1. Different scope of application: Flat welded steel flanges are suitable for connecting carbon steel pipes with a nominal pressure not exceeding 2.5MPa. The sealing surface of flat welding flanges can be made into three types: smooth, concave convex, and mortise and tenon groove. Smooth flat welding flanges are widely used in situations where the medium conditions are relatively mild, such as low-pressure non purified compressed air and low-pressure circulating water. Welding flanges are used on pipelines that transport expensive, flammable, and explosive media. Welding flanges are not easily deformed, have good sealing, and are widely used. The nominal pressure PN is around 16MPa.

2. Different welding methods: When welding flat flanges, only single-sided welding is required, and there is no need to weld the inner port of the pipeline and flange connection; The welding installation of butt welded flanges requires double-sided welding of the flanges. So the use of butt welding is to reduce stress concentration. Generally, butt welding flanges are mostly neck flanges, also known as nipple flanges.

3. Different prices: Flat welding flanges are relatively cheaper; However, due to the additional process, the installation cost, labor cost, and auxiliary material cost of welded flanges are higher, and the price is relatively more expensive.