EN10210 ERW Black Steel Pipe Urban Construction Water Engineer

Welded Steel Pipe 3 Inch Urban Construction Water Engineering ERW Steel Pipe

The forming process generally adopts the rolling cold forming method.The diameter of high frequency straight seam welded steel pipe is generally small, generally below 660mmor 26in outside diameter. 

Physical seamless refers to the difference between the metallographic structure inside the weld and the base metal, which results in the decrease of the mechanical properties of the weld area. It is necessary to take measures to make it uniform and consistent.The high frequency welding thermal process of ERW steel tube results in the gradient of temperature distribution near the edge of the tube blank, and forms the characteristic areas such as melting zone, semi-melting zone, superheated structure, normalizing zone, incomplete normalizing zone and refiring zone.

Among them, the austenite grains in the overheated area grow rapidly due to the welding temperature above 1000℃, and the hard and brittle coarse grain phase will be formed under the cooling condition. In addition, the existence of temperature gradient will produce welding stress.In this way, the mechanical properties of the weld area are lower than that of the base metal. Physical seamless is to heat the weld area to AC3(927℃) through the local conventional heat treatment process of the weld area, namely the use of intermediate frequency induction heating device, and then carry out the air cooling process with a length of 60m and a speed of 20m/ min, and then water cooling when necessary