Influence of p, As and Sb on the susceptibility to SCC of a-b' brasses

摘要

The influence of P, As and Sb on the susceptibility to SCC ofα-β' brasses in different non ammoniated solutions was studied.Two series of brasses were tested: the first one with only 5 - 10% ofβ' phase and the second one with 54-56% ofβ' phase. The VB group elements were present at two different concentrations.Susceptibility to SCC was evaluated by SSRT, at a strain rate of 1×10{sup}-6 s{sup}-1, in concentrated (1M) or diluted (50 and 200 ppm) solutions of Na{sub}2SO{sub}4, NaNO{sub}2, NaCl, at room temperature.The brasses of second series were found to be more susceptible to SCC than those of the first series in all the environments studied. Sb drastically increased SCC susceptibility of the brasses of the first series, while As showed a beneficial effect. Thethree VB group elements produced a limited inhibiting effect on susceptibility to SCC in the second series of brasses.Susceptibility to SCC of all the brasses was compared with the tendency to dezincification, measured by means of the 6509 ISO Standard Test. The influence of the VB group elements on the two types of corrosion was not comparable.