U71Mn and U75V are two types of steel commonly used for railway tracks, and there are some key differences between them.
1. Chemical composition differences
The main difference between U71Mn and U75V is the carbon content and the added alloying elements. U71Mn has a carbon content of 0.71% and has added manganese, while U75V has a carbon content of 0.75% and has added vanadium .
Specifically, the carbon content of U71Mn ranges from 0.65%-0.77%, while the carbon content of U75V ranges from 0.71%-0.8% .
2. Mechanical property differences
In terms of fatigue resistance, studies have shown that U71Mn has better ductility and fatigue resistance than U75V rail .
However, U75V performs better in terms of rolling contact fatigue crack initiation life and wear growth rate. For example, the wear growth rate of U75V heat-treated rail is 12.1% lower than that of U71Mn, and the crack initiation life is extended by 31.1% .