JFE Steel Corporation (JFE) and Mitsui O.S.K Lines, LTD. (MOL) have developed an advanced new corrosion-resistant steel plate called JFE-Steel for Ship Inside Protection - for Oil Tankers (JFE-SIPTM-OT). A five-year research project has proven that the new material limits deterioration of crude oil cargo tanks.
The company will fully adopt this new corrosion-resistant steel plate on bottom and upper plates of the cargo oil tanks of an MOL operated very large crude carrier (VLCC) to be launched in November 2008. The adoption of this material on upper deck plate is the world’s first.
- Characteristics –
* The new corrosion-resistant steel plate, which combines several particular elements significantly reduces corrosion by slowing down pitting (the creation of small holes in the metal) *1 2 to one fifth of the level seen with conventional materials.
* It shows excellent corrosion-resistance, even for general corrosion*1 which occurs on rear side of the tank’s upper plate.
* It has the same weldability and machining performance as conventional steel plates used in the hull structure.
* It reduces maintenance work in dry dock, which is conducted every two and a half year.
In current vessels, the bottom plate of the cargo oil tank is covered with an corrosion-resistant membrane, but pitting occurs when the membrane gets chipped. It corrodes up to about 4mm annually. If no action is taken, this poses a risk to safety. General corrosion will occur at the rear of the upper plate in the cargo oil tank due to the effects of hydrogen sulfide. As corrosion spreads, it may reduce the strength of the hull structure, too.
MOL and JFE conducted research and determined the corrosion process on actual vessels to increase the safety of the hull and enhance the safety of navigation. This led to the development of the new corrosion-resistant steel. MOL believes tankers adopting this new corrosion-resistant material, which does not require painting, offers economic and safety benefits. In addition, it helps to reduce CO2, emissions. MOL expects this technology to become mainstream in environment-friendly tankers that will provide safer, more efficient, more reliable service. MOL and JFE plan to promote the effectiveness of this innovative material on a global scale.