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ASME/ANSI B16.5 Forged Flange Fittings

Views: 112     Author: Good Du     Publish Time: 2023-03-07      Origin: Site

ASME/ANSI B16.5 is the American standard for flanges and flange fittings and is recognized all over zhe world.  

ASME/ANSI B16.5 Flange fittings are widely used in engineering design and involve a wide range of parts.  It is an essential part of pipe design, pipe fitting valves, but also is necessary component for equipment and equipment parts (such as manholes, mirror liquid level meter, etc.) .  Flange fittings have good strength and sealing, simple structure, low cost, can be repeatedly disassembled, and they are widely used in industrial furnace, thermal engineering, water supply and drainage, heating and ventilation, automatic control and other fields.

Classification of flange fittings

  • According to the standard of chemical industry:integral pipe flange, threaded flange, welding plate flange, welding neck flange, slip-on-welding flange, socket welding flange, butt welded lap joint flange, flat welded lap joint flange, lined flange cover, blind flange.

  • According to the petrochemical industry standard:threaded flange, welding neck flange, slip on flange, socket weld flange, lapped joint flange, blind flange).

  • According to the mechanical industry standard: integral pipe flange, welding neck flange, welding plate flange, butt welded lap joint flange, welded lap joint flange, flanged ring lap joint flange, blind flange.

  • According to the national standard: integral flange, threaded flange, butt welded flange, flat welded flange with neck, welded flange with neck socket, butt welded ring  neck lap joint flange, flat welded flange, butt welded lap joint flange, welded lap joint flange, flanged ring lap joint flange, blind flange.

     In addition to the functional design of flanges, their size is the factor most likely to influence the selection of flanges when designing, maintaining and updating piping systems.  And the flange must be considered in connection with the pipe and the use of gaskets to ensure the correct size.

  • Outside diameter: Outside diameter is the distance between the two opposite edges of the flange face.

  • Thickness: Thickness is measured from the outside of the rim.  

  • Bolt circle diameter: This refers to the distance between relative bolt holes measured from center to center.  

  • Pipe size: Pipe size refers to the corresponding size of the flange.  

  • Nominal aperture: Nominal aperture is the size of the inside diameter of the flange connector.

      Flange fittings are classified primarily according to their ability to withstand different temperatures and pressures.  It is specified by using the letter or suffix "#", "lb", or "class".  These are interchangeable suffixes that also vary by region or supplier.  Common  classifications are as follows:

  • class 150lb

  • class 300lb

  • class 400lb

  • class 600lb

  • class 900lb

  • class 1500lb

  • class 2500lb

       The same pressure and temperature tolerances vary depending on the material used, flange design, and flange size.   the pressure level decreases with increasing temperature.

ASME/ANSI B16.5 Flange Fittings Form of Sealing Surface

  • The forms of container flanges are: flat, concave and convex surface, tenon and groove surface, etc. The concave and convex surface and tenon surface are the most commonly used.  

  • The form of the tube flange is: full plane, surface, concave and convex surface, tenon and joint surface five.  The first four are commonly used sealing covers.


Welding Plate Flange

Welding plate flange is suitable for connection of steel pipe with nominal pressure not exceeding 2.5MPa.  The sealing surface of flat welded flange can be made of smooth, concave and convex and tenon type three.  The application of smooth flat welding flange is large.  Because the flange is welded directly with the steel pipe, the flange plate is easy to deformation in low stress state . It is suitable for low pressure situations.


Slip-On Welding Flange

The lower neck height improves the stiffness and bearing capacity of the flange.The lower neck height improves the stiffness and bearing capacity of the flange. Compared with the butt welding flange, the welding workload is large, the electrode consumption is high。It can not support  repeated bending and temperature fluctuations with high temperature and high pressure . The stallation is convenient, it can omit the weld patting and kneading process, so it is more popular.


Welding Neck Flange

The neck butt welding flange is not easy to deform, sealed well, widely used.It has the corresponding rigidity and elasticity requirements and reasonable butt welding thinning transition, the welding distance from the joint surface is large, the joint surface is free from welding temperature deformation.It takes a more complex cough body structure, suitable for pressure or temperature fluctuations of the pipeline or high temperature, high pressure and low temperature pipeline.It is generally used for PN greater than 2.5MPa pipe and valve connection;  Also used to transport expensive, flammable, explosive medium pipeline.


Integral Pipe Flange

Integral flange refers to the import and export flange of the pump, valve, machine and other mechanical equipment connected with the pipeline, usually made of these pipeline equipment, as a part of the equipment.


Socket Welding Flange

Socket welding flange refers to the pipe end inserted into the flange ring ladder,and  welded in the pipe end and outside of the flange, there are two kinds of neck and no neck.The flange with neck tube has good rigidity, small welding deformation and good sealing. It can be used for the occasion of 1.0~10.0MPa pressure.The type B flange of the container is also a socket welding flange, which is used for the occasion of high sealing requirements.  Socket welding flange can be checked according to the whole flange.


Threaded Flange

Threaded flange is a kind of non-welded flange. the inner hole of the flange processed into pipe thread to connect with threaded pipe matching . Compared with welding flange, it has the characteristics of convenient installation and maintenance, and can be used in some occasions where welding is not allowed on site.


Butt Welded Lap Joint Flange

Butt welded lap joint flange is a movable flange, which is generally matched on the water supply and drainage accessories.Each end of the expansion joint has a flange, which is directly connected with the pipe and equipment in the project with bolts.Butt welded lap joint flange is generally to save materials, its structure is divided into two parts, pipe part connect to the pipeline , another end made into butt welding ring.  Flanges are made of low grade material,  pipes are made of the same material as pipeline .  But the disadvantage is low strength at the welding ring.


Flat Welded Lap Joint Flange

Flat welded lap joint flange is almost same at butt welded lap joint flange. The sole difference is welding manner.


Blind Flange

There is no hole in the middle of the flange for sealing the pipe plug.  The function of blind flange is the same as welding head and wire buckle cap, except that the blind flange can be removed at any time, but welding head is not.

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