BE95-1142 Metallurgical Control of Filiform Corrosion of Aluminium Rolled Products
The future of the aluminium rolling industry in Europe depends on large volume production and sale of coil treated painted products. The present market is mainly for architectural applications which is under serious threat in coastal areas of Belgium and Holland due to filiform corrosion experienced in service. The future market is in automotive sheet that has enormous market potential both for body panels and for automotive structures. Prevention of corrosion of painted sheet in automotive applications is therefore of paramount importance particularly as this market is in its infancy and confidence in the usage of aluminium must be maintained. In particular, filiform and other forms of underfilm corrosion, must be prevented irrespective of the metal source (primary, remelt or recycled), the casting technique (direct chill, electromagnetic or continuous), the fabrication practice, the surface treatment technology and the alloy system. In addition, all processes used, especially in surface treatment, must be environmentally friendly and economically attractive. The use of recycled metal is an important issue as the automotive industry will soon be faced with an EC law which will demand that car manufacturers take back used cars and ensure subsequent recycling and similar legislative measures are under consideration for the building industry.
The key need is to understand how the metallurgy of the aluminium substrate as determined by metal source alloy composition, casting, processing and surface treatment controls filiform corrosion resistance. Once this understanding is achieved composition control and modified production practices will be developed and instigated to ensure that irrespective of metal source the inherent resistance to filiform corrosion of coated aluminium substrates as determined by the underlying metal is maximised.
Substrates of alloys for architectural and automotive applications will be provided and filiform corrosion tested by the industrial partners using primary, remelt and recycled metal. The experience of the industrial partners as major European aluminium companies will be combined with the proven research expertise of the two university based partners who have shown how advanced and unique electrochemical and electron metallographic techniques can be combined to determine the role of the aluminium substrate in filiform corrosion of coated aluminium products.
The consortium comprises a manufacturer of coated aluminium sheet (AlcanD) and a manufacturer of mill finished aluminium sheet (Hoog) from primary and remelt metal using direct chill casting and-electromagnetic casting respectively, end-users and manufacturers (Hydro and HunterD) who are interested in extensive use of both recycled and primary metal and the use of roll-casters. The industrial partners Hoog and Hydro have already established strong links with the universities TUDelft and NTH respectively.
Funding SchemeCSC - Cost-sharing contracts
3008 AB Rotterdam
1970 CA Ijmuiden
2628 AL Delft