Connection of welded steel pipes and galvanized steel pipes
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How to connect welded steel pipes and galvanized steel pipes: by threading or welding?
Threaded or socketed connections shall be used; welding is not permitted.
It cannot be welded directly; threading is required to connect them
1# yuzhu_200699 Welding, threaded connection, free connection. Although welding provides a strong connection, it is not recommended as it makes installation and subsequent maintenance difficult, and the components are not easy to disassemble. Free connections are not very secure and can only withstand low levels of pressure; if the ends of the connection are not properly fixed, it is easy for them to come loose under high pressure. This is especially true in winter when pipes freeze – as water turns to ice, its volume expands, causing the pipes to stretch out at both ends. Building construction codes require that galvanized steel pipes be connected only by threading
Either threaded connection or welding is acceptable. Just choose according to your actual situation. Of course, choosing a threaded connection also depends on whether you can machine the appropriate threads for it.
Thank you all. What I need to do now is install a vent pipe at the outlet of the circulation pump. The diameter of the circulation pump’s outlet pipe is DN700 (carbon steel pipe), and I want to use a DN50 vent pipe. So what type of material should be used for this vent pipe? How can a galvanized steel pipe be connected to the outlet pipe? Is welding possible? Is it inconvenient to thread carbon steel pipes?
For this marine application, isn’t socketing also a type of welding? I think it depends on the type of medium and the requirements of the client. In principle, threaded connections are preferable; if welding is necessary, either butt welding or socketing can be used, but be sure to apply a zinc-rich primer
It can be tapped; ordinary 20# steel pipes can be tapped, but for DN50 it is recommended to use a socket connection
It can be welded or connected using flanges
Galvanized pipes cannot be welded; flange connections can be considered as an alternative