Uneven nodular corrosion resistance of Zr-4 alloy

Some bright stripes with several millimeters in width and several tens of millimeters in length appeared on the surface of Zr-4 plates in certain batches of the products. Autoclave corrosion tests, composition analysis by energy dispersive spectrometer (EDS), and texture measurement were used to investigate the essentials of bright stripes and their effect on the nodular corrosion resistance. The results showed that the contents of Fe and Cr alloying elements were somewhat higher, and (0001) texture factor (fN) is larger in bright stripe area than that in the surrounding area. Nodular corrosion resistance on the bright stripe area was much better than the surrounding area after corrosion test at 500℃/10.3 MPa in superheated steam after 3 h exposure. The uneven distribution of Fe and Cr alloying elements and the difference of texture factor between the bright stripes and their surrounding area were contributed to the different nodular corrosion resistance. The uneven component of the ingot was the main reason.