Correlation between Microstructure, Hardness and Corrosion of Welded Joints of Disc Rotors.

In the present work, correlation between microstructure, hardness and corrosion was investigated in the three different zones including base metal (BM), heat affected zone (HAZ) and weld metal (WM) of welded rotors in terms of the traditional micro-hardness testing and the potentiodynamic polarization experiments. The results revealed that Micro-hardness did not only depend on the content of martensites, since the hardness of WM was higher than that of BM, but the martensites content of BM was much more than that in WM. The precipitation of carbides increased as the width of lathy tempered martensites grows larger, which caused the hardness increasing and the corrosion resistance decreasing. In addition, with the decreasing of the grain size, the higher the hardness value and the corrosion resistance were increasing. [ABSTRACT FROM AUTHOR]