Stainless steel is an alloy with a minimum of 10.5% chromium and contains enough chromium to form a passive layer of chromium oxide which prevents any corrosion of the surface and blocks corrosion from spreading into the internal structure of the metal. Stainless steel also contains varying amounts of nickel, carbon, silicon, and manganese. Our stainless steel products are type 304 steel with an 18:8 ratio. This means the stainless steel contains a ratio of 18% chromium to 8% nickel. We also have some industrial filter housings and NSF Certified UV systems that utilize a 316 type stainless steel for greater resistance to corrosion.
Where is Stainless Steel Used?
A type 304 stainless steel is the material of choice for the food processing, dairy, and brewing industries. 304 is also used by the water industry for filter housings, fittings, UV disinfection systems, flow restrictors, water distillers, and faucets.
Does Stainless Steel Corrode?
Even though stainless steel is much more resistant to corrosion than other forms of metal, it can corrode in some circumstances. In normal water based environments, stainless steel will not corrode. But in aggressive conditions where there is low oxygen, high salinity or poor circulation, there is a potential for corrosion. An example of this would be in the marine industry where stainless steel is exposed to salt water. Typically, coating the steel with epoxy can help prevent this corrosion.
Use a chlorine- and chloride-free stainless steel detergent or cleaner when washing stainless steel products.
Will Chlorine Damage Stainless Steel?
Chlorides are problematic with austenitic stainless steel like type 304, as they can cause pitting, crevice corrosion, and stress corrosion cracking. The generally recommended maximum chloride level for 304 stainless steel is only 200ppm, or 1000ppm for 316 stainless steel. Typical municipal water supplies will not affect austenitic stainless steels because of their low free chlorine levels, but free chlorine levels of as little as 25ppm can have damaging effects on the stainless steel. When using dish detergent or dish washing soap, use chlorine and chloride free options.
Is Stainless Steel Non-Magnetic?
It is a common practice to use a magnet to test the quality of stainless steel. However, it is not always true that stainless steel is will not be magnetic. The degree of magnetic response or magnetic permeability is derived from the microstructure of the steel. Type 304 stainless steel that is completely non-magnetic would have a magnetic permeability score of 1. In practice, this is not achieved. There is always a small amount of ferrite or martensite in the steel, causing it to score between 1.05 to 1.11. During the cold forming process, stainless steel can become slightly magnetic. Machining or polishing can also cause stainless steel to be magnatized. This does not change the elemental make-up of the stainless steel in any way; it is just a result of stress and pressure exerted on the stainless steel.