Flanges

Precision CNC Machined Flanges & Flange Assemblies

Custom and standard flanges manufactured to AS9100D aerospace standards. From pipe flanges to complex mounting flanges, we deliver precision machined components meeting ANSI, DIN, SAE, and custom specifications with complete face flatness control, pressure testing, and full material traceability for critical aerospace, defence, and industrial applications.

±0.01mm
Face Flatness
ANSI/DIN
Standards
Pressure
Tested
AS9100D
Quality Assured

Precision Flange Manufacturing

Our precision CNC machining capabilities deliver flanges with exceptional accuracy for critical sealing and mounting applications. Whether you require standard ANSI/DIN pipe flanges or complex custom mounting flanges, we combine advanced multi-axis machining with rigorous quality control to ensure perfect face flatness, precise bolt hole patterns, and complete dimensional accuracy.

From small instrument flanges to large industrial pipe flanges up to 600mm diameter, we manufacture components from a comprehensive range of materials including carbon steel, stainless steel, titanium, and specialty alloys. Every flange undergoes face flatness verification, dimensional inspection, and pressure testing as required to ensure leak-free performance in demanding applications.

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Key Applications

Piping Systems

Oil & gas, chemical processing, hydraulic systems, pneumatic lines

Aerospace Assemblies

Engine mounting flanges, fuel system connections, structural interfaces

Mechanical Equipment

Motor mounting, gearbox flanges, pump connections, bearing housings

Industrial Process

Vessel connections, tank flanges, manifold interfaces, duct systems

Types of Flanges We Manufacture

Comprehensive range from standard pipe flanges to custom precision components

Weld Neck Flanges

High-pressure pipe flanges with long tapered hub for butt welding.

  • ANSI B16.5, B16.47 standards
  • Raised face or flat face
  • Class 150 to 2500 ratings
  • Superior stress distribution

Slip-On Flanges

Cost-effective flanges that slip over pipe and are fillet welded.

  • ANSI B16.5 compliant
  • Easy alignment and welding
  • Lower cost vs weld neck
  • Class 150 to 600 common

Blind Flanges

Solid flanges used to seal the end of piping systems or vessels.

  • Complete system isolation
  • Pressure testing access
  • Future expansion provision
  • All pressure classes

Socket Weld Flanges

Flanges with internal socket for small bore piping systems.

  • Small bore applications (≤2")
  • Single fillet weld
  • High fatigue strength
  • Minimal internal crevice

Threaded Flanges

Flanges with internal threads for pipe connection without welding.

  • NPT or BSPT threads
  • No welding required
  • Low/medium pressure applications
  • Easy installation/removal

Lap Joint Flanges

Two-piece design with stub end for systems requiring alignment.

  • Rotating flange face
  • Easy bolt hole alignment
  • Used with stub ends
  • Lined pipe systems

Mounting Flanges

Custom flanges for motor mounting, equipment attachment, and structural interfaces.

  • SAE and custom patterns
  • Motor/gearbox mounting
  • Complex bolt patterns
  • Precision face flatness

Orifice Flanges

Specialized flanges for flow measurement and orifice plate installation.

  • Pressure tapping provisions
  • Orifice plate slots
  • Flow metering applications
  • ANSI compliant designs

Custom Flanges

Engineered flanges designed to unique specifications and requirements.

  • Non-standard dimensions
  • Special materials
  • Unique bolt patterns
  • Integrated features

Flange Standards & Specifications

Manufacturing to international standards and custom specifications

ANSI/ASME Standards

  • • ANSI B16.5 (NPS ½" to 24")
  • • ANSI B16.47 (NPS 26" to 60")
  • • ASME B16.1 (cast iron flanges)
  • • Class 150, 300, 600, 900, 1500, 2500
  • • Raised face, flat face, RTJ

DIN/EN Standards

  • • DIN 2527, 2566, 2573, 2576
  • • EN 1092-1 (steel flanges)
  • • PN 6, 10, 16, 25, 40, 63, 100
  • • Form A, B, C, D, E, F
  • • DN 10 to DN 2000

SAE/Aerospace

  • • SAE J518 (hydraulic flanges)
  • • SAE J2494 (fuel flanges)
  • • MS and AN specifications
  • • Code 61, 62 SAE flanges
  • • Aerospace flange patterns

Custom Specifications

  • • Customer drawings
  • • OEM specifications
  • • Proprietary designs
  • • Special pressure ratings
  • • Unique bolt patterns

Materials for Flanges

Comprehensive material selection for pressure, temperature, and corrosion requirements

Carbon Steel

  • A105: Forged flanges, general service
  • A350 LF2: Low temperature service
  • A694 F52/F60: High-pressure piping
  • 1020/1045: Machined from bar stock
  • A516 Gr 60/70: Pressure vessel flanges

Benefits: High strength, economical, weldable

Stainless Steel

  • 304/304L (F304/F304L): General corrosion resistance
  • 316/316L (F316/F316L): Marine, chemical service
  • 321 (F321): High temperature applications
  • 347 (F347): Stabilized for welding
  • Duplex 2205: High strength, corrosion resistant

Benefits: Excellent corrosion resistance, cleanable surfaces

Alloy Steel

  • A182 F11/F22: High temperature (Cr-Mo)
  • A182 F5/F9: Moderate temperature service
  • A182 F91: Advanced high temperature
  • 4140/4340: High strength applications
  • Inconel 625/718: Extreme temperature

Benefits: High temperature strength, creep resistance

Specialty Materials

  • Titanium Gr 2/5: Aerospace, chemical service
  • Hastelloy C-276: Extreme corrosion resistance
  • Monel 400/K-500: Marine environments
  • Aluminum 6061: Lightweight applications
  • Nickel 200/201: Caustic service

Benefits: Specialized performance, extreme environments

Technical Capabilities & Specifications

Precision manufacturing for critical sealing and mounting applications

Machining Capabilities

Diameter Range 25mm to 600mm
Face Flatness ±0.01mm per 100mm
Bolt Hole Tolerance ±0.25mm (ANSI standard)
Surface Finish (Face) Ra 3.2µm to 6.3µm
Bore Tolerance ±0.5mm to ±2.0mm
Thickness Range 10mm to 150mm
CNC Axes 3-Axis to 5-Axis

Features & Operations

Face Machining

Raised face, flat face, male/female, RTJ grooves

Bolt Holes

Drilled, reamed, tapped, counterbored, spot-faced

Hub Machining

Weld prep bevels, tapered hubs, step bores

Sealing Surfaces

O-ring grooves, gasket seats, spiral wound grooves

Special Features

Tap holes, lifting eyes, drain holes, vent holes

Marking

Stamping, engraving, etching for identification

Pressure Class Capabilities

ANSI Classes

Class 150 290 psi @ 100°F
Class 300 740 psi @ 100°F
Class 600 1480 psi @ 100°F
Class 900 2220 psi @ 100°F
Class 1500 3705 psi @ 100°F
Class 2500 6170 psi @ 100°F

DIN/EN Ratings

PN 6 6 bar
PN 10 10 bar
PN 16 16 bar
PN 25 25 bar
PN 40 40 bar
PN 63/100 63/100 bar

Temperature Ratings

Pressure ratings vary with temperature according to ASME B16.5:

Example: Class 150 carbon steel rated for 290 psi @ 100°F reduces to 230 psi @ 400°F

Consult pressure-temperature charts for specific material and temperature combinations

Surface Treatments & Coatings

Corrosion protection and surface enhancement options

Painting/Coating

Epoxy, polyurethane, or specialized coatings per spec

Hot-Dip Galvanizing

Superior corrosion protection for outdoor/marine service

Electroplating

Zinc, cadmium, nickel plating to ASTM specifications

Passivation

Stainless steel chemical treatment per ASTM A967

Electroless Nickel

Uniform coating, excellent corrosion resistance

Polishing

Mechanical polishing for sanitary/cleanroom applications

Heat Treatment

Stress relief, normalization, hardening as required

Sandblasting

Surface preparation for coating or aesthetic finish

Quality Assurance & Testing

Comprehensive inspection ensuring dimensional accuracy and integrity

Dimensional Verification

Complete dimensional inspection to drawing specifications.

  • Face flatness measurement
  • Bolt hole pattern verification
  • Diameter and thickness checks
  • CMM inspection available

Pressure Testing

Hydrostatic testing to verify pressure integrity.

  • Hydrostatic test per ASME
  • Pneumatic testing available
  • Leak detection
  • Test documentation

Material Verification

Complete material traceability and certification.

  • Material test reports (MTR)
  • XRF alloy verification
  • Heat number traceability
  • Chemical composition certs

NDT Services

Non-destructive testing for critical applications.

  • Liquid penetrant (PT)
  • Magnetic particle (MT)
  • Ultrasonic testing (UT)
  • Radiographic testing (RT)

Surface Quality

Surface finish and integrity verification.

  • Surface roughness testing
  • Visual inspection per AQL
  • Face finish verification
  • Coating thickness measurement

Documentation

Complete quality documentation package.

  • AS9102 First Article Inspection
  • Certificate of Conformance
  • Material certifications
  • Dimensional reports

AS9100D Certified Manufacturing

Our AS9100D quality management system ensures every flange meets aerospace and industrial standards with complete traceability and rigorous inspection protocols.

AS9100D Certified
ISO 9001:2015
Full Traceability

Design Guidelines for Flanges

Best practices for flange design and selection

Best Practices

  • Standard compliance: Use ANSI, DIN, or SAE standards whenever possible for availability and interchangeability
  • Pressure rating: Select pressure class based on maximum operating pressure and temperature conditions
  • Gasket selection: Specify appropriate gasket type for face finish (raised face typically Ra 3.2-6.3µm)
  • Bolt sizing: Follow ASME PCC-1 guidelines for bolt size, torque, and number of bolts
  • Flange thickness: Ensure adequate thickness for pressure containment and bolt loading
  • Weld preparation: Specify bevel angle and root face per AWS D1.1 or ASME IX

Design Considerations

  • Material compatibility: Match flange material to pipe/system material to avoid galvanic corrosion
  • Temperature effects: Account for thermal expansion and pressure de-rating at elevated temperatures
  • Face finish: Specify appropriate surface finish for gasket type (smoother for soft gaskets)
  • Bolt loading: Provide adequate flange thickness to prevent excessive bending under bolt loads
  • Accessibility: Consider clearance for bolt installation and torquing
  • Corrosion allowance: Add material thickness for corrosive service environments

Engineering Support Available

Our engineering team provides comprehensive support for flange selection and design:

Pressure class selection
Material recommendations
Custom flange design
Gasket compatibility
Bolt specification
DFM optimization

Industries We Serve

Precision flanges for critical applications across diverse sectors

Oil & Gas

Pipeline flanges, wellhead components, refinery equipment

Aerospace

Engine mounting flanges, fuel system, hydraulic connections

Chemical Processing

Reactor flanges, process piping, tank connections

Power Generation

Steam systems, turbine connections, cooling systems

Marine

Seawater systems, ballast piping, engine room equipment

Water Treatment

Distribution systems, treatment plants, pump stations

HVAC

Ductwork connections, boiler flanges, chiller systems

Pharmaceutical

Sanitary flanges, process vessels, clean room systems

Frequently Asked Questions

Common questions about flange manufacturing

What is the difference between slip-on and weld neck flanges?

Weld neck flanges have a long tapered hub that is butt welded to the pipe, providing superior strength and fatigue resistance for high-pressure applications. Slip-on flanges slip over the pipe and are fillet welded on both sides, offering easier alignment and lower cost but reduced strength compared to weld neck designs. Weld neck flanges are preferred for Class 600 and higher pressures, while slip-on flanges are common in Class 150-300 applications.

Can you manufacture flanges to custom bolt patterns?

Yes, we frequently manufacture custom flanges with non-standard bolt patterns, diameters, and configurations. Provide us with your drawing or specifications including bolt circle diameter, number of holes, hole size, and flange dimensions. We can match existing equipment interfaces or design entirely new flange patterns to your requirements.

What face finishes are available for flanges?

We offer all standard face finishes including: raised face (RF), flat face (FF), ring-type joint (RTJ), male and female (M&F), and tongue and groove (T&G). Raised face is most common, with typical surface finish of Ra 3.2-6.3µm (125-250 micro-inch). For special applications, we can provide smoother finishes or specialized groove patterns for spiral-wound or ring gaskets.

Do you provide pressure testing and certification?

Yes, we provide hydrostatic pressure testing per ASME B16.5 or customer specifications. Testing is performed at 1.5 times the rated working pressure. We provide complete test documentation including test pressure, duration, and results. Material certifications (MTR), Certificate of Conformance (C of C), and AS9102 First Article Inspection Reports are available for aerospace applications.

What is the typical lead time for standard ANSI flanges?

Lead times vary based on size, quantity, and material. Standard ANSI flanges machined from stock can typically be completed in 2-3 weeks. Flanges requiring forging or special materials may take 4-6 weeks. Large diameter flanges (>24") or high pressure classes (1500/2500) typically require 6-8 weeks. Rush services are available for urgent requirements.

Can you machine flanges from forgings or castings?

Yes, we frequently machine flanges from forged or cast blanks. For high-pressure applications and large sizes, forged flanges offer superior strength and grain structure. We can source forgings per ASTM A105, A182, or other specifications, or machine customer-supplied forgings. Forged flanges are mandatory for Class 600 and higher in many codes.

What tolerances do you hold on face flatness?

We routinely achieve face flatness of ±0.01mm per 100mm diameter, which exceeds ASME B16.5 requirements. For critical sealing applications, we can provide even tighter flatness control with verification documentation. Face flatness is measured with precision straight edges and dial indicators or optical measurement systems.

Do you manufacture flanges for sanitary/hygienic applications?

Yes, we manufacture sanitary flanges for pharmaceutical, food processing, and biotechnology applications. These typically use 316L stainless steel with electropolished surfaces (Ra < 0.4µm) and special gasket grooves for silicone or EPDM seals. We follow 3-A sanitary standards and provide material certifications documenting surface finish and cleanliness.

Ready to Order Your Flanges?

Upload your flange specifications or drawings for a detailed quote. Our engineering team will review your requirements and recommend optimal materials, pressure ratings, and manufacturing methods.