The use and features of galvanized steel pipe
Use of galvanized steel pipe:
Often said galvanized pipe is now mainly used for conveying gas, heating. Galvanized pipe as a water pipe, after several years of use, the pipe produces a lot of rust and scale, the yellow water flowing out not only contaminates the sanitary ware, but also contains the bacteria bred on the inner wall; The high content of heavy metals in water caused by rust is seriously harmful to human health. In the 1960s and 1970s, the developed countries in the world began to develop new types of pipes and gradually banned galvanized pipes. China's Ministry of Construction and other four ministries and commissions also issued a clear ban on galvanized pipes from 2002. At present, the cold water pipe of the new community has rarely used galvanized pipe, and the hot water pipe can also temporarily use galvanized pipe.
Galvanized steel welding process features:
Galvanized steel is generally in low carbon steel coated with a layer of zinc plating layer is generally 20um thick. Zinc has a melting point of 419°C and a boiling point of 908°C. In welding, zinc melts into a liquid floating on the surface of the weld pool or at the root of the weld. Zinc has a large solid solubility in iron, and the zinc liquid will deeply etch the low melting point zinc of the weld metal along the grain boundary to form "liquid metallization". These brittle phases reduce the plasticity of the weld metal and crack under the action of tensile stress. If the fillet welds are welded, especially the fillet welds of T-shaped joints, the penetration cracks are most likely to occur.