INFLUENCE OF MICROSTRUCTURE OF AH32 CORROSION RESISTANT STEEL ON CORROSION BEHAVIOR

Abstract

International martime organization (IMO) has approved and considered corrosion resistant steel as the only alternative for anti-corrosion coating since May 2010. The implementation of the standard will have a profound impact on ship building, steel, shipping and other industries. At present, Japan has a relatively mature technology, South Korea has completed the pre-development work, while China has only carried out some preliminary studies. If the technology is blocked, a large number of steel needs to be imported which would push up the cost of construction of the shipbuilding industry, and has a direct impact on the orders of shipping enterprises. The amount of steel for cargo oil tank in China is more than two million tons each year, and therefore, the localization of research and application of corrosion resistant steel for cargo oil tanks has become an urgent task. The impact of microstructure of the existing shipbuilding steel on corrosion behavior in simulated corrosion environment is studied based on the standard in this paper to develop our own corrosion resistant steel. According to the standard, immersion test was used to measure the corrosion process of AH32 corrosion resistant steel in the bottom simulated environment of cargo oil tanks. Using gravimetric measurement, electrochemical polarization and impedance methods, scanning electron microscopy and electron probe et al, the influence of microstructure of AH32 corrosion resistant steel on its corrosion behav- iors was analysed. The experimental results showed that: during the test simulating the corrosion of the