Em sistemas de tubulação, o face de flange is a critical feature that determines how two flanges seal together with the help of a gasket. Sem revestimento adequado, even the strongest flanges and the best bolts cannot prevent leaks. Two of the most widely recognized standards for flanges are ASME B16.5 e 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, suas funções, 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

• Classificações de pressão: Aula 150 para a aula 2500

• Common in small- to medium-diameter piping systems

ASME B16.47

• Capas flanges de aço de grande diâmetro de NPS 26 para NPS 60

• Two series: Série A (heavier, for high-pressure applications) e Série B (isqueiro, econômico, derived from MSS SP-44)

• Classificações de pressão: Aula 75 para a aula 900

Junto, these two standards cover nearly the entire range of industrial flanges used in oil and gas, processamento químico, geração de energia, tratamento de água, e engenharia naval.

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What is Flange Facing?

O face de flange 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, temperatura, e tipo de fluido.

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

1. Rosto levantado (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 para 2500

Aplicativos: Oil refineries, plantas químicas, sistemas de tratamento de água

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2. Rosto plano (FF)

• Entire face of the flange is flat

• Usually used with cast iron and fiberglass piping

• Designed for low-pressure, aplicações não críticas

Aplicativos: Distribuição de água, conexões da bomba, tubulações de baixa pressão

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3. Junta tipo anel (RTJ)

• A machined groove accommodates a metallic ring gasket

• Provides metal-to-metal seal

• Withstands very high pressure and temperature

• Available in Classes 600 e acima

Aplicativos: Offshore drilling, petroquímico, high-pressure gas systems

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4. Língua e sulco (T&G)

• Um flange tem uma lingueta elevada, e o outro tem uma ranhura correspondente

• Prevents gasket displacement during installation

• Provides excellent alignment

Aplicativos: Trocadores de calor, reatores químicos, custom piping assemblies

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5. Masculino e Feminino (M&F)

• Semelhante a T&G but with flat mating surfaces

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

• Ensures accurate gasket positioning

Aplicativos: Specialty piping, aeroespacial, and chemical systems

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Surface Finish Requirements

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

• Acabamento em estoque: Mais comum, concentric or spiral serrated finish (Ra 125–500 µin)

• Acabamento Suave: For soft gaskets, provides improved contact area (Ra 63–125 µin)

• Acabamento em Água Fria: 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. Pressão e temperatura operacional

• Para de alta pressão, alta temperatura applications → RTJ is recommended

• Para baixa pressão, ambient conditions → FF or RF may be sufficient

2. Tipo de junta

• Juntas macias (borracha, PTFE): Require smooth finishes

• Metallic gaskets (ferida em espiral, 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. Custo e Disponibilidade

• 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

Indústria de Petróleo e Gás

• RTJ flanges for offshore rigs, dutos submarinos, e refinarias

• RF flanges for midstream and downstream processing

Química e Petroquímica

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

• Corrosion-resistant alloys required for aggressive chemicals

Geração de energia

• RTJ flanges for high-pressure steam lines

• RF flanges for cooling water systems

Tratamento e Distribuição de Água

• FF flanges for low-pressure water pipelines

• RF flanges for desalination and wastewater plants

Marinha e Construção Naval

• 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 prevenção de vazamentos. Poorly selected or incorrectly finished facings lead to gasket failure, tempo de inatividade, and costly repairs. Engineers must evaluate the material de junta, bolt torque, and pressure-temperature rating when specifying flange facings.

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Conclusão

Flange facing is a critical element of ASME B16.5 and B16.47 flanges, ensuring reliable sealing and safe operation in diverse industries. Rosto levantado is the most commonly used, Rosto plano is preferred for low-pressure systems, e Junta tipo anel is indispensable for high-pressure, aplicações de alta temperatura. Other facings such as Língua & Sulco e Male & Female are used in specialized systems requiring precision alignment.

For industries seeking reliable, soluções de flange de alta qualidade, sasa oblonga ofertas 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 oblonga ensures long-term safety, desempenho, 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.