Trong hệ thống đường ống, cái mặt bích is a critical feature that determines how two flanges seal together with the help of a gasket. Without proper facing, even the strongest flanges and the best bolts cannot prevent leaks. Two of the most widely recognized standards for flanges are ASME B16.5 Và ASME B16.47. While both cover different flange size ranges, their facing types share common design principles and applications.

This article provides a detailed guide on flange facing for B16.5 and B16.47 flanges, explaining the types of facings, chức năng của họ, and the key considerations engineers must evaluate when selecting the right flange connection for industrial projects.

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Overview of B16.5 and B16.47 Flanges

ASME B16.5

• Covers flanges and flanged fittings from NPS ½ to NPS 24

• Xếp hạng áp suất: Lớp học 150 đến lớp 2500

• Common in small- to medium-diameter piping systems

ASME B16.47

• bìa mặt bích thép đường kính lớn từ NPS 26 đến NPS 60

• Two series: Dòng A (heavier, for high-pressure applications) Và Dòng B (nhẹ hơn, tiết kiệm chi phí, derived from MSS SP-44)

• Xếp hạng áp suất: Lớp học 75 đến lớp 900

Together, these two standards cover nearly the entire range of industrial flanges used in oil and gas, xử lý hóa chất, phát điện, xử lý nước, và kỹ thuật hàng hải.

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What is Flange Facing?

các mặt bích is the finish applied to the surface of the flange that comes into contact with the gasket. Its purpose is to ensure tight sealing, proper load distribution, and gasket retention. Different facing types are specified depending on the application’s pressure, nhiệt độ, và loại chất lỏng.

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Common Flange Facing Types for B16.5 and B16.47

1. Mặt nâng lên (RF)

• Most widely used facing type

• A small area around the bore is raised above the bolt circle

• Standard roughness ensures gasket grip

• Used in Classes 150 ĐẾN 2500

Ứng dụng: Oil refineries, nhà máy hóa chất, hệ thống xử lý nước

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2. Mặt phẳng (FF)

• Entire face of the flange is flat

• Usually used with cast iron and fiberglass piping

• Designed for low-pressure, ứng dụng không quan trọng

Ứng dụng: Phân phối nước, pump connections, đường ống áp suất thấp

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3. Loại vòng chung (RTJ)

• A machined groove accommodates a metallic ring gasket

• Provides metal-to-metal seal

• Withstands very high pressure and temperature

• Available in Classes 600 trở lên

Ứng dụng: Khoan ngoài khơi, hóa dầu, high-pressure gas systems

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4. Lưỡi và rãnh (T&G)

• One flange has a raised tongue, and the other has a matching groove

• Prevents gasket displacement during installation

• Provides excellent alignment

Ứng dụng: Bộ trao đổi nhiệt, lò phản ứng hóa học, custom piping assemblies

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5. Nam và Nữ (M&F)

• Tương tự với T&G but with flat mating surfaces

• Male flange has a raised portion; female flange has a matching recess

• Ensures accurate gasket positioning

Ứng dụng: Specialty piping, hàng không vũ trụ, và hệ thống hóa chất

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Surface Finish Requirements

ASME standards specify the surface roughness of flange facings to ensure proper gasket interaction:

• Kết thúc chứng khoán: Phổ biến nhất, concentric or spiral serrated finish (Ra 125–500 µin)

• Kết thúc mịn màng: For soft gaskets, provides improved contact area (Ra 63–125 µin)

• Kết thúc bằng nước lạnh: Extremely smooth finish for special soft gaskets (Ra ≤ 63 µin)

Key Point: The correct surface finish prevents leakage and extends gasket life.

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Key Considerations for Selecting Flange Facing

1. Áp suất và nhiệt độ vận hành

• Vì áp suất cao, nhiệt độ cao applications → RTJ is recommended

• Vì low-pressure, ambient conditions → FF or RF may be sufficient

2. Loại đệm

• Miếng đệm mềm (cao su, PTFE): Require smooth finishes

• Miếng đệm kim loại (vết thương xoắn ốc, RTJ): Require serrated or grooved facings

3. Piping Material Compatibility

• Cast iron and non-metallic pipes → Use Flat Face

• Steel and alloy pipelines → Use Raised Face or RTJ

4. Maintenance and Accessibility

• RF and FF flanges are easier to assemble and maintain

• RTJ flanges require precise machining and ring gasket handling

5. Chi phí và tính sẵn có

• RF and FF are cost-effective and widely available

• RTJ, T&G, and M&F are more expensive but necessary for critical service

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Applications of B16.5 and B16.47 Flange Facing

Công nghiệp dầu khí

• RTJ flanges for offshore rigs, đường ống ngầm, và nhà máy lọc dầu

• RF flanges for midstream and downstream processing

Hóa chất và hóa dầu

• RF and T&G flanges in reactors and distillation units

• Corrosion-resistant alloys required for aggressive chemicals

Phát điện

• RTJ flanges for high-pressure steam lines

• RF flanges for cooling water systems

Xử lý và phân phối nước

• FF flanges for low-pressure water pipelines

• RF flanges for desalination and wastewater plants

Hàng hải và đóng tàu

• Stainless steel RF flanges for seawater cooling

• RTJ flanges for marine exhaust and fuel systems

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Flange Facing and Leak Prevention

The correct flange facing directly influences phòng chống rò rỉ. Poorly selected or incorrectly finished facings lead to gasket failure, thời gian ngừng hoạt động, and costly repairs. Engineers must evaluate the vật liệu đệm, bolt torque, and pressure-temperature rating when specifying flange facings.

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Phần kết luận

Flange facing is a critical element of ASME B16.5 and B16.47 flanges, ensuring reliable sealing and safe operation in diverse industries. Mặt nâng lên is the most commonly used, Mặt phẳng is preferred for low-pressure systems, Và Loại vòng chung is indispensable for high-pressure, ứng dụng nhiệt độ cao. Other facings such as Lưỡi & rãnh Và Male & Female are used in specialized systems requiring precision alignment.

For industries seeking reliable, giải pháp mặt bích chất lượng cao, sasa thuôn dài ưu đãi ASME B16.5 and B16.47 flanges with precise facings tailored to specific applications. With strict adherence to global standards and advanced manufacturing technology, sasa thuôn dài ensures long-term safety, hiệu suất, and efficiency in piping systems worldwide.

By carefully considering flange facing types, engineers and buyers can optimize system integrity, reduce leakage risks, and extend the service life of critical piping components.