Forged Flanges

As supplied, 17-4PH is usually in the solution-treated condition (Condition A). It can be heat treated at different temperatures to offer a wide range of properties. (We also hold stock in H1150+H1150, and annealed block).

Types of Forge Flanges

It is important to consider the strength of the flanged joint when choosing a flange for an application. To facilitate maintenance operations, used flanges instead of welded connections can be disassembled quickly and easily. It is necessary to use flanges for many water distribution systems because the water pressure is so high that welds or screws would be dangerous to use. For example, threaded joints can be subject to heavy pressure and compression when they are used in pipelines. Forged flanges manufacturers can easily adapt the system to different applications by choosing from various flanges and washers available from stock.

Welding Neck Flange

There is a long tapered hub on the welding neck flange that can be welded to a pipe. Typically, this type of flange is used in applications involving high pressure or high/low temperature where fluid flow is unrestricted (the flange bore matches the pipe bore). A WN is shaped like a truncated cone, with a cone angle specified in degrees from vertical when used to align pipe ends or provide a location for a weld bead for pressure tight joints.

A flap-type flange (“FW”), on the other hand, has a flat hub that can be welded with wire or rolled onto a pipe end by pressing it into position against the pipe surface. A low-pressure and high-temperature joint connection is typically made with this flange. A welding neck flange (“WN”) features a long tapered hub that can be welded to a pipe. The FW is usually soldered, brazed, or welded onto pipe ends.

Typically, this flange is used in high-pressure and high/low-temperature applications that require unrestricted fluid flow.

Long Welding Neck

A long weld neck flange extends the neck (tapered hub) and acts as a boring extension. These flanges are commonly used on vessels, columns, and barrels. They are also available for heavy barrels (HB) and equal barrels (E). Designed for general use. Types of flanges: Tapered hub (long weld neck) flanges: These extend the neck of barrels, columns, and vessels. Those with a hollow stem (short weld neck) flange are easy to transport and handle, like barrels or columns. Often used on long weld neck flanges.

Slip-On Flange

A slip-on flange is attached to a pipe or fitting with two fillet welds, one inside and one outside. For a slip-on flange to be connected by a fillet weld, the bore of the flange must be larger than the pipe’s outside diameter. so that the fillet weld can be made. A slip-on flange has a metal cap covering its hole, which is then bolted to a fitting or pipe with two threaded holes.

Weld Neck Vs Slip On Flange

When it comes to connector design, slip-on flanged connections are more fragile over time than welding neck flanged connections (under similar service conditions). The following factors seem to explain this:

• Unlike socket weld flanges, welding neck flanges have a tapered hub, which distributes mechanical stress more evenly between the pipe and the flange
• Welding neck joints have only one welding area instead of two, Unlike socket weld flanges, welding neck flanges can also be attached to pipes and fittings.

Threaded Flange

The opposite end has a female thread, generally NPSM, according to ASME B1.20.1, which must be tightened first.

Many types of pipe use male threaded connections; this includes most sizes and types of PVC pipe. These nuts and pipe threads must be compatible to join them together. Cast iron, CPVC, ABS, and ABS-R pipes are examples of pipes with female connections.

The use of threaded flanges is also mandatory in explosive areas since welding would be hazardous.

Socket Weld Flange

As a result of the gap between the pipe end and the socket shoulder, socket weld flanges are prone to corrosion and are used for pipes with small diameters and high pressures that do not transport highly corrosive fluids. Because socket weld flanges have one fillet weld instead of two, their static strength is the same as slip-on flanges, but their fatigue strength is greater.

Lap Joint Flange

Unlike slip-on flanges, lap joint flanges have a radius at the intersection of the flange face and bore to accommodate the flanged portion of the stub end.

Stainless steel or nickel alloy pipelines can be fitted with lap joint flanges and stub ends at a cost-effective price since the lap joint flange can be made from a lower grade (generally carbon steel) than the stub end (which must match the pipe grade, as it is in contact with the conveyed fluid).

Therefore, this arrangement has two advantages:

1. Ensures that the pipeline’s flanged joints are made from low-grade materials;
2. In order to assist with bolt alignment, the lap joint flange can be rotated around the pipe.

Blind Flange

There is no center hole in blind flanges, which are used to seal pipelines, valves, and pressure vessels, as well as to block fluid flow.

As a result of system pressure and bolting forces, blind flanges must endure significant mechanical stress. There must be a flange that is at least one inch thick, preferably thicker. The flange should not be in contact with the bolts. If this is not possible, the flange should have a radius or be shaped to avoid contact.

In addition to providing easy access to the pipeline, blind flanges can also be used in pressure vessels as manholes since they can be unbolted to allow operations inside the pipe terminal end. Usually, blind flanges are bolted to plugs, which make the connection between the flange and the pipeline. A blind flange seals with an O-ring or gasket around its circumference. It provides an airtight seal because the plug remains stationary as the pipeline rotates.

Types of special flanges

Nipoflange

                                                                                                                                    Nipoflange

The Nipoflange is used for branch pipelines at 90 degrees and is made by combining a welding neck flange with a forged Nicolet. A Nipoflange is one solid piece of forged steel, unlike two products welded together.

The piping staff must weld the Nipolet part to the run pipe and bolt the flanged part to the branched pipe to install a Nipoflange.

There are several materials available for nickel flanges, including carbon steel forged flanges ASTM A105 (for high-temperature service), ASTM A350 (for low-temperature service), and ASTM A182 (for stainless steel grades, such as duplex and super duplex), and nickel alloys (Inconel, Incoloy, Hastelloy, etc).

A reinforced Nipoflange offers more mechanical strength than a standard Nipoflange.

Weldoflange

                                                                                                                    Weldoflange

Nipoflanges combine a weld neck flange with a branch fitting (a Weldolet in this instance). A weld flange is comprised of a solid piece of forged steel, not of separate parts welded together.

Elboflange And Latroflange

It is possible to branch pipelines at 45 degrees using elboflanges (combinations of a flange and an Elbolet).

                                                                                                                           Elboflange

Swivel Flange

The alignment of bolt holes between two mating flanges is greatly improved with swivel ring flanges, which are commonly used when installing large-diameter pipelines, subsea and offshore pipelines, pipeworks in shallow waters, and other similar environments. In the petrochemical and water management industries, swivel flanges can handle oil, gas, hydrocarbons, water, chemicals, and other demanding fluids.

A large-diameter pipeline, for example, is fitted with a welding neck flange at one end and a swivel flange at the other: the operators can align the bolt holes much easier and faster by simply rotating the swivel flange.

In petrochemical applications, ANSI/ASME B16.5 or ASME B16.47 are the most common standards for swivel ring flanges.

                                                                                                                   Swivel flange

All standard shapes of common flanges, such as weld-necks, slip-ons, lap joints, socket welds, etc., are available in swivel flanges, along with a wide range of sizes and pressure ratings (from 3/8″ to 60″ and 150 to 2500).

carbon steel forged flanges (ASTM A105), alloy steel (ASTM A182 F1, A182 F5, A182 F9, A182 F91), and stainless steel (ASTM A182 F304, A182 F304L, A182 F316, A182 F316L).

Expanding Flange (“Expander”)

                                                                                                             Expander flange

It is used to increase the bore of a pipeline or to connect pipes to other mechanical devices such as pumps, compressors, and valves with different sizes of inlets. The expanding flange in the picture represents a welding neck flange with a larger bore on the non-flanged end.

Run pipe bores can only be increased by one or two sizes with expanding flanges (for example, from 2 to 3 inches or a maximum of 4 inches).

In comparison to a buttweld reducer and a standard flange (which is the standard solution for pipe bore increases above two sizes), expander flanges are cheaper (and lighter).

A105 (high-temperature carbon steel), A350 (LTCS), and ASTM A182 (stainless steel and above).

The ANSI/ASME B16.5 standard specifies the pressure ratings and dimensions of expanding flanges with raised or flat faces (RF, FF).

The drawing of an ASME expanding flange.

Reducing Flange (“Reducer”)

                                                                                                                     Reducer flange

Pipelines can only be reduced by one or two sizes safely with reducer flanges (otherwise, a butt weld reducer with a standard flange must be used). In general, reducing flanges are not available from stock in most sizes or material grades. The specifications, sizes, and material grades of reducing flanges are similar to those of expander flanges.

Lastly, a spectacle blind (or a ring spacer or spade) mechanically isolates pipes between them. More information on piping can be found in another section of our Wiki.

Orifice Flanges

Pipeline orifice flanges are used to measure fluid flow via a flow nozzle mounted on the flange itself. Pressure tappings are machined into the flange, eliminating the need for separate pipe tappings.

Spectacle Blind

A spectacle blind is a simple safety device that is installed between two pipe flanges, and its open end serves as a spacer, allowing uninterrupted flow. It is rotated between the flanges when the flow needs to be stopped. 

Paddle Flange

The Puddle Flange Jis 16k is used for sealing all around the outside of pipes. Puddle Flange Jis 5k is especially suitable for applications where pipes pass through concrete structures. Puddle Flanges Class 300 are installed during construction. Since pipes passing through concrete do not bond to the concrete, and water can pass along the pipe’s external surface, the Puddle Flange Class 600 acts as a barrier to this flow.

Equivalent class designation for forged fittings

• Class 3000 Forged Socket Weld Fittings for SCH 80 / XS Pipe
• Class 6000 Socket Weld Pipe Fittings for SCH 160 Pipe
• Class 9000 Forged Steel Fitting for SCH XXS Pipe

Fitting Wall Thickness in Forged Steel

Advantages:

Having a connection that has been forged with FCI will eliminate certain aspects of the fabrication process in the shop. By using a reinforced pad, it is possible to eliminate the need for cutting, drilling, laying out, forming, and tapping the weep holes that are associated with standard pads.

It is important to note that the fabrication of a Nozzle neck eliminates the need to inspect plate necks, cut and bevel the pipe, weld, form and lay out the pipe. As a result, there is no longer a need to weld and fit the flange to the pipe or forge a neck that is cylindrical during the component fabrication process. A reinforced pad installation does not require the welding of the pieces to the shell of the vessel or the neck of the nozzle in order to complete the installation process.

Raw Material for Forged Flange:

As the raw material for forged steel flanges is generally pipe billets, the ingots are continuously hammered after they have been cut after which they are continuously hammered, thus eliminating defects such as segregation and looseness within the ingots.

Applications Of Forge Fittings

•  Oil and Gas Pipeline
•  Chemical Industry
•  Plumbing
•  Heating
•  Water Supply Systems
•  Paper & Pulp Industry
•  General Purpose Applications
•  Fabrication Industry
• Food Processing Industry
•  Structural Pipe