The types of flange vary from:
- Weld-neck flanges
- Slip-on flanges
- Threaded flanges
- Blind flanges
- Socket Weld flanges
- Orifice flanges
Now, you should know about each flange in detail. These types are produced in bulk by flange suppliers in UAE.
Weld-neck flange: these have a long tapered hub. The tapered hub goes gradually over to the wall thickness. The long tapered hub is beneficial as it provides a necessary reinforcement. There is an effect on the flange thickness to pipe or fitting wall thickness. The effect is repeated bending caused by line expansion or other variable force.
It is vital to bore these flanges to match the mating pipe’s inside diameter. Thus, there will be no restriction on product flow. As a result of this, turbulence at the joint and erosion are also reduced.
Slip-on flange: You can use it to establish a connection with the pipe; two fillet welds are needed both on the inside and outside of the flange. It would be best if you assured that space is provided not to damage the flange face while it’s being welded.
However, this flange carries a disadvantage as well. A pipe has to be welded first, followed by a fitting. Combining a flange and elbow or a flange and tee is impossible. It is because named fittings do not come with a straight end.
Socket Weld flange: These are used on small-size and high-pressure piping. They bear a similar static strength as Slip On flanges. One fillet weld is fitted outside the flange if you want to connect to the pipe. Creating a space between the flange and fitting is a must before welding.
Bottoming clearance is an essential step in a Socket-Weld to reduce the residual stress at the root of the weld. The residual stress occurs during the solidification of the weld metal. This flange bears a disadvantage too. It is the gap that has to be made.
It has to be ensured that there is no crack between the pipe and the flange, or else it can give corrosion problems.
Lap-Joint flange: It does not have a raised face. Used in conjunction with a Lap Joint Stub End, these flanges have the exact dimensions as any other flange. This flange is identical to a Slip flange, except that there is a radius at the intersection of the flange face.
There is a bore to accommodate the flanged portion of the Stub End. These have some advantages, including the freedom to swivel around the pipe and lack of contact with the fluid.
Threaded flange: These are used for special situations. One plus point is that it can be attached to the pipe without welding. In conjunction with the threaded connection, it’s wise to use a seal weld. If the wall thickness is thin, then a threaded flange is not suitable. As a cutting thread on a pipe is not possible, thus, you should use a wall with a thickness in it.
Blind flange: The speciality of this flange is that it is manufactured without a bore. These are also used to blank off the ends of the piping. Blind flanges of larger sizes are the most highly stressed flange types.
Another speciality that adds a plus point is that most of these stresses are of bending types near the centre. These flanges have no standard inside diameter; hence they are appropriate for higher pressure and temperature applications.
Flange faces
The common names are the plain/flat, raised and ring-type joint (RTJ). The easiest to identify is the Raided Face Flange. It is widely used in process plant applications. But before knowing about all these, you should have a basic idea of a flange face. A Flange Face is the surface area that receives the gasket.
Each flange has a different face which requires different gaskets. Flanges should never be mated to prevent leakage of the joint. Three types of flange gaskets used are non-metallic, semi-metallic and metal gaskets.
Advantages of stainless steel flanges
- Excellent service in a wide range of atmospheric environments
- Resistant to crevices
- Has a high versatility
- Has a great strength
- Excellent temperature and pressure tolerance
- Resistant to corrosion, although internal corrosion within the piping system takes place sometimes
- It’s pretty easy to inspect these
It’s common for metals to be vulnerable to rust, chemicals, and other environmental factors. Thus, it’s wise to use adaptable flanges to these factors. Stainless steel, with high corrosion resistance, is a perfect choice. This property of stainless steel makes it useful in virtually any application in various conditions and environments.
Thus, the advantages of stainless steel flanges outnumber its disadvantages. It means you can use flanges for a wide application in the piping system.