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Types of flanges

Types of flanges

Flanges are parts that are connected to each other between shafts and are used for connection between pipe ends; they are also useful for flanges on equipment inlets and outlets, And can be used as connection between two equipments, example reducer flanges. Flange connection or flange joint refers back to the detachable connection of flange, Gasket and bolt as a team of combined sealing structure. Pipe flange refers back to the flange used for piping in the pipeline installation, And used on the equipment refers to the inlet and outlet flange of the equipment. There are holes in the flange, and the bolts tightly connect the two flanges. The flanges are sealed with gaskets. Flanges are divided into threaded (screw connection) flanges, welding flanges and clip flanges.

Flanges are usually employed in pairs, very poor-work pipes can use wire flanges and welding flanges with pressures greater than 4 kg. Add sealing points within the two flanges, immediately after tighten with bolts. Flanges with different pressures have different thicknesses, and the bolts they use are also different. When the water pump and valve are connected to the pipeline, some parts of these equipments are also made into corresponding flange shapes, also called flange connection. All connecting parts that are closed at the same time by using bolts around the two planes are generally called "flanges". For example, the connection of ventilation pipes, such parts can be called "flange parts". But this connection is only a part of the equipment, Such as the text between the flange and the pump, It is not easy to call the pump 'flange parts'. Smaller ones such like valves Wait, always be called 'flange parts'.


Here are some different types of flanges:

(1) Different diameter flange
Technical parameters: in accordance with national standards
Quality standard: Manufactured in strict accordance with the relevant standards formulated by the state
Product specification: DN15-DN2000
Product packaging: wooden box or other
Product color: metal color
Product features: anti-corrosion, acid and alkali resistance, long service life, etc., reasonable price calculation, smooth surface, acid and alkali resistance, high temperature resistance, beautiful appearance, strong texture performance.
Production process: professional overall forging, forging manufacturing, plate cutting, plate rolling, etc.
Processing method: high-precision CNC lathe turning, ordinary lathe finishing turning, argon arc welding and other processing
Nominal pressure sch5s, sch10s, sch20s, sch30s, sch40s, etc.
Manufacturing standards: national standard, American standard, Russian standard, Japanese standard, etc.
Material: 201, 304, 316, 316L, 0Cr18Ni9, 321, 202, etc.
Uses: Widely used in water conservancy, electric power, power stations, pipeline fittings, industry, pressure vessels, etc.
Connection method: flange nut, bolt connection.

(2) Stainless steel flange
Specifications: 1/2″~240″(10-6000)
Pressure rating: 0.6MPa ~ 32MPa, 150Lb ~ 2500Lb, PN0.25-PN42.0
Material: 304, 304L, 321, 316, 316L, 310S and other materials
Standards of the Ministry of Chemical Industry: HG5010-52~HG5028-58, HGJ44-91~HGJ65-91, HG20592-2009 (PN series), HG20615-2009 (Calss series)
Application range: Boiler pressure vessel, petroleum, chemical industry, shipbuilding, pharmaceutical, metallurgy, machinery, food and other industries.

(3) Pressure vessel flange
Specification: DN300~3000
Product Notes: Pressure Vessel Flange Application Industries: HVAC, Electricity, Building Water Supply, Pressure Vessel Fittings, Pressure Pipe Fittings.
Product Category: Flange Series
Application industries: HVAC, electricity, building water supply, pressure vessel fittings, pressure pipe fittings.
Application technical parameters
Seal Nominal pressure PN, MPa (bar) 0.6 1.0 1.6 2.5 4.0 6.4
Concave-convex surface (MFM) DN1300~3000 DN300~3000 DN400~2000 DN300~800
Tenon and groove surface (TG) DN1300~3000 DN300~3000 DN300~3000 DN300~800
Full Flat (FF) DN300~3000 DN300~3000 DN300~3000 DN300~800

(4) flat welding flange
Flat welding flanges include plate flat welding flanges and neck flat welding flanges.
Plate Flat Welding Flange (PL)
Flat welding flanges are suitable for steel pipe connections with a nominal pressure not exceeding 2.5MPa. The sealing surface of the flat welding flange can be made into three types: smooth type, concave-convex type and tongue-and-groove type. The smooth flat welding flange is the most widely used. It is mostly used in the case of moderate medium conditions, such as low-pressure non-purified compressed air and low-pressure circulating water.
Neck flat welding flange (SO)
The neck height of the flat welding flange with neck is relatively low, which improves the rigidity and bearing capacity of the flange. Compared with the butt welding flange, the welding workload is large, the electrode consumption is high, and it cannot withstand high temperature and high pressure, repeated bending and temperature fluctuations, but the on-site installation is more convenient, and the process of welding seam scratching can be omitted, which is more popular.

(5) Butt welding with neck (WN)
Butt Weld Flange: Welding neck flanges are often referred to as "high hub" flanges. Its purpose is to divert pressure from the piping, thereby reducing high stress concentrations in the flange base. Neck flange welding is best designed for butt welding those flanges due to their inherent structural value. However, the price is relatively high, because the production process of the product is complicated.
Threaded (threaded) flange: The threaded flange is connected with screws. But the center of the product has the thread size corresponding to the tube. Its main advantage is that it can be assembled without soldering.
In addition, there are sliding flanges and lap flanges.

(6) Socket welding flange (SW)
Sealing surface form: raised surface (RF), concave-convex surface (MFM), tongue and groove surface (TG), ring joint surface (RJ)
Material: Carbon Steel: ASTM A105, 20#, Q235, 16Mn, ASTM A350 LF1, LF2 CL1/CL2, LF3 CL1/CL2, ASTM A694 F42, F46, F48, F50, F52, F56, F60, F65 ,F70;
Alloy Steel: ASTM A182 F1, F5a, F9, F11, F12, F22, F91, A182F12, A182F11, 16MnR, Cr5Mo, 12Cr1MoV, 15CrMo, 12Cr2Mo1, A335P22, St45.8/Ⅲ, 35CrMoV, 45CrMo, etc.
Manufacturing standards: ANSI B16.5, GB/T9117.1-2000—GB/T9117.4-200, etc.

(7) Threaded flange (TH)
Nominal diameter of threaded flange: DN8 ~ DN100 Working pressure: 1.0 ~ 2.5 (MPa) Material of plate type threaded flange: stainless steel, carbon steel, alloy steel.
Application of threaded flange: suitable for thread locking and sealing of industrial and civil pipes such as fire protection, gas, hot and cold water, air conditioning, air pressure pipes, oil pipes, instruments, hydraulic pipes, etc.
Flange cover (BL)
Flange cover, also known as blind flange, is a flange without a hole in the middle, which is used to seal the pipe plug. There are many types of sealing surfaces, including flat surfaces, convex surfaces, concave-convex surfaces, tongue-and-groove surfaces, and ring connection surfaces.
Sealing surface: flat surface (FF), raised surface (RF), concave-convex surface (MFM), tongue and groove surface (TG), ring joint surface (RJ)
Production materials:
Carbon Steel: ASTM A105, 20#, Q235, 16Mn, ASTM A350 LF1, LF2 CL1/CL2, LF3 CL1/CL2, ASTM A694 F42, F46, F48, F50, F52, F56, F60, F65, F70 ;
Stainless steel (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.

(8) Loose flange
Loose sleeve flange with neck butt welding ring
Loose sleeve flange with butt welding ring loose sleeve neck flange, butt welding ring loose sleeve plate flange, flat welding ring loose sleeve flange, plate type turned over loose sleeve flange, in addition, in order to meet the needs of locking after the device, There are holes in the rod, and these holes can prevent the bolt from loosening when it is subjected to vibration. Some flange bolts without threads have to be thinner, which are called thin rod flange bolts. This kind of flange bolts is conducive to the connection of variable force. There are special high-strength bolts on the steel structure, the head will be bigger, and the size will also change. Hot-dip galvanized round steel is to make the molten metal react with the iron matrix to form an alloy layer.

Flat welding ring loose flange (PJ/SE)
Flat welding ring loose sleeve flange is a movable flange, which is usually matched with the water supply and drainage fittings (the most common on the expansion joint). Pipes and equipment are connected with bolts. The purpose of using flat welding ring loose sleeve flange is generally to save materials. Its structure is divided into two parts. One end of the pipe part is connected to the pipe, and the other end is made into a flange. The flange is made of low-grade material, while the pipe part is made of the same material as the pipe, so as to save material.

Advantages of flat welding ring loose flange:
1. Cost saving. When the pipe material is special and expensive, the cost of welding flanges of the same material is high.
2. It is not convenient for welding or processing or requires high strength. Such as plastic pipes, glass steel pipes and the like.
3. It is convenient for construction. For example, it is not easy to align the flange bolt holes during connection or prevent the flange bolt holes from changing in the future when the equipment is replaced.

Disadvantages of flat welding ring loose flange:
1. Low pressure.
2. The strength of the welding ring is low (especially when the thickness is less than 3mm)
Flat welding ring loose flange production standard:
National standard: GB/T9112-2000 (GB9113·1-2000~GB9123·4-2000)
American Standard: ANSI B16.5 Class150, 300, 600, 900, 1500 (WN, SO, BL, TH, LJ, SW)
Japanese standard: JIS 5K, 10K, 16K, 20K (PL, SO, BL, WN, TH, SW)
German standard: DIN2573, 2572, 2631, 2576, 2632, 2633, 2543, 2634, 2545 (PL, SO, WN, BL, TH)
Ministry of Chemical Industry standard: HG5010-52~HG5028-58, HGJ44-91~HGJ65-91
Flange standard: HG20592-2009 (PN series)\HG20615-2009 (Calss series)
Standards of the Ministry of Machinery: JB81-59~JB86-59, JB/T74-1994, JB/T79-94~JB/T86-94
Pressure vessel standards: NB/T47020-2012~NB/T47027-2012, JB1157-82~JB1160-82 B16.47A/B B16.39 B16.48

Ring groove flange and flange cover, large-diameter flat flange, large-diameter high-neck flange, figure-eight blind plate, butt-welding ring loose flange 6, swivel flange, anchor flange, overlay welding/overlay welding method orchid
Standard number of welded steel flanges for marine use: This standard is applicable to marine products and marine engineering products. The main materials are: carbon steel, alloy steel, low temperature steel, stainless steel.
Forged flange connection is to connect two pipes, pipe fittings or equipment, and forged flange connection is an important connection method for pipeline construction. The forged flange connection is easy to use and can withstand greater pressure. In industrial pipelines, forged flange connections are widely used. In the home, the pipe diameter is small, and it is low pressure, and the connection of the flange stamping elbow is not visible. If you are in a boiler room or a production site, there are flanged pipes and equipment everywhere. The chromium content is 0.1% to 0.5% (forged flanges generally do not contain chromium), the carbon content is less than 1.0%, and the forged flanges are manufactured by high-temperature forging. Although some forged flanges have a surface hardness (HRC) It can reach ≥56 (the hardened layer is only about 15 mm). Because the hardenability of the forged flange material is poor, the hardness of the core is generally only more than 30 degrees. Under normal circumstances, the forged flange is often treated with water quenching.

Flange protection cover (flange protection joint)
Flange guards are mainly used for corrosion protection of flange connections in all industries. The flange protection head of this product is used to protect the flange face (raised face or ring joint). Double-ended studs and washers are free from corrosion. This product is suitable for 316 ss stainless steel and non-metallic (plastic), and it is manufactured in sizes from ½” to 144” ANSI, API and AWWA flange connection diameters. Flanged head systems combined with flanged packing provide protection in harsh application environments.
The structure of the flange seal cover:
316 stainless steel strip or non-metallic strip
316 ss casting
316 ss worm gear clamps
Closed slot neoprene layer (temp. – 34.4°C to 82°C)
ECH rubber liner (temp. – 34.4°C to 149°C) safety relief valve can release 5 psi
Advantages of Mysterco Flange Enclosures: Easy to install, no special tools required, easy to inspect, durable connection (not easily damaged), UV stable non-metallic material, reusable.

Flange Packing System
Suitable for temperatures up to 80°C.
Flange packing is a unique solution to long-term corrosion problems.
Flange packing is a coating based on a composite polar polymer. The creamy form allows it to be used without pretreatment. The viscoelastic formulation allows this material to flow into spaces and voids, creating a good seal that resists corrosion.
Flange Packing Systems Flange packing saves time and money because of its ease of use. Provides long-term protection.
Properties: Bonds to Steel, FBE (Fused Epoxy Powder), Polyurethane, Polyethylene Advanced Resistance Weather/Salt Resistant Temperature Range From -51°C to 80°C Fills Entire Gap Removable/Reuse Flange Surface Without Excessive Pretreatment is gently injected using a manual or pneumatic gun with a flexible nozzle. This ensures that the annular gap is completely filled before sealing with CZ wrapping tape.
E-2400/E2000 High Temperature Flange Packing - Suitable for temperatures up to 149°C.
E-2400/E2000 high temperature anti-corrosion flange packing is a product designed to protect flange connections from corrosion at high temperatures up to 149°C.
E-2400/E2000 is a non-electrolytic method of corrosion protection of steel flanges, bolts, pipes and structures with a gel.
Use ASTM-B1117 salt spray test to test the nut and bolt assembly for 2000 hours, and the area protected by E2000/2400 can still be turned by hand. Proper use of E2000/2400 helps protect flange connections from corrosion.

(9) High temperature flange seal
The parts of high temperature flanges often need to be sealed at high temperature. If there is no good sealant for additional sealing in the separate pressure area, it will be affected by the pressure, which will cause inaccuracy or deformation of production, that is to say, in the separate pressure area. Leakage occurs underneath, requiring unscheduled repairs. The best application in the field of high temperature flat sealing is Bocus high temperature sealant. Its special formula makes it inert in the standard application of steam and gas turbines and high temperature flanges, so it can withstand hot air, steam, water, light fuel Oils and lubricants, resistant to crude oil and natural gas.

It is a one-component, paste sealant, industrial use, high-quality sealing mixture, suitable for working conditions that require high temperature and pressure on smooth and flat sealing surfaces (butt joints). Spread on dry surface with plaster knife or rubber spatula. Because the sealing product will not solidify, but its consistency will change slightly to maintain flexibility and elasticity, so there is no time requirement in use, and it can be put into operation immediately after construction without waiting. If it is necessary to repair the high-temperature sealing surface with scratch damage, it should be used in conjunction with Bocus high-temperature F series repair products.

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