Flat welded flanges application in the pipe fitting

Pipe flanges that are made to standards called out by Asme B16.5 or ASME B16.47, and MSS SP-44. They are typically made from forged materials and have machined surfaces. ASME B16.5 refers to nominal pipe sizes (NPS) from ½" to 24". B16.47 covers NPSs from 26" to 60". Each specification further delineates flanges into pressure classes: 150, 300, 400, 600, 900, 1500 and 2500 for B16.5, and B16.47 delineates its flanges into pressure classes 75, 150, 300, 400, 600, 900. However these classes do not correspond to maximum pressures in psi. Instead, the maximum pressure depends on the material of the flange and the temperature. For example, the maximum pressure for a Class 150 flange is 285 psi, and for a Class 300 Flange it is 740 psi (both are for ASTM A105 Carbon Steel and temperatures below 100F).

Flat welded Steel Flange: for nominal pressure not exceeding 2.5MPa Steel Pipe connection. Flat welding flange sealing surface can be made of smooth, bump and tongue and groove type three. Smooth flat welding flange application Maximum. Used for medium conditions more moderate circumstances, such as low pressure non-purified compressed air, low pressure circulating water, which has the advantage of cheaper prices. Welded flange for pressure or temperature fluctuations in the pipeline or high temperature, high pressure and low temperature pipes, but also for the delivery of expensive, flammable, explosive media pipeline. Welded flange is not easy to deformation, sealed, widely used, nominal pressure PN at about 16MPa. Butt flanges are flanges with neck and tube transition and butt welded to the tube. Butt Weld Steel Flange: It is used for the counter welding of flange and pipe, with reasonable structure, strong strength and rigidity, withstand high temperature and high pressure, repeated bending and temperature fluctuation, reliable sealing. Nominal pressure is 0.25 ~ 2.5MPa Butt flange with concave and convex sealing surface. Flat welding and butt welding are flanges and pipe connections when the welding method, flat welding flange welding only need to single-sided welding does not require welding pipe and the flange of the mouth, the welding flange flange installation requires double-flange Surface welding. Welded flange flange and pipe connections used in the welding method for butt welding and pipe and pipe welding similar to the general diameter of the small argon arc welding base, hand welding cover, large diameter Only use double-sided welding.

There are many different flange standards to be found worldwide. To allow easy functionality and interchangeability, these are designed to have standardised dimensions. Common world standards include ASME (USA), DIN (European), BS10 (British/Australian), and JIS/KS (Japanese/Korean).


ASME/ANSI B16.5flange provides
Flange Type :
Thread Flange
Blind Flange
Slip On Flange
Weld Neck Flange
Spectacle Blind Flange
Spacer & Spade
LWN Flange
Orifice Flange
flange dimensions for pipes ranging 1/2" to 24" - in classes ranging 150 to 2500.
Steel Pipe Dimensons - Schedule 40
Steel Pipe Dimensions - Schedule 80