Share this
The flange is otherwise known as flange or flange. 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 a connection between two types of equipment, for example, reducer flanges. The flange joint is a device used for flange sealing.
1. Application:
Flange joints are a kind of part that is widely used in engineering design and involve a wide range of areas. It is an indispensable part of piping design, pipe fittings and valves, and also an essential component in equipment and equipment parts (such as manholes, sight glass liquid level gauges, etc.). In addition, flange joints are often used in other professions, such as industrial furnaces, thermal engineering, water supply and drainage, heating and ventilation, and automatic control.
2. Material:
Forged steel, WCB carbon steel, stainless steel, 316L, 316, 304L, 304, 321, chrome molybdenum steel, chrome molybdenum vanadium steel, molybdenum dititanium, rubber lining, fluorine lining material.
10 types of flanges and their characteristics
1. Plate flat welding flange
Plate flat welding flange (chemical standard HG/T20592, national standard GB/T9119, mechanical JB/T81).
advantage:
The material is convenient to obtain, simple to manufacture, low in cost and widely used.
shortcoming:
The rigidity is poor, so it should not be used in chemical process piping systems with supply and demand, flammable, explosive and high vacuum requirements, and in high and extremely hazardous occasions.
2. Slip-on flange with neck
Neck flat welding flange belongs to the national standard flange standard system, is one of the forms of national standard flange (also known as GB flange), and is one of the commonly used flanges on equipment or pipelines.
advantage:
On-site installation is more convenient, and the process of welding seam scratching can be omitted.
shortcoming:
The neck height of the flat welding flange 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.
3. Welding neck flange
advantage:
The connection is not easy to deform, the sealing effect is good, and it is widely used. It is suitable for pipelines with large temperature or pressure fluctuations or high-temperature, high-pressure and low-temperature pipelines. It is also used for pipelines that transport expensive media, flammable and explosive media, and toxic gases.
shortcoming:
The neck butt welding flange is bulky, heavy, expensive, and difficult to install and position, so it is more likely to be bumped during transportation.
4. Integral flange
The integral flange is a flange connection method. It is also a kind of neck butt welding steel pipe flange. The materials are carbon steel, stainless steel, alloy steel, etc.
Among various domestic standards, IF is used to represent the integral flange. It is mostly used in pipelines with high pressure, and the production process is generally casting.
In the flange type, an “IF” is used to indicate the type of the integral flange. Generally, it is a raised surface (RF). If it is used in flammable, explosive, highly and extremely hazardous working conditions, you can choose the seal of the convex and concave surface (MFM) and the tongue and groove surface (TG) except the RF surface. face form.
5. Socket welding flange
The socket welding flange is a flange that is welded to the steel pipe at one end and connected with bolts at the other end.
Applications:
Boiler pressure vessel, petroleum, chemical industry, shipbuilding, pharmaceutical, metallurgy, machinery, food and other industries.
It is often used in pipelines with PN≤10.0MPa and DN≤40.
6. Threaded flange
The threaded flange is a non-welding flange that processes the inner hole of the flange into pipe threads and matches with the threaded pipe to realize the connection.
advantage:
Compared with flat welding flange or butt welding flange, threaded flange has the characteristics of convenient installation and maintenance, and can be used on some pipelines where welding is not allowed on site. Alloy steel flanges have sufficient strength but are not easy to weld, or the welding performance is not good, and threaded flanges can also be selected.
shortcoming:
Under the conditions of sharp temperature changes of the pipeline or the temperature is higher than 260 °C and lower than -45 °C, it is recommended not to use threaded flanges to avoid leakage.
7. Butt welding ring loose flange
The butt-welding ring loose flange is a movable flange piece, which is usually matched with the water supply and drainage fittings. When the manufacturer leaves the factory, there is a piece of the flange at each end of the expansion joint, which is directly connected to the pipeline and equipment in the project with bolts.
effect:
The purpose of using butt welding ring loose sleeve flange is generally to save material. 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 butt welding ring. 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.
advantage:
Cost saving. When the pipe material is special and expensive, the cost of welding flanges of the same material is high.
It is not convenient for welding or processing or requires high strength, such as plastic pipes, glass steel pipes and the like.
It is convenient for construction, such as the flange bolt holes are not easy to align when connecting or preventing the flange bolt holes from changing in the future when the equipment is replaced.
shortcoming:
Low pressure and low strength at the welding ring (especially when the thickness is less than 3mm)
8. Flat welding ring loose flange
The flat welded ring loose flange is a movable flange, which is directly connected to the pipeline and equipment in the project with bolts.
The purpose of using a flat welded ring loose sleeve flange is generally to save materials. Its structure is divided into two parts.
advantage:
It is convenient for welding or processing or requires high strength, such as plastic pipes and glass steel pipes.
It is convenient for construction, such as the flange bolt holes corresponding to facilitate alignment during connection or prevent the flange bolt holes from changing in the future when equipment is replaced.
When the price is high, save money. When the pipe material is special, the cost of welding flanges of the same material is high.
shortcoming:
Accept low pressure.
The strength of the welding ring is low (especially when the thickness is less than 3mm).
9. Flange cover
Also known as a blind flange and blind plate, it is a flange without a hole in the middle, which is used to seal the pipe plug. The function is the same as that of welded head and threaded cap, except that the blind flange and threaded cap can be removed at any time, while the welded head cannot.
10. Lining flange cover
The lined flange cover is a blind flange, and the side close to the medium is surfacing with stainless steel as a whole. The lined flange cover is used as a blind plate on the pipeline with the corrosive medium. The difference from the ordinary flange cover is that an anti-corrosion lining is added on the contact surface with the medium.
For pipe fittings, please link: https://bekingpiping.com