There are several ways to connect steel pipes: welding, groove clamp connection, flange connection, wire connection, and socket connection. Generally speaking, galvanized steel pipe refers to galvanized straight seam welded pipe, which is rolled into a steel pipe with galvanized steel and welded by submerged arc welding. There is a weld on the pipe wall, so it is called a welded pipe. This kind of pipe cannot be welded. Welding will destroy the galvanized layer and seriously affect the corrosion resistance of the steel pipe. Usually threaded connection, threaded flange connection, grooved clamp connection. The galvanized seamless steel pipe can be welded. Due to the high hardness of the seamless steel pipe, it is difficult to twist the wire, so it is generally welded, or welded flange connection, rolled groove clamp connection.
The connection method also has requirements on the pipe diameter. DN15~DN100 is suitable for threaded connection, and DN65~DN400 or larger models are suitable for flange connection. DN80~DN200 can also be connected by grooves. Because galvanized steel pipes cannot be welded, the maximum specification is usually DN200, and DN300 can also be purchased in the market, and it is difficult to buy larger than this size.
