The butt-welding ring loose flange is a movable flange piece, which is usually matched with the water supply and drainage fittings. When the manufacturer leaves the factory, there is a piece of the flange at each end of the expansion joint, which is directly connected to the pipeline and equipment in the project with bolts.
The purpose of using butt welding ring loose sleeve flange is generally to save material. Its structure is divided into two parts. One end of the pipe part is connected to the pipe, and the other end is made into a butt welding ring. The flange is made of low-grade material, while the pipe part is made of the same material as the pipe, so as to save material.

The role of butt welding ring loose flange
1. Cost saving. When the pipe material is special and expensive, the cost of welding flanges of the same material is high.
2. It is not convenient for welding or processing or requires high strength. Such as plastic pipes, glass steel pipes and the like.
3. It is convenient for construction. For example, it is not easy to align the flange bolt holes during connection or prevent the flange bolt holes from changing in the future when the equipment is replaced.

Disadvantages of butt welding ring loose flange:
1. Low pressure.
2. The strength of the welding ring is low (especially when the thickness is less than 3mm)

Standards for butt weld ring loose flanges:
National standard: GB/T9112-2000 (GB9115.1-2000~GB9115.4-2000)
American Standard: ANSI B16.5 Class150, 300, 600, 900, 1500 (WN, SO, BL, TH, LJ, SW)
Japanese standard: JIS 5K, 10K, 16K, 20K (PL, SO, BL, WN, TH, SW)