A Comprehensive Analysis of the Types, Materials, Execution Standards, and Application Scenarios of Steel Strip Flanges

 

Steel strip flanges are indispensable connecting components in pipeline systems, undertaking the functions of sealing and fixing between pipelines, equipment, and valves. Their diverse designs, material adaptability, and standard compliance enable them to be widely used in key fields such as petroleum, chemical engineering, construction, and shipbuilding.

 

I. Main Types and Characteristics of Steel Strip Flanges

1.Weld - Neck Flanges

Weld - neck flanges are widely used in medium - and low - pressure pipeline systems due to their simple structure and low cost. They are easy to weld, but have relatively weak rigidity and are not suitable for high - pressure or explosive medium environments. The sealing surface is usually designed as a flat or raised face.

2.Slip - On Flanges with a Neck

By adding a neck structure, the rigidity and load - bearing capacity of the flanges are improved, making them suitable for medium - pressure scenarios. However, they require a large amount of welding and have limited adaptability to high - temperature and high - pressure environments.

3.Butt - Weld Flanges

They feature high - strength welds and excellent sealing performance, and are specially designed for high - pressure, high - temperature, or low - temperature pipelines, commonly found in petroleum and natural gas transportation systems. Sealing surface forms include raised faces, male - female faces, and tongue - and - groove faces.

4.Ring - Type Joint Flanges

These flanges use an annular groove in combination with a metal gasket, offering excellent sealing performance and are often used in pipelines carrying high - pressure and high - risk media.

5.Socket - Weld Flanges

The design with one end welded and the other end bolt - connected simplifies the installation process and is suitable for pipeline layouts with limited space.

6.Blind Flanges

They are used to close the ends of pipelines to prevent medium leakage and are key components for maintenance or system isolation.

Other types such asThreaded Flanges (for low - pressure and small - diameter pipelines),Lap - Joint Flanges (which can be rotationally adjusted), andSpecial Flanges (such as the Weldoflange composite design) further expand the application scenarios of flanges.

 

II. Material Selection and Performance Adaptation

The selection of flange materials should be based on a comprehensive consideration of the medium characteristics, temperature, and pressure:

-Carbon Steel (WCB): Economical and practical, suitable for general working conditions.

-Stainless Steel (Series 304/316/L): Highly corrosion - resistant, used in chemical and marine environments.

-Alloy Steel (Chromium - Molybdenum, Chromium - Molybdenum - Vanadium): Resistant to high temperature and high pressure, suitable for power stations and oil - refining equipment.

-Special Materials: Such as fluorine - lined materials and Monel alloy, specifically used in highly corrosive or extreme environments.

 

III. Execution Standard Systems and Pressure Ratings

1.International Mainstream Standards

   -European System (PN Series): It includes 9 pressure ratings from PN2.5 to PN160, with the unit of bar, such as the HG/T20592 standard.

   -American System (Class Series): It covers 6 grades from Class150 to Class2500, marked in pound - force per square inch (LB), such as the ASME B16.5 standard.

2.Domestic Standards

National standards (GB), Ministry of Machinery standards (JB), Ministry of Chemical Industry standards (HG), etc., ensure that flange designs match the requirements of domestic projects.

 

IV. Core Application Fields

1.Industrial Field: Connecting high - temperature and high - pressure pipelines in petroleum refining, natural gas transportation, and power stations.

2.Construction Field: Installing medium - and low - pressure pipelines in water supply and drainage, and heating, ventilation, and air - conditioning systems.

3.Special Scenarios: Sealing connections in ship pipelines, aviation hydraulic systems, and nuclear facilities.

 

V. Key Points of Installation and Maintenance

1.Model Selection Matching: Select the flange type, material, and sealing surface form according to the medium pressure, temperature, and corrosiveness.

2.Precise Installation: Avoid problems such as misaligned or mis - drilled holes and ensure that the bolts are evenly tightened.

3.Leakage Prevention: Use engine oil or lead powder to assist with sealing. Regularly check the condition of gaskets and clean the residues on the sealing surfaces.

4.Working Condition Adaptation: Leave space for thermal expansion in high - temperature environments. For corrosive media, give priority to stainless steel or fluorine - lined materials.

 

The efficient connection and sealing performance of steel strip flanges are directly related to the safe operation of pipeline systems. Through scientific model selection, standardized installation, and regular maintenance, the reliability of the system can be significantly improved and its service life can be extended.