Fretting and fretting corrosion behavior of novel micro alloyed rail steels

The fretting behavior of two novel rail steels of composition Cu-Ni and Cr-Cu-Ni has been studied and compared with that of C-Mn and Cu-Mo rail steels. The rail steels were fretted in dry condition and in 3.5% NaCl solution. All the four rail steels exhibited similar fretting behavior in dry condition. The morphological features of the wear scar surface indicated delamination process as the main wear mechanism. The wear damage in 3.5% NaCl was lower compared to that in dry condition for all the rail steels due to lubricating effect of the solution. Fretting in presence of 3.5% NaCl resulted in lower wear volume for Cu-Ni and Cr-Cu-Ni rail steels. The friction coefficient for Cr-Cu-Ni rail steel was lower than that of C-Mn, Cu-Mo and Cu-Ni rail steels. Scanning electron microscopy (SEM) showed better adherence of tribo-electro-chemical layers formed on Cu-Ni and Cr-Cu-Ni rail steel than the C-Mn and Cu-Mo rail steels. This has been related to the improved fretting corrosion behavior of Cu-Ni and Cr-Cu-Ni rail steels.