Flanges

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Flanges

At Dhanlaxmi Stainless, we specialize in the production and supply of a diverse range of industrial flanges designed to meet international quality benchmarks. Our product offerings include flanges manufactured from premium materials such as Stainless Steel (grades ASTM A182 F304, F304L, F304H, F316, F316L, F317, F317L, F321, F310, F347, and 904L), Duplex & Super Duplex Steels (UNS S31803, S32750, S32760), and various Nickel Alloys including Hastelloy (B564 B2, C276, C22), Incoloy (Alloy 20, A286, 800H/HT, 825), Inconel (600, 601, 625, 718, 725), and Monel (400, K500). We also offer options in Carbon Steel (ASTM A105, A694 F42, A350 LF2) and Alloy Steel (ASTM A182 F1, F5, F9, F11, F22, F91).

Our flanges are available in sizes ranging from ½" NB to 72" NB and come in pressure classes of 150#, 300#, 600#, 900#, 1500#, and 2500#. The types we offer include Slip-On, Threaded, Lap Joint, Socket Weld, Weld Neck, Blind (Dummy), Orifice, RTJ (Ring Type Joint), Long Weld Neck, and Table Flanges (D, E, F, H).

Engineered for durability, dimensional accuracy, and resistance to corrosion, our flanges are extensively utilized across sectors like Oil & Gas, Petrochemical, Power Plants, Marine Applications, and Water Treatment Facilities. Each flange undergoes stringent quality checks and can be supplied with all relevant testing certifications and third-party inspection reports as required.

Specification of Flanges

Flanges – Specifications
Product Name Industrial Pipe Flanges
Size Range 1/2" NB to 72" NB
Pressure Rating 150#, 300#, 600#, 900#, 1500#, 2500#
Available Materials
  • Stainless Steel & Duplex Steel
  • Nickel Alloy, Inconel, Incoloy & Monel
  • Carbon Steel & Alloy Steel
Material Grades Stainless Steel: ASTM A182 F304, F304L, F304H, F316, F316L, F317, F317L, F321, F310, F347, 904L
Duplex / Super Duplex: UNS S31803, S32750, S32760
Hastelloy: ASTM B564 B2, C276, C22
Incoloy: Alloy 20, A286, 800H/HT, 825
Inconel: ASTM B564 Alloy 600, 601, 625, 718, 725
Monel: ASTM B564 Monel 400, K500
Carbon Steel: ASTM A105, A694 F42, A350 LF2
Alloy Steel: ASTM A182 F1, F5, F9, F11, F22, F91
Copper Alloys: Brass, Pure Copper, Cupro Nickel 90/10 (C70600), Cupro Nickel 70/30 (C71500)
Types Slip-On Flange, Weld Neck Flange, Socket Weld Flange, Blind Flange (Dummy Flange), Threaded Flange, Lap Joint Flange, Orifice Flange, RTJ Flange (Ring Type Joint), Long Weld Neck Flange, Table Flanges (Table D, E, F, H)
Standards ASME B16.5, ASME B16.47, BS 4504, DIN, EN 1092-1, ANSI
End Connections Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ)
Applications Oil & Gas, Petrochemicals, Refineries, Power Plants, Shipbuilding, Chemical Plants, Water Treatment Facilities, Nuclear Projects, Offshore Platforms, and Process Piping Systems.

Dimensional Standards of Flanges

Flange Type Size (NPS) Dimensions (mm) Number of Bolts Bolt Hole Diameter (mm) Standard
Outer Diameter (OD) Bolt Circle Diameter (BCD)
Weld Neck Flange 1/2" - 72" 90 - 1850 60 - 1750 4 - 40 15 - 68 ASME B16.5 / B16.47
Slip-On Flange 1/2" - 72" 90 - 1850 60 - 1750 4 - 40 15 - 68 ASME B16.5 / B16.47
Blind Flange 1/2" - 72" 90 - 1850 60 - 1750 4 - 40 15 - 68 ASME B16.5 / B16.47
Threaded Flange 1/2" - 24" 90 - 900 60 - 860 4 - 20 15 - 52 ASME B16.5
Socket Weld Flange 1/2" - 4" 90 - 210 60 - 165 4 - 8 15 - 22 ASME B16.5
Lap Joint Flange 1/2" - 72" 90 - 1850 60 - 1750 4 - 40 15 - 68 ASME B16.5 / B16.47
Orifice Flange 1/2" - 24" 90 - 800 60 - 765 4 - 20 15 - 45 ASME B16.36
RTJ Flange (Ring Type Joint) 1/2" - 36" 100 - 1250 75 - 1200 4 - 32 15 - 64 ASME B16.5 / B16.47
Long Weld Neck Flange 1/2" - 24" 100 - 850 70 - 800 4 - 20 15 - 52 ASME B16.5
Table Flange (D, E, F, H) 1/2" - 36" 95 - 920 65 - 880 4 - 24 14 - 50 BS 10 / BS 4504

Types of Flanges

Weld Neck Flange

Weld Neck Flanges are designed to handle high pressure, high temperature, and hazardous conditions. Their long tapered hub ensures even stress distribution and a secure, leak-proof weld connection with the pipe.

  • Ideal for pipelines under extreme stress or pressure
  • Long neck design minimizes turbulence and erosion
  • Available in Stainless Steel, Duplex, Carbon & Alloy Steel
  • Supplied with MTCs, NACE, and third-party inspection (if required)
Weld Neck Flange

Slip-On Flange

Slip-On Flanges are designed to slide over the end of a pipe and are then welded both inside and outside for strength and leak prevention. These flanges are ideal for lower pressure applications and are easier to align than weld neck types.

  • Economical and easy to install and align
  • Suitable for low-pressure, non-critical piping systems
  • Commonly used in cooling water, firefighting, and low-pressure steam lines
  • Available in Stainless Steel, Carbon Steel, Alloy Steel, Duplex & Nickel Alloys
Slip-On Flange

Threaded Flange

Threaded Flanges are designed with internal threads that allow them to be screwed onto the pipe without welding. These flanges are ideal for systems where welding is not feasible or allowed due to hazardous conditions.

  • Allows easy assembly without welding
  • Suitable for low-pressure, non-cyclic applications
  • Ideal for small-diameter, high-pressure piping
  • Offered in Stainless Steel, Carbon Steel, and special alloys
Threaded Flange

Socket Weld Flange

Socket Weld Flanges are designed for small-bore piping systems with high pressure. The pipe is inserted into the socket end and then fillet welded around the top, creating a strong and smooth flow path with reduced turbulence and leakage risk.

  • Perfect for small-diameter high-pressure pipelines
  • Provides strong structural reinforcement with a fillet weld
  • Ensures smooth bore for enhanced flow characteristics
  • Available in Stainless Steel, Carbon Steel, Alloy Steel, and more
Socket Weld Flange

Lap Joint Flange

Lap Joint Flanges are used with stub ends and are ideal for systems requiring frequent disassembly. These flanges rotate freely around the stub end, making bolt alignment easy and reducing overall installation effort—especially for large or rigid pipe systems.

  • Ideal for piping systems that require frequent dismantling
  • Enables easy bolt alignment thanks to its rotating design
  • Cost-effective when used with high-grade stub ends
  • Commonly used in low-pressure and non-critical applications
Lap Joint Flange

Blind Flange

Blind Flanges are solid disks used to close the end of piping systems or pressure vessel openings. They allow for easy access to the system when needed and are commonly used in high-pressure applications where future expansion or inspection is required.

  • Used to seal the ends of piping or valve systems
  • Ideal for pressure testing, inspection, and expansion
  • Withstands high pressure and stress conditions
  • Available in various sizes and materials to suit different needs
Blind Flange

Long Weld Neck Flange

Long Weld Neck Flanges (LWN) are similar to standard weld neck flanges but have an extended neck, making them ideal for high-pressure and high-temperature applications. They are commonly used in process piping, vessel connections, and high-integrity systems.

  • Designed for use in high-pressure and high-temperature environments
  • Long neck provides added reinforcement and stress distribution
  • Ideal for equipment nozzles, heat exchangers, and pressure vessels
  • Manufactured in Stainless Steel, Carbon Steel, Alloy Steel & more
Long Weld Neck Flange

Orifice Flange

Orifice Flanges are used in conjunction with orifice meters to measure the flow rate of liquids or gases in pipelines. They are typically provided in pairs and include tapped holes for mounting pressure gauges and instrumentation.

  • Specifically designed for flow measurement applications
  • Includes pressure tap holes and jack screws for ease of use
  • Supplied with gaskets, orifice plates, and bolts on request
  • Suitable for steam, gas, and liquid metering systems
Orifice Flange

Spectacle Blind Flange

Spectacle Blind Flanges are primarily used for positive isolation in piping systems. They consist of a solid plate (blind) and a ring (spacer) connected by a web or bar, allowing operators to block or open the pipeline easily by rotating the unit.

  • Designed for quick and safe flow isolation in pipelines
  • Simple rotating design allows switching between open and blind positions
  • Commonly used during maintenance or pressure testing operations
  • Available in multiple grades of Stainless Steel, Carbon Steel & Alloys
Spectacle Blind Flange

Ring Type Joint (RTJ) Flange

RTJ Flanges are precision-machined flanges designed to ensure leak-proof metal-to-metal sealing in high-pressure and high-temperature applications. These flanges use a specially shaped metallic ring that fits into a hexagonal groove for optimal sealing integrity.

  • Engineered for critical applications requiring high sealing reliability
  • Used in oil & gas, offshore, and high-temperature processing units
  • Compatible with ANSI and API standards for pressure classes up to 2500#
  • Available in stainless steel, duplex, carbon steel, and high nickel alloys
Ring Type Joint Flange

Applications of Flanges

Flanges play a vital role in enabling reliable connections across various demanding industries.

Oil & Gas Industry

Used in high-pressure pipelines, offshore rigs, and refineries for leak-proof and durable connections.

Petrochemical Plants

Handles corrosive chemicals and extreme temperatures in chemical processing and transport systems.

Power Generation

Essential in thermal, nuclear, and hydro power plants for connecting turbines, boilers, and piping.

Shipbuilding & Marine

Used in marine engines and piping systems for their corrosion resistance and mechanical strength.

Water Treatment Plants

Enable seamless flow control in desalination units, filtration systems, and water supply lines.

General Engineering

Applicable across heavy machinery, structural pipelines, and process equipment.