NYLON INSERT LOCK NUTS

Super Industries
“Global Manufacturer of Heavy & Custom Engineered Fasteners for Oil & Gas, Power & EPC Contractors.”

1. Industry Context & System Relevance

Role in Bolted Joint Integrity

Nylon Insert Lock Nuts are deployed in bolted assemblies where self-loosening due to vibration, cyclic loading, or dynamic forces presents a measurable risk to joint integrity.

In engineered systems, bolted joints are subjected to:

• Transverse vibration
• Axial cyclic loading
• Thermal expansion and contraction
• Rotational or oscillatory motion

Under such conditions, standard threaded fasteners may experience loss of preload, leading to:

• Reduced clamp force
• Joint separation
• Fatigue failure
• Structural instability

Nylon Insert Lock Nuts address this by introducing prevailing torque, which resists rotational loosening independent of clamp load.

Application Environments

Oil & Gas Installations

• Pipe supports and clamps
• Equipment skids
• Valve assemblies
• Non-critical flange bolting (where permitted)

Refineries & Petrochemical Plants

• Rotating equipment guards
• Structural steel connections
• Cable tray systems
• Instrument mounting structures

Power Plants

• Turbine auxiliary systems
• Boiler structures
• Electrical enclosures
• Vibration-prone support systems

Offshore Structures

• Deck equipment
• Secondary structural fastening
• Marine exposure assemblies

Heavy Machinery

• Pumps and compressors
• Gear assemblies
• Engine mounting systems

Railways & Infrastructure

• Track components (non-primary load joints)
• Signal equipment
• Structural fastening

Automotive & Mechanical Assemblies

• Engine components
• Suspension systems
• Chassis assemblies

Selection vs Alternative Locking Methods

Comparison with Standard Hex Nuts

Standard hex nuts rely solely on:

• Friction between threads
• Clamp load

Limitations:

• Susceptible to loosening under vibration
• No inherent locking mechanism

Comparison with Double Nut (Jam Nut) Systems

Jam nut systems:

• Require precise tightening sequence
• Increase assembly time
• Introduce dependency on installer skill

Limitations:

• Inconsistent preload distribution
• Space constraints in compact assemblies

Comparison with Thread-Locking Adhesives

Adhesives (e.g., anaerobic compounds):

• Provide chemical locking
• Require curing time
• Sensitive to contamination

Limitations:

• Difficult disassembly
• Temperature sensitivity
• Not suitable for all materials

Engineering Justification for Nylon Insert Lock Nuts

Nylon Insert Lock Nuts are selected where:

• Reusable locking is required
• No curing time is acceptable
• Installation simplicity is necessary
• Moderate temperature conditions exist
• Controlled prevailing torque is preferred

2. Technical Definition

Functional Classification

Nylon Insert Lock Nuts are defined as:

Prevailing Torque Type Hex Nuts with Integrated Polymer Insert for Self-Locking Thread Engagement

They function independently of clamp load to resist loosening.

Construction Elements

A Nylon Insert Lock Nut consists of:

1. Metallic hex nut body
2. Internal thread (metric or imperial)
3. Polyamide (nylon) insert located at the top end

The insert is mechanically retained within a recess and does not rotate independently.

Thread System Compatibility

Metric Threads

• ISO metric coarse and fine pitch
• Tolerance class: 6H (internal thread)

Imperial Threads

• UNC (Unified National Coarse)
• UNF (Unified National Fine)
• Tolerance class: 2B

Geometry Types

Standard Height (DIN 985 / ISO 10511)

• Reduced height
• Suitable for moderate load applications

High Type (DIN 982 / ISO 7040)

• Increased height
• Higher thread engagement
• Improved load distribution

Insert Positioning

• Located at the top of the nut
• Engages after initial thread engagement
• Ensures controlled deformation during tightening

3. Locking Mechanism & Engineering Principle

Fundamental Operating Principle

The locking action is achieved through:

Elastic Deformation of Nylon Insert

When the bolt enters the nylon section:

• The insert deforms elastically
• Radial pressure is exerted on the bolt threads
• Interference fit is created

Radial Pressure & Friction Generation

The nylon insert applies:

• Radial compressive force
• Increased contact area
• Enhanced friction coefficient

This generates:

Prevailing torque independent of clamp load

Prevailing Torque vs Installation Torque

Prevailing Torque

• Torque required to overcome friction of insert
• Exists before clamp load is developed

Installation Torque

• Total torque applied during tightening
• Includes:
  • Thread friction
  • Bearing friction
  • Prevailing torque

Torque-Tension Relationship

The relationship between applied torque and generated preload is:

   

Where:

• F = Clamp force
• T = Applied torque
• K = Nut factor (friction coefficient)
• d = Nominal diameter

In Nylon Insert Lock Nuts:

• The K factor increases due to insert friction
• This must be considered during torque specification

Self-Locking Behavior

Unlike standard nuts:

• Locking is mechanical and friction-based
• No external locking device required
• No reliance on preload retention alone

Resistance to Vibration-Induced Loosening

Under vibration:

• Micro-movements attempt to rotate the nut
• Nylon insert provides continuous resistance
• Energy is dissipated through friction

This reduces:

• Rotational displacement
• Loss of clamp force

Friction Coefficient Influence

Factors affecting friction:

• Surface finish of threads
• Coating type
• Lubrication condition
• Nylon insert deformation characteristics

Typical behavior:

• Higher friction than standard nuts
• More stable under dynamic conditions

Reusability & Torque Degradation

Nylon Insert Lock Nuts are reusable within limits.

Performance Behavior Over Cycles

• First installation: Maximum prevailing torque
• Subsequent uses:
  • Gradual reduction in torque
  • Insert wear and relaxation

Engineering Consideration

• Reuse permitted only if:
  • Prevailing torque remains within standard limits
• Excessive reuse leads to:
  • Loss of locking function

Limitations of Locking Mechanism

Temperature Sensitivity

• Nylon softens at elevated temperatures
• Loss of elastic recovery above threshold

Chemical Exposure

• Certain hydrocarbons and chemicals may degrade insert

Mechanical Wear

• Repeated installation cycles reduce effectiveness

Functional Summary

Nylon Insert Lock Nuts provide:

• Controlled prevailing torque
• Resistance to loosening under vibration
• Reusable locking capability (within limits)
• Simplified installation without auxiliary locking devices

They are not intended for:

• High-temperature applications exceeding nylon limits
• Critical pressure-retaining joints unless specified
• Environments with aggressive chemical exposure affecting polymers

4. Applicable Standards (ASTM / DIN / ISO / ASME)

Nylon Insert Lock Nuts are governed by dimensional, mechanical, and functional standards that define geometry, material strength, and prevailing torque performance. Selection for EPC projects requires strict alignment with these standards.

International Dimensional & Functional Standards

ISO Standards

ISO 7040

• High-type hexagon nuts with nylon insert
• Metric thread system
• Higher nut height for improved load distribution

ISO 10511

• Standard height nylon insert lock nuts
• Reduced height version of ISO 7040

ISO 2320

• Governs prevailing torque performance testing
• Defines:
  • Minimum prevailing torque
  • Maximum prevailing torque
  • Reusability performance criteria

DIN Standards

DIN 985

• Standard height nylon insert lock nuts
• Equivalent to ISO 10511

DIN 982

• High-type nylon insert lock nuts
• Equivalent to ISO 7040

ASME / ANSI Standards

ASME B18.16.6

• Covers inch-series nylon insert lock nuts
• Includes UNC and UNF threads
• Defines:
  • Dimensions
  • Tolerances
  • Mechanical requirements

ASTM Material Standards

ASTM A194

• Covers carbon and alloy steel nuts
• Applicable grades:
  • Gr. 2H (carbon steel, high strength)
  • Gr. 7 / 7M (alloy steel for higher temperature)

Standards Mapping to Engineering Requirements

Standard	Scope	Thread System	Application Suitability
ISO 7040	High-type lock nuts	Metric	High-load structural applications
ISO 10511	Standard-type lock nuts	Metric	General industrial use
DIN 985	Standard height	Metric	Machinery, automotive
DIN 982	High type	Metric	Heavy-duty assemblies
ASME B18.16.6	Nylon insert lock nuts	UNC/UNF	US EPC projects
ASTM A194	Material specification	Both	High-pressure & high-strength bolting
ISO 2320	Performance testing	Both	Prevailing torque validation

Temperature & Application Compatibility

Standard / Component	Temperature Limitation	Remarks
Nylon Insert (PA6/PA66)	~120°C (continuous)	Above this, torque retention reduces
ASTM A194 Gr. 2H	Up to ~425°C (metal only)	Insert becomes limiting factor
ASTM A194 Gr. 7	Higher temperature capability	Requires non-nylon locking alternative

Engineering Note:
For applications exceeding nylon temperature limits, all-metal prevailing torque nuts are recommended.

5. Material & Grade Options

Material selection is governed by:

• Load requirements
• Environmental exposure
• Compatibility with bolt material
• Temperature conditions

Carbon Steel Options

Property Class 8 / ASTM A194 Gr. 2H

Characteristics:

• High tensile strength
• Suitable for structural and mechanical applications
• Economical for large-scale projects

Typical applications:

• Structural steel assemblies
• Machinery fastening
• Industrial equipment

Stainless Steel Options

A2-70 (Equivalent to 304 Stainless Steel)

• Moderate strength
• Good corrosion resistance
• Suitable for general outdoor environments

A4-80 (Equivalent to 316 Stainless Steel)

• Higher corrosion resistance
• Suitable for:
  • Marine environments
  • Chemical plants
  • Offshore structures

Alloy Steel Options

ASTM A194 Gr. 7 / 7M

• High strength at elevated temperatures
• Improved creep resistance
• Used in:
  • Power plants
  • High-pressure systems

Limitation:
Nylon insert restricts temperature capability.

Material Compatibility Considerations

Bolt Grade	Recommended Nut Grade
8.8	Class 8 / A194 2H
10.9	Alloy steel (Gr. 7)
B7	A194 Gr. 2H / Gr. 7
Stainless A2-70	A2-70 nut
Stainless A4-80	A4-80 nut

Mismatch can result in:

• Thread stripping
• Uneven load distribution
• Premature failure

Material Comparison Table (MANDATORY)

Grade	Yield Strength (MPa)	Tensile Strength (MPa)	Temperature Limit	Corrosion Resistance	Typical Application
Class 8 / Gr. 2H	~640	~800	~120°C (insert limit)	Moderate (requires coating)	Structural & machinery
A2-70	~450	~700	~120°C	Good	Outdoor, general industrial
A4-80	~600	~800	~120°C	High	Marine, offshore
Gr. 7	~720	~860	Limited by insert	Moderate	High-strength assemblies

6. Nylon Insert Material Properties

Polymer Composition

Nylon inserts are typically manufactured from:

• Polyamide 6 (PA6)
• Polyamide 66 (PA66)

These materials provide:

• Elastic deformation capability
• Wear resistance
• Dimensional stability

Thermal Properties

Property	Typical Value
Melting Temperature	220–260°C
Glass Transition Temperature	~50°C
Continuous Operating Temperature	Up to ~120°C

Mechanical Behavior

• Elastic deformation under load
• Recovery after unloading (within limits)
• Gradual degradation with repeated cycles

Chemical Resistance

Resistant to:

• Oils
• Greases
• Fuels (limited exposure)

Sensitive to:

• Strong acids
• Oxidizing agents
• Certain solvents

Aging & Environmental Effects

Factors affecting performance:

• UV exposure (long-term degradation)
• Thermal cycling
• Moisture absorption

Effect:

• Reduction in elasticity
• Decrease in prevailing torque

Functional Limitation Summary

Nylon insert performance is limited by:

• Temperature
• Chemical exposure
• Mechanical wear

For critical applications outside these limits, metallic locking systems are required.

7. Heat Treatment (Metal Component)

Heat treatment is applied to the metallic nut body to achieve specified mechanical properties.

Quenching & Tempering

Applicable to:

• Carbon steel
• Alloy steel nuts

Process:

1. Heating to austenitizing temperature
2. Rapid quenching
3. Tempering to achieve desired hardness

Objectives

• Achieve required tensile strength
• Improve toughness
• Ensure uniform microstructure

Hardness Range

Grade	Typical Hardness (HB/HRC)
Class 8 / 2H	24–35 HRC
Gr. 7	28–38 HRC

Stress Relieving

Performed to:

• Reduce residual stresses
• Improve dimensional stability
• Prevent distortion

Microstructure Control

Critical for:

• Fatigue resistance
• Crack prevention
• Load-bearing consistency

Case Hardening (If Applicable)

Used selectively for:

• Wear resistance improvement
• Surface hardness enhancement

Not typical for standard nylon insert lock nuts but may be used in specialized applications.

Manufacturing Process

Manufacturing of Nylon Insert Lock Nuts follows controlled industrial processes aligned with EPC quality expectations.

Process Flow

1. Raw Material Inspection

• Chemical composition verification
• Mechanical property validation

2. Forging

Cold Forging

• Used for smaller sizes
• High dimensional accuracy
• Improved grain flow

Hot Forging

• Used for larger diameters
• Reduced forming stress

3. Thread Tapping

• Internal threads created using precision taps
• Ensures:
  • Pitch accuracy
  • Thread class compliance (6H / 2B)

4. Heat Treatment

• Applied as per grade requirements
• Ensures mechanical strength compliance

5. Surface Finishing

• Cleaning and preparation
• Application of coating (if required)

6. Nylon Insert Installation

• Insert press-fitted into machined recess
• Controlled interference fit
• Ensures retention during operation

7. Prevailing Torque Testing

• Conducted as per ISO 2320
• Verification of torque range

8. Final Inspection

• Dimensional verification
• Thread gauge inspection
• Visual inspection

9. Marking & Traceability

• Grade marking
• Manufacturer identification
• Batch traceability

8. Surface Finish Options

Surface finishing affects both:

• Corrosion resistance
• Thread fit and torque characteristics

Zinc Plating

• Electroplated coating
• Moderate corrosion resistance
• Common for indoor applications

Hot Dip Galvanizing (HDG)

• Thick zinc coating
• Suitable for outdoor and structural use
• Requires thread oversizing

Black Oxide

• Minimal corrosion protection
• Used where coating thickness must be minimal

PTFE Coating

• Reduces friction
• Improves chemical resistance
• Used in specialized environments

Mechanical Galvanizing

• Uniform coating without hydrogen embrittlement
• Suitable for high-strength fasteners

Passivation (Stainless Steel)

• Enhances corrosion resistance
• Removes free iron contamination

Coating vs Thread Fit Consideration

Coating Type	Impact on Threads
Electroplating	Minimal
HDG	Requires oversized threads
PTFE	Reduces friction
Mechanical Galvanizing	Moderate impact

A. Dimensional Table (Metric Series – Reference per ISO 7040 / DIN 982 / DIN 985)

The following table provides standard dimensional references for Nylon Insert Lock Nuts. Actual dimensions may vary based on standard (ISO/DIN/ASME) and coating condition.

Thread Size	Pitch (mm)	Nut Height (m) mm	Width Across Flats (s) mm	Nylon Insert Diameter (Approx.) mm
M6	1.0	6.0 – 8.0	10	5.5 – 6.0
M8	1.25	8.0 – 10.0	13	7.5 – 8.0
M10	1.5	10.0 – 12.0	17	9.5 – 10.0
M12	1.75	12.0 – 14.0	19	11.5 – 12.0
M16	2.0	16.0 – 18.0	24	15.5 – 16.0
M20	2.5	18.0 – 22.0	30	19.0 – 20.0
M24	3.0	22.0 – 28.0	36	23.0 – 24.0
M30	3.5	26.0 – 34.0	46	29.0 – 30.0
M36	4.0	30.0 – 38.0	55	35.0 – 36.0

Dimensional Engineering Notes

• Nut height affects:
  • Thread engagement
  • Load distribution
• Insert diameter determines:
  • Interference fit
  • Prevailing torque magnitude
• Pitch accuracy is critical for:
  • Load sharing
  • Thread life

B. Torque Chart (MANDATORY)

The tightening torque must consider:

• Thread condition (dry/lubricated)
• Coating type
• Nut factor (K)
• Additional prevailing torque due to nylon insert

Indicative Torque Values (Metric – Property Class 8.8 Bolts)

Size	Torque (Dry) Nm	Torque (Lubricated) Nm
M6	10 – 12	7 – 9
M8	24 – 30	18 – 22
M10	48 – 60	35 – 45
M12	85 – 105	65 – 80
M16	210 – 260	160 – 200
M20	410 – 510	310 – 390
M24	710 – 880	540 – 670
M30	1400 – 1700	1050 – 1300

Torque Adjustment for Nylon Insert Lock Nuts

• Add prevailing torque value to tightening torque
• Avoid over-tightening due to:
  • Increased friction
  • Insert deformation

Engineering Note

Torque values are application-dependent and must be verified through:

• Joint design calculations
• Field validation
• Project specifications

C. Prevailing Torque Table (MANDATORY – Reference ISO 2320)

Prevailing torque is measured before clamp load is applied.

Typical Prevailing Torque Values

Thread Size	Min Torque (Nm)	Max Torque (Nm)	Typical Reuse Cycles
M6	0.5	2.0	3 – 5
M8	1.0	3.5	3 – 5
M10	1.5	5.0	3 – 5
M12	2.0	7.0	3 – 5
M16	3.5	12.0	2 – 4
M20	5.0	18.0	2 – 4
M24	7.0	25.0	2 – 3

Performance Behavior

• Initial torque: Maximum resistance
• Subsequent cycles:
  • Reduction due to insert wear
• Rejection criteria:
  • Torque below minimum specified

Inspection Requirement

Prevailing torque must be verified:

• At manufacturing stage
• During third-party inspection (if required)

D. Preload Calculation Guide (MANDATORY)

Torque–Preload Relationship

   

Where:

• F = Clamp force (N)
• T = Applied torque (Nm)
• K = Nut factor (typically 0.18–0.25 for steel fasteners)
• d = Nominal bolt diameter (m)

Engineering Considerations

• Nylon insert increases effective K value
• Results in:
  • Lower preload for same torque (if not adjusted)
• Requires:
  • Torque correction or calibration

Sample Calculation

Given:

• Bolt size: M12 (d = 0.012 m)
• Torque applied: 90 Nm
• Nut factor: 0.20

Calculation:

   

Practical Adjustment

For Nylon Insert Lock Nuts:

• Add prevailing torque (e.g., 5 Nm)
• Effective tightening torque:
  • 90 + 5 = 95 Nm input
• Actual preload derived from net torque

Clamp Load Importance

Adequate preload ensures:

• Joint stability
• Resistance to fatigue
• Prevention of separation

E. Mechanical Property Table

Material Grade	Yield Strength (MPa)	Tensile Strength (MPa)	Hardness	Elongation (%)
Class 8	~640	~800	24–35 HRC	~12
ASTM A194 2H	~650	~850	24–35 HRC	~14
A2-70	~450	~700	HRB 95 max	~30
A4-80	~600	~800	HRB 95 max	~25
Gr. 7	~720	~860	28–38 HRC	~16

Engineering Interpretation

• Higher strength grades:
  • Suitable for high-load applications
• Stainless grades:
  • Lower strength but higher corrosion resistance
• Selection must match bolt strength

F. Corrosion Resistance Comparison Table

Material Type	Marine Environment	Chemical Exposure	High Humidity	Industrial Use
Carbon Steel (Plated)	Low	Low	Moderate	Moderate
HDG Carbon Steel	Moderate	Low	High	High
Stainless A2-70	Moderate	Moderate	High	High
Stainless A4-80	High	High	High	High
PTFE Coated	High	High	High	Specialized

Engineering Selection Guidance

• Marine / Offshore → A4-80
• General Industrial → A2-70 or plated steel
• Structural Outdoor → HDG
• Chemical Plants → PTFE or A4

9. Inspection & Quality Control

Inspection ensures compliance with:

• Dimensional standards
• Mechanical properties
• Functional performance

Prevailing Torque Testing (ISO 2320)

Procedure:

• Nut is rotated on test bolt
• Torque measured:
  • Before seating
  • After multiple cycles

Acceptance criteria:

• Must fall within specified range

Proof Load Testing

• Ensures nut withstands:
  • Specified axial load
• Prevents:
  • Thread stripping
  • Plastic deformation

Hardness Testing

Methods:

• Rockwell hardness test
• Brinell hardness test

Purpose:

• Verify heat treatment effectiveness

Thread Gauge Inspection

Tools:

• GO / NO-GO gauges

Checks:

• Thread pitch accuracy
• Fit tolerance (6H / 2B)

Coating Thickness Testing

Methods:

• Magnetic thickness gauge
• Micrometer measurement

Ensures:

• Corrosion protection compliance
• Thread compatibility

Salt Spray Testing

• Conducted as per ASTM B117
• Evaluates corrosion resistance

Visual & Dimensional Inspection

Includes:

• Surface defects
• Insert placement
• Marking verification

Certification & Documentation

EN 10204 Certification

• 3.1 Certificate
  • Manufacturer test results
• 3.2 Certificate
  • Third-party verified results

Third-Party Inspection (TPI)

Conducted by:

• Independent inspection agencies

Scope:

• Witness testing
• Document verification
• Batch approval

Traceability System

Ensures:

• Batch identification
• Material traceability
• Inspection history tracking

10. Industries Served

Nylon Insert Lock Nuts are utilized across multiple industries where moderate temperature conditions, vibration resistance, and controlled locking performance are required. Their application is governed by engineering specifications, load classification, and environmental constraints.

Oil & Gas Industry

Application Scope

• Equipment skids and modular units
• Pipe support structures
• Instrumentation mounting systems
• Secondary fastening in non-pressure retaining components

Engineering Considerations

• Not typically used in primary pressure-retaining flange joints unless explicitly specified
• Temperature limitations must be validated against process conditions
• Material selection aligned with corrosion environment

Power Generation Sector

Application Areas

• Turbine auxiliary systems
• Boiler external structures
• Electrical panel fastening
• Cable support assemblies

Performance Requirements

• Resistance to vibration from rotating equipment
• Stability under cyclic loading
• Compatibility with structural steel assemblies

Infrastructure & Structural Engineering

Typical Usage

• Steel framework connections (secondary)
• Bridge accessories and support components
• HVAC structural supports
• Industrial buildings

Engineering Constraints

• Load-bearing capacity must be validated
• Not preferred for critical structural joints requiring high preload retention under temperature variation

Railways & Transportation

Applications

• Signal equipment fastening
• Coach assembly components
• Trackside equipment

Operational Conditions

• Continuous vibration environment
• Exposure to dust, moisture, and mechanical shock

Heavy Engineering & Industrial Machinery

Use Cases

• Pumps and compressors
• Gearboxes and drive systems
• Conveyor systems
• Engine assemblies

Functional Requirement

• Resistance to loosening under dynamic loads
• Ease of maintenance and reassembly

Automotive & Mechanical Assemblies

Applications

• Suspension components
• Engine mounting
• Chassis assemblies

Engineering Focus

• Repeatability of assembly
• Controlled locking without adhesives

11. Procurement & Installation Practices

Procurement and installation of Nylon Insert Lock Nuts must align with project specifications, installation procedures, and inspection requirements.

Installation Procedure

Step-by-Step Engineering Practice

1. Thread Inspection
   • Verify cleanliness and absence of damage
   • Ensure compatibility with bolt thread class
2. Initial Engagement
   • Hand-tighten until nylon insert is engaged
3. Torque Application
   • Apply torque using calibrated torque wrench
   • Account for prevailing torque
4. Final Tightening
   • Achieve specified installation torque
   • Avoid impact tools where torque control is critical

Lubrication Considerations

• Lubrication may be applied to metal threads only
• Avoid lubrication contact with nylon insert
• Excess lubrication may:
  • Reduce friction excessively
  • Affect preload accuracy

Reuse Guidelines

Reuse is permitted under controlled conditions:

Inspection Before Reuse

• Check insert integrity
• Verify prevailing torque manually

Rejection Criteria

• Insert deformation or damage
• Reduced resistance during engagement

Engineering Recommendation

• Limit reuse to defined cycles (typically 2–5) depending on size and application

Storage Conditions

Environmental Requirements

• Store below 30–35°C ambient temperature
• Avoid direct sunlight and UV exposure
• Protect from moisture and contaminants

Impact on Performance

Improper storage may lead to:

• Nylon aging
• Reduced elasticity
• Lower prevailing torque performance

Handling Practices

• Avoid mechanical damage to insert
• Prevent contamination with oils or chemicals
• Maintain packaging integrity until installation

12. Custom Engineering Capabilities

Super Industries supports project-specific requirements for Nylon Insert Lock Nuts through controlled manufacturing and engineering customization.

Dimensional Customization

• Non-standard thread sizes
• Custom pitch configurations
• Special nut heights
• Modified insert dimensions

Material Customization

• Project-specific alloy selection
• High-strength grades
• Stainless steel variants for corrosive environments

Surface Coating Customization

• PTFE-coated fasteners for low friction applications
• Heavy-duty galvanization for outdoor exposure
• Specialized coatings for chemical resistance

High-Temperature Alternatives

Where nylon is not suitable:

• Supply of all-metal prevailing torque lock nuts
• Alternative locking systems for elevated temperature applications

Marking & Traceability

• Project-specific marking
• Heat number traceability
• Batch identification aligned with EPC documentation

Bulk Supply Capability

• Large-volume production for EPC projects
• Scheduled dispatch aligned with project timelines
• Packaging customization based on logistics requirements

13. Export Capability & Global Supply

Super Industries operates as a global exporter of Nylon Insert Lock Nuts, supporting EPC contractors and international procurement teams.

Export Regions

• United States (ASME / ASTM compliance)
• European Union (DIN / ISO compliance)
• Middle East (Oil & Gas projects)
• Southeast Asia (Infrastructure and industrial projects)

Documentation Support

Each shipment can be supported with:

• EN 10204 3.1 / 3.2 certification
• Material test certificates (MTC)
• Dimensional inspection reports
• Heat treatment records
• Coating test reports
• Prevailing torque test reports

Packaging Standards

• Export-grade packaging
• Corrosion protection measures
• Batch-wise segregation
• Labeling with traceability details

Logistics Capability

• Containerized shipments
• Air and sea freight coordination
• Compliance with international shipping standards

Third-Party Inspection Integration

• Pre-dispatch inspection by approved agencies
• Documentation verification
• Compliance certification for project approval

14. Engineering Selection Guidance

When to Use Nylon Insert Lock Nuts

Recommended for:

• Moderate temperature environments (<120°C)
• Vibration-prone assemblies
• Applications requiring reusable locking
• Assemblies where adhesives are not preferred

When Not to Use

Not recommended for:

• High-temperature applications exceeding nylon limits
• Critical pressure-retaining flange joints
• Severe chemical exposure environments
• Applications requiring zero torque degradation over time

Alternative Solutions

• All-metal lock nuts
• Double nut systems (where space permits)
• Chemical thread locking (controlled environments)

Engineering Compliance Summary

Nylon Insert Lock Nuts supplied by Super Industries are designed to comply with:

• ISO / DIN dimensional standards
• ASME / ASTM material specifications
• ISO 2320 prevailing torque requirements
• EPC project documentation requirements
• Third-party inspection protocols

Final Engineering Conclusion

Nylon Insert Lock Nuts function as prevailing torque locking fasteners designed to mitigate loosening in vibration-prone assemblies through controlled frictional resistance generated by a polymer insert.

From an engineering and EPC procurement perspective, their performance is defined by:

• Insert material behavior (polyamide limits)
• Torque-preload relationship adjustments
• Prevailing torque consistency across reuse cycles
• Compatibility with bolt grade and application environment

Their correct application requires:

• Adherence to international standards (ISO, DIN, ASME, ASTM)
• Proper torque control during installation
• Verification of prevailing torque performance
• Consideration of temperature and chemical exposure limits

When selected within defined operating parameters, Nylon Insert Lock Nuts provide:

• Reliable resistance to self-loosening
• Simplified installation without auxiliary locking devices
• Controlled and repeatable locking performance

For EPC contractors, consultants, and inspection agencies, the suitability of Nylon Insert Lock Nuts depends on clear alignment between application conditions, material selection, and standard compliance.