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What is a Flange?

Standard we supply

Most common flange types

Regardless of custom sizing or specifications, the fundamental design of most flanges falls under six common styles created to close, connect, cover, or support pipes and pipe systems.

Slip-on Flanges
Slip-on Flanges
Slip-on Flanges - are all bored slightly larger than the O.D. of the pipe.
ASTM A335 P22 alloy pipe
Weld Neck Flanges
Weld Neck Flanges - is normally referred to as the high hub flange.
Blind flanges
Blind Flanges
Blind Flanges - available to seal both pipes and vessels
Lap Joint Flanges
Lap Joint Flanges
Lap Joint Flanges - available in a range of sizes to pair with stub end fittings for easy dismantling
Threaded Flanges
Threaded Flanges
Threaded Flanges - engineered to fit pipes with external threads for weld-free fits
Blind flanges
Socket-weld Flanges
Socket-weld Flanges - designed with a socket fit and top weld for ideal inner flow in pipe systems

Specialty flange

Except the most used standard flanges, there are still a number of specialty flange such as:

Spectacle Blind Flange
Spectacle Blind Flange
Spectacle Blind Flange consist of a connected ring (spacer) and a plate (spade).
Long Weld Neck Flange
Reducing Flange
Reducing Flange is used on projects that require the fitting together of different sized pipes.
Weldoflange, Nipoflange
Weldoflange / Nipoflange
Weldoflange / Nipoflange is a combination of a Welding Neck flange and a supposedly Weldolet or Nipolet.
Orifice Weld Neck Flanges
Orifice Flanges
Orifice Flanges generally come with either Raised Faces or RTJ (Ring Type Joint) facings.
Expander Flange
Expander Flange
Expander Flange is using a separate reducer-welding neck flange combination.
Anchor flange
Anchor flange
An anchor flange is a device installed on a pipeline to combat axial movement.
Large Diameter Flanges
Large Diameter Flanges
The large diameter flange is used to connect or to block off two very large diameters sized pipes.
NW Long Weld Neck Flanges
Long Weld Neck Flange
Long Weld Neck Flange is normally referred to as the high hub flange.

Material Grades and Performance

Custom pipe flanges can be manufactured from a wide variety of materials and material grades.

Stainless steel flange
Alloy Steel flanges accord to ASTM A182 F1, F5a, F9, F11, F12, F22, F91
Carbon Steel Flanges
Forged steel flange

Carbon steel is a popular solution, as are stainless steel and specialty alloys, depending upon the industry. Plate and forged are also common, as are titanium and aluminum for lightweight jobs.

Flange connection
Pipeline & fittings with flanges

Pipe Flange helps to connect piping components in a piping system with the use of bolted connections and gaskets.

Flanges Manufacturing Process

Our manufacturing process is highly sophisticated and is divided into various departments supervised by experienced industry experts.

Raw material

1. Raw Material

  • Raw Material Check
  • Quantity Check
  • Visual & Dimension Check

2. Material Inspection

  • Chemical Analysis Check
  • Preservation Analysis Certificate
Steel material cutting

3. Material Cutting

  • Weight Measuring
  • Cut Surface Check
  • Marking
Flange forging

4. Flange forging

  • Material Grade Check
  • Weight Measuring
  • Temperature Control
Heat Treatment

5. Heat Treatment

  • Normalizing
  • Tempering, Q.T
  • Solution Treatment
  • Mechanical Test
Forging Rolling

6. Forging Rolling

  • Material Grade Check
  • Weight Measuring
  • Temperature Check
  • Dimension Check
Final Inspection

7. Final Inspection

Rust Prevention

8. Rust Prevention

  • Preserve Check
  • Marking on the flange
  • Tectyl 506or Pickling or etc. Coating
Well packing

9. Wel lPacking

  • Packing Spec. Check
  • Packing Inspection
  • Delivery

Requirements are valid for normal situation, in special you have to contact us to introduce.

Raw Materials:
The usual materials of flanges include stainless steel, carbon steel, aluminum and plastic.

Beginning with this process,the system controls the quality of all incoming materials as per the raw material test certificate of the material. Mild Steel Flanges ( MS ) are of premium quality that ensures high durability, strength and resistivity to varied non-supporting conditions. Also, checking in each size for chemical and physical properties of these materials at Government approved laboratory.

Flange materials acc. to ASTM

Dimensions from carbon steel and stainless steel flanges are defined in the ASME B16.5 standard. The material qualities for these flanges are defined in the ASTM standards.

The Packing Works for Steel Flanges  >>

Steel flanges must be packed with seaworthy packing method then delivery to customers, usually the packing way include wooden box, wooden pallet, iron & steel cage, iron & steel pallet etc. Because of the normal wooden boxes or wooden pallets have to do fumigation treatment, we usually use plywood pallet or plywood case or box to pack steel flanges without fumigation treatment. Whatever plywood or iron & steel packing way, they must be seaworthy, strong, waterproof and easy for loading and unloading.

Marking on the flange
Shipping mark stick to outside of package. Following shall be marked on flange body

Mark on the flange


  • Manufacturer logo
  • ASTM material code
  • Material Grade
  • Service rating (Pressure-temperature Class))
  • Size
  • Thickness (Schedule)
  • Heat No
  • Special marking if any QT (Quenched and tempered) or W (Repair by welding)

About DM Special Steel Ltd

Our team are highly trained and experienced in servicing and producing all types of steel supplies. Whether you've got a large construction project, or need parts for industrial machinery, our team of steel fabrication consultants will ensure that your project is provided with the parts you need, when you need them.