Galvanic Corrosion in Pump casing

[mechanical2014]

A pump is being installed offshore, while pump casing is of Duplex Stainless Steel, casing bolts are of carbon steel(A193-B7 ). What is the possibility of galvanic corrosion for this combination due to moisture in marine atmosphere?

 

[Artisi]

Fairly high I should imagine, why not change all hardware to stainless steel?

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[mechanical2014]

Expected. Is this a Good idea to use suitable coating and keep spare bolts (CS). Introduce changeover of the same in periodic maintenance (Once a year). Just a thought!!!

 

[Artisi]

Why?

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[1gibson]

If the pump configuration is such that the bolts aren't "wetted fasteners" then there may be no standard to point to that requires duplex bolting for the duplex case.

Higher strength than A193-B8M (316) may be required, and B7 is the economical option. Don't go to lower strength hardware without checking with the manufacturer.

 

[TenPenny]

In the pumps we have supplied offshore, if the pump material is Duplex, the customer generally requests all bolting to be Duplex as well.

 

[mechanical2014]

Thanks Everyone!!