В промышленных трубопроводных системах, тот поверхность фланца is one of the most critical sealing surfaces. Whether you’re manufacturing a new flange or restoring an old one, the accuracy of flange face machining directly determines the integrity of your piping connections. Done properly, it ensures long-term sealing performance and compliance with global standards. Done poorly, it can lead to leaks, системный сбой, and costly downtime.

Так, how do you machine a flange face correctly? В этой статье, we’ll walk you through the entire process — from surface preparation to tool selection, machining techniques, and final inspection. Whether you’re a plant maintenance engineer, fabricator, or QC inspector, this guide provides everything you need to know.

SASA FLANGE, a trusted global manufacturer of precision flanges, ensures that every flange face we produce is machined to perfection — according to ASME, EN, и стандарты, ориентированные на клиента.

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What Is a Flange Face and Why It Must Be Machined Accurately

А поверхность фланца is the contact surface that mates with a gasket or another flange in a piping system. It ensures pressure sealing when bolts are tightened. Over time or during manufacturing, imperfections on this surface can lead to sealing failures.

Key goals of flange face machining:

• Achieve correct плоскостность и параллелизм

• Create the right surface roughness for gasket grip

• Ensure точность размеров within tolerance

• Avoid leakage under pressure or temperature fluctuations

The type of gasket used (например, спиральная рана, резина, ПТФЭ) determines what finish and texture are required.

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Распространенные типы фланцев

Before machining, identify the face type to apply the correct method:

1. Поднятое лицо (РФ)

• Most common type in ASME flanges

• Requires a spiral serrated or stock finish

2. Плоское Лицо (ФФ)

• Must be entirely flat for soft gasket sealing

• Используется в системах низкого давления.

3. Кольцевое соединение (РТЖ)

• Features a machined groove for metallic gaskets

• Requires high-precision CNC contouring

4. Male-Female and Tongue & Канавка

• Requires alignment of corresponding profiles

• Used in high-seal, alignment-critical systems

SASA FLANGE manufactures all these flange face types, precisely machined to required tolerances and surface finishes.

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Tools and Equipment Needed

Flange face machining can be done either in a factory setting or on-site. The tools used depend on the application and flange size:

🛠 Factory CNC Machining Tools:

• Horizontal lathes

• Vertical turning lathes (VTL)

• CNC boring and facing machines

• Surface profilometers

🛠 Portable On-Site Facing Machines:

• ID or OD-mounted flange facing machines

• Magnetic or hydraulic base units

• Hand-held rotary tools (for light resurfacing)

The machining tool must be rigid, vibration-free, and capable of producing the desired surface finish.

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Step-by-Step Guide: Как обработать поверхность фланца

Шаг 1: Clean and Inspect the Flange

Remove all dirt, коррозия, шкала, and old gasket residue. Visually inspect for:

• Deep pitting or grooves

• Warping or distortion

• Rust around bolt holes or face

If the damage is minor, machining may proceed. If severe, replacement is advised.

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Шаг 2: Set Up the Flange Securely

• If machining in-shop, mount the flange firmly in a lathe or CNC chuck.

• For in-situ repair, align and clamp the portable machine accurately to the flange’s center.

• Verify flatness using a dial indicator.

Proper alignment prevents uneven cuts and off-center faces.

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Шаг 3: Select the Right Cutting Tool and Feed Rate

• For spiral serrated finishes: Use a radial feed tool and advance at a slow, consistent rate (обычно 0.8 mm/rev for ASME stock finish).

• For smooth finishes: Use a fine insert and slower feed rate.

• For RTJ: Use a form tool matching the groove profile.

Tool material should match the flange’s hardness — carbide inserts for stainless steel or hardened alloy flanges.

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Шаг 4: Begin Machining

• Start from the center and move outward in a spiral path.

• Keep spindle RPM within optimal limits (например, 60–120 RPM depending on size).

• Monitor chip formation, tool wear, and surface quality.

Use coolant as needed to minimize heat and improve finish.

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Шаг 5: Measure Surface Finish and Flatness

Once machining is complete:

• Используйте surface roughness tester (профилометр) to measure AARH (Средняя арифметическая высота шероховатости).

  • Common standards:

    • 125–250 ААРХ (stock finish for spiral wound gaskets)

    • ≤ 125 ААРХ (smooth finish for soft gaskets)

• Проверять плоскостность with a straight edge and feeler gauge or laser alignment tools.

• Verify face thickness and bore diameter match specifications.

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Шаг 6: Apply Anti-Corrosion Coating (if required)

In corrosive environments, apply:

• Rust preventive oil

• Epoxy paint (on non-sealing surfaces)

• PTFE spray or film (for marine or chemical service)

Do нет coat the actual sealing face unless specified by the gasket or application.

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Machining Tips for Optimal Results

• Always machine with a new or freshly sharpened tool for critical flanges

• Использовать bore-matched flanges to minimize turbulence and erosion

• Maintain correct tool overhang to avoid chatter

• Recheck machine calibration before precision jobs

• Ensure gasket seating width is not altered during resurfacing

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Standards That Govern Flange Face Machining

The following global standards specify machining tolerances and finishes:

• ASME B16.5 / Б16.47 (НАС.)

• EN 1092-1 (Европа)

• МСС СП-6 – Finish and marking specifications

• API 6А – High-pressure flange faces in oil & газ

• ISO 7005 – International flange standard

SASA FLANGE adheres to these standards in all flange production and provides full documentation (EN 10204 3.1/3.2) on request.

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Applications That Require Precision Machined Flange Faces

Machined flange faces are critical in:

• Нефтеперерабатывающие и химические заводы

• Производство электроэнергии (steam and nuclear)

• Еда, напиток, и фармацевтическая промышленность

• Cryogenic and high-temperature systems

• Hydraulic and high-pressure equipment

In any system where sealing failure is unacceptable, machining precision is non-negotiable.

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Почему выбирают SASA FLANGE for Precision-Machined Flanges?

В SASA FLANGE, every flange face is machined using advanced CNC equipment and verified by trained inspectors to meet:

• Exact surface finish specifications (спиральный зубчатый, гладкий, RTJ groove)

• Flatness and parallelism tolerances

• Pressure class and dimensional conformity

We supply carbon steel, нержавеющая сталь, дуплекс, and nickel alloy flanges in all sizes and standards, ready for use in demanding projects worldwide.

SASA FLANGE — Where Every Surface Counts. Engineered for Excellence.

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Заключение

Так, how do you machine a flange face? With the right tools, methods, and quality controls, you can restore or create a flange surface that ensures leak-proof sealing and long-term system performance.

Whether manufacturing a new flange or resurfacing an existing one, the process requires skill, standards compliance, and precision machining — all of which are at the core of what we do at SASA FLANGE.

For guaranteed performance, certified accuracy, and professional support, доверять SASA FLANGE to deliver your next critical connection.