Cu and P elements effect in the 05CuPCrNi steel

The addition of Cu and P elements to 05CuPCrNi steel is mainly for improving the corrosion resistance and solid solution strengthening of ferrite. Cu is the main and commonly used alloy element to improve atmoSPHEric corrosion resistance. The addition of Cu to 05CuPCrNi steel can form a dense copper oxide thin layer between the corrosion layer of the steel and the rich copper layer, thereby slowing and inhibiting the continued growth of the medium Corrosion inside the steel plate. When the Cu content is greater than 0.15%, its resistance to atmospheric corrosion will increase slowly. P is an effective element in alloying elements to improve atmospheric corrosion resistance. It is an anode depolarizer. In the electrolyte solution, it can accelerate the uniform dissolution of steel and the oxidation rate of iron, and help form a uniform rust layer on the surface of the 05CuPCrNi steel. And the boundary with the inner rust layer is obvious, thereby improving the corrosion performance of steel.

TB/T 1979 05CuPCrNi plate chemical composition(%, by mass):

The Cu in the 05CuPCrNi steel is controlled at 0.25%-0.35%, and the lower limit of P is controlled at 0.07%-0.10%, which can meet the requirements of atmospheric corrosion resistance. Cr element is also one of the alloying elements that improve the atmospheric corrosion resistance of low-alloy steel, but it generally has a significant effect when the Cu element is combined. Cr element has a low corrosion potential and is an element with a tendency to passivation. It promotes the formation of a densely oxidized passivation film on the surface of the steel in the atmosphere, thereby improving the corrosion resistance of the steel.

　　
In the atmospheric corrosion process, the content of Cr element is controlled at 0.30%-0.45%. Ni is also one of the effective alloying elements resistant to atmospheric corrosion. When the Ni content is less than or equal to 1% and the steel contains Cu, the effect of improving the corrosion resistance is not obvious.

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