What is an integral flange?
It is a flange connection method. It is also a type of butt-weld steel pipe flange with a neck. The materials include carbon steel, stainless steel, alloy steel, etc.
In various domestic standards, IF is used to represent integral flanges. It is mostly used in pipelines with higher pressures. The production process is generally casting.
In the flange type, an "IF" is used to represent the type of integral flange.
It is generally a raised face (RF). If it is used in flammable, explosive, high, and extremely hazardous conditions, you can choose the sealing surface of the convex and concave surface (MFM) and the tongue and groove surface (TG) in addition to the RF surface.
What is the difference between an integral flange and a butt-weld flange?
Different appearance
The pipe end of the integral flange is thicker than that of the butt-weld flange. The inner diameter of the integral flange is the same as the nominal diameter except for PN1.6MPa and DN450. The neck height of the integral flange is high, and the wall thickness is relatively thick. The reference standard of the neck flange can clearly see it.
Different applications
1. An Integral flange is a flange connected to the equipment, such as the flange on the valve. This flange is an integral part of the valve and is not connected by welding. Integral flanges are mostly used in equipment manufacturing and are rarely used in pipeline design.
2. The necked butt-welded flange is used in conjunction with valves, pumps, and other equipment. It is welded to the pipeline. The tail interface size is consistent with the outer diameter and wall thickness of the corresponding pipeline and can be directly butt-welded.
Different technical requirements
1. Integral flange
Another meaning of national standard flanges is flanges produced according to the dimensions and tolerance ranges required by national standards, which are different from flanges produced according to non-standard dimensions, also called second-standard flanges (some people call them non-standard flanges, which is incorrect). Usually, some unscrupulous merchants will reduce the thickness and outer diameter of the flange to save materials.
There are also flanges made of scrap steel or scrap steel. Usually, this kind of steel is waste with substandard chemical composition and mechanical properties. What's worse, flanges are produced by private steel mills. The steelmaking technology used in this private steelmaking is outdated and cannot guarantee mechanical properties and welding properties. It may not be welded with steel pipes when used, or the steel itself has cracks, pores, etc., and it will leak after welding.
So try to use national standard flanges when buying flanges. If funds are limited and you choose a second-standard flange, you must carefully observe and measure the flange size and test its material to avoid being deceived.
2. Butt-weld flange
1) Butt-weld flanges should be ultrasonically inspected and have no delamination defects.
2) They should be cut into strips along the rolling direction of the steel, bent, and welded into a circular ring, and the surface of the steel should form a cylindrical ring. Steel plates shall not be directly machined into necked butt-weld flanges.
3) The butt weld of the circular ring should be a full penetration weld.
4) The butt weld of the annular ring should be post-weld heat treated and 100% radiographic or ultrasonic testing should be performed, and the radiographic testing should meet the requirements of Level II of JB4730, and the ultrasonic testing should meet the requirements of Level I of JB4730.
In conclusion, the above is the difference between integral flanges and butt-welded flanges. If you have any questions, please feel free to consult us.
