The structure of the uppermost surface layer for commercial bearings w
ith poor grinding procedures has been studied by means of transmission
electron microscopy, electron probe X-ray microanalysis and Auger ele
ctron spectroscopy methods. It was found that a new etching-resistant
phase with a comet shape appeared, which was identified by structure a
nalysis as being (Cr, Fe)7C3 carbides. We supposed the formation of th
e new etching-resistant phase was due to the grinding beat and grindin
g force.