The results show that the impedance arc radius of the cryogenic BV AH40 steel plate after soaking is smaller than that of the steel sample without cryogenic treatment, mainly because the corrosion product layer on the surface of the steel sample without cryogenic treatment is more dense after soaking. In the low frequency region, the impedance value of the low-temperature treated steel sample is less than that of the non-low-temperature treated steel sample.
The morphology of corrosion products showed that the surface of BV AH40 steel plate soaked at low temperature showed pitting corrosion, while the surface of BV AH40 steel plate soaked at room temperature showed uniform corrosion.
Pitting pits damage the corrosion product layer on the surface of BV AH40 steel plate, resulting in the substrate surface of BV AH40 steel plate cannot be completely covered by the product layer, resulting in reduced impedance and increased corrosion current density.
