A grinding roll was cracking after heat treatment. The cracks appearance looks straight. The cracked grinding roll was examined
through the chemical composition analysis, macro-and micro-fractography as well as
microstructure. The results show that the macro-fracture surface has light spots, and
metallographic observation at low-magnification revealed a lot of serrated cracks. The flake caused the grinding roll cracking. The micro-fractography showed discontinuous secondary cracks. Around the secondary cracks, there are many transgranular quasi-cleavage facets, which micro-appearance consistents with one of the flake. Microstructure was mixture of crassitude martensite, bainite, pearlite and ferrite. Metallographic surface has serration transgranular cracks discontinuouly distributed. Around the cracks there are no decarbonized. It can be concluded, that the grinding roll cracking was caused by flake. The formation of the flake was related to hydrogen content of the material, heat treatment microstructure defects and other factors.