Abstract: Effects of different-sized MnS inclusions in spring steel on its corrosion mechanism in the presence and absence of micro-crevices originally formed around the inclusion were investigated by accelerated immersion test in 3% FeCl3. The experimental results showed that the number of inclusions associated with existing original micro-crevices was larger than that in their absence and the content of element S decreased monotonically with decreasing size of MnS inclusions regardless of the existence of original micro-crevices. Severe corrosion occurred at MnS inclusions associated with original micro-crevices, therefore, the crevice corrosion susceptibility with original micro-crevices was greater than without. At last, we insured that local corrosion susceptibility around the MnS inclusions increased and then decreased with increasing size of the inclusion up to 12 μm. And the corrosion products were also detected by Raman spectroscopy.
Authors: Qing Liu, Weining Shi, Shufeng Yang, Weihua Zhang, Jingshe Li, and Xueliang Zhang
Keywords: Local Corrosion Susceptibility, Mns Inclusion Size, Immersion Test, Raman Spectroscopy