Connection of large-diameter galvanized steel pipes
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Looking at the Piping classes developed by the company in the past, for galvanized steel pipes, threaded connections are used for pipes up to 4”, while welding is employed for pipes larger than 4”. I wonder if it’s convenient to apply zinc coating again after welding galvanized steel pipes Especially the internal part? Please give some advice, thank you!
This post was last edited by Thank goodness you're here on 2019-10-24 at 14:31. Can’t zinc be added inside after welding, right? Unless the pipe is pulled out again for galvanizing. Unless the weld that requires zinc supplementation is very close to one end of the pipeline, use a brush to apply a couple of coats of zinc-rich primer inside it.
Galvanizing is not possible inside such pipes, and their service life is even shorter than that of carbon steel pipes due to galvanic corrosion.
Use a brush to apply the zinc-rich primer there a couple of times; however, doing this has no real purpose – the fluids inside the pipes will wash it away in just a few moments, and the paint layer still represents a risk