both the pearlite and bainite transformations are delayed