Bolting material for piping on LPG barge
Bolting material for piping on LPG barge
(OP)
Dear all,
We are preparing material spec for pipelines mounted on small LPG barge.
Owner wants to use carbon steel pipes and flanges (pressure depend on cargo, max 18barg). Deck of barge can be exposed to seawater piplinees, so pipelines will be painted to avoid corrosion.
Because of seawater, i would like to use stainless steel studs with nuts: ASTM A320 B8M/ ASTM A193 Gr. 8M. I know that main players (SHI, HHI) in LPG carriers design and manufacturing using this grade of stud/nuts.
Have You got any remarks or comments?
Best regarda,
MA
We are preparing material spec for pipelines mounted on small LPG barge.
Owner wants to use carbon steel pipes and flanges (pressure depend on cargo, max 18barg). Deck of barge can be exposed to seawater piplinees, so pipelines will be painted to avoid corrosion.
Because of seawater, i would like to use stainless steel studs with nuts: ASTM A320 B8M/ ASTM A193 Gr. 8M. I know that main players (SHI, HHI) in LPG carriers design and manufacturing using this grade of stud/nuts.
Have You got any remarks or comments?
Best regarda,
MA





RE: Bolting material for piping on LPG barge
You might end up with corrosion issues if you use stainless fixings with carbon steel flanges especially with moisture around.
Look at this link:-
http
desertfox
RE: Bolting material for piping on LPG barge
RE: Bolting material for piping on LPG barge
Desertfox:
I heard about some issue with corrosion in that type of connection. But i'm wondering if that painting agianst corrosion on piping components can be helpful and isolate materials.
Most of temperature and pressure indicators which i have seen (onshore, offshore) are made of SS and bolted to carbon steel flanges by SS bolts/nuts. For longlife service it could br subject to control. But is it really big issue?
Ash9144:
Design temperature is 0 - 50 deg C, Max ambient temperature is 40 deg C. Pipelines will be used to carry gas (liquid, vapour). So temperature would not be higher then mentioned above.
I do understand that for high temperature service differences in thermal expansion are very important, but for ambient it should not be a problem ?.
MA
RE: Bolting material for piping on LPG barge
Well paint should insulate it however are you sure the paint will be consistant in the flange hole.
desertfox
RE: Bolting material for piping on LPG barge
Steve Jones
Materials & Corrosion Engineer
http://www.oilandgaspeople.com/cv/11499664
http://www.linkedin.com/pub/8/83b/b04
RE: Bolting material for piping on LPG barge
Look at this link on stainless 316 grade:-
http://w
desertfox
RE: Bolting material for piping on LPG barge
RE: Bolting material for piping on LPG barge
Have You got any idea what is the difference in price between B8M and coated B7?
MA
RE: Bolting material for piping on LPG barge
RE: Bolting material for piping on LPG barge
Most - but not all - do not corrode if NOT exposed to wear or rubbing. Those that ARE "touched" or bumped or exposed to contact from deck gear, chains, ropes, people's hands and tools, cables or power hookups, moving hatches, loads, cargo, hoses, people walking by .... etc, etc, etc, do immediately begin corroding. Obviously anything regularly bolted and unbolted MUST NOT be preserved by painting - you'll have to accept the cost penalty of chrome or stainless.
Yacht fittings and rope gear and deck cleats are chrome and brass and stainless for a reason!