G. Bi, R. Hao, Shanghai Baosteel Equipment Maintenance Co., Ltd, Shanghai, PRC, Shanghai, China
The CrB2/CoCrAlY coating on the continuous anneal hearth rolls has combined the performance of good anti build-up with wear resistance etc. But it was found by thermodynamic theory calculation that oxygen can affect the properties of the hearth roll coating. Not only the Cr and Al elements in the matrix are easily oxidized, but also the CrB2 ceramic phase has the possibility to transform into Cr2O3. It obviously that these oxides will react with the MnO which existed on the surface of the steel sheets and the brittle Mn-Cr-O and/or Mn-Al-O phases are formed, which reduce the properties of the coating and result in the failed coating. Therefore, this paper researches the behavior of CrB2/CoCrAlY coating in oxygen environment through testing and analyzing the failed coating.
Key wordsFHearth Roll Coating, Oxygen, Mn-O Oxides.
