Mặt bích là thành phần thiết yếu trong hệ thống đường ống, đóng vai trò là đầu nối cơ khí để nối ống, van, máy bơm, và các thiết bị khác. Họ cung cấp một cách an toàn, kết nối chống rò rỉ đồng thời cho phép tháo gỡ dễ dàng, điều tra, và bảo trì. Flanges are used in industries such as oil and gas, xử lý hóa chất, xử lý nước, phát điện, đóng tàu, và hệ thống HVAC. To ensure proper application and performance, flanges are classified into several types based on their structure, phương thức kết nối, đánh giá áp lực, and application environment. This article provides a detailed classification of commonly used flanges, offering insight into their features, thuận lợi, and typical uses.

---

1. Classification by Connection Method

Mặt bích cổ hàn

A weld neck flange features a long tapered hub that is welded to the pipe. This design transfers stress to the pipe, reducing the concentration at the base of the flange. Weld neck flanges are suitable for high-pressure, high-temperature applications where strength and durability are critical.

Thuận lợi:

• Sức mạnh tuyệt vời và khả năng chống mệt mỏi

• Smooth bore transition reduces turbulence

• Ideal for repeated bending and temperature cycles

Ứng dụng: Đường ống dẫn dầu và khí đốt, nhà máy hóa chất, high-pressure steam lines.

---

Mặt bích trượt

Slip-on flanges are slipped over the pipe and welded on both the inside and outside. They are easier to align than weld neck flanges and are widely used in low- to medium-pressure systems.

Thuận lợi:

• Simple installation and alignment

• Lower initial cost than weld neck flanges

• Suitable for applications with limited space

Ứng dụng: Hệ thống xử lý nước, HVAC piping, low-pressure industrial lines.

---

Mặt bích hàn ổ cắm

This flange has a socket where the pipe is inserted before being fillet welded at the outside. Socket weld flanges are used for smaller diameter, đường ống cao áp.

Thuận lợi:

• Smooth bore flow path

• Thích hợp cho áp suất cao, small-size pipelines

• Good fatigue strength

Ứng dụng: Hệ thống thủy lực, chemical process piping, high-pressure gas distribution.

---

mặt bích có ren

Threaded flanges have internal threads that match the pipe threads, allowing connection without welding. They are ideal for low-pressure, ứng dụng không quan trọng.

Thuận lợi:

• Không cần hàn

• Suitable for flammable environments where welding is hazardous

• Easy to install and remove

Ứng dụng: Hệ thống phòng cháy chữa cháy, dòng tiện ích, compressed air piping.

---

Mặt bích chung

Mặt bích khớp nối được sử dụng với một đầu còn sơ khai, allowing the flange to rotate freely for easy bolt alignment. They are often used in systems requiring frequent disassembly.

Thuận lợi:

• Căn chỉnh dễ dàng trong quá trình cài đặt

• Reusable in different piping assemblies

• Ideal for systems subject to frequent maintenance

Ứng dụng: Chế biến thực phẩm, cây dược phẩm, corrosive environments where flanges can be made from a less expensive material and the stub end from a corrosion-resistant alloy.

---

Mặt bích mù

A blind flange has no bore and is used to seal off the end of a piping system or pressure vessel opening.

Thuận lợi:

• Allows access for inspection and cleaning

• Can be installed or removed without disturbing the piping system

• Available in high-pressure ratings

Ứng dụng: Pressure vessel closures, pipeline isolation points, maintenance access ports.

---

2. Classification by Face Type

Mặt nâng lên (RF)

The most common flange facing type, the raised face has a small raised area for gasket seating, improving the sealing capability.

Ứng dụng: Dầu khí, xử lý hóa chất, hệ thống nước.

---

Mặt phẳng (FF)

The gasket surface is in the same plane as the bolt circle face. Commonly used with cast iron equipment.

Ứng dụng: Xử lý nước, ứng dụng áp suất thấp, non-metallic piping.

---

Loại vòng chung (RTJ)

Uses a metal ring gasket to achieve a high-integrity seal for high-pressure, ứng dụng nhiệt độ cao.

Ứng dụng: Refinery equipment, high-pressure steam lines, offshore oil platforms.

---

Lưỡi và rãnh (T&G)

A male (tongue) flange fits into a female (groove) mặt bích, providing precise gasket positioning.

Ứng dụng: Specialty chemical processing, high-integrity sealing systems.

---

3. Classification by Pressure Rating

ASME Pressure Classes

• Lớp học 150

• Lớp học 300

• Lớp học 600

• Lớp học 900

• Lớp học 1500

• Lớp học 2500

The higher the class, the thicker and stronger the flange to withstand higher pressures.

---

EN / DIN PN Ratings

PN 6, PN 10, PN 16, PN 25, PN 40, PN 63, PN 100, PN 160.
PN stands for nominal pressure in bars at a reference temperature.

---

Xếp hạng áp suất JIS

5K, 10K, 16K, 20K, 30K.
Commonly used in Japanese and some Asian market applications.

---

4. Classification by Manufacturing Method

Mặt bích rèn

Produced by forging steel billets, offering superior mechanical properties and grain structure.

Ứng dụng: Đường ống cao áp, offshore structures, nhà máy điện.

---

Mặt bích đúc

Manufactured by casting molten metal into molds. More economical for complex shapes but may have lower mechanical strength than forged flanges.

Ứng dụng: Hệ thống nước, low-pressure chemical processing.

---

Mặt bích tấm

Cut from plate material and machined to specifications. Economical but generally limited to lower pressure ratings.

Ứng dụng: Low-pressure piping, ventilation systems.

---

5. Special Purpose Flanges

Mặt bích lỗ

Designed for use with orifice meters to measure flow rate in pipelines. Includes tapped holes for pressure measurement.

Ứng dụng: Flow measurement in oil, khí đốt, and water pipelines.

---

Mặt bích mù cảnh tượng

Consist of a connected pair of metal discs, one solid and one with an opening, used to isolate a section of pipe.

Ứng dụng: Maintenance operations, system isolation in refineries and chemical plants.

---

Giảm mặt bích

Allow connection between pipes of different diameters without the need for a separate reducer fitting.

Ứng dụng: Space-constrained piping layouts, dự án trang bị thêm.

---

Importance of Choosing the Right Flange Type

The correct flange classification ensures safety, khả năng tương thích, and performance in the intended application. Mismatched flange types can lead to leaks, mất áp suất, or mechanical failures. Selecting the correct flange also simplifies maintenance and ensures compliance with applicable standards.

---

Standards Governing Flanges

Flanges must conform to international standards to ensure quality and interchangeability. Các tiêu chuẩn chung bao gồm:

• ASME B16.5 (Mặt bích ống và phụ kiện mặt bích)

• ASME B16.47 (Mặt bích thép đường kính lớn)

• EN 1092-1 (European Standard for Steel Flanges)

• JIS B2220 (Japanese Industrial Standard for Flanges)

Các nhà sản xuất thích sasa thuôn dài produce flanges in compliance with these standards to guarantee performance in diverse applications.

---

Phần kết luận

Flanges are critical components in any piping system, and understanding their classification helps in selecting the right product for specific operational requirements. Whether based on connection type, kiểu khuôn mặt, đánh giá áp lực, manufacturing method, or special function, each flange type serves a unique purpose.

By aligning flange selection with industry standards and application needs, engineers and procurement teams can ensure long-term reliability, sự an toàn, and cost-effectiveness in their piping systems. Partnering with experienced manufacturers like sasa thuôn dài ensures that flanges are produced to precise specifications, ready to perform in even the most demanding environments.