A flange is used to create a reliable, detachable joint between pipes and equipment. A typical flanged joint is secured with bolts and sealed by a gasket, helping the system withstand pressure, temperature, and vibration. For buyers and inspectors, clear flange markings and matching MTCs are essential for confirming material grade, rating, and traceability.
High-quality stainless steel flanges from Sunhy are designed for demanding industrial service:
| Feature | Benefit |
|---|---|
| Corrosion Resistance | Handles water, chemicals, and harsh pipe environments. |
| High Strength | Withstands heavy-duty and high-heat pipe systems. |
| Passive Film Self-Repair | Helps maintain corrosion protection even after minor surface damage. |
| Reduced Maintenance | Keeps your system running longer and cuts downtime. |
What is a Flange?
Definition
A flange is a protruded rim or ridge that connects pipes, valves, or equipment in a piping system.
In practice, a flange provides a rigid, alignable surface for bolting and gasket sealing. It strengthens the joint, stabilizes movement at connection points, and helps prevent fluid or gas leakage. Because flanged joints are removable, they also simplify inspection, cleaning, and component replacement. For a broader overview of designs and applications, see what is a flange. A basic definition can also be found on tight, leak-proof seal references in general engineering use.
Sunhy supplies stainless steel flanges manufactured to international standards with clear material identification and traceability for project and inspection needs.
Main Function
The main function of a flange is to securely join pipes and equipment while allowing easy disassembly for maintenance.
A bolted, gasketed flange joint supports system expansion, modification, and routine service without cutting or re-welding the pipeline. When properly selected and installed, flanges provide reliable sealing performance and mechanical strength across a wide range of operating conditions.
Here are the key roles of flanges in piping systems:
- Serve as the protruding rim that allows pipes, valves, and equipment to connect.
- Enhance the strength of the joint.
- Enable easy disassembly for inspection and maintenance.
- Allow system flexibility for expansion and modification.
- Provide a tight seal to prevent leaks.
| Flange Function | Benefit to You |
|---|---|
| Secure Connection | Keeps pipes and equipment joined safely |
| Leak-Proof Seal | Prevents fluid or gas loss |
| Easy Maintenance | Simplifies inspection and repair |
| System Flexibility | Supports expansion and upgrades |
Sunhy stainless steel flanges are produced with precision machining and controlled manufacturing processes to support consistent fit-up, sealing, and long-term reliability in demanding environments.
What Are Flanges Used For?
Applications in Piping Systems
Flanges are used to connect, seal, and support pipe systems across many industries.
They are a common joining method for pipes, valves, pumps, and equipment where a strong and removable connection is required. The ability to assemble and disassemble sections efficiently makes flanges especially practical for maintenance-intensive systems.
The table below summarizes common industries where flanges are widely used and the practical benefits they provide:
| Industry | Applications | Benefits |
|---|---|---|
| Oil and Gas | Pipeline systems, refineries, offshore platforms | High pressure and temperature tolerance, durability |
| Chemical Processing | Chemical reactors, piping systems, storage tanks | Corrosion resistance, leak prevention |
| Power Generation | Boiler systems, turbine systems, cooling systems | High-temperature performance, reliability |
| Water and Wastewater Treatment | Water distribution, treatment plants, pumping stations | Versatility, leak-free connections |
| Food and Beverage | Processing equipment, packaging systems | Hygienic design, durability |
You often see Sunhy stainless steel flanges in petrochemical, marine, and pressure vessel applications. These flanges are selected for corrosion resistance, strength, and compliance with commonly required international standards.
Benefits in Industrial Use
Flanged joints improve serviceability, safety, and system flexibility.
They allow sections to be opened for inspection or cleaning without cutting the pipe, which reduces downtime and supports efficient upgrades over the life of the installation.
- Flanged joints provide secure, leak-proof connections suitable for pressure- and temperature-driven service.
- They allow different pipe materials and sizes to be integrated within the same system when properly specified.
- Customizing flanges for special projects helps meet unique media, space, or standard requirements.
- Quick assembly and disassembly supports efficient maintenance planning and reduces shutdown time.
- Stainless steel options offer strong resistance to corrosion and surface damage in aggressive service environments.
Note: Material selection, correct gasket choice, and controlled bolt tightening are key to achieving reliable long-term performance in any flanged joint.
In most industrial systems, flanges remain a practical choice for building safe, reliable, and maintainable piping networks.
Pipe Flanges: Types and Components
Common Flange Types
Many common types of flanges are used in industrial piping systems.
Pipe flanges connect pipes, valves, and equipment to form strong, serviceable joints. Understanding the common flange types helps engineers and buyers select designs that match pressure class, temperature range, and maintenance needs.
- Weld Neck Flange – Typically used for high-pressure and high-temperature pipelines.
- Slip-On Flange – Common in low- to moderate-pressure piping systems.
- Socket Weld Flange – Used for small-diameter, higher-pressure lines.
- Blind Flange – Used to seal off pipe ends or valves.
- Lap Joint Flange – Suitable for systems requiring frequent dismantling.
- Threaded Flange – Used in lower-pressure applications where welding is not preferred.
- Long Weld Neck Flange – Often specified for pressure vessels and heat exchangers.
Sunhy offers a wide range of pipe flanges, including blind, lap joint, slip-on, socket weld, threaded, and weld neck flanges. Precision forging and machining help ensure consistent dimensions and reliable sealing performance.
| Flange Type | Joint Integrity | Weld Type | Typical Use |
|---|---|---|---|
| Weld Neck | High | Butt weld | High-pressure systems |
| Slip-On | Medium | Fillet weld | Low-pressure systems |
| Socket Weld | Medium | Fillet weld | Small-diameter, high-pressure |
| Lap Joint | NA | None | Frequent dismantling |
| Threaded | Low | None | Non-welded, low-pressure |
| Blind | NA | None | Sealing ends |
Key Components
A standard flanged joint includes several key components.
The flange, gasket, bolts, and nuts work together to ensure alignment, load transfer, and sealing performance.
| Component | Description |
|---|---|
| Flange Body | A thick round disc that withstands pressure and connects pipe sections. |
| Sealing Surface | The area that touches the gasket and ensures a tight seal. |
| Bolt Holes | Holes for bolts that hold flanges together securely. |
| Gasket | A material placed between flanges to fill gaps and prevent leaks. |
You can rely on Sunhy’s manufacturing capabilities for both standard and custom pipe flanges. Sunhy produces flanges with a maximum machining diameter of 3200 mm and can handle workpieces up to 10 tons, meeting demanding project requirements.
Understanding flange types and joint components helps support correct selection, installation, and long-term maintenance planning.
How Does Flange Connection Work?
Connection Process
A flanged connection is assembled using flanges, bolts, and a gasket.
This method creates a strong, serviceable joint that can be disassembled for inspection, modification, or replacement as needed.
Here is how does flange connection work:
- Gather the right tools and materials:
- Flanges (choose the correct type for your application)
- Gaskets (select based on pressure, temperature, and fluid)
- Bolts and nuts (ensure proper size and grade)
- Torque wrench
- Lubricant for bolts
- Align the pipe ends:
Place the flanges on the pipe ends and confirm face alignment. Poor alignment can lead to uneven gasket loading and leakage. - Insert the gasket:
Center the gasket between the flange faces to ensure uniform sealing contact. - Install bolts and nuts:
Insert bolts through the flange holes, lubricate as required, and hand-tighten nuts for initial positioning. - Tighten bolts in a star pattern:
Use a torque wrench and follow a crisscross (star) tightening sequence to apply even gasket stress. Follow the recommended torque values for the flange size and bolt grade. - Check the connection:
Inspect alignment and tightness, and re-torque after initial thermal cycling if the procedure requires it.
Tip: A controlled star-pattern tightening method helps avoid uneven bolt load and improves sealing reliability.
Sunhy’s precision manufacturing supports consistent bolt-hole alignment, sealing surface finish, and dimensional tolerances, which helps simplify assembly and improve joint reliability.
Ensuring Leak-Proof Seals
Leak prevention depends on correct alignment, gasket selection, and controlled bolt tightening.
Common leak causes include uneven bolt load, damaged gasket materials, or contaminated sealing surfaces. You can prevent these issues by following standardized installation practices.
Follow these steps to achieve a leak-proof seal:
- Clean the flange faces:
Remove dirt, oil, and debris from the flange surfaces before assembly. - Select the correct gasket:
Choose a gasket based on the system’s pressure, temperature, and the media being handled. In general, spiral wound gaskets are widely used for higher-pressure and higher-temperature service, while PTFE gaskets are often specified for chemical and hygiene-sensitive applications. The table below summarizes common gasket types, typical use cases, and material options.
| Gasket Type | Typical Use Case | Material Examples |
|---|---|---|
| Spiral Wound | High temperature / high pressure | SS316 with graphite or PTFE |
| Compressed Fiber | Low pressure, general service | Non-asbestos, aramid fiber |
| PTFE Sheet | Food, chemical, non-metal piping | Virgin PTFE or filled PTFE |
| Metal Ring (RTJ) | High-pressure pipelines | Soft iron, stainless steel, Inconel |
| Graphite | High heat, aggressive media | Flexible graphite, stainless steel inserts |
- Center the gasket:
Ensure the gasket sits evenly between the flange faces. - Tighten bolts evenly:
Use a torque wrench and tighten bolts in a star pattern. Lubricate bolts for uniform tension where required. - Inspect and maintain:
Check the joint for leakage, corrosion, or bolt loosening. Re-torque after thermal cycling if specified by procedure.
Note: Routine inspection and torque verification help catch early issues and extend gasket and joint life.
Sunhy’s quality control includes dimensional inspection, bolt-hole alignment checks, and sealing surface verification. The company follows commonly required standards such as ASME, ASTM, DIN, and ISO 9001 to support consistent fit-up and reliable sealing performance.
| Sunhy Quality Control Measure | Description |
|---|---|
| Compatibility Checks | Ensure flange faces and materials match your system requirements. |
| Torque Specifications | Follow correct torque values to prevent joint failure. |
| Regular Inspections | Inspect and maintain flanged connections to avoid leaks. |
| Compliance Assurance | Meet global standards with high-precision CNC machining and testing. |
Summary:
A reliable flanged connection depends on correct component selection, proper assembly practices, and routine maintenance. Precision manufacturing and consistent inspection help improve long-term sealing and safety performance.
Advantages of Using Flanges
Easy Maintenance
Flanges make maintenance and inspection simple and fast.
Flanged joints can be opened without cutting the pipe, which reduces labor time and helps shorten shutdown windows. This is especially valuable in systems that require regular inspection, cleaning, or component replacement.
| Advantage | Description |
|---|---|
| Easy Disassembly | You can quickly separate sections for cleaning or inspection. |
| Excellent Sealing | Flanges use gaskets to provide reliable seals, even under high pressure. |
| Reliable Access | You get straightforward access for repairs or upgrades. |
- Flanges can be assembled in tight spaces where welding is less practical.
- They support efficient system modifications during plant upgrades.
- Inspection and replacement can be carried out with standard tools and controlled procedures.
Sunhy’s stainless steel flanges meet ISO 9001 and PED standards to support consistent performance in maintenance-critical environments.
Strength and Safety
Flanges deliver strong joint integrity for demanding service conditions.
In higher-pressure and higher-temperature systems, properly specified flanges help distribute loads evenly and maintain gasket compression. This reduces the risk of leakage and supports safe operation across long service cycles.
| Feature | Description |
|---|---|
| High-Pressure Design | Flanges work well in oil refineries and gas pipelines. |
| Thick Flange Body | You get better load distribution and joint stability. |
| Leak-Proof Performance | Gaskets and precise machining ensure a secure seal. |
| Certified Quality | Sunhy flanges pass strict global standards for safety and reliability. |
- Well-designed transitions can help reduce turbulence and local stress concentration.
- Robust joint design contributes to predictable inspection intervals and maintenance planning.
- Standardized flange systems can help simplify inventory for large-scale projects.
Note: Correct selection of flange type, material, gasket, and bolt grade is essential for meeting project safety and reliability targets.
Choose the right flange to keep your pipe system safe and efficient.
You need to match flange type, material, and standards to your application. The table below shows what to consider:
| Factor | Why It Matters |
|---|---|
| Operating Conditions | Handles pressure and temperature in your pipe |
| Material Compatibility | Prevents corrosion and damage |
| Proper Installation | Stops leaks and keeps your system reliable |
Sunhy stainless steel flanges are designed to support long service life and stable sealing performance when correctly specified and installed.
FAQ
What materials can you use for flanges?
Stainless steel, carbon steel, and alloy steel are common choices.
Material selection should match the system’s pressure, temperature, and corrosion environment. Stainless steel flanges are often specified where chloride exposure, moisture, or aggressive media are concerns.
How do you choose the right flange type?
Match the flange type to your system’s pressure, temperature, and maintenance needs.
Weld neck flanges are commonly used for higher pressure, slip-on flanges for lower pressure, and lap joint flanges where frequent dismantling is required.
Tip: Confirm project standards and dimensional requirements before final selection.
Can you reuse gaskets when reconnecting flanges?
No, you should always use a new gasket.
A new gasket helps ensure proper compression and sealing reliability. Reusing old gaskets increases leak risk and may compromise joint integrity.
What standards do Sunhy flanges meet?
Sunhy flanges meet ASME, ASTM, DIN, and EN1092-1 standards.
Products are supplied with standard documentation and quality controls aligned with commonly required certifications such as ISO 9001 and PED where applicable.
How do you prevent leaks in flange connections?
Use the correct gasket, tighten bolts evenly, and inspect regularly.
Good results depend on clean sealing faces, controlled torque application, and correct alignment.
- Clean flange faces
- Use proper torque
- Inspect after installation
