Iron contamination occurs when there is a deposit of iron surface of stainless steel. Oxidation of the iron results in the accumulation of rust staining. This staining can be slight and only appear on the surface, or can cause severe pitting or marks.
Common sources of iron contamination include:
- Stainless steel coming into contact with any other steel or iron materials
- Tools and parts previously used on steel or iron
- Environment and atmosphere – the area the stainless steel is kept in, including the air, water or other chemicals used to clean the surface
Possible consequences of iron contamination include:
- Reddish-brown or rust deposits on the surface
- Process contamination
- High enough levels of iron could accelerate some forms of corrosion
Avoiding Iron Contamination
Despite a wide variety of possible sources, iron contamination can be avoided.
Frequently, contamination occurs when non-stainless steel processing or equipment is used. Workshops that handle mixed metals or debris are a frequent source of contamination.
International Corrosion Services exclusively treats stainless steel so there is no risk of cross contamination. Soft slings are used for all crane movements, ensuring the stainless steel is free from scratches and damage.
Testing for Iron Contamination
ICS can perform testing for iron contamination, in line with American standards ASTM A380 and A967. Ferroxyl testing, which can detect both free iron or iron oxide, is the best method for testing and is able to detect even small levels of contamination.
The Ferroxyl test indicates the presence of Fe2+ irons by turning blue. It is often used to detect rusting.
Due to its high sensitivity, this test is best used when no traces of free iron or iron oxide are acceptable on stainless steel. It can detect contamination, marks, residual salt, iron dust and deposits – whether these are caused by pickling solutions or welding.
Ferroxyl testing can be conducted to determine if austenitic stainless steel requires pickling, or has been pickled to a satisfactory standard.
ICS offer both onsite and inhouse Ferroxyl testing.