The continuous use of stainless steel as the material of choice in the food and beverage and pharmaceutical industries since its discovery 105 years ago is proof of its hygienic, long lasting and reliable properties in countless applications.
The addition of a minimum of 11% chromium to steel produces a thin, passive, chrome oxide layer on the surface which protects the steel against most corrosive attacks. Stainless steels are uniquely qualified as a metal for hygienic applications not only because of their long service life, availability and fabricability, but also because they are corrosion resistant, non-contaminating and can be polished to very smooth finishes. They are strong and rigid and can withstand heat and chemical sterilisation treatments. They are tough at low temperatures -269° C and can withstand temperatures as high as 925° C (continuous) or 870° C (intermittent). In addition they are 100% recyclable.
A comprehensive range of hygienic tubing, fittings and valves is carried in stock by NDE Stainless Steel in Montague Gardens for fast turnaround for the Cape’s food and beverage and pharmaceutical industries, together with a stock of ultra-hygienic tube systems.
Other products used widely in hygienic industries and stocked by NDE include a full range of flat sheets in 304L and 316L for tanks and containers; square tubing mainly for platforms and frameworks; schedule material for water and steam lines, together with BSP fittings; as well as aluminium for cladding and walkways in hygienic plants.
With many years of experience in a wide range of hygienic applications, NDE also offers technical advice on optimum grades and materials for harvest and for many types of hygienic processing.
There are many grades of stainless steel available within the Austenitic, Martensitic, Ferritic and Duplex range of steels. The Austenitic range of steel is by far the most popular with grades 304L (EN1.4301) 18Cr. 8Ni and grade 316L (EN1.4401) 16Cr. 10Ni.2Mo. outstripping production of the other grades. These grades are very compatible with each other allowing integration.
Good weldability allows for a full range of welding. To eliminate bacteria entrapment and contamination in the weld area – which is critical in hygienic processing – welds should be purged. Weld specifications ANSI/AWS D10.4-86: ANSI/AWS D18.1. 2009: ANSI/AWSD18.2. 2009 could apply.
Differentiation should be made between direct off mill (D.O.M.) tube and ASTM A270 Hygiene tube.
ASTM A270 longitudinally welded hygiene tube should have the internal weld bead removed and finished to RA (roughness average) 1.6 micron. The internal RA finish should be 0.8micron
B.P.E (Biopharm Equipment) products can be supplied from the Dockweiler range which NDE represents in southern Africa.
