Corrosion Behavior and Susceptibility to Stress Corrosion Cracking of Leaded and Lead-Free Brasses in Simulated Drinking Water

Abstract

Duplex α + β’ brasses are widely used in drinking water distribution systems for tube fittings, valves, and ancillaries because they are low cost, easy to fabricate, and exhibit high mechanical strength. However, depending on application conditions and alloy composition, they may undergo dealloying and stress corrosion cracking. In this research, three different brass types, two leaded (CW617N and CW602N) alloys and one lead-free brass (CW724R), were investigated to assess their corrosion behavior and susceptibility to stress corrosion cracking (SCC) in simulated drinking water (SDW) solutions containing different chloride concentrations, compatible with drinking water composition requirements according to Moroccan standard NM 03.7.001. The corrosion behavior was assessed by electrochemical tests such as polarization curve recording and electrochemical impedance spectroscopy (EIS) monitoring, coupled to SEM-EDS surface observations. The susceptibility to SCC was investigated by slow strain rate tests (SSRT). The tests showed that corrosion was mainly under diffusion control and chlorides slightly accelerated corrosion rates. All alloys, and particularly CW617N, were affected by SCC under the testing conditions adopted and in general the SCC susceptibility increased at increasing chloride concentration.

Machinable Leaded and Eco-Friendly Brass Alloys for High Performance Manufacturing Processes: A Critical Review

“…Furthermore, protective coatings can be employed to further enhance the corrosion resistance of the material. As the Zn content range where this effect occurs is extensive, there are limited alloy design strategies that can be employed as of yet to alleviate SCC in brasses [86,87,95,96]. The fracture caused by SCC usually follows an intergranular path with multiple branching patterns.…”

Cracking Analysis of a Brass Clamp Mounted on the Main Transformer in the Power Grid System

“…Due to the unique combination of non-magnetism, good machinability, superior corrosion resistance [1], relative strength, higher thermal conductivity [2], electrical conductivity, formability [3], and low cost, brasses are widely used in drinking water distribution systems [4,5], heat-transfer units [2], and other industries for water filtration [6], elbow fitting [7], nuts [8], etc. Brasses are copper-zinc alloys with the Zn content between 5% and 40% [9].…”

“…The dezincification behavior of low-Pb duplex brasses has been systematically studied by Michael et al Results showed that in addition to less β' phase fraction, a small α grain size with high aspect ratio can also improve the dezincification resistance [12]. Silicon brasses were investigated to increase strength or produce environment-friendly alloys with excellent dezincification resistance [4,13]. CuZn21Si3P forms a complex triple-phase, containing about 60% of α phase with some Si-rich κ (Cu8Zn2Si) phase and γ (Cu4ZnSi) phase.…”