Restoring Shine to An Icon
THE MAGAZINE DEVOTED TO NICKEL AND ITS APPLICATIONS
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THE ATOMIUM IN BRUSSELS reopened in February 2006 following renovations which cost €25 million.
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THESE 18-METRE-DIAMETER spheres were re-clad with corrosion-resistant, electropolished
S31603 stainless steel.
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Why electopolished stainless steel was chosen to renovate Belgium's Atomium
By Dr. Gerry Crawford
Nickel Magazine, May 2006 -- Built for the 1958 World’s Fair, the Atomium depicts the body-centred cubic crystal structure of elemental iron metal. Originally clad in aluminum sheet, the structure was not intended to remain standing after the 1958 Exhibition, but its popularity endured, to the point where it has become a major landmark on the Brussels skyline.
During the intervening half-century, however, the nine 18-metre-diameter aluminum-clad steel spheres have lost some of their sheen. It was therefore decided in 2004 to re-clad the steel spheres and support structures with corrosion-resistant stainless steel sheet elecropolished to a mirror finish so that the Atomium can remain a compelling tourist attraction for several decades. As a result, the Atomium was re-opened in February, 2006, after nearly two years of renovation and a total investment of €25 million.
The aluminum cladding was replaced with stainless steel sheet because weather had dulled the surface
appearance. Seventy tonnes of 1.2-mm-thick, electropolished
S31603 stainless steel sheet were required. Cladding the curved surfaces of the spheres and support
columns with stainless steel sheet was a major engineering challenge. The trick was to cut the sheet into
triangles of different sizes.
There were 720 triangles per sphere, and 15 of these were pre-welded together to form 48 larger, curve-formed
triangles for installation on the spheres. By cutting the sheet into triangles, engineers were able to
minimize the duration of installation work on the spheres, even though the large, 16-square-metre panels,
each of which weighed 480 kg, required careful handling.
The triangles were electropolished, which resulted in a very thin but continuous surface oxide layer, thereby contributing to corrosion resistance. Other advantages to electropolishing include:
- a smooth surface free from impurities and surface defects;
- resistance to adhesion of foreign matter;
- ease of cleaning and maintenance, and
- an aesthetically compelling, shiny mirror finish.
The refurbishing of the Brussels Atomium is another example of the superior properties and attractiveness of stainless steel in architectural applications. Stainless will shine indefinitely with minimum cleaning and maintenance. And even if the Atomium is dismantled decades from now, the stainless steel can, and doubtless will, be completely reclaimed, recycled and reused.
The stainless steel sheet was supplied by the Ugine and ALZ plant of the Arcelor group, Genk, Belgium.
The electropolishing of the formed stainless triangles was done, one by one, by Chimiderouil of Mons, Belgium.
The forming work was sub-contracted by Belgo Metal to
Witte van Moort of Vriezenveen, Netherlands, and voestalpine’s subsidiary, Matzner, in Bissendorf,
Germany.
Information for this article was kindly provided by Benoit van Hecke of Euro Inox, Brussels.
Dr. Gerry Crawford is a Toronto-based consultant to the Nickel Institute.
PHOTOS: Atomium and Arcelor Group
Arcelor Group |
