GI Bolts corrosion 1

[Merc-]

Hi All,

We have found that Galvanized Stud bolts are heavily corroded. What is the corrective action to rectify the corrosion problem here?

Corroded material: Stud bolts
Occurrence: Interconnecting piping, Pump suction-discharge connections
Atmosphere: Near Sea open atm

Its been observed that same bolts inside the process building are not corroded.

 

[mrfailure]

Galvanizing is by design a sacrificial coating. You will first see a corrosion problem outside where you have exposure to moist salt air but you may eventually have the same problem inside where concentrations of salt/moisture would be lower. Studs should be replaced using a robust coating/plating.

 

[EdStainless]

Were these double weight galv?
Have you ever used fluoropolymer coated hardware?

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[TugboatEng]

Use flat faced flanges!!!

 

[dik]

Oh, FFFs

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[weldstan]

How long have the bolts been in service? Of course the outside marine atmosphere bolts would corrode due to condensation of watr and exposure to the salty mists while the bolts inside would not be similarly exposed. We used flurocarbon covered bolting on a North Sea facing gas processing plant in Scotland.