Flat welding flanges include plate flat welding flanges and neck flat welding flanges.
Plate flat welding flange (PL)
Flat welding flanges are suitable for steel pipe connections with a nominal pressure not exceeding 2.5MPa. The sealing surfaces of flat welding flanges can be made into three types: smooth, concave and convex and tongue and groove. The smooth flat welding flange has the largest application. It is mostly used when the medium conditions are relatively mild, such as low-pressure unpurified compressed air and low-pressure circulating water.
With neck flat welding flange (SO)
The neck height of the flat-welded flange with neck is lower, which improves the rigidity and bearing capacity of the flange. Compared with butt-welded flanges, the welding workload is large, the electrode consumption is high, and it cannot withstand high temperature and pressure, repeated bending and temperature fluctuations, but it is more convenient for on-site installation and can omit the process of welding seam scratching. It is more popular.
(5) Butt welding with neck (WN)
Butt welding flange: neck flange welding is usually called "high hub" flange. The purpose is to transfer the pressure of the pipeline, thereby reducing the high stress concentration in the flange base. Neck flange welding is the best design for butt welding those flanges that are provided due to their inherent structural value. However, the price is relatively high because the production process of the product is complicated.