Metal flange: Component Specs, Materials & Applications

Component Specifications

Definition

A metal flange is a mechanical component designed as a flat, circular disc with evenly spaced bolt holes around its perimeter and a central opening. It serves as a critical connection point in piping and machinery systems, allowing for the assembly, disassembly, and maintenance of system sections. In viewport applications, it typically secures the viewport window to the housing, ensuring a pressure-tight or vacuum-tight seal while permitting visual inspection. Flanges are engineered to withstand specific pressures, temperatures, and mechanical loads, with surfaces often machined to precise flatness or grooved for gasket seating.

Working Principle

The flange works by creating a bolted joint between two mating surfaces. When bolts are tightened through the aligned holes, compressive force is applied, pressing a gasket (placed between the flanges) into the sealing surface. This compression deforms the gasket to fill microscopic imperfections, forming a leak-proof barrier. The flange distributes the clamping force evenly around the perimeter, maintaining seal integrity under operational stresses such as internal pressure, vibration, or thermal expansion.

Materials

Common materials include carbon steel (e.g., ASTM A105), stainless steel (e.g., 304/316 for corrosion resistance), alloy steel (e.g., ASTM A182 F11/F22 for high temperatures), and aluminum for lightweight applications. Material selection depends on factors like pressure rating, temperature, fluid compatibility, and environmental conditions.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Face Type	Raised face (RF), Flat face (FF), Ring-type joint (RTJ)
Thickness	Varies by pressure class and material
Nominal Size	DN 50 to DN 500 (or NPS 2" to 20")
Surface Finish	125-250 microinches Ra for gasket seating
Pressure Rating	PN 6 to PN 40 (or Class 150 to Class 300)
Bolt Circle Diameter	As per ASME B16.5 or DIN standards

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards

ISO 7005-1, ASME B16.5, DIN 2501, EN 1092-1

Parent Products

This component is used in the following industrial products

Viewport

A transparent window integrated into a vacuum chamber wall to allow visual observation of internal processes without breaking vacuum.

View Product Details

Engineering Analysis

Risks & Mitigation

Leakage due to improper gasket installation or bolt torque
Corrosion in aggressive environments
Mechanical failure from overpressure or vibration
Misalignment during assembly causing seal failure

FMEA Triads

Trigger: Insufficient bolt torque or uneven tightening
Failure: Gasket compression loss leading to leakage
Mitigation: Follow torque specifications using calibrated tools; use cross-tightening sequence

Trigger: Material corrosion from chemical exposure
Failure: Flange degradation and loss of structural integrity
Mitigation: Select corrosion-resistant materials (e.g., stainless steel); apply protective coatings; implement regular inspections

Trigger: Thermal cycling causing bolt relaxation
Failure: Reduced clamping force and seal failure
Mitigation: Use high-temperature gaskets; re-torque bolts after initial heat cycles; consider spring washers

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

Dimensional tolerances per ASME B16.5: flange thickness ±1.5mm, bolt hole spacing ±1mm, face flatness within 0.8mm across diameter

Test Method

Pressure testing per ASME BPVC Section VIII: hydrostatic test at 1.5x design pressure; leak testing with helium mass spectrometry for vacuum applications; visual and dimensional inspection per ISO 9001

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

Check the legal entity, factory address, ownership, certifications, and direct contacts.

CNFX does not score or rank suppliers. Buyers must verify all claims and documents with the legal manufacturer before ordering.

Manufacturers of Metal flange

2 companies list this product among what they make. Company figures are quoted from each company's own website; every card states where the relationship came from.

HLC Metal Parts Ltd

Dongguan, Guangdong, CN

IATF16949 ISO13485

Also makes: CNC Machined Part, Plastic Injection Molded Part, Finishing Assembly and 4 more

Listed on the company's own website · profile compiled by CNFX from public sources

View profile Send enquiry

ZENGO Airandus

Ningbo, Zhejiang, CN

Also makes: Ventilation Fan, Centrifugal Fan, Flexible Duct and 9 more

Listed on the company's own website · profile compiled by CNFX from public sources

View profile Send enquiry

Manufacturer listings support early research and capability understanding. They are not certification, ranking, or transaction guarantees.

Related Components

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Main Frame

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Shaft Bearing

Precision component supporting rotating shafts in vibration motors to reduce friction and maintain alignment.

Seal Groove

Precision-machined groove in aluminum bearing housings designed to accommodate sealing elements for fluid containment and contamination prevention.

Frequently Asked Questions

What is the purpose of a flange in a viewport?

In a viewport, a flange secures the transparent window (e.g., glass or polycarbonate) to the equipment housing, ensuring a sealed enclosure that allows visual monitoring while maintaining pressure, vacuum, or containment integrity.

How do I select the right flange material?

Choose based on operating conditions: carbon steel for general service, stainless steel for corrosive environments, alloy steel for high temperatures, and consider factors like pressure, temperature, fluid type, and cost.

What are common flange face types?

Raised face (RF) for most applications, flat face (FF) for low pressure, and ring-type joint (RTJ) for high-pressure/temperature services. The face type affects gasket selection and sealing performance.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification

This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

Metal flange