Degradation of steels in the hulls of river ships

The surface corrosion of skin plates of the hulls of river ships is caused by the interaction of oxygen and hydrogen with the iron surface at the sites of damage to the protective lacquer coatings on the outer surface of the hull. The inner surface of the hull is subjected to the action of the condensates of water vapor with different degrees of acidity. Furthermore, near the fuel tanks, hydrogen-containing media (mainly, the hydrocarbon fuel) also affect the inner surface of the hull. As a result of hydrogenation, the plasticity of the skin plates of the fuel tanks sharply decreases, which is confirmed by the data of measurements of their impact toughness and microhardness, as well as by the results of microfractographic examinations. The contemporary hull plates subjected to thermomechanical treatment reveal a significant improvement of their plastic characteristics as compared with the requirements of the existing standard specifications. __________ Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 43, No. 3, pp. 117–120, May–June, 2007.