Corrosion on 430 stainless steel bolt head after salt-spray test

[mrippo]

I am a mechanical engineer working in the CATV (cable TV) industry, and after a recent salt-spray test, the 430 stainless steel bolts (passivated) which fasten our clam-shell enclosure design together for the outdoor environment have shown signs of rust (particularly in the bolt head region). The entire unit was suspended in a salt-spray chamber and subjected to a salt-spray condition of 95 degrees F for 14 days within a salt-fog solution containing 5% sodium chloride (salt).

Can anyone shed some light why the passivation process in the 430 stainless may have been interrupted and the salt-spray solution was allowed to attack the underlying metal?

 

[WKTaylor]

You will get a lot more response on the corrosion forum: forum338.

As a guess: the paasivation [natural oxide] is being erroded and cannot reform under the constant salt spray. Regards, Wil Taylor

 

[DangerDog]

400 series stainless steels are more apt to corrode than 300 series, is there a reason you picked a 400 series?

 

[GregLocock]

If it is for salt spray with aluminium components then use 316, rather than 314. Cheers

Greg Locock