[1] Also known as a blank flange, it is a flange without holes in the middle, used for sealing pipe ends. The sealing surfaces come in various types, including flat, raised, concave-convex, tongue-and-groove, and ring-connection surfaces. Flange cover sealing surfaces: Flat (FF), Raised (RF), Concave-Convex (MFM), Tongue-and-Groove (TG), Ring-Connection (RJ) [2] Flange cover production materials: Carbon Steel (Carbon Steel): ASTM A1, Q235, 16MnASTM A350LF1, LF2CL1/CL2, LF3CL1/CL2, ASTM A694 F42, F46, F48, F50, F52, F56, F60, F65, F70.
Stainless Steel: ASTM A182 F304, 304L, F316, 316L, 1Cr18Ni9Ti, 0Cr18Ni9Ti, 321, 18-8
Alloy Steel: ASTM A182 F1, F5a, F9, F11, F12, F22, F91, A182F12, A182F11, 16MnR, Cr5Mo, 12Cr1MoV, 15CrMo, 12Cr2Mo1, A335P22, St45.8/Ⅲ; Pipe Fittings Connections – Also known as non-standard pipes, these are connecting components used in pipeline installation for purposes such as changing pipe diameters, branching, altering pipeline direction, and sealing pipe ends.
Main types of pipe fitting connections include threaded, socket-weld, and electrofusion welding. Flange connection [1] involves placing a gasket between a pair of flanges that are fixed at two pipe ends, and then securing them with bolts to create a removable [1].
This connection is primarily used for joining cast iron pipes, lined rubber pipes, non-ferrous metal pipes, and flanged valves, etc. The connection between the process equipment and the flange also utilizes flanged connections.
The primary features of flange connections are ease of disassembly, high strength, and excellent sealing performance. When installing flanges, it is required that the two flanges remain parallel, the sealing surfaces of the flanges must not be damaged, and they must be cleaned thoroughly. The gaskets used for flanges should be selected according to the design specifications. Socket and Spigot Connections Socket and spigot connections are mainly used for cast iron pipes, concrete pipes, ceramic pipes, plastic pipes, etc., equipped with socket and spigot joints in [1].
The pipe spigot joints are categorized into two types: rigid spigot joints and flexible spigot joints. Rigid spigot joints involve inserting the pipe's spigot into the socket of another pipe, aligning them, and first sealing with a filling material before using a sealing material to ensure a secure, enclosed connection.
Flexible socket connection joints consist of placing an elastic rubber ring on the stopper of the pipeline socket, then applying force to insert the pipe end, forming a sealed pipe that can accommodate a certain range of displacement and vibration[1].
Screw Thread Connections [1], also known as threaded connections, involve joining pipes with pipes, pipes with [1], and valves through the use of male and female threads.
This connection is primarily used for joining steel pipes, copper pipes, and high-pressure [1] pipes. The majority of threaded steel pipes are currently threaded using threading machines, while high-pressure pipes with stringent requirements for thread accuracy and surface roughness must be machined with lathes. Blind flange [1], a flange without a center hole, is used to seal pipe ends. There are various types of sealing surfaces, including flat, convex, concave-convex, tenon-groove, and ring joint surfaces. Blind flange [1], also a flange without a center hole, is used to seal pipe ends. The types of sealing surfaces are diverse, including flat, convex, concave-convex, tenon-groove, and ring joint surfaces. Loose flange blanks [1], which come in three forms: flat-welded steel ring loose flange, plate-type rolled edge loose flange, and butt-welded ring loose flange.
2. [1] A loose flange is attached to the pipe end using flanging and steel rings, allowing the flange to move on the pipe end. The steel rings or flanges serve as the sealing surface, while the primary function of the flange is to clamp them together. Consequently, due to being blocked by the steel rings or flanges, the loose flange does not come into contact with the medium.
3. [1] The loose flange is suitable for connecting steel, aluminum, and other non-ferrous metals, as well as stainless steel and acid-resistant containers, and for corrosion-resistant pipelines. Its nominal pressure PN is 1.6 MPa. Weld Neck Flange [1] A weld neck flange refers to a flange with a neck and a round tube transition, which is connected to the pipe by welding.
Welding Flanges are suitable for pipelines with significant fluctuations in pressure or temperature, as well as for high-temperature, high-pressure, and low-temperature pipelines. They are also used in pipelines transporting expensive, flammable, and explosive media. Welding Flanges are not prone to deformation, provide good sealing, and have a wide range of applications. The nominal pressure PN is approximately 16 MPa. Plate Weld Flanges [1] are flanges where the pipe is inserted into the flange and焊接. Plate Weld Flanges are divided into two types: Necked Plate Weld Flanges and Plate Weld Flanges.
The advantages of flat welding flanges are their simple manufacturing process and low cost, but they require substantial welding work and consume a lot of welding rods. They are not suitable for high temperatures, high pressures, repeated bending, or temperature fluctuations and are generally used in pipelines with PN≤2.5MPa, at normal temperatures, and with operating temperatures t≤0℃. Pressed Elbows - Also known as [1] stamping elbows or seamless elbows, pressed elbows are formed by pressing carbon steel, stainless steel, acid-resistant steel, and low-alloy steel seamless pipes into shape within specially designed molds. Stampings - [1] Stamping welded elbows are made by using sheets of the same material as the pipe, stamped into half-ring elbows using stamping molds, and then welding the two half-rings together to form a complete elbow. Due to the varying welding standards for different types of pipelines, these elbows are typically shipped as semi-finished products with the halves temporarily fixed together. The actual welding is performed on-site based on the pipeline weld quality level, hence they are also referred to as half-welded elbows.

Ship flanges are used on vessels, where flanges are components that connect pipes to each other. They are attached to the ends of pipes. Flanges have holes for bolts, allowing two flanges to be tightly fastened together. Gaskets are used between the flanges for sealing.
Flange connections involve securing two pipes, fittings, or equipment to separate flange plates first, then inserting a flange gasket between them and tightening them together with bolts to complete the connection. Some fittings and equipment come with a built-in flange plate and are also considered flange connections.
A detachable coupling. It can be categorized into container flanges and pipe flanges based on the connected parts. In terms of structural type, there are integral flanges, loose flange, and threaded flanges. Common integral flanges include flat welding flanges and socket welding flanges. Flat welding flanges have lower rigidity and are suitable for pressure p≤4MPa; socket welding flanges, also known as high-neck flanges, have higher rigidity and are suitable for high-pressure and high-temperature conditions.