Flanges Rusted bolts ... ? 1

[mostafaabdelazim]

i have a problem that too much bolts in my plant are rusted and corroded what are the possible ways to fix this problem other than HOT BOLTING what i mean is ways for cleaning ?

 

[gerhardl]

Questions about corrosion are probably more suited for the Corrosion engineering forum. I am unsure if you are asking for a cleaning (and protection) process for the existing bolts, or how to avoid the problem in the future.

For the last issue it all depends on the cause of corrosion, and where the corrosion has attacked, and how much damage it has caused. The cause can be atmospheric (acid atmospher, salt etc), galvanic (wrong materials against each other), other chemical corrosion types in addition to missing protection and/or wrong types of bolts.

If you want to avoid change of bolts to another type or material, 'sandblasting' by dry co2 might perhaps be an idea (protect windings), in addition to fluids for cleaning and protection.

 

[MikeHalloran]

I worked briefly as a maintenance mechanic in a chemical plant. Much of the piping was outdoors.

SOP was to coat all flange bolts and nuts liberally, all surfaces, with Never-Seez at first and every installation. That protected many of them well enough to re-use after just wire brushing off the bird droppings and such. If they were too corroded to unscrew easily, we'd discard and replace them.

Of course, nothing in that plant required exotic alloys, so replacing a bolt set was probably cheaper than cleaning it anyway.



Mike Halloran
Pembroke Pines, FL, USA

 

[moltenmetal]

For low temperatures, some use fluoropolymer coated studs and nuts. In less corrosive environments, for temperatures below 200 C, others get by with zinc coated studs and nuts with a liberal application of antisieze grease. For high temperatures, your options are more limited.