Flange connections involve securing two pipes, fittings, or equipment to separate flange discs first, then inserting a flange gasket between the two discs and fastening them together with bolts to complete the connection. Some fittings and equipment come with built-in flange discs and are also considered flange connections. Flange connections are an essential method for pipeline construction.
Flange connections can be categorized by their connection methods as follows: flat welding flange, socket welding flange, blind flange, threaded flange, and flange cover with socket welding ring.
Socket flanges, slip-on flat welding flanges, ring groove face flanges and flange covers, large diameter flat flanges, large diameter long neck flanges, winged blind flanges, and socket welding ring flanges, etc.


Flat焊接flanges are suitable for steel pipeline connections with 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 suitable for...
Usage. Commonly used in milder medium conditions, such as low-pressure non-purified compressed air, low-pressure circulating 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 consumes more welding rods.High-pressure andComplex bending and temperature fluctuations, but easy on-site installation, allowing for the skipping of the weld seam rubbing process, making it popular.


Flat Weld Ring Flanged Hub is a movable flange, commonly used with water supply and drainage accessories (most often found on expansion joints). When the manufacturer ships the product, each end of the expansion joint is equipped with a flange, which is directly connected to the pipeline and equipment in the project using bolts. The general purpose of using a Flat Weld Ring Flanged Hub is to save materials. Its structure is divided into two parts: one part connects to the pipe, and the other part is formed with a flange. The flange is made of low-grade material, while the pipe section uses the same material as the pipeline, achieving the goal of material savings.

Loose fit flange with welding ring, loose fit socket weld neck flange, welding ring loose fit plate flange, flat welding ring loose fit plate flange, and inverted loose fit flange. Additionally, to meet the locking needs after installation, there are bolts with holes that prevent loosening due to vibration. Some flange bolts have smooth rods without threads and need to be made thin, known as slender rod flange bolts. These 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 produces an alloy layer through the reaction of molten metal with the iron substrate.