Is a galvanized pipe just coated with a layer of zinc on its surface? Can it be welded directly to carbon steel pipes?
Thread Content
Is a galvanized pipe just coated with a layer of zinc on its surface? Can it be welded directly to carbon steel pipes? Most of those I’ve seen use threaded connections. Why is that?
**The standard GB/T3091-2008 \"Welded steel pipes for low-pressure fluid transport\" does mention galvanized pipes; these involve a galvanized surface. Nowadays, hot-dip galvanized pipes are mostly used as they provide corrosion resistance. In particular, hot-dip galvanized pipes should be chosen for pipes that will be buried underground； As for the connection method, I have never seen hot-dip galvanized pipes that are welded together; they are all connected using threads. They are used as protective pipes or air pipes. Last edited by minjie061 on 2009-4-18 15:01.]
Under normal circumstances, both galvanized pipes and carbon steel pipes require anti-corrosion treatment
Galvanized pipes and carbon steel pipes can be welded; it is just necessary to choose the appropriate welding material depending on the type of material. Generally, galvanized pipes are used for water supply and are manufactured according to British standards; therefore, they come with corresponding pipe threads and connection fittings, which is why threaded connections are commonly used.
As I understand it, galvanized pipes are generally not welded but connected by threading, as welding would damage their galvanized coating. I’m not sure if this understanding is correct. Additionally, galvanizing can be applied not only to the surface but also to the inner walls of pipes. This post was last edited by swallowam on 2009-4-19 01:41]
Galvanized pipes can be welded, but they are generally not welded. If there are special requirements or restrictions that necessitate welding, the welded areas generally need to be treated and then galvanized again.
Galvanized steel pipes are generally connected using threads; in special cases, welding can be used, and the weld seam should be treated with anti-corrosion measures afterward.
When welding galvanized pipes with steel pipes, the galvanizing layer on the galvanized pipe must be removed to prevent weak welds
It indeed has just an additional layer of galvanizing; the material is carbon steel in both cases. Direct welding poses no problem. As for why threaded connections are used, it is because: 1) to protect the galvanized layer from being damaged ； 2 is that it has high requirements for the cleanliness of the medium inside the pipe.