Recently, ship owners require saving cost of the inspection and repair due to corrosion in crude oil tanks of oil tanker. There are two types of corrosion in crude oil tank, the general corrosion of upper deck plate and the pitting corrosion of bottom plate. On the basis of the results of field examinations on many VLCCs (Very Large Crude Carriers) by the shipbuilding research association of Japan, simulated corrosion test methods were established. The corrosion resistant steel was developed by the study on the effects of alloying elements on corrosion behavior of steels. Laboratory test results revealed that the developed steel has twice or more corrosion resistance compared with conventional steel in corrosion environments of both upper deck plate and bottom plate, and mechanical properties of the base metal and the characteristics of the welded joint are equivalent to conventional steel. It was found that corrosion resistance is improved by the action of alloying elements in the low pH condensed water on the upper deck plate, and by the formation of protective sulfide film including alloying elements on the bottom plate.
Development of corrosion resistant steel for cargo oil tanks
Entwicklung eines korrosionsfesten Stahls für Ölladetanks
2006
4 Seiten, 9 Bilder, 3 Tabellen, 3 Quellen
Conference paper
English
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