Difference between WN flange and SO flange

Weld neck flange(WN)?and?slip on flange(SO)?are the most commonly used flanges. There are two main differences between them.

Different Welding methods:?when welding flat welding flanges, only one side welding is needed, and the inner mouth of the pipeline and the flange connection is not needed. The welding installation of the butt welding flange requires double flange welding. Therefore, flat welded flanges are generally used for low and medium pressure pipelines, butt welded flanges are used for connection of medium and high pressure pipelines, butt welded flanges are generally at least PN2.5MPa. Butt welding flanges are mostly neck flanges, also called high neck flanges. Therefore, the installation cost, labor cost and auxiliary material cost of butt welding flange are higher, because there is one more process.

Different connection methods:?the biggest difference in structure between the neck welded flange and the neck butt welded flange is the difference in the connection method of the nozzle and the flange. The neck welded flange is generally connected to the flange and the flange, But the neck butt welding flange is the flange butt joint. Flat welded flanges can generally only be connected to pipes, but not directly to butt welded fittings; butt welded flanges can generally be directly connected to all butt welded pipe fittings (including elbows, tees, reducers, etc.), of course Also include pipes.