The Top 10 Leading Varieties of Flages in Brief


Montex Forge Industries is a Leading Manufacturer which has an extensive Stockholder of piping products for the Oil, Gas,Petrochemical and Nuclear Industries. Montex forge Manufacturer of butt-weld fittings, forged fittings, compression fittings, outlets, flanges & long radius bends elbows.

Our primary priority is quality. We maintain high quality standards thanks to our dedicated employees and solid infrastructure. We guarantee that only the highest quality materials are utilised in the manufacturing of our goods. Materials Test Certificates are provided with each material we offer.

Let’s Take a Look at Flanges and its Types


Flanges are used to connect valves, pipes, pumps and other equipment to make a pipework system. These are usually welded or threaded. Two flanges are connected together by bolting them with gaskets to provide a seal that provides easy access to the piping system. Available in various types depending on factors of the piping system.

Types of Flanges :

We have explained the types of flanges used in the piping systems depending on their sizes and other factors. Let’s have a look at them.

1. Threaded Flanges -This type of flange looks nearly identical to Slip-on flanges yet the key difference is that threaded had been bored out of match the inside diameter of a particular pipe. It had a taper pipe threads in its bore conforming to ASME B1.20.1 and can be used in piping systems where welding flange onto the pipe is not possible, such as highly explosive areas where welding can develop potential risk. It is fixed onto the pipe that has additional threads to the taper pipe galvanized and cast iron piping is commonly used with threaded. Main benefit here is that it can be installed without welding.

2. Weld Neck Flanges -This type of flange is also known as a tapered hub flange or high-hub flange. It has a neck that can move the pipe tension, thereby reducing the pressure gathered in the bottom of it. It is compatible with pipelines which operate at high or low temperatures and withstand high pressure. It is effortlessly identifiable at the long tapered end, which slowly passes through the wall thickness from a pipe or fitting. The long tapered hug provides significant shielding for use in multiple applications involving high pressure, sub-zero and/or high temperatures. A weld neck flange comprises a circular fitting with a protruding edge around circumference. It has been used successfully at pressure up to 5,000 psi.

3. Slip On Flanges -This type of flange is fundamentally a ring placed over the end of the pipe, with a flange face extending from the end of the pipe by sufficient distance to apply a welded bead to the inner diameter. As the name suggests these flanges slip over a pipe, hence called Slip-On flange also called SO flange. It’s a kind of flange that is slightly bigger than the pipe and slides over the pipe, top and bottom can be connected directly to equipment or pipe by filet welding the SO flange. It is used to insert the pipe into the flange’s inner hole. These are suitable choices for low-pressure applications and are excessively utilized in many fluid pipelines.

4. Socket Weld Flanges -This type of flange is only connected on the outside by one filet weld, and is often not advised for critical services. Mostly used for small-bore lines. Their static strength is equivalent to Slip On flanges, but their fatigue strength is 50% higher than double-welded than slip-on flanges. Before welding, a gap must be formed in the socket weld flange between the flange or fit and the pipe. The objective of its bottom clearance is generally to minimize the residual pressure at the weld root that could occur during weld metal solidification. Its drawback is the right space, which must be made. The crack between the pipe and flange can cause corrosion problems by corrosive products, and mostly in stainless steel pipe systems. It is not allowed in some processes, also it has the principle that it must always be welded first by a pipe and simple by a fitting.

5. Blind Flanges -This type of flanges are produced without a bore and are utilized to blank off the ends of pipes, valves and pressure vessel openings. The point of view of internal pressure and bolt loading, the most overstressed flange type are bland flanges, especially in bigger size. Nevertheless, most of these pressures are bending types near the center, as there is no standardized inner diameter, these flanges are ideal for higher pressure temperature systems. The function of these flanges is to obstruct a segment of the pipe or nozzle on a vessel that is not in use. It will often be blanked off with a blind flange for pressure checks in a plant or simply because the consumer does not need all the nozzles that were provided on the tank.

6. Lap joint Flanges -This type of flanges are used with stub ends when the pipe is made of expensive material. A carbon steel flange can be added to the stainless steel pipe system because this one will not come into contact with the substance in the pipe. The stub ends will be butt-welded to the pipe and flanges will remain loose. The inner radius of these flanges is beveled to clear the stub end radius. These are almost similar, except the radius at the intersection of the flange face and bore to accommodate the flanged portion of the stub end. Their ability to hold pressure is little, if any, stronger than that with fatigue life of the assembly is only 1/10th that of Weld neck flange. Therefore, used in low-pressure and non-critical applications

7. Plate Flanges -Often his type of flange is known as flat flanges. It has a gasket surface in the same plane as the face of the bolting circle. It is also called flat-face flange. Applications using flat face flanges are often those in which a casting is made of the mating flange or flanged fitting. They are used when the counter-flanged are flat flanges are often those in which a casting is made of the mating flange or flanged fitting. It is used when the counter-flanges are flat faced. This condition happens primarily when connected to cast iron equipment valves and specialties. ASME B31.1 states that when connecting flat face cast iron flanges to carbon steel flanges, the raised ace of the carbon steel flange must be removed and full face gasket is needed. (These 7 flanges are mentioned on the website and the rest aren’t.)

8. Reducing Flanges -This type of flange is designed for when the size of the pipe changes. It is predominantly matching the larger pipe size (NPT) but having smaller bore matching the smaller pipe size (NPT). These flanges generally come in neck flanges generally come in neck flanges that are blinf, slip-on, threaded and weld. They are available in all pressure classes and offer an excellent alternative to connecting two different pipe sizes. This type of flange should not be used if an unexpected change, such as at a pup, would cause unnecessary turbulence.

9. Square Flanges -This type of flange is made in compliance with JIS B2291/JIS F7806 standards. They are often used for connections between pipe-to-pipe and pipe-to-components. They are often used in the line of hydraulic systems where a passage of fluids occurs and are made of two materials which are steel and stainless steel. A full set of squares is made up of oring, bolts, female flange and male flange. The female part is listed as part A. Part B identifies male parts and an full set is AB

10. Expander Flanges -This type of flange, referred to as EXPF, represents a welded neck flange but the hub extends to a large size (one or two sizes). If you have a limited space or just need to connect to a wider pipe diameter, it provides a convenient place for equipment, pumps and vents. The compact size saves space compared with a reducer- welding neck flange which can eliminate the use of flange and reducer. They are also considered a cost-effective alternative to using the reducer welding neck flange separately. Pressure ratings and dimensions comply with ANSI/ASME B1. It has raised face and installation requires a single butt-weld.

These steel flanges are manufactured from different materials such as carbon steel, low alloy steel, Stainless steel flanges, Duplex steel flanges, Super duplex, Steel flanges, Monel flanges, Inconel flanges, Hastelloy flanges, Nickel flanges and combination of Exotic materials (stub) and other backing materials. We always assured that there is no damage during transit. In case of exports, standard export packaging is done in wooden cases. Our official inspection agencies can be called


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