In this post, we want to treat certain aspects of the use of stainless steel in the drinking water sector. Stainless steel thanks to their chemical composition can passivate and resist in particularly aggressive environments.
Drinking water and corrosion resistance. It’s a huge plus to stainless steel!
In the case of water the choice to use stainless steel is dictated by the following fundamental factors:
- chemical composition of the material
- presence of chloride
- flow conditions
- bacterial load
It is in fact necessary that the material that is used ensures a long life and without the need of maintenance. Austenitic stainless steels are the most suitable for this purpose. Thanks to a passive surface that characterizes them and gives them the resistance to corrosion.
Precautions to be taken during processing and installation.
During processing and the implementation to avoid corrosion it is necessary to take a few precautions.
- avoid any contamination that may happen during storage (example steel)
- avoid any contamination that might be happen for machining tools which previously used on carbon steels
- carry out the welding of the joints with the filler material by using an electrode compatible with base metal
- provide the use of connecting elements made in stainless steel for mechanical joints (to avoid corrosion by galvanic coupling)
- carry out the decontamination of surfaces with pickling and passivating calibrated products. (example detergents which don’t have the color of water, soap and water added to soda or steam)
Water cycle. Which stainless steel should we use?
As mentioned previously the austentic stainless steels types are those that have an increased use in the water cycle. In particular those in AISI 304 and AISI 316.
According to the law of the Ministry of Health from March 21th, 1973, only certain types of stainless steels can be used in contact with drinking water. (and more generally with food)
They are shown in the table leaf below.
Visit our web shop Inoxmare!
Check prices and availability of our products in stainless steel! Over 20,000 items including bolts, fittings, marine accessories and solar to choose.