Kinetics and Microstructural Control
Chrome-Molybdenum Steel for Rails 

· The key to increasing the service life of rails is to increase their wear resistance, particularly in curved track sections.
· High wear resistance requires a fine pearlitic microstructure that can be obtained in a 0.7 wt% C steel by heat treating the rail.
· Adding Chromium (0.6wt%) and Molybdenum (0.2wt%) to the Fe/C alloy shifts the "nose" of the CCT curve to lower temperatures. This gives a higher nucleation rates and a finer pearlite microstructure under the same cooling conditions as standard rails.

From: Mosaic 4 (1980) 10