304L 321 Flange Stainless Steel Flange

1. Plate Slip-On Flange

Plate Slip-On Flanges (Chemical Standard HG20592, National Standard GB/T9119, Mechanical Standard JB/T81): They are readily available, simple to manufacture, low-cost, and widely used. However, they have poor rigidity and should not be used in chemical process piping systems involving supply and demand, flammability, explosiveness, or high vacuum requirements, or in highly hazardous environments. Sealing surface types include flat and raised faces.

2. Necked Slip-On Flanges

Necked Slip-On Flanges belong to the national standard flange system. They are a form of national standard flanges (also known as GB flanges) and are commonly used flanges on equipment or pipelines.

Necked Slip-On Flanges have a lower neck height, which improves flange rigidity and load-bearing capacity. Compared to butt-weld flanges, they require more welding effort and electrode consumption, and cannot withstand high temperatures, high pressures, repeated bending, and temperature fluctuations. However, they are easier to install on-site and can eliminate the need for weld seam slapping and rubbing.

3. Neck-Welding Flange

Neck-Welding Flange (full name: Slip-On Steel Pipe Flange, English name: Slip-On, abbreviated as SO)

Like plate-type slip-on flanges, neck-welding flanges are flanges that connect steel pipes, fittings, etc. through a fillet weld to equipment or pipelines.

Neck-welding flanges have sealing surface types:

Raised Face (RF), Concave Face (FM), Male Face (M), Tenon Face (T), Grooved Face (G), and Full Face (FF).

4. Integral Flange

Integral flanges are a type of flange connection. They are also a type of neck-welding steel pipe flange. Materials include carbon steel, stainless steel, and alloy steel. In various domestic standards, integral flanges are designated as IF. They are primarily used in high-pressure pipelines. They are generally manufactured using a casting process.

Among flange types, the designation "IF" is used to designate integral flanges. Generally, the flange is raised face (RF). For applications involving flammable, explosive, high-altitude, or extremely hazardous environments, flange types such as male-female (MFM) and tongue-and-groove (TG) are available.

5. Socket Weld Flange

A socket weld flange is a flange that is welded to a steel pipe at one end and bolted to the other end.

Sealing surface types: Raised face (RF), male-female (MFM), tongue-and-groove (TG), and ring joint (RJ).

Applications: Boilers, pressure vessels, petroleum, chemical, shipbuilding, pharmaceutical, metallurgy, machinery, stamped elbows, and food processing. Socket weld flanges are commonly used in pipes with a PN ≤ 10.0 MPa and a DN ≤ 40.

6. Threaded Flange

A threaded flange is a non-welded flange with the inner bore machined into a pipe thread. It is then connected to threaded pipe. Compared to slip-on or butt-weld flanges, threaded flanges are easier to install and maintain, and can be used on pipelines where welding is not permitted on site. Alloy steel flanges offer sufficient strength, but are difficult to weld or have poor welding performance. Threaded flanges are also an alternative. However, threaded flanges are not recommended for use in pipes with rapid temperature fluctuations or where the temperature is above 260°C and below -45°C to avoid leakage.

7. Butt-weld Loose Flange

Butt-weld Loose Flanges are removable flanges typically used with plumbing fittings. They are shipped with a flange at each end of the expansion joint, allowing for direct bolted connections to pipes and equipment in the project.

Purpose: Butt-weld Loose Flanges are generally used to save material. Their structure consists of two parts: one end of the pipe is connected to the pipe, and the other end is a butt-weld ring. The flange is made of low-grade material, while the pipe is made of the same material as the pipe, achieving this material savings.

Butt-weld Loose Flanges:

1. Cost savings. When the pipe material is special and expensive, welding a flange of the same material is costly.

2. Applications where welding or processing is difficult or where high strength is required, such as plastic pipes and fiberglass pipes.

3. Ease of construction. For example, it can be difficult to align the flange bolt holes during connection, or to prevent the flange bolt holes from shifting during future equipment replacement.

8. Slip-on Flange

Slip-on flanges are removable flanges. They are directly bolted to pipes and equipment in the project. The purpose of using slip-on flanges is generally to save material. Their structure consists of two parts: one end connects to the pipe, and the other end is a flanged flange, which the flange fits over. The flange is made of lower-grade material, while the pipe portion uses the same material as the pipe, thus saving material.

Slip-on flanges:

1) They are easy to weld or process, or require high strength, such as plastic pipes and fiberglass reinforced plastic pipes.

2) They facilitate construction, such as aligning the flange bolt holes during connection, to prevent the flange bolt holes from shifting during future equipment replacement.

3) They save costs when the price is high. When the pipe material is special, welding a flange of the same material is costly.

9. Flange Cover

Also known as blind flange or blind plate. This flange is a flange without a central hole and is used to seal pipe plugs. Its function is similar to welded caps and threaded caps, except that blind flanges and threaded caps can be removed at any time, while welded caps cannot. There are many different sealing surface types, including flat face, raised face, grooved face, tongue-and-groove face, and ring joint face. Production is primarily in the Mengcun area.

Flange Cover Sealing Surfaces: Flat Face (FF), Raised Face (RF), Grooved Face (MFM), Tongue-and-Groove (TG), Ring Joint (RJ).

10. Lined Flange Cover

A lined flange cover is a blind flange with stainless steel overlay welded on the side facing the media, forming a single piece. Lined flange covers are used as blind flanges on pipelines with corrosive media. Unlike ordinary flange covers, they have an anti-corrosion lining on the media-contacting surface.

11. American Standard Slip-On Flange

A slip-on flange cover is connected to pipe ends. It primarily connects pipes. Slip-on flanges with necks have holes for bolts, tightening the two flanges. A gasket seals the gap between the flanges. A slip-on flange connection consists of a pair of flanges, a gasket, and several bolts and nuts. The gasket is placed between the sealing surfaces of the two flanges. After the nuts are tightened, the gasket deforms when the specific pressure on the gasket surface reaches a certain value, filling any irregularities on the sealing surface and ensuring a leak-proof connection. Flange connections are removable and can be categorized as container flanges or pipe flanges based on the components they connect. Slip-on flanges with necks are suitable for connecting steel pipes with a nominal pressure not exceeding 2.5 MPa.

Slip-on flanges with necks are used for butt welding flanges to pipes. Their rational structure offers high strength and rigidity, and they can withstand high temperatures, high pressures, repeated bending, and temperature fluctuations, providing reliable sealing. Slip-on flanges with necks for nominal pressures between 0.25 and 2.5 MPa utilize a concave and convex sealing surface.

12. American Standard Butt-Weld Flanges

American Standard flanges are used to connect pipes to each other and are attached to the pipe ends. ANSI butt-weld flanges are manufactured by either forging or casting. Depending on the neck, ANSI butt-weld flanges can be categorized as either necked or non-necked. ANSI butt-weld flanges consist of two flange plates and a flange gasket, bolted together to complete the connection. ANSI flanges have eyelets, which bolt to secure the two flanges. A gasket seals the gap between the flanges.