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Stainless steel Huck bolts - broken end corrosion
- Thread starter trainguy
- Start date
BridgeSmith
Structural
I wouldn't think applying zinc-rich paint to stainless steel would do anything...except flake off later.
Its important to understand how galvanizing and zinc-rich paints protect carbon steel.
Remember, when carbon steel corrodes, it forms big flakes that fall away. Zinc protects against this corrosion. Stainless steel forms an oxide layer, but does not flake .....
It is a good idea to review the galvanic series ....
You could also post your question in the "Corrosion Engineering" forum and get a better answer
MJCronin
Sr. Process Engineer
Remember, when carbon steel corrodes, it forms big flakes that fall away. Zinc protects against this corrosion. Stainless steel forms an oxide layer, but does not flake .....
It is a good idea to review the galvanic series ....
You could also post your question in the "Corrosion Engineering" forum and get a better answer
MJCronin
Sr. Process Engineer
Yes. Zinc on stainless steel could make it worse.
There is a mechanism of liquid metal embrittlement when stainless steel contacts with zinc and it is susceptible to brittle fracture especially in fire case. It is common practice to avoid any contact between the two as clearly described in section 4.5.5 and table 4-9 of API 571. )
(Quoted from API 571 section 4.5.5.6)
300 series SS should be protected to avoid contact with galvanized components and overspray from zinc and inorgarnic zinc coatings.)
(Unquoted)
If the bolt is just to open to air (NOT submerged nor internal bolt of process fluid), the use of bare stainless steel bolt will be O.K as oxide film as CR2O3 on ss can protect the surface from atmospheric corrosion.
Lee SiHyoung,
Engineer - Material & Corrosion Specialist
WorleyParsons Oman Engineering,
cap1a79@gmail.com
There is a mechanism of liquid metal embrittlement when stainless steel contacts with zinc and it is susceptible to brittle fracture especially in fire case. It is common practice to avoid any contact between the two as clearly described in section 4.5.5 and table 4-9 of API 571. )
(Quoted from API 571 section 4.5.5.6)
300 series SS should be protected to avoid contact with galvanized components and overspray from zinc and inorgarnic zinc coatings.)
(Unquoted)
If the bolt is just to open to air (NOT submerged nor internal bolt of process fluid), the use of bare stainless steel bolt will be O.K as oxide film as CR2O3 on ss can protect the surface from atmospheric corrosion.
Lee SiHyoung,
Engineer - Material & Corrosion Specialist
WorleyParsons Oman Engineering,
cap1a79@gmail.com
EdStainless
Materials
In general you are better off leaving the SS bare. If you coat it then you have formed a crevice corrosion situation, and every little holiday in the coating will be a corrosion initiation point.
If people have to provide galvanic protection for SS they prefer to use thermal spray Al and then cover it with a sealer.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube
If people have to provide galvanic protection for SS they prefer to use thermal spray Al and then cover it with a sealer.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube
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