Flange connection involves securing two pipes, fittings, or equipment to separate flange plates first, then inserting a flange gasket between the two flanges and fastening them together with bolts, thus completing the connection. Some fittings and equipment come with a flange plate already attached, which also falls under flange connection. Flange connection is an essential method for pipeline construction.
According to the method of connection, flange types can be classified as: flat welding flange, socket welding flange, slip-on welding flange, saddle welding flange, threaded flange, flange cover, and lug welding ring flange.
Socket flanges, slip-on flat焊接flanges, ring groove flanges and flange covers, large diameter flat flanges, large diameter high-neck flanges, L-shaped blind flanges, socket welding flanges, etc.


Flat焊接flanges are suitable for steel pipeline connections with nominal pressures 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...
Usage. Commonly used under mild medium conditions, such as low-pressure non-purified compressed air, low-pressure recirculating water.
The neck height of a socket weld flange is lower, which improves the rigidity and load-bearing capacity of the flange. Compared to a welding neck flange, it requires more welding work and higher consumption of welding rods.High-pressure andBendable and resistant to temperature fluctuations, yet easy to install on-site, allowing for the omission of the welding seam rubbing process, making it quite popular.


The flat welding ring loose flange is a movable flange plate, commonly used with plumbing and drainage accessories (most often on expansion joints). When the manufacturer ships the product, each end of the expansion joint comes with a flange, which is directly connected to the pipeline and equipment in the project using bolts. The general purpose of using the flat welding ring loose flange is to save materials. Its structure is divided into two parts: the pipe section connects to the pipe and has a flange edge on the other end, while the flange section is fitted over the flange edge. 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.

Loose-bolt flanges with socket welding rings, socket welding flanges with neck, socket welding flat ring flanges, flat ring loose flanges, and loose flanges with flipped flat rings. Additionally, to meet the locking requirements after installation, there are flanges with bolted holes to prevent loosening during vibration. Some flange bolts have smooth shanks without threads and need to be made thin, known as slender shank flange bolts. These bolts are beneficial for connections subjected to variable forces. There are special high-strength bolts used on steel structures, which have 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.