Effects of Cu microalloying on corrosion behavior of spring steel 54SiCr6

Springs made of low-alloy carbon steels are often exposed to the effects of a corrosive environment, such as high humidity and concentration of road salt, rain and snow erosion, temperature fluctuations in combination with dynamic loading and mechanical wear. One of the possibilities to improve their resistance in a corrosive environment is their microalloying by Cr, Ni, Mo or Cu. This study tested the effect of microalloying of 54SiCr6 steel by copper on the corrosion behavior in model rainwater and saltwater. The corrosion resistance of the steel samples was tested using electrochemical tests by measuring the polarization resistance and the anodic parts of the potentiodynamic curves at three different temperatures. The surface of the steel samples was observed using SEM/EDS, surface analysis, and XRD diffraction. The measurement results showed that copper in the amount of approx. 1.5 wt % does not affect the microstructure of the spring steel 54SiCr6 after the heat treatment significantly, but improves the corrosion resistance during short-term exposure in both model rainwater and saltwater.