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A flange is a flat or raised ring-like component used to connect two pipes or other objects. It can be both an independent component or an integral component of machines and equipment like pumps, valves, pipe fitting, etc It usually has bolt holes around the perimeter for attaching it to another flange or other component with bolts, studs, or screws. Flanges are commonly made from materials such as steel, stainless steel, cast iron, copper alloy, brass, or plastic, and are used in a wide range of applications, which typically include chemical process technology plants, oil and gas plants, refineries, energy, waterworks, sewerage, and other industries.


 There are several factors that influence the flange selection. To name a few, these typically include.

  1. Piping System Parameters:
    The type of fluid, pressure, temperature, flow rate, and size of the piping system are important factors that determine the type of flange required.

  2. Material Compatibility:
    The flange material should be compatible with the piping material and the fluid flowing through the system.

  3. Flange Standard:
    Different flange standards exist, such as ANSI, ASME, API, DIN, JIS, BS, BIS, and others. The flange is required to conform to the standard required by the piping system.

  4. Flange Facing:
    The facing of the flange should be compatible with the facing of the mating flange to ensure a leak-free connection.

  5. Flange Type:
    The type of flange required depends on the application, pressure, and temperature of the system. For example, a weld neck flange is suitable for high-pressure applications, while a slip-on flange is suitable for low-pressure applications.

  6. Environmental Conditions:
    Environmental factors, such as corrosive or abrasive materials, UV radiation, and temperature variations, may influence the selection of a flange and flange material.

  7. Cost:
    The compatible flange types also need to be weighed against the cost of the flange. Example A cast iron flange of a nominal diameter is cheaper in comparison to a forged body flange of the same diameter.  



  Depending on how the flanges are attached to the pipe, they can be further classified into the following.

  • Weld neck flanges:
    This type of flange is welded onto the end of a pipe. It has a long, tapered hub that gradually transitions to the pipe's outer diameter, which provides an ideal transition for the flow of fluids. This flange is suitable for high temperatures and pressure applications where the flange is subjected to a lot of stress.

  • Threaded flanges: 
    This type of flange has threads on the inside, allowing it to be screwed onto a pipe having threads on the outside. It is commonly used in low-pressure applications. This is relatively easy to fit but not suitable for high pressure and temperature. It is commonly used in applications where the flange needs to be easily removed for maintenance or cleaning.

  • Socket-welded flanges:
    This type of flange has a plain hole with a shoulder at the bottom. The pipe is inserted into the hole to butt against the shoulder and is then welded into place with a fillet weld around the outside. This type of flange is generally used for small-diameter pipes.

  • Slip-On Flange:
    A slip-on flange slides over the end of the pipe and is then welded in place. This type of flange is easy to install and is commonly used in low-pressure applications.

  • Lapped flange
    A lap joint flange (LJF) is an assembly of two elements involving a stub end and a lap joint ring flange (also called a ‘lap joint flange’). The stub end is actually not part of a lap joint flange. However, a lap joint flange is always used in conjunction with a stub end, so both parts are often collectively referred to as a ‘lap joint flange’. 

  • Blind flanges:
    Blind flanges are a form of a blanking plate that is bolted to another pipe flange to isolate a section of piping or terminate piping.


Scan Rock Traders can supply all the above types of flanges. It can supply flanges per different popular standards and customer specifications. These standards include ANSI/ASME 16.5B, ISO 7005, AS 4087, AS 2129, API etc  

Please click on the link below to view the different sizes which can be made available. Sizes not listed above can also be made available upon request.

Flange Sizes as per Different Standards

Our Products


U 10/ 35 Durham Street,
St. Lucia-4067, Queensland, Australia.


07 3705 9644



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