ASME B16.5 Carbon steel flanges are critical components of industrial piping systems used to connect pipes, valves, pumps, and other equipment, and are used in a wide range of industries such as oil and gas, chemical processing, and water treatment because of their durability, strength, and cost-effectiveness. They are available in a variety of types, each designed to meet the specific needs of different applications. In this article, we will discuss the main types of carbon steel flanges, their features and their uses in different industries.
Weld Neck Flange（WN）:
Weld neck flanges have a long tapered neck that gradually transitions to the pipe and are designed to help reduce stress concentrations in the weld area, providing greater mechanical strength and higher resistance to leakage.
Advantages：
✅High Strength Connection: Due to its long tapered neck design, it provides uniform stress distribution when welded and is suitable for high pressure and high temperature environments.
✅Leakage resistance: weld neck flanges form a strong connection by welding, providing excellent leakage resistance and are commonly used in critical systems.
Area of Application：
•Oil & Gas: High Pressure Oil/Gas Pipelines
•Chemical Industry: High Temperature High Pressure Reactor Piping
•Power Industry: Supercritical Boiler Steam Piping
•Aerospace: Fuel & Hydraulic Systems
Slip On Flange（SO）:
Slip on flanges have a simple design that allows them to be easily slid into the pipe and secured by welding. Due to its ease of installation, it is commonly used in low pressure applications and has a low cost of construction.
Advantages：
✅Easy to install: slip on flanges can be slid directly into the pipe and welded in place, simplifying the installation process and reducing costs.
✅Cost-effective: Compared with other types of flanges, slip on flanges are less expensive to produce and install and are suitable for low pressure systems.
Area of Application：
•Water treatment plants: low and medium pressure water transmission lines
•HVAC: chilled water/cooling water recirculation systems
•Food and pharmaceutical: sanitary piping
•Building water supply and drainage: building water supply/firefighting piping
Threaded Flange （TH）:
Threaded flanges have internal threads that allow them to be tightened to the pipe without the need for welding. This makes them ideal for special environments where welding is not suitable, especially in hazardous or highly corrosive systems.
Advantages：
✅No need to weld: the threaded flange can be screwed directly into the pipeline without welding, suitable for environments where welding is difficult or not allowed.
✅Easy to dismantle: the threaded connection makes the flange easier to dismantle, suitable for systems that require frequent maintenance.
Area of Application：
•Fire-fighting systems: sprinkler networks
•Gas engineering: low-pressure branch piping
•Mining machinery: temporary compressed air lines
•Agricultural irrigation: mobile water delivery systems
Socket Weld Flange（SW）:
Socket weld flanges are used for smaller diameter pipes where the pipe is inserted into the socket of the flange and secured by welding to form a strong connection. They are typically used in high pressure systems and provide a tight sealing performance.
Advantages：
✅High strength sealing: by inserting into the pipe and welding, it provides a strong and well sealed connection, suitable for small diameter pipes and high pressure systems.
✅Reduced risk of leakage: socket weld flanges are suitable for systems subjected to higher pressures and the high strength of the welded joint reduces the risk of leakage.
Area of Application：
•Fine chemical industry: small diameter corrosive media transportation
•Pharmaceutical equipment: aseptic process piping
•Hydraulic system: high-pressure instrumentation piping
•Semiconductor manufacturing: high-purity gas transportation system
Blind Flange（BL）:
Blind flanges are flanges without holes that are used to close off ports or ends of pipelines. They are typically used where temporary or permanent closure of portions of piping is required, such as for repairs or system modifications.
Advantages：
✅Sealing pipeline ports: blind flanges can effectively seal the ports of pipelines or valves, and are suitable for occasions where pipeline sections need to be isolated or closed.
✅Withstand high pressure: blind flanges are able to withstand extremely high pressure and are widely used in high-pressure environments such as oil, natural gas and other high-pressure environments.
Area of Application：
•Refineries: pipeline isolation overhaul
•Nuclear power plants: main steam system pressure testing
•LNG storage tanks: safety relief valve blocking
•Marine engineering: compartment piping system sectional pressure testing
Lap Joint Flange（LAPJ）:
The lap joint flange is used in conjunction with the stub end and has the characteristic of easy disassembly. It is suitable for systems that require frequent disassembly and reassembly, especially when the piping needs to be inspected, cleaned or repaired on a regular basis.
Advantages：
✅Ease of disassembly and maintenance: the lap joint flanges are fitted with stub ends for quick disassembly and are suitable for systems that require regular inspection and maintenance.
✅Low Pressure Suitability: lap joint flanges are particularly suitable for low pressure systems, allowing for quick assembly and easy post maintenance.
Area of Application：
•Coal Chemical: Pulverized Coal Gasification Plant
•Food Processing: CIP Cleaning Piping
•Offshore Platforms: Flexible Riser Connections
•Bioengineering: Fermenter Piping
ZIZI specializes in the production of flanges made of different kinds of carbon steel flanges, and the products are widely used in many industries, such as petroleum, chemical industry, electric power, shipbuilding, pharmacy, foodstuff, construction and so on.
We are professional in manufacturing and exporting flanges in various materials.
