Evaluation of the Corrosion Resistance of Tubing of Various Strength Groups

摘要

The corrosion resistance of tubing pipes of four strength groups is evaluated: E, ?, K and D by measuring the saturation current density of steel anodic dissolution. It is shown that tubing of increased strength (groups E and ?) has lower corrosion resistance compared with pipes of strength groups D and K. The low corrosion resistance of tubing of strength groups E and ? is associated with the formation of adverse structural components, in particular high-carbon martensite having a high dislocation density. Formation of this structure is due to the fast cooling rate of the pipes in sprayer equipment. In order to increase the corrosion resistance of tubing of strength groups E and ? it is recommended that additional heat treatment consisting in particular of quenching and tempering is performed in order to relieve internal stresses within the steel.