Flange connection involves fixing two pipes, fittings, or equipment to separate flange discs first, then inserting a flange gasket between the two flanges and securing them together with bolts, thereby completing the connection. Some fittings and equipment come with a flange disc already attached, which also falls under flange connection. Flange connection is an important method for pipeline construction.
According to the type of connection, flange connections can be classified into: flat welding flange, socket welding flange, blind flange, threaded flange, and flange cover, necked socket welding ring gasket.
Socket flange, slip-on welding neck flange, ring groove face flange and cover, large diameter flat flange, large diameter high neck flange, blind flange with bevel, socket welding neck flange, etc.


Flat welding flanges are suitable for steel pipeline connections with a nominal pressure not exceeding 2.5 MPa. The sealing surfaces of flat welding flanges can be made in three types: smooth, concave-convex, and tenon-slot. Smooth flat welding flanges are used for...
Quantity. Commonly used under mild medium conditions, such as low-pressure non-purified compressed air, low-pressure recirculating water.
The neck height of the socket welding flange is lower, which improves the rigidity and load-bearing capacity of the flange. Compared to the welding neck flange, it requires more welding work and higher consumption of welding rods.High-pressure andBend and temperature fluctuations, but the on-site installation is convenient, and the process of welding seam patting and bruising can be omitted, making it popular.


A flat welding ring loose flange is a movable flange plate, commonly used with plumbing and drainage accessories (most often with expansion joints). When the manufacturer ships the product, each end of the expansion joint has a flange, which is directly connected to the pipeline and equipment in the project with bolts. The general purpose of using a flat welding ring loose flange is to save materials. Its structure is divided into two parts: the pipe section connects to the pipeline at one end and is flanged at the other, while the flange section is slipped over the flange. The flange is made of low-grade material, and the pipe section is made of the same material as the pipeline, achieving the goal of material savings.

Sleeve flanged loose fit neck flanges, sleeve flanged plate flanges, flat flanged loose fit plate flanges, and plate flanged inverted loose fit flanges. Additionally, to meet the locking requirements after installation, there are bolts with holes in the shank to prevent loosening due to vibration. Some法兰bolts have a smooth shank without threads and need to be made finer, referred to as fine shank法兰bolts. These法兰bolts are beneficial for connections subjected to variable forces. Special high-strength bolts are used on steel structures, with larger heads and varying sizes. Hot-dip galvanized round steel is produced by causing the molten metal to react with the iron substrate to form an alloy layer.