Super Smooth Stainless for Catering

HyClean SuperBrush, Avesta Sheffield's high performance stainless steel aimed at the catering and domestic appliance markets, has won the company the annual ‘Made in Sheffield’ award (figure 1). The award is given to a local company that has developed a product most likely to enhance the city’s reputation for quality, excellence and innovation around the world. The new stainless steel certainly looks the part, with a silky smooth finish produced by advanced surface brushing technology developed by Avesta Sheffield.

Figure 1. An industrial kitchen layout utilising the HyClean SuperBrush stainless steel.

The material was launched last year, after having invested £1.5 million in a new stainless steel processing line to produce HyClean SuperBrush. The self contained production facility on the company's Sheffield site is initially producing about 40,000 tonnes of the material, mainly as coil, in both austenitic and ferritic grades. The entire production process is handled in-house, from melting through to cold rolling and then finishing.

HyClean SuperBrush is produced from a dedicated base material that is processed on the new Imeas brushing line. The material passes through three nylon brushes that are impregnated with abrasive grains of aluminium oxide, silicon carbide and then aluminium oxide again. This creates a very smooth, repeatable surface that is hygienic, easy to clean and aesthetically pleasing. In Italy, where many of the major professional and domestic appliance manufacturers are based, there is a growing demand for brushed surfaces. Other potential markets included France, Germany, Portugal, Sweden, the Netherlands and Switzerland.

Avesta Sheffield carried out technical research in conjunction with Corns to demonstrate SuperBrush’s improved surface properties and performance compared to similar grades. The tests assessed roughness, hygienic quality and ease of cleaning. Thanks to the high quality brushing operation on the dedicated base material, SuperBrush has a much smoother surface than other conventional stainless steel finishes. Its surface roughness, Ra, is about 0.15 microns compared to 0.7 for a dull grit polish and 0.29 for a fine grit polish. This means that the material is less likely to entrap food deposits and bacteria in its relatively shallow surface ‘troughs’, leading to improved hygiene. The research incorporated a comparison of surface hygiene after a standard cleaning test in which each stainless steel finish was contaminated with equal measures of bacteria. The ‘hygiene index’ score for SuperBrush was 105, compared to 14 for the dull grit polish and 60 for the fine grit polish.

These qualities, plus its aesthetically pleasing smoothness, have ensured that the material has met with what the company describes as ‘phenomenal success’ among some of the world’s leading catering equipment manufacturers including Electrolux, Ariston, Zanussi and Lincat. It is being used by makers of professional catering and refrigeration equipment, as well as manufacturers of consumer products such as kitchen extractor hoods, cooking hobs and ovens, and washing machines. In addition, development work is ongoing for use in sinks, microwave ovens, vacuum cleaners and road transportation of bulk liquids.

In the UK, the first company to use SuperBrush was Lincat, the manufacturer of commercial catering equipment for restaurants and hotels. The company co-operated in the development of the material and now uses more than 700 tonnes of steel each year in its OPUS700 range of cookers.

The new material is finding other areas of application thanks to its surface characteristics. The surface smoothness can play an important role in keeping buildings looking clean when the material is used in architectural applications. The lack of surface grooves make it difficult for dirt to get stuck on the surface, and when rain water washes over the building, it is more easily cleaned. In addition, the material offers a consistent surface appearance to architects, maintaining its aesthetic characteristics from panel to panel, thanks to the uniform production process. The product has been selected for developments including Inatel in Cascais, Portugal, and buildings in the Canary Wharf development in London, UK.

Primary author: Steven Hill

Source: Materials World, vol. 9, p. 19 February 2001.


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