Corrosion of Stainless Steel
Corrosion of Stainless Steel
(OP)
I have a client who is wondering why some of their stainless steel guardrails/handrails are showing signs of surface corrosion after one winter. These are exterior guardrails. The stainless steel is Type 304, with a light sandblasted finish.
DaveAtkins






RE: Corrosion of Stainless Steel
RE: Corrosion of Stainless Steel
Even without initial contamination from tools, the surface would typically need to be acid pickled to remove surface iron after manufacture. Pickling removes the iron exposed on the surface, exposing chromium. The chrome oxidizes quickly to form the characteristic chrome oxide layer that protects high-chromium stainless from weathering.
Also, residual stresses from fabricating stainless steel can result in stress corrosion cracking.
Uncontrolled, the pitting corrosion may continue deeper into the steel. As with any steel, chlorides can increase the incidence of corrosion.
RE: Corrosion of Stainless Steel
An expert is a man who has made all the mistakes which can be made in a very narrow field
RE: Corrosion of Stainless Steel
The pattern of corrosion will also help to determine its cause. Both TX and JC noted that.
Check the finishing process. If acid washed, check the type of acid used. If nitric acid was used, that could be an issue.
RE: Corrosion of Stainless Steel
Dik
RE: Corrosion of Stainless Steel
Also if the handrails are riveted often the mantle in these rivets are normal steel, staining everything in their path.
An expert is a man who has made all the mistakes which can be made in a very narrow field