Stainless Steel --> Iron Oxide?
Stainless Steel --> Iron Oxide?
(OP)
From my understanding, stainless steel is an iron alloy consisting of carbon, chromium, nickel. Chromium and nickel atoms form oxides that seal iron off from oxidizing.
How do the oxides seal the iron, does it have something to due with the crystal structure?
How exactly does does iron oxide occur from abrasion with a steel object?
How do the oxides seal the iron, does it have something to due with the crystal structure?
How exactly does does iron oxide occur from abrasion with a steel object?
Field Test Engineer w/BSME
I heart Beer Brewing & Traditional Hotrods





RE: Stainless Steel --> Iron Oxide?
Non stainless particles ( free iron ) are transferred to the surface of the stainless part from the steel object.
B.E.
The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them. Old professor
RE: Stainless Steel --> Iron Oxide?
Why/how does a stainless steel weldment some times form iron oxides at its welds
Field Test Engineer w/BSME
I heart Beer Brewing & Traditional Hotrods
RE: Stainless Steel --> Iron Oxide?
Richard www.6sproductivitycom.com
RE: Stainless Steel --> Iron Oxide?
You can clean the surface, but unless you completely remove the "stain", it will remain (obviously). This "stain" is a often a mixture of iron and chromium oxides and it can be very hard. It usually takes abrasive methods to remove it. Of course, you are also removing the protective chromium oxide layer adjacent to the "stain", so you would want to allow the surface to "passivate" prior to putting such a cleaned part back into service.
rp
RE: Stainless Steel --> Iron Oxide?
If the tested area turns blue you have free iron present.
Some juristictions are now limiting this test, because it uses cyanide compounds.
It is also possible to remove the stain by electro passivation.
B.E.
The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them. Old professor
RE: Stainless Steel --> Iron Oxide?
There are other tests for free Fe on the surface.
= = = = = = = = = = = = = = = = = = = =
Plymouth Tube
RE: Stainless Steel --> Iron Oxide?
As suggested by berkshire, Feroxyl test can be used to detect free iron on surface of Stainless Steel (SS).
A possible cause of iron oxides at welds could be also the welding consumable used, if not appropriate the local Chromium content could fall down and avoid the formation of Chromium Oxide.
Other possible causes for oxidation of stainles steel can be:
- uncorrect sandblasting consumable (e.g. abrasive for carbon steel material grades used on SS material),
- pickling of SS material not sufficient,
If present, the carbon steel embedded in the surface is very difficult to remove and it usually requires long/aggressive pickling.
From my experience, the best way to remove free iron/Fe is to re-perform sandblasting with appropriate abrasive for Stainless Steel materials, followed by an accurate pickling.
Hope this helps, regards.
Attilio Brambilla
//it.linke din.com/pu b/attilio- brambilla/ 25/465/544
Material Engineer
http: