Stainless Steel Bolts & Mild Steel Potential Corrosion
Stainless Steel Bolts & Mild Steel Potential Corrosion
(OP)
Hi,
We are working in a water treatment plant and will be installing stainless steel bolts in a piping system. The piping system will consist of mild steel flanges connecting with ductile iron body butterfly valves. Piping is located indoors in northern Texas so while subject to humidity it will not be subject to any salt spray. Can anyone see a reason Stainless Steel bolts would need to be isolated from the mild steel/Ductile Iron?
We are working in a water treatment plant and will be installing stainless steel bolts in a piping system. The piping system will consist of mild steel flanges connecting with ductile iron body butterfly valves. Piping is located indoors in northern Texas so while subject to humidity it will not be subject to any salt spray. Can anyone see a reason Stainless Steel bolts would need to be isolated from the mild steel/Ductile Iron?





RE: Stainless Steel Bolts & Mild Steel Potential Corrosion
And as long as you have the anti-seize out it may not be a bad idea to put some between the fasteners and the steel and iron to at least reduce the SSTL being contaminated with iron which could cause the appearance of the SSTL rusting.
RE: Stainless Steel Bolts & Mild Steel Potential Corrosion
RE: Stainless Steel Bolts & Mild Steel Potential Corrosion
RE: Stainless Steel Bolts & Mild Steel Potential Corrosion
Why are you changing to SS hardware ?
Difficulties with removal for service, perhaps ?
Or Spiffy-ing up the station for public tours?
regards,
Dan T
RE: Stainless Steel Bolts & Mild Steel Potential Corrosion
RE: Stainless Steel Bolts & Mild Steel Potential Corrosion
Here some guidelines that i found on the web.
http://www.anzor.com.au/blog/the-dos-and-donts-of-...
RE: Stainless Steel Bolts & Mild Steel Potential Corrosion
RE: Stainless Steel Bolts & Mild Steel Potential Corrosion
If this gets wet it will bleed rust all over and you will have accelerated galvanic attack there which can result in loss of tightness.
You need bolts with rolled threads and you need a good anti-seize compound designed for Stainless Steel.
I am partial to the ones with Cu in them, but there are many that work.
And pray that it is rare that these will be taken apart.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube
RE: Stainless Steel Bolts & Mild Steel Potential Corrosion
I'd be checking bolt strength requirement for the flange class of piping. Some SS bolts are pretty cheesy, with yield strengths a lower percentage of UTS than "real" bolts.
RE: Stainless Steel Bolts & Mild Steel Potential Corrosion
IF NOT then CRES [nickel alloy] will be highly dissimilar to steel and initiate corrosion on a mass scale
Regards, Wil Taylor
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