(2) the ferrule Road, the role of the strong grinding heat and cooling liquid, the thin surface layer instantaneous secondary Worn fire grinding white layer is formed, to produce a higher grinding tensile stress, causing the grinding cracks and grinding burns.

(3) topping the tempering is insufficient, resulting martensite matrix remains the brittleness of the high hardness, high residual stress, and the microstructure the nonuniformity, easily procure stress superposition and induce grinding cracks and grinding burn.

(4) can be considered the 6205 premature bearing failure the metallurgical defects of the material, the result of the combined effects of heat treatment defects and grinding cracks factors. Inhomogeneity of the microstructure (cross-sectional differences in the organization) and local tensile stress of the surface crack root cause.

(5), the vibration and the expansion force of the bearing when installed precisely for chipping the the natural external force and time, resulting in priming the ferrule a sudden brittle chipping off blocks.