Flange Nut Manufacturer | Custom Hex Flange Nuts & DIN 6923 Fasteners

Flange Nut Manufacturing Process: DIN 6923, Quality Control and OEM Sourcing

Flange nuts are widely used in industrial mechanical assemblies where a threaded fastening component with an integral bearing surface is required.

A hex flange nut combines a hexagonal nut body with a flange beneath the nut. Compared with a conventional hex nut without a washer, 

this design can provide a larger bearing surface and may reduce the number of separate assembly components.

However, a larger flange does not automatically guarantee uniform load distribution, prevent vibration loosening or eliminate the need for every type of washer.

Reliable performance depends on the complete bolted joint, including material properties, thread engagement, flange geometry, tightening conditions and the mating components.

For design engineers, flange nut selection begins with dimensional compatibility, bearing pressure, thread strength and joint loading.

For manufacturing engineers and production managers, the important questions concern forming feasibility, thread quality, automated assembly, process stability and inspection.

For purchasing managers and supplier development teams, the decision also involves manufacturing route, technical equivalence, 

material and coating requirements, MOQ, lead time and long-term supply consistency.

JUXIN FASTENERS supplies industrial flange nuts, locking nuts and drawing-based fastening components for international OEM applications.

This guide explains flange nut manufacturing methods, engineering considerations, common defects, industrial applications and supplier qualification requirements.

What Is a Hex Flange Nut?

A hex flange nut is an internally threaded fastener with an external hexagonal drive and an integral flange at one end.

Its principal features include:

• Hexagonal wrenching surfaces

• Internal thread

• Integral flange

• Defined overall height

• Specified flange diameter

• Defined material and mechanical properties

The flange provides a bearing surface that may be larger than the bearing face of a conventional hex nut.

This can be useful where the joint design benefits from a wider contact area.

Key Engineering Consideration

The effective bearing area depends on flange geometry, contact flatness, surface condition and the mating material.

An integral flange does not automatically replace a hardened washer, sealing washer or other specially specified washer.

DIN 6923 Flange Nuts and Product Variations

DIN 6923 is a widely recognized designation for hexagon flange nuts.

However, procurement teams should identify the exact product configuration rather than relying on the generic description flange nut.

Non-Serrated Hex Flange Nuts

These have a flange bearing surface without intentional locking serrations.

They may be suitable for selected machinery, equipment housings and general industrial connections.

Serrated Flange Nuts

These incorporate serrations beneath the flange.

The serrations may provide additional resistance to rotation in certain assemblies by interacting with the mating surface.

However, their effectiveness depends on the joint and must not be assumed for all vibration conditions.

All-Metal Locking Flange Nuts

These incorporate a prevailing-torque locking feature, depending on the design.

Their locking function is different from the bearing function of the flange.

Nylon Insert Locking Nuts

Nylon insert locking nuts are another fastening category and should not be treated as equivalent to an all-metal locking flange nut.

Product Selection Matrix

Engineering Recommendation

Identify the exact flange and locking configuration on the drawing or purchase specification.

How Are Flange Nuts Manufactured?

Flange nut manufacturing depends on the product geometry, material, mechanical requirements and purchasing volume.

Two important manufacturing routes are cold forming and CNC machining.

Cold Forming

Cold forming is commonly used for suitable standard and high-volume flange nut production.

CNC Machining

CNC turning and milling may be appropriate for selected custom geometries, low-volume orders or materials that are difficult to form.

The correct manufacturing route should be selected after reviewing the actual drawing and production requirements.

Manufacturing Stage 1: Raw Material Selection

The manufacturing process begins with material selection.

Potential materials include:

• Carbon steel

• Alloy steel

• Stainless steel

• Brass

• Other drawing-specified materials

Material selection depends on:

• Mechanical requirements

• Formability

• Machinability

• Corrosion exposure

• Temperature

• Thread performance

• Cost

Carbon Steel

May be suitable for general industrial flange nuts where the specified mechanical properties and corrosion protection requirements are satisfied.

Alloy Steel

May be selected where particular mechanical properties or heat-treatment responses are required.

Stainless Steel

May be selected for suitable corrosion-sensitive applications.

A2 and A4 stainless steel fastener designations are commonly encountered.

Brass

May be considered for selected electrical, mechanical or corrosion-related applications where its properties are appropriate.

Important Principle

Material grade and finished fastener property class are different requirements.

A particular steel grade does not automatically establish the finished nut's mechanical performance.

Manufacturing Stage 2: Material Preparation

For cold-formed flange nuts, suitable wire or bar stock may be prepared for the forming process.

For machined products, bar stock or other suitable starting material may be used.

Relevant controls can include:

• Material identification

• Starting dimensions

• Surface condition

• Material consistency

The actual preparation method depends on the manufacturing route.

Manufacturing Stage 3: Cold Heading and Flange Formation

Cold forming can produce the nut body and flange through suitable forming operations.

Depending on the tooling and product design, the process may include:

• Material upsetting

• Hexagonal body formation

• Flange formation

• Hole preparation

• Dimensional control

Potential Manufacturing Benefits

• Efficient material utilization

• Suitability for volume production

• Repeatable geometry under controlled conditions

• Reduced machining requirements

Manufacturing Limitations

Cold forming feasibility depends on:

• Material formability

• Flange diameter

• Nut height

• Hexagonal dimensions

• Hole geometry

• Tooling design

• Production quantity

OEM Design Recommendation

Large flange diameters or unusual geometries should be reviewed for forming feasibility before tooling is approved.

Manufacturing Stage 4: CNC Turning and Milling for Custom Flange Nuts

Not every flange nut requires CNC machining.

However, machining may be appropriate for selected custom products.

Potential Machining Operations

• Turning the flange diameter

• Machining special profiles

• Producing non-standard heights

• Milling wrenching features

• Preparing special holes

• Finishing drawing-specific dimensions

When CNC Machining May Be Appropriate

• Prototype development

• Selected low-volume orders

• Unusual flange geometry

• Special materials

• Drawing-specific dimensional requirements

Commercial Consideration

A machined prototype and a cold-formed production version may have different tooling, unit cost and dimensional characteristics.

Before moving from prototype to volume production, the manufacturing route should be reviewed and approved.

Manufacturing Stage 5: Internal Thread Tapping

Internal thread quality is critical to flange nut performance.

The thread must engage correctly with the specified mating screw or bolt.

Important Thread Characteristics

• Nominal diameter

• Thread pitch

• Thread tolerance

• Thread alignment

• Effective thread engagement

• Surface condition

Potential Thread Defects

• Oversized thread

• Undersized thread

• Damaged thread

• Incomplete thread

• Poor alignment

• Burrs

• Contamination

Thread Inspection

Suitable thread gauges and inspection methods may be used according to the product specification.

Production Implication

A flange nut may appear dimensionally correct externally while still having an unacceptable internal thread.

For high-volume OEM assembly, thread defects can cause feeding problems, installation delays, cross-threading and rework.

Metric and Inch Thread Systems

Metric threads should be specified using the applicable ISO thread designation.

UNC and UNF are different Unified inch-series thread systems.

BSW and BSF are separate thread systems.

These systems are not directly interchangeable.

Important Rule

A nominal metric-to-inch diameter conversion does not establish thread compatibility.

Manufacturing Stage 6: Heat Treatment

Some steel flange nuts require heat treatment to achieve specified mechanical properties.

The process depends on the material and product specification.

Potential Requirements

• Hardness

• Proof-load performance

• Material condition

• Mechanical strength

ISO 898-2 may be relevant for specified metric carbon steel and alloy steel nuts.

Important Limitation

Heat treatment does not automatically guarantee better fatigue performance or longer service life.

The finished nut must meet the applicable requirements.

Manufacturing Stage 7: Surface Treatment

Surface treatment may be used for corrosion protection, appearance or assembly requirements.

Zinc Plating

May provide suitable corrosion protection in selected industrial environments.

Zinc-Nickel Coating

May be considered where specified corrosion protection is required.

Zinc-Flake Coating

May be suitable for certain fastener systems depending on the coating specification.

Black Oxide

Provides a dark appearance with corrosion performance dependent on the complete treatment.

Stainless Steel

May be selected where suitable corrosion resistance is required without relying on a conventional plated steel configuration.

Relevant Standards

ISO 4042 may apply to electroplated fasteners.

ISO 10683 may apply to specified non-electrolytically applied zinc-flake coating systems.

Important Production Consideration

Coating can affect thread fit and friction.

The thread and coating specifications must therefore be considered together.

Manufacturing Stage 8: Inspection and Quality Control

Quality control should address the characteristics that affect both assembly and joint performance.

Dimensional Inspection

Potential checks include:

• Width across flats

• Nut height

• Flange diameter

• Flange thickness

• Hole geometry

• Internal thread dimensions

Mechanical Property Verification

Depending on the specification, relevant tests may include:

• Hardness

• Proof-load testing

• Other required mechanical tests

Surface Inspection

Potential checks include:

• Coating appearance

• Coating thickness

• Surface defects

• Corrosion-related test requirements

Locking Performance

For applicable prevailing-torque locking nuts, the required locking characteristics and test method should be defined separately.

Supplier Qualification Principle

Inspection frequency and documentation must be agreed for the actual project.

A generic flange nut description does not establish that every production batch receives every possible test.

Engineering Design: Flange Diameter and Bearing Pressure

The flange is one of the main reasons engineers select this nut configuration.

A larger bearing surface may reduce nominal contact pressure compared with a smaller bearing area.

However, actual pressure distribution depends on:

• Flange geometry

• Mating surface flatness

• Material hardness

• Surface finish

• Joint preload

• Component stiffness

Thin Sheet Metal Applications

Flange nuts may be considered in suitable thin-sheet assemblies.

However, thin sheet metal may experience:

• Local indentation

• Permanent deformation

• Coating damage

• Joint relaxation

Engineering Recommendation

Evaluate the complete fastening arrangement rather than relying on flange diameter alone.

For blind-side or sheet metal applications, alternatives may include self-clinching nuts, blind rivet nuts, weld nuts or cage nuts.

Thread Engagement and Joint Strength

A flange nut must provide suitable internal thread engagement for the mating bolt.

The required engagement depends on:

• Nut height

• Thread geometry

• Material

• Mechanical properties

• Bolt strength

• Joint loading

Important Principle

A high-strength bolt does not automatically create a high-strength joint if the mating nut or connected material is unsuitable.

Vibration Resistance: Flange Nut vs. Locking Nut

A standard non-serrated flange nut is not inherently self-locking.

The flange increases the available bearing area but does not independently prevent rotation.

Serrated Flange Nuts

Serrations may provide additional resistance to rotation in suitable applications.

However, they may also damage certain coatings or soft surfaces.

All-Metal Locking Nuts

An all-metal prevailing-torque locking nut uses a separate locking mechanism.

Such designs may be appropriate for certain temperature or vibration requirements, depending on the specification.

Engineering Recommendation

Select the locking method according to the actual joint, not simply the product name.

Flange Nut Applications in Automotive and EV Equipment

Flange nuts may be used in suitable automotive mechanical assemblies.

Potential applications include:

• Mechanical brackets

• Equipment housings

• EV battery equipment supports

• Vehicle production fixtures

• Auxiliary mechanical components

Engineering Considerations

• Vibration

• Corrosion

• Temperature

• Joint loading

• Tightening consistency

• Surface compatibility

Important Limitation

General industrial flange nuts are not automatically qualified for safety-critical steering, braking or suspension connections.

Industrial Machinery and Automation

Potential applications include:

• CNC machinery

• Mechanical fixtures

• Automation equipment

• Packaging machinery

• Material handling systems

• Industrial equipment frames

Production Considerations

• Tool accessibility

• Nut feeding

• Thread engagement

• Tightening repeatability

• Inspection

• Rework

Electrical and Telecommunications Equipment

Flange nuts may be used in suitable mechanical fastening applications involving:

• Electrical cabinets

• Control panels

• Telecom enclosures

• Power conversion equipment

• Equipment supports

Engineering Considerations

• Sheet metal thickness

• Electrical clearance

• Corrosion

• Coating compatibility

• Assembly access

HVAC and Building Equipment

Potential applications include:

• HVAC equipment housings

• Mechanical brackets

• Ventilation equipment

• Industrial equipment supports

Engineering Considerations

• Vibration

• Corrosion

• Maintenance access

• Joint loading

Construction and Structural Applications

Flange nuts may be used in selected construction-related equipment and mechanical assemblies.

However, general industrial flange nuts should not automatically be substituted into structural steel bolting assemblies.

Applicable structural specifications and project approval must govern such connections.

Production-Line Consistency and Defect Prevention

Manufacturing engineers and production managers should evaluate flange nuts as part of the complete assembly process.

Incoming Inspection

Depending on project requirements, checks may include:

• Product identification

• Flange geometry

• Hexagonal dimensions

• Internal thread

• Material and mechanical property documentation

• Coating condition

Automated Assembly

For automated nut installation, important considerations include:

• Nut orientation

• Feeding stability

• Tool engagement

• Thread starting

• Tightening consistency

Common Production Problems

Production Recommendation

Define measurable acceptance criteria for the characteristics that affect assembly performance.

OEM Supplier Qualification and Purchasing Decisions

Procurement managers and supplier development teams should compare flange nuts using complete technical specifications.

Recommended RFQ Information

Supplier Substitution Checklist

Before approving an alternative flange nut, verify:

• Thread compatibility

• Flange dimensions

• Hexagonal dimensions

• Material

• Mechanical properties

• Coating

• Locking characteristics

• Inspection requirements

A visually similar flange nut may not be dimensionally or functionally equivalent.

Total Installed Cost

Purchasing decisions should consider:

• Unit price

• Manufacturing route

• Tooling

• Assembly cycle time

• Inspection

• Rework

• Inventory

• Supplier qualification

• Delivery reliability

A lower unit price does not always produce the lowest installed cost.

Frequently Asked Questions

What is the main advantage of a flange nut?

Its integral flange provides a defined bearing surface and may reduce the need for a separate washer where the joint design permits.

Are flange nuts manufactured by CNC turning?

Some custom flange nuts are machined, but cold forming is common for suitable standard and high-volume products.

Are DIN 6923 flange nuts self-locking?

Not automatically. A flange nut requires a defined locking feature or suitable joint design to achieve the required resistance to loosening.

What is the difference between serrated and non-serrated flange nuts?

Serrated flange nuts have teeth beneath the flange, while non-serrated versions do not.

Can a flange nut replace a standard hex nut and washer?

Only after verifying bearing geometry, material, mechanical properties and the complete joint requirements.

Can stainless steel flange nuts be used outdoors?

Suitable stainless steel grades may be considered, but corrosion performance depends on the actual environment.

What information is required for a custom flange nut quotation?

A drawing, thread designation, material, mechanical property requirements, coating, quantity and delivery requirements are important.

Can JUXIN FASTENERS review custom flange nut drawings?

Yes. Drawing-based inquiries can be reviewed for geometry, materials, mechanical properties, coatings and quotation requirements.

JUXIN FASTENERS: Flange Nuts and OEM Fastening Solutions

JUXIN FASTENERS supplies industrial fastening components and supports drawing-based OEM inquiries for international manufacturers.

Relevant product categories include:

• Hex flange nuts

• DIN 6923 flange nuts

• Serrated flange nuts

• Non-serrated flange nuts

• Carbon steel flange nuts

• Stainless steel flange nuts

• All-metal locking nuts

• Nylon insert lock nuts

• Hexagon nuts

• Weld nuts

• Blind rivet nuts

• Self-clinching nuts

• Threaded inserts

• Custom CNC-machined fasteners

Specific dimensions, materials, mechanical properties, coatings, inspection requirements, MOQ and lead time are confirmed during project review.

Request a Flange Nut Engineering Review and OEM RFQ

Are you sourcing DIN 6923 flange nuts, serrated flange nuts, stainless steel flange nuts or custom flange nuts for automotive equipment, 

industrial machinery, electrical enclosures, HVAC systems or other OEM applications?

JUXIN FASTENERS welcomes inquiries from design engineers, structural engineers, mechanical engineers, manufacturing engineers, production managers, 

procurement specialists, purchasing managers, supplier development teams and supply chain managers.

For an efficient technical and commercial review, please provide:

2D drawing or applicable standard + thread designation + flange dimensions + serration or locking type + material + mechanical property class 

+ coating + application + inspection requirements + sample quantity + annual purchasing volume + target delivery schedule

Our team can review your requirements, discuss suitable standard or drawing-based options, confirm sample arrangements and prepare quotation information.

Company: Juxin Fasteners

Website: https://www.juxinfasteners.com/

Email: info@juxinfasteners.com

Send your flange nut drawings and RFQ to JUXIN FASTENERS for technical evaluation and quotation.