In December 2025, one of our regular clients placed new order to us. This order covers most of our business scope from butt-weld steel fittings, flanges, stud bolts and nuts and so on. This page is concentrate on flange items which are both in ASTM A694 F52 material, following ASME B16.5 standard and with Class 2500 pressure.

ASME B16.5 Flanges Order List

ASME B16.5 Standard Overview

ASME B16.5 is the American standard for pipe flanges and flanged fittings, covering sizes NPS ½ to 24″. It standardizes dimensions, materials, pressure-temperature ratings, marking, and testing for steel flanges. This standard ensures safety and interchangeability in piping systems across industries.

ASME B16.5 Covered Pressure Classes

The standard defines seven standard pressure classes, indicating a flange’s pressure-containing capability at specified temperatures. These classes are designated in pound ratings: 

• Class 150, 300, 400 – Low to medium pressure
• Class 600, 900, 1500 – High pressure
• Class 2500 – Very high pressure

Class ratings represent pressure capacity in PSI at specified temperatures. Higher classes have thicker dimensions and stronger construction.

B16.5 Covered Flange Types

ASME B16.5 primarily standardizes the following common flange types:

• Weld Neck Flange
• Slip-On Flange
• Socket Weld Flange
• Threaded Flange
• Lap Joint Flange
• Blind Flange

ASME B16.5 Weld Neck Flanges

ASME B16.5 weld neck flange features a long, tapered hub for butt-welding to the pipe. They are designed for butt-welding to the pipe, providing excellent structural integrity and fatigue resistance. The long neck makes them ideal for high-pressure and extreme temperature applications.

B16.5 Weld Neck Flanges in Class 2500

ASME B16.5 Class 2500 weld neck flanges represent the highest pressure rating in the B16.5 standard, designed for extreme service conditions. Their robust construction, standardized dimensions, and reliable performance make them essential for critical high-pressure applications across multiple industries. Proper selection, installation, and maintenance ensure safe, long-lasting performance in demanding operational environments.

Advantages of Class 2500 Flanges

1. Extreme Pressure Containment
Withstands pressures up to 2500 PSI, making them suitable for critical high-pressure systems.

2. Superior Structural Integrity
The weld neck design provides optimal stress distribution, minimizing fatigue failure risk.

3. Leak Prevention
Precise machining and compatible gasket surfaces ensure reliable sealing under extreme conditions.

4. Temperature Versatility
Maintains performance across wide temperature ranges when properly specified.

5. Standardized Compatibility
ASME standardization ensures proper fit with valves, pumps, and other B16.5 components.

6. Reduced Turbulence
Smooth bore transition minimizes pressure drop and flow disturbance.

Inspections Photos

Applications

• Oil & Gas Industry
• Power Generation
• Chemical Processing
• Petrochemical
• Specialized Applications

The post ASME B16.5 Class 2500 Weld Neck Flanges appeared first on Quality Manufacturer of Industrial Pipe Fittings.

Recently, we received an order from our regular customer in Nigeria,which includes products such as carbon and stainless steel fittings, and flanges. One of the products is an API 6A flange made of ASTM A694 F60 material. API 6A flange is often used in the petroleum and natural gas industry and is resistant to high pressure and temperature, so the quality requirements for the flange are relatively strict. we (Shanghai Zhucheng Pipe Fitting Manufacturing Co., Ltd.) has been committed to the production and sales of pipes and fittings for more than ten years. We are very familiar with the production standards and requirements of API6A flanges. Therefore, we quickly won this order with professional product knowledge and competitive pricing.

Purchase Order List

What Is API 6A Flange

API 6A flange is a flange manufactured according to the production standards established by the American Petroleum Institute (API), suitable for use in high-temperature and high-pressure pipeline systems. Its special size and design enable it to meet the requirements of high pressure and high sealing performance in fields such as petroleum, chemical, and natural gas. The size of API 6A flange is relatively special, so when welding with pipelines, special interfaces or transition sections need to be set by the flange manufacturer to ensure that the wall thickness and outer diameter can match the ASME pipeline.

Dimensions&Pressure Ratings

In terms of pressure rating, the API 6A flange has a wide range of pressure ratings, including but not limited to 13.8 MPa (2000 PSI), 20.7 MPa (3000 PSI), 34.5 MPa (5000 PSI), 69.0 MPa (10000 PSI), 103.5 MPa (15000 PSI), and 138.0 MPa (20000 PSI). Choosing the appropriate level of stress depends on the expected work pressure and work environment.

API 6A TYPE 6B 2000PSI Dimension

API 6A TYPE 6BX 10000PSI Dimension

API 6A Flange VS ASME Flange

Material and pressure rating: The material selection and pressure rating of API 6A flanges are higher than those of ASME flanges to adapt to higher operating pressures. This design makes API 6A flanges more suitable for high pressure working environments.

Size and interface: The size of API 6A flange is relatively special, and compared to ASME flange, its aperture size is larger. Therefore, when welding with pipelines, API 6A flanges need to be equipped with special interfaces or transition sections set by the flange manufacturer to ensure that their wall thickness and outer diameter can match the ASME pipeline. This design makes API 6A flanges more flexible and adaptable when connecting pipelines.

In addition, one type of API 6A flange, Type 6BX flange, requires the use of BX type gasket rings. The main difference between this type of gasket and ASME gasket is that there is a pressure through-hole on the section of the through ring, which can serve as a pressure self sealing seal. At the same time, the gasket also needs to use coatings and coatings to facilitate sealing and bonding, and there are specific requirements for the surface roughness of the gasket and groove to ensure sealing effectiveness.

Overall, there are significant differences between API 6A flanges and ASME flanges in terms of material, pressure rating, size, and interface design. The choice of flange to use depends on the specific working environment and engineering requirements.

In practical applications, it is necessary to consider various factors comprehensively, such as working pressure, pipeline connection requirements, sealing performance, etc., in order to choose the most suitable flange type. At the same time, it is also necessary to follow relevant standards and specifications to ensure the safety and reliability of flanges.

The post API 6A Flange Order From Nigeria Customer appeared first on Quality Manufacturer of Industrial Pipe Fittings.