Study on Corrosion Resistance of Al, Ni Brass with Processing State

The dezincification corrosion resistance of complex aluminum-brass HA172-2.5-1 was studied by weight-loss, metallographic analysis method and energy dispersive spectroscopy. The effect of processing states and Al content (2.0%, 2.5%, 3.0%) in brass on zinc corrosion resistant was investigated. The research result shows that corrosion resistant is affected greatly by processing state, as-cast organization is loose and with much beta phrase, the dezincification of beta phrase is easy in corrosion solution, corroded at 75 degrees C in 1% CuCl2 solution for 30 days. The dezincification layer of as-cast brass is over 137.3 mu m. Compare with the as-cast alloy, the corrosion depth of brass plate hot-rolled is only about 70.6 mu m, because the recrystallization process and the beta phase dissolved into a phase during hot rolling process, the construction is more condense than that in as-cast state. The corrosion goes easily along the grains orientation which occurs in cold rolling, and existence of residual stress accelerates stress corrosion, which turns higher corrosion rate than that hot-rolled brass. The corrosion velocity enhances with the increase of Al content in brass.