Flange Types and Sizes Guide: Comprehensive Pipe Flange Solutions

As a cornerstone in piping systems, flange types and sizes dictate critical factors such as flow integrity, maintainability, and safety in industries including petrochemical, metallurgy, water treatment, and beyond. Selecting the appropriate flange type and size is pivotal for achieving operational efficiency, pipeline longevity, and regulatory compliance. This comprehensive guide delves deep into the technical parameters, manufacturing process, industry certifications, and application advantages of flange types and sizes.

The global industrial flange market reached USD 8.3 billion in 2023, with a projected CAGR of 4.5% (2024–2030) as per industry studies. With increasing demand for custom solutions, precision, and corrosion resistance, end-users from refinery, oil & gas, and power generation sectors demand a variety of pipe flange types and sizes optimized for their specific environments.

Standard flange types and sizes are classified based on design, material, connection, sealing, and application. The table below compares major pipe flange types and typical specification ranges:

Raw Material Selection

e.g. Stainless Steel, Carbon Steel

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Forging/Casting

Shape formation, grain refinement

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CNC Machining

Drilling, Facing, Precision Cuts

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Surface Treatment

Anti-corrosion, Polishing

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Testing & Inspection

ISO/ANSI, PMI, Hydrostatic

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Packing & Delivery

Client-labelled, Export Standard

• Material grades: ASTM A105, A182 F304/316, A350 LF2, etc. for meeting diverse industry needs.
• Manufacturing methods: Forging delivers superior mechanical strength (Yield Strength: 205–355MPa), while casting suits complex profiles but slightly lower strength.
• Precision: CNC turning ensures dimensional tolerances within ±0.1mm, vital for sealing and assembly.
• Inspection: 100% PMI (Positive Material Identification), Hydrostatic Testing, Ultrasonic Flaw Detection per ANSI/ISO standards.
• Surface protection: Epoxy/Painting for carbon steel; passivation for stainless steel.
  

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• Spiral wound gaskets: Superior for high-temp (>500℃) & high-pressure sealing needs.
• Ring Type Joint: Used in critical pressure vessels, oil & gas systems.
• PTFE: Best suited for highly corrosive applications, pharmaceutical, or food piping.

• Material Quality: Sourced certified raw materials only (with ISO 9001 and ASTM/EN/ASME material traceability).
• Precision Manufacturing: CNC turning, high-definition boring, and full QA traceability across all flange types and sizes.
• Custom Engineering: Special alloys (Duplex, Inconel, Titanium) and bespoke sizing to suit harsh operating conditions.
• Surface Protection: Electropolishing and epoxy paint for maximum corrosion resistance; lifespans reach 15–30+ years.
• International Testing: Each flange tested per EN 10204 3.1/BSP/ANSI B16.5 standards for dimension, composition, and hydrostatic performance.
• Fast Turnover: Average production/delivery: 7–25 days depending on volume and custom request; rush services available.

• Petrochemical: High-pressure, sour service with RTJ and duplex steel flanges, spiral wound gaskets.
• Metallurgy: Large diameter slip-on & weld neck flanges for slurry and process lines.
• Water Treatment: Coated carbon steel or stainless slip-on flanges for corrosion resistance and easy installation.
• Power Generation: Alloy RTJ/weld neck flanges for superheated steam lines with metal gaskets.
• Food & Pharma: Polished stainless, PTFE gaskets; meets FDA/3A standards.

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Q1: What are the main materials for industrial flanges?

A: Carbon steel (A105, Q235), stainless steel (304/316, Duplex 2205), and alloy steel (F11, F22, Inconel) are prevalent. Selection depends on media, temperature, and pressure requirements.

Q2: What is the function of a raised face (RF) vs. ring type joint (RTJ)?

A: RF provides enhanced gasket compression; RTJ delivers metal-to-metal sealing, essential for high-pressure, high-temperature critical joints.

Q3: How is flange size designated?

A: By Nominal Diameter (DN/NPS), Pressure Class (PN/CL), facing type, bolt circle, and number of bolt holes—per ASME, EN, and ISO standards.

Q4: What installation standards govern flange connections?

A: ASME B16.5 (US), EN 1092 (EU), and GB/T 9112–9123 (Asia). All require gasket surface finish and bolt torque control for leak proof service.

Q5: What is Positive Material Identification (PMI) in flange manufacturing?

A: PMI uses XRF/Optical analysis to verify alloy composition against order specs—crucial to safety-sensitive industries.

Q6: How do you select the correct type of gasket for flanges?

A: Consider process pressure, temperature, media compatibility, and flange surface. Spiral wound for high-pressure, PTFE for corrosive, and graphite for thermal cycling applications.

Q7: What is the typical delivery period and warranty for custom flanges?

A: Standard sizes in stock ship in 3–7 days. Custom fabricated flange types and sizes are delivered in 7–25 days. Warranty up to 3 years with lifetime technical support.

• Delivery: Stock flanges: 2–7 business days. Custom: 7–25 business days, urgent service on request.
• Warranty: Up to 36 months for all flange types and sizes, covering leakage and manufacturing defects.
• Support: 24/7 technical response, application analysis, on-site support within 24–48h in urgent cases. ISO/EN/CE-certified documentation.
• Traceability: Every flange with unique batch code, full 3.1B certification, and production reports available to client.

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• Brazil Offshore Gas Project: Custom alloy weld neck flanges delivered zero-leakage over 3 years and passed API 607 fire-test protocols (industry forum reference).
• German Chemical Plant: PTFE-coated slip-on flanges cut yearly maintenance by half, per operator testimonial.
• Asian Water Utility: Stainless socket weld flanges reduced downtime by 31% and exceeded ISO 9001 durability specs in municipal use.