Flat welding and butt welding refers to two different types of the flange and pipe joint welding modes. Manufacturing standard of welding flange, and flat welding flange is different, so is the applicable occasion.
Here is a brief induction of the two methods of welding flanges to the pipes, and two types of flanges.
Butt welding flange, the diameter and wall thickness of the flange end should be same as the pipe to be welded, just like two pipes to be welded together. Butt welding has better welding performance and less corrosion, used to reduce stress concentration. Generally, the pressure for butt welding flanges is at least PN2.5mpa. Flange welding installation requires double welding of the flange. Butt welding flanges with a neck flange is also called high neck flange. As the method calls for one more working procedure, the installation cost of welding flange, labor cost and auxiliary material cost are higher.
Flat welding flange refers to the flange whose groove at the joint machined, is a little larger than the outer diameter of the pipe, in which the pipe is inserted for welding. Flat welding flange is generally used for low and medium pressure pipes. As for the welding method, it only calls for welding at one side. And there is no need to weld the connection of pipe and flange of the end’s inner side. Generally speaking, the welding performance is better than socket welding, and difficulty is smaller.