1. Material:
Forged steel, WCB carbon steel, stainless steel, 316L, 316, 304L, 304, 321, chromium-molybdenum steel, chromium-molybdenum-vanadium steel, molybdenum-titanium, rubber-lined, fluorine-lined materials.
2. Classification:
Flat-welded flanges, necked flanges, butt-welded flanges, ring-connected flanges, socket-weld flanges, and blind plates, etc.
3. Execution Standards:
There are GB series (national standard), JB series (Machinery Department), HG series (Chemical Department), ASME B16.5 (American standard), BS4504 (British standard), DIN (German standard), and JIS (Japanese standard).
Plate butt-welded flange
Advantages:
Easy to obtain materials, simple to manufacture, low cost, widely used. Disadvantages:
It has poor rigidity, so it cannot be used in chemical process piping systems with supply and demand requirements, flammable, explosive, and high vacuum conditions, or in highly dangerous or extremely hazardous situations.
The sealing surface types include flat and raised surfaces.
2. Necked Flat Welded Flange
The necked flat welded flange is one of the commonly used flanges on equipment or pipelines.
Advantages:
It is more convenient for on-site installation and can omit the process of welding seam hammering and cracking. Disadvantages:
The neck of the necked flat butt-welded flange is relatively low, which improves the stiffness and load-bearing capacity of the flange. Compared with the butt-welded flange, the welding workload is greater, the amount of welding rods consumed is higher, and it cannot withstand high temperature, high pressure, repeated bending and temperature fluctuations.
3. Necked Butt-Welded Flange
The sealing surface forms of the necked butt-welded flange include:
Raised face (RF), concave face (FM), convex face (M), mortise face (T), groove face (G), and full plane (FF).
Advantages:
The connection is less likely to deform, the sealing effect is good, it is widely used, and it is suitable for pipelines with significant temperature or pressure fluctuations, as well as high-temperature, high-pressure and low-temperature pipelines, and also for pipelines transporting expensive media, flammable and explosive media, and toxic gases. Disadvantages:
The necked butt-weld flange is large in size, heavy in weight, expensive in price, and difficult to install and position. Therefore, it is more prone to being damaged during transportation.
