Steel that keeps rust at bay

Citation

(2003), "Steel that keeps rust at bay", Anti-Corrosion Methods and Materials, Vol. 50 No. 4. https://doi.org/10.1108/acmm.2003.12850dad.001

Steel that keeps rust at bay

Steel that keeps rust at bay

Keywords: Steel, Rust, Corrosion

Aluzink AZ 185 from SSAB Swedish Steel is the only design steel in Europe to meet the requirements for corrosivity class C4. This means that the Swedish climate equipment manufacturer, PM Luft, has chosen to manufacture its products – which are exposed to severe corrosion – in Aluzink (Plate 1).

SSAB Swedish Steel has developed the material as coated steel sheet for designs used in severely corrosive environments. The coating, a combination of aluminium, zinc and silicon, provides a very good protection against corrosion and, in many cases, can replace aluminium and stainless steel.

"We have succeeded in retaining the steel's superb forming properties and reasonable cost level, while the anti-corrosion properties are in the same corrosivity class as aluminium," comments Henrik Eriksson, Marketing Manager for Aluzink at SSAB Swedish Steel. "We can offer the material in a number of strength categories, which means that a high strength variant of Aluzink is also available."

The climate equipment is often exposed to extreme humidity. Highly corrosion-resistant material is therefore required.

"Air can contain a lot of moisture that often condenses in our products, which consequently need to meet exacting anti-corrosion requirements," says Conny Nilsson, Head of Market Support at PM Luft AB. "Manufacturing costs cannot be too high if we are going to sell our products on the global market. Aluzink has proven to be the best material for us. It has got the edge on aluminium when it comes to our product designs, in addition to which it gives a superb surface finish throughout the manufacturing process. Aluzink is therefore our material of choice for those product parts which are exposed to corrosion."

Plate 1

The demand for climate treatment is growing everywhere. The right kind of air regulation at the right temperature, moisture level and air turnover are decisive as regard to comfort in the workplace, public indoor environments and shops. Moreover, industry requires increasingly accurate air flow control in the production environment, concurrent with exacting demands in the form of growing eco-awareness and low long-term life cycle costs. "The demand for a good indoor climate with a high level of hygiene is constantly growing," Mr Nilsson explains. "Climate equipment which sustains rust damage is difficult to keep clean and soon becomes unusable. If these kinds of products are properly serviced – and if they are made of the right material – they can be operated continuously, year after year, without rusting."

Aluzink is divided into different classes, depending on the thickness of the coating. Aluzink 185, which has a 25 µm coating on each side of the steel sheet, is the most resilient. This thickness means that it meets the exacting requirements for corrosivity class C4 in conformity with European standards. The material has a very long lifespan in normal environments and, moreover, is a good choice for industrial environments, polluted city environments and coastal areas. When shearing, the sheared edges are protected against corrosion since the surface contains zinc.