Non-Standard Flange Manufacturer for Custom Industrial Applications

Introduction

Have you ever struggled to find a flange that simply doesn't exist in standard catalogs? We hear this question from customers around the world almost every day. Standard flanges work well for many pipeline systems, but industries such as petrochemical processing, power generation, shipbuilding, pressure vessels, and heavy machinery often require custmized solutions that standard products cannot provide.

As a professional Non-standard Flange Manufacturer, we understand that every industrial project has unique technical requirements. A flange may need an uncommon outside diameter, a special bolt pattern, higher pressure resistance, or a unique material capable of handling corrosive or high-temperature environments. These challenges require engineering experience, precision manufacturing, and strict quality control.

At Zhejiang Songlin Flange Co., Ltd., we specialize in designing and manufacturing Custom Industrial Flanges that match our customers' exact specifications. Our production facility is located in Longwan, Wenzhou—known worldwide as China's Valve City. Equipped with advanced CNC machining centers, comprehensive inspection equipment, and an experienced engineering team, we provide customized flange solutions that help customers improve installation efficiency, system reliability, and long-term operating safety.

Rather than simply selling products, we work alongside our customers from design consultation to final delivery. Every Custom Flange we manufacture is produced according to engineering drawings, international standards where applicable, and strict inspection procedures to ensure dependable performance in demanding industrial environments.

Whether your project requires one prototype or thousands of production pieces, our goal remains the same: delivering reliable non-standard flange solutions with consistent quality and responsive service.

On This Page

• What Is a Non-Standard Flange?

• Why Choose Custom Non-Standard Flanges?

• How We Manufacture Non-Standard Flanges

• Material Selection Guide

• Industrial Applications

• How to Select the Right Non-Standard Flange

• Frequently Asked Questions

• Conclusion

What Is a Non-Standard Flange?

A Non-Standard Flange is a flange manufactured according to customer-specific dimensions rather than following standard specifications such as ASME B16.5, EN 1092-1, DIN, JIS, or GOST. These flanges are engineered for equipment or piping systems that require unique dimensions, materials, pressure ratings, or sealing designs.

In many industrial facilities, standard flanges cannot meet every engineering requirement. Equipment manufacturers often design machines with customized connections to improve performance, reduce installation space, or meet specialized operating conditions.

A non-standard flange may differ in several ways:

• Outside diameter

• Bore diameter

• Bolt circle diameter

• Bolt hole quantity

• Bolt hole size

• Thickness

• Facing type

• Pressure rating

• Material

• Surface finish

Instead of forcing equipment to fit available flange standards, engineers design flanges specifically for the application. This improves compatibility and reduces installation problems.

Some common custom flange types include:

• Large diameter flanges

• Heavy-duty Pressure Vessel Flanges

• Thick forged flanges

• Special sealing flanges

• Custom ring joint flanges

• Oversized welding neck flanges

• Tube Sheets

• Equipment connection flanges

Because every project differs, production usually begins with customer drawings or technical specifications.

Why Non-Standard Flanges Matter

Industrial systems continue to become more specialized.

Modern production plants demand:

• Higher operating pressures

• Higher temperatures

• More aggressive chemicals

• Larger equipment

• Better sealing performance

• Longer service life

Standard products cannot always satisfy these requirements.

For example, a refinery expansion project may require a flange measuring over 2,000 mm in diameter with a special groove for a metallic gasket. Such a product is unavailable in ordinary catalogs and must be manufactured according to engineering drawings.

Likewise, pressure vessel manufacturers frequently request thicker flanges with customized bolt patterns to distribute stress more evenly.

This is where experienced manufacturers make the difference.

Why Choose Custom Non-Standard Flanges?

From our manufacturing experience, customers usually request custom flanges for five major reasons.

1. Unique Equipment Design

OEM equipment often uses proprietary dimensions.

Instead of redesigning expensive machinery, engineers simply customize the flange.

This approach saves both engineering time and production costs.

2. Better Mechanical Performance

A customized flange can improve:

• Structural strength

• Load distribution

• Bolt stress

• Sealing reliability

• Fatigue resistance

These improvements become especially important in high-pressure systems.

3. Extreme Operating Conditions

Industries frequently encounter:

• High temperatures above 500°C

• Cryogenic environments

• Corrosive chemicals

• Offshore saltwater exposure

• Abrasive media

Custom material selection helps extend equipment life.

4. Reduced Installation Time

When flange dimensions perfectly match equipment, installation becomes easier.

Contractors spend less time modifying pipelines, enlarging bolt holes, or fabricating adapters on site.

This reduces labor costs and minimizes project delays.

5. Long-Term Cost Savings

Although custom flanges may cost more initially, they often reduce overall project expenses through:

• Fewer leaks

• Lower maintenance

• Longer service life

• Less downtime

• Better equipment compatibility

For many industrial operators, these long-term savings far exceed the initial investment.

Comparison: Standard vs Non-Standard Flanges

Source: ASME B16.5, EN 1092-1, Zhejiang Songlin Flange Manufacturing Experience.

How We Manufacture Non-Standard Flanges

Every successful custom flange begins with careful engineering.

Unlike standard products, non-standard flanges require communication between engineers and customers before production starts.

Step 1 – Technical Review

We first evaluate:

• Engineering drawings

• Pressure requirements

• Operating temperature

• Medium type

• Material specifications

• Welding requirements

• Inspection standards

If necessary, our engineers discuss possible improvements before production begins.

Step 2 – Material Selection

Material selection directly affects performance.

Depending on the application, we recommend:

• Carbon steel

• Stainless steel

• Duplex stainless steel

• Alloy steel

• Nickel alloy

• High-temperature alloy

Each material offers different advantages for corrosion resistance, strength, machinability, and service life.

Step 3 – CNC Machining

Our factory utilizes advanced CNC machining centers to achieve excellent dimensional accuracy.

Precision machining allows us to produce:

• Accurate bolt holes

• Smooth sealing faces

• Consistent thickness

• Tight dimensional tolerances

Automation also improves production efficiency and repeatability.

Step 4 – Inspection

Quality inspection includes:

• Dimensional inspection

• Surface finish inspection

• Material verification

• Hardness testing

• Non-destructive testing when required

Every batch is inspected before shipment.

Step 5 – Packaging and Delivery

Industrial Flanges often travel long distances by sea or land.

Proper packaging protects:

• Machined sealing surfaces

• Bolt holes

• Flange faces

• Identification markings

Protective coatings and export-grade packaging help ensure products arrive in excellent condition.

Material Selection Guide for Non-Standard Flanges

Selecting the right material is one of the most important decisions when designing a Non-Standard Flange. Even a perfectly machined flange may fail prematurely if the material does not match the operating environment.

When we discuss a new project with our customers, we don't simply ask for dimensions. We also want to understand the working pressure, operating temperature, process medium, installation environment, expected service life, and maintenance schedule. These factors help us recommend the most suitable material instead of the most expensive one.

Below are the materials we commonly manufacture.

Carbon Steel

Carbon steel remains the most economical choice for many industrial piping systems.

Typical advantages include:

• High mechanical strength

• Good machinability

• Cost-effective production

• Wide availability

• Suitable for medium-pressure systems

It is widely used in:

• Oil transmission

• Natural gas pipelines

• Water treatment plants

• Industrial utilities

• General manufacturing

Common grades include ASTM A105 and A350 LF2.

Stainless Steel

When corrosion becomes a concern, stainless steel is often the preferred solution.

Benefits include:

• Excellent corrosion resistance

• Attractive surface finish

• Long service life

• Low maintenance

• Good weldability

Typical industries include:

• Food processing

• Pharmaceutical manufacturing

• Chemical plants

• Marine engineering

• Clean energy equipment

Popular materials include ASTM A182 F304, F304L, F316, and F316L.

Alloy Steel

For elevated temperatures and high-pressure systems, alloy steel provides greater strength than ordinary carbon steel.

These flanges are commonly installed in:

• Steam pipelines

• Thermal power stations

• Refineries

• Petrochemical plants

• Pressure vessels

Typical grades include ASTM A182 F11, F22, and F91.

Duplex Stainless Steel

Some applications require both strength and corrosion resistance.

Duplex stainless steel offers:

• Higher yield strength

• Better resistance to chloride corrosion

• Longer fatigue life

• Improved resistance to stress corrosion cracking

It performs particularly well in offshore engineering and seawater applications.

Nickel-Based Alloys

Extremely aggressive chemical environments often require nickel alloys.

These materials maintain excellent performance under:

• Strong acids

• High temperatures

• Oxidizing environments

• High-pressure chemical processing

Although more expensive, they significantly increase equipment reliability in demanding applications.

Material Comparison

Source: ASTM A182 Specification, ASME Boiler & Pressure Vessel Code, Material Property References.

Industrial Applications of Non-Standard Flanges

Every custom flange tells a different engineering story.

Unlike standard catalog products, non-standard flanges are usually developed to solve a specific challenge.

Below are several industries where we frequently supply customized flange solutions.

Oil and Gas Industry

Oil and gas projects often operate under extremely demanding conditions.

Flanges must withstand:

• High pressure

• High temperature

• Corrosive media

• Offshore environments

• Continuous operation

Many customers request customized welding neck flanges with increased wall thickness to improve structural strength.

Petrochemical Plants

Chemical production involves numerous corrosive liquids and gases.

Depending on the medium, engineers may require:

• Special sealing surfaces

• Alloy materials

• Larger bolt patterns

• Increased corrosion allowance

Custom manufacturing ensures every flange matches process requirements precisely.

Pressure Vessel Manufacturing

Pressure vessels rarely use identical connection dimensions.

Manufacturers often provide detailed engineering drawings specifying:

• Outside diameter

• Thickness

• Bolt layout

• Facing design

• Welding preparation

Since safety is critical, dimensional accuracy becomes especially important.

Power Generation

Power stations frequently operate above 500°C with high-pressure steam.

In these environments, flange failure is simply not acceptable.

Customized alloy steel flanges help improve:

• Thermal stability

• Pressure resistance

• Service life

• Maintenance intervals

Shipbuilding and Offshore Engineering

Marine equipment experiences constant exposure to saltwater and humidity.

To reduce corrosion, customers commonly choose:

• Stainless steel

• Duplex stainless steel

• Protective coatings

• Precision-machined sealing faces

Reliable sealing helps minimize maintenance during long-term offshore operation.

Water Treatment Systems

Large municipal water projects often require oversized flanges.

Instead of ordering expensive imported components, many engineering companies choose locally manufactured custom flanges designed according to project drawings.

This approach shortens delivery time while maintaining high quality.

Real Customer Scenario

One of our customers manufactures large industrial mixers for the chemical industry.

Their equipment required a flange with:

• An oversized outside diameter

• A unique bolt hole arrangement

• Additional sealing grooves

• Increased flange thickness

No international standard matched these dimensions.

Our engineering team reviewed the drawings, optimized several machining details, and produced prototypes within a short production cycle.

After installation, the customer reported smoother assembly and improved sealing performance compared with previous fabricated solutions.

This project demonstrates how customized engineering can solve practical installation problems while reducing long-term maintenance costs.

How to Select the Right Non-Standard Flange

Choosing the correct flange involves much more than selecting dimensions.

We usually recommend evaluating the following factors.

1. Working Pressure

Higher pressure generally requires:

• Greater thickness

• Stronger materials

• Improved bolt design

• Better sealing surfaces

Ignoring pressure ratings may shorten equipment life.

2. Operating Temperature

Materials behave differently under heat.

For example:

• Carbon steel performs well at moderate temperatures.

• Alloy steel handles high-temperature steam.

• Stainless steel performs well in many corrosive environments.

Always consider both pressure and temperature together.

3. Process Medium

Ask yourself:

• Is the fluid corrosive?

• Does it contain chloride?

• Is it acidic?

• Does it contain abrasive particles?

The answers determine material selection.

4. Connection Type

Different equipment requires different flange designs.

Examples include:

• Welding Neck

• Slip-On

• Socket Weld

• Threaded

• Lap Joint

• Blind Flange

• Custom Pressure Vessel Flange

Selecting the correct connection improves installation efficiency.

5. Manufacturing Capability

Not every supplier can manufacture highly customized flanges accurately.

When evaluating a manufacturer, consider:

• CNC machining capability

• Engineering support

• Inspection equipment

• Material traceability

• Export experience

• Delivery reliability

These factors often influence project success more than price alone.

Practical Buying Tips

After serving customers from different industries, we have learned several lessons worth sharing.

✔ Provide complete engineering drawings whenever possible.

✔ Include pressure and temperature data in your inquiry.

✔ Specify the working medium.

✔ Confirm inspection standards before production.

✔ Discuss packaging requirements for international shipping.

Early communication usually reduces manufacturing time and avoids unnecessary revisions later.

Comparison of Standard and Custom Manufacturing Processes

Frequently Asked Questions (FAQ)

1. What information should I provide when requesting a custom non-standard flange?

The more technical information you can provide, the faster we can prepare an accurate quotation and production plan.

We recommend including:

• Technical drawings (2D or 3D)

• Outside diameter (OD)

• Inside diameter (ID)

• Thickness

• Bolt hole quantity and diameter

• Bolt circle diameter (BCD/PCD)

• Facing type (RF, FF, RTJ, or custom)

• Material grade

• Pressure rating

• Operating temperature

• Applicable standards or inspection requirements

• Required quantity

If complete drawings are unavailable, our engineering team can also assist in developing a suitable manufacturing solution based on your equipment specifications.

2. Can you manufacture flanges according to our drawings?

Yes.

This is one of our core strengths.

At Zhejiang Songlin Flange Co., Ltd., most of our Non-Standard Flange projects are produced according to customer drawings rather than standard catalogs.

Our engineering team carefully reviews each drawing before production begins to verify dimensions, machining feasibility, material selection, and quality requirements. If we identify opportunities to improve manufacturability or reduce production costs without affecting performance, we will discuss them with you before manufacturing.

3. Which international standards do your products comply with?

Although non-standard flanges are manufactured according to customer drawings, we also produce products based on internationally recognized standards whenever required, including:

• ASME B16.5

• ASME B16.47

• EN 1092-1

• DIN Standards

• JIS Standards

• GOST Standards

• HG/T Standards

• GB/T Standards

Our quality management process follows internationally accepted manufacturing practices to ensure dimensional accuracy, material traceability, and reliable performance.

4. What inspections do you perform before delivery?

Quality control is integrated into every stage of production.

Depending on project requirements, inspections may include:

• Raw material verification

• Chemical composition analysis

• Mechanical property testing

• Dimensional inspection

• Surface roughness measurement

• Hardness testing

• Ultrasonic Testing (UT)

• Magnetic Particle Testing (MT)

• Penetrant Testing (PT)

• Positive Material Identification (PMI)

• Hydrostatic or pressure-related inspections when applicable

Inspection reports can be supplied upon request.

5. What industries do you mainly serve?

Over the years, we have supplied custom flange solutions for customers in a wide range of industries, including:

• Oil and gas

• Petrochemical processing

• Power generation

• Shipbuilding

• Marine engineering

• Pressure vessel manufacturing

• Water treatment

• Chemical processing

• Mining

• Heavy machinery

• Paper production

• Food processing

• Pharmaceutical equipment

Every industry presents different technical challenges, which is why customized engineering remains at the heart of our manufacturing philosophy.

Why Customers Choose Zhejiang Songlin Flange Co., Ltd.

Selecting a flange supplier involves much more than comparing prices. A dependable manufacturing partner should provide technical expertise, stable quality, responsive communication, and consistent delivery.

At Zhejiang Songlin Flange Co., Ltd., we continue to invest in advanced manufacturing equipment and process improvement because we understand that every flange plays an important role in the safety and reliability of an industrial system.

Our strengths include:

Advanced Manufacturing Equipment

Our factory is equipped with advanced CNC machining centers and precision processing equipment capable of manufacturing complex custom flange geometries with excellent dimensional consistency.

Comprehensive Quality Management

Quality is monitored throughout the manufacturing process—from raw material procurement to final inspection.

Every production stage follows documented procedures designed to minimize defects and ensure product consistency.

Engineering Support

Our engineering team works closely with customers during project development.

Whether you require design optimization, material recommendations, or production feasibility analysis, we provide practical technical support based on years of manufacturing experience.

Flexible Production Capacity

We can support:

• Prototype development

• Small-batch production

• Medium-volume orders

• Large-scale manufacturing

This flexibility allows us to meet the needs of equipment manufacturers, EPC contractors, distributors, and industrial end users.

Global Export Experience

Our products are supplied to customers in multiple international markets.

We understand export packaging, logistics coordination, technical documentation, and international communication, helping overseas customers complete projects more efficiently.

Best Practices for Maintaining Non-Standard Flanges

Even a high-quality flange requires proper installation and maintenance to achieve its full service life.

We recommend the following practices:

Inspect Before Installation

Always verify:

• Sealing surface condition

• Bolt hole alignment

• Surface cleanliness

• Material identification

• Dimensions

Minor contamination on sealing surfaces may lead to leakage after installation.

Use Appropriate Bolts and Gaskets

The flange is only one component of the connection.

Selecting compatible bolts, nuts, washers, and gaskets is equally important for achieving reliable sealing performance.

Apply Correct Bolt Tightening Procedures

Uneven bolt tightening is one of the most common causes of flange leakage.

We recommend:

• Cross-pattern tightening

• Multi-stage torque application

• Calibrated torque tools

Following proper tightening procedures helps distribute gasket pressure evenly.

Schedule Regular Inspection

For systems operating under high pressure or severe conditions, periodic inspections should include:

• Bolt condition

• Corrosion

• Surface damage

• Leakage

• Vibration effects

Preventive maintenance is generally less expensive than emergency repairs.

Conclusion

Finding the right Non-Standard Flange Manufacturer is about more than obtaining a custom component—it is about partnering with a supplier that understands your engineering challenges and can deliver reliable, long-term solutions.

At Zhejiang Songlin Flange Co., Ltd., we combine advanced CNC machining technology, experienced engineers, comprehensive inspection systems, and a customer-focused approach to manufacture high-quality custom flanges for demanding industrial applications. From slip-on flanges and welding neck flanges to Pressure Vessel Flanges, large-diameter flanges, tube sheets, and fully customized designs, every product is manufactured with precision and carefully inspected before shipment.

We believe that successful cooperation begins with understanding our customers' needs. By listening carefully, providing practical engineering advice, and maintaining strict quality standards throughout production, we help customers reduce installation challenges, improve equipment reliability, and lower long-term operating costs.