Corrosion Resistant, Code Compliant Steam Piping bolts
Corrosion Resistant, Code Compliant Steam Piping bolts
(OP)
I am the engineer at the hospital in American Samoa, located about half way between Hawaii and New Zealand. The hospital is at 17 feet above sea level, and half a mile up a narrow valley. Mild steel used indoors exhibits surface rust in about 2 weeks. We replace our galvanized steel centrifugal cooling tower fan wheels annually, as they literally disintigrate and fly apart. Materials failure is a major problem.
I am specifying a rotoclave to deal with our medical waste. I visited the factory, and we are changing a lot of the hardware to 316 SS in order to deal with the corrosion.
I am trying to find corrosion resistant steam piping flange bolts/studs. We run 60PSI steam (appx 300F). My boiler rep (in Hawaii) states that ONLY ASME B31.1 classed studs are legal. There is no governing authority on-island, though I am charged with complying with US codes and standards.
A bolt vendor whom I trust in LA has suggested studs meeting A193-B8M, which are 316ss, hi tensile. He indicated that these are suitable for use up to 800F.
Could anybody with knowledge of this situation please comment? I would have thought that code compliant, corrosion resistant steam piping flange bolts would have been a little easier to find, but it seems like I'm breaking new ground here...
Thanks
I am specifying a rotoclave to deal with our medical waste. I visited the factory, and we are changing a lot of the hardware to 316 SS in order to deal with the corrosion.
I am trying to find corrosion resistant steam piping flange bolts/studs. We run 60PSI steam (appx 300F). My boiler rep (in Hawaii) states that ONLY ASME B31.1 classed studs are legal. There is no governing authority on-island, though I am charged with complying with US codes and standards.
A bolt vendor whom I trust in LA has suggested studs meeting A193-B8M, which are 316ss, hi tensile. He indicated that these are suitable for use up to 800F.
Could anybody with knowledge of this situation please comment? I would have thought that code compliant, corrosion resistant steam piping flange bolts would have been a little easier to find, but it seems like I'm breaking new ground here...
Thanks





RE: Corrosion Resistant, Code Compliant Steam Piping bolts
RE: Corrosion Resistant, Code Compliant Steam Piping bolts
Are the lines insulated?
Are they in service all of the time?
I would rather see you use epoxy paint to protect CS than use stainless. Chloride stress cracking is a real risk if these lines ever get damp.
= = = = = = = = = = = = = = = = = = = =
Corrosion, every where, all the time.
Manage it or it will manage you.
http://www.trent-tube.com/contact/Tech_Assist.cfm
RE: Corrosion Resistant, Code Compliant Steam Piping bolts
The stainless bolting/fasteners may not be the best choice. Stainless will thermally expand more than carbon steel fasters upon heat-up of the steam system.
A premium epoxy or teflon coating for the bolting may be a better choice.
There is a good discussion here:
http://hghouston.com/dcforum/DCForumID2/139.html
Gimmie a star...
RE: Corrosion Resistant, Code Compliant Steam Piping bolts
If corrosion conditions warrant stainless, connect SS items of different microstructures. E.g., 18Cr-2Ni-12Mn or Custom 455 with 304 or 316. Carpenter Technology also sells proprietary 'Gall-Tough' (UNS S20161) and 'Gall-Tough Plus' nitrogen-strengthened austenic SS which resist galling. See Carpenter Stainless Steels. Selection. Alloy Data. Fabrication.
or
http://w
[free registration required for free downloads]
You can also use an anti-seize thread lubricant to minimize galling, silver plating, pre-oxidation in air to at 1300oF to form a thicker, non-galling dark oxide, use dry film lubricant, etc.