Flange Nut

1. Industry Context

Flange nuts are critical fastening components developed to improve load distribution, vibration resistance, and joint reliability in mechanically loaded assemblies. Unlike conventional hex nuts requiring separate washers, flange nuts integrate a bearing flange directly into the nut geometry, simplifying assembly while improving performance consistency.

Across global industries, flange nuts are extensively deployed where:

• Assembly speed must be optimized
• Surface damage must be minimized
• Load distribution over thin or softer materials is required
• High vibration environments exist
• Repeatable torque–tension performance is essential

Major Industrial Deployment Sectors

Industry	Functional Requirement
Structural Steel	Load spreading & reduced embedment
Oil & Gas	Reliable preload under vibration
Power Generation	Thermal cycling resistance
Automotive & OEM	High-speed automated assembly
Petrochemical	Corrosion-resistant clamping
Heavy Equipment	Shock & dynamic load resistance
Rail & Infrastructure	Long-life maintenance-free joints
Offshore & Marine	Corrosion + vibration control

SM Fasteners manufactures flange nuts aligned with ISO 9001-certified quality systems, enabling traceable supply suitable for EPC projects and third-party inspection environments.

2. Technical Definition

A flange nut is a hexagonal internally threaded fastener incorporating an integral washer-like flange at the bearing surface.

Key Functional Elements

1. Hex body for torque application
2. Internal precision thread
3. Integrated flange (plain or serrated)
4. Enlarged bearing surface

The flange performs two essential engineering functions:

• Redistributes compressive load
• Increases frictional resistance

This eliminates the need for separate washers while improving joint stability.

3. Load Mechanics & Force Behavior

3.1 Fundamental Fastener Principle

All bolted joints operate by converting tightening torque into clamping force (preload).

$$T = K \times F \times D$$

Where:

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

Flange nuts influence this relationship by modifying the bearing friction component.

3.2 Force Distribution Mechanism

Standard hex nuts concentrate compressive stress under a limited contact area.

Flange nuts increase contact area by 30–70%, producing:

• Lower bearing stress
• Reduced joint embedment
• Improved fatigue life

Stress Distribution Comparison

Parameter	Hex Nut	Flange Nut
Contact Area	Small	Large
Surface Damage Risk	Higher	Reduced
Washer Requirement	Yes	No
Load Distribution	Concentrated	Distributed
Assembly Time	Longer	Faster

3.3 Preload Behavior

Preload must exceed service loads to prevent joint separation.

Flange geometry stabilizes preload through:

• Reduced localized yielding
• Controlled friction interface
• Lower settlement losses

Typical preload target:$$Preload = 70\% \text{ of Proof Load}$$

3.4 Torque–Tension Relationship

Torque energy distribution:

Energy Component	Percentage
Thread Friction	40–50%
Bearing Surface Friction	35–45%
Useful Bolt Stretch	10–15%

The flange modifies bearing friction, improving repeatability during controlled tightening.

4. Joint Design Principles

4.1 Washer Elimination Strategy

Flange nuts replace washers where:

• Space constraints exist
• Automated assembly lines operate
• Assembly consistency is required

Engineering benefits include:

• Reduced component count
• Lower installation error probability
• Improved inventory control

4.2 Joint Stiffness Considerations

Joint stiffness ratio:$$C = \frac{K_b}{K_b + K_j}$$

Where:

• $K_b$Kb​ = Bolt stiffness
• $K_j$Kj​ = Joint stiffness

Flange nuts increase effective joint stiffness by enlarging compression zones.

4.3 Vibration Resistance

Serrated flange nuts create mechanical locking through:

• Radial tooth engagement
• Micro-penetration into mating surface
• Increased prevailing torque

Common in:

• Automotive suspension
• Rotating equipment
• Railway assemblies

4.4 Bearing Pressure Control

Bearing stress:$$\sigma_b = \frac{F}{A}$$

Increasing flange area reduces stress concentration, preventing:

• Surface brinelling
• Coating damage
• Relaxation losses

4.5 Failure Prevention Philosophy

Correctly specified flange nuts mitigate:

• Self-loosening
• Fretting corrosion
• Fatigue cracking
• Embedment relaxation

5. Functional Role in Industrial Assemblies

flange nuts act as:

• Load distributors
• Anti-loosening devices
• Assembly simplifiers
• Structural preload stabilizers

SM Fasteners engineers flange nuts suitable for high integrity joints used in global EPC projects.

Typical Engineering Assemblies

Assembly	Function
Structural connections	Load spreading
Pump skids	Vibration resistance
Pressure equipment	Uniform compression
Automotive chassis	Rapid installation
Offshore modules	Corrosion resistance

6. Mechanical Behavior Under Service Loads

Static Loading

Maintains clamping force preventing separation.

Dynamic Loading

Flange increases friction damping.

Thermal Cycling

Large bearing area minimizes preload loss.

Shock Loading

Distributes impulse stresses.

7. Thread Engagement Requirements

Minimum engagement:

Material	Engagement Length
Steel	1 × Diameter
Stainless Steel	1.25 × Diameter
Aluminum	2 × Diameter

8. Common Failure Mechanisms

Fatigue Failure

Caused by fluctuating tensile stress.

Mitigation: Proper preload + flange load distribution.

Shear Failure

Occurs when joint slips.

Mitigation: Correct preload selection.

Hydrogen Embrittlement

Risk in high-strength plated fasteners.

Control: Certified baking procedures at SM Fasteners.

Stress Corrosion Cracking

Critical in:

• Chloride environments
• H₂S service

Materials selected according to NACE MR0175 / ISO 15156.

9. Friction & Nut Factor Influence

Typical nut factor values:

Condition	K Value
Dry	0.20–0.25
Zinc Plated	0.18
Lubricated	0.12–0.15
PTFE Coated	0.10–0.13

Flange surface finish directly affects tightening accuracy.

10. Engineering Selection Criteria

Selection must consider:

• Bolt grade compatibility
• Operating temperature
• Corrosion environment
• Required preload
• Installation method
• Inspection accessibility

SM Fasteners supports custom engineering for project-specific flange nut configurations, including advanced alloys and PEEK polymer fasteners for electrically isolated or chemically aggressive environments.

11. Product Types and Variants

Flange nuts are engineered in multiple configurations to address specific mechanical, environmental, and installation requirements. Selection must consider vibration conditions, surface hardness, accessibility, and preload reliability.

11.1 Standard Hex Flange Nut (Plain Bearing Face)

Description

• Integral washer flange
• Smooth bearing surface
• Non-locking configuration

Engineering Purpose

• Load spreading
• Surface protection
• Assembly simplification

Typical Applications

• Structural steel connections
• General machinery
• Pressure equipment assemblies
• EPC skid fabrication

11.2 Serrated Flange Nut (Prevailing Torque Type)

Design Characteristics

• Radial serrations under flange
• Self-locking action
• Increased friction resistance

Functional Mechanism

Serrations create micro-penetration into mating material, increasing resistance against rotational loosening.

Advantages

• Eliminates lock washers
• Excellent vibration resistance
• Improved preload retention

Limitations

• Not recommended for coated or painted surfaces requiring preservation
• Not suitable for soft materials

11.3 Heavy Series Flange Nut

Features

• Increased height
• Larger thread engagement
• Higher load capacity

Used where:

• High tensile bolts (10.9 / 12.9)
• Structural applications
• Heavy equipment joints

11.4 Metric vs Unified Flange Nuts

Thread System	Primary Regions	Standard Use
Metric (ISO)	Europe, India, Middle East	EPC & infrastructure
UNC	North America	Structural & heavy equipment
UNF	Aerospace & precision	High fatigue resistance
BSW	Legacy UK systems	Maintenance retrofit
BSF	Fine pitch British	Older installations

SM Fasteners manufactures flange nuts compatible with global interchangeability requirements.

11.5 High-Temperature Alloy Flange Nuts

Manufactured in:

• Inconel
• Incoloy
• Hastelloy
• Nickel alloys
• SMO 254

Applications include:

• Gas turbines
• Refinery heaters
• LNG cryogenic systems

11.6 Corrosion-Resistant Stainless Flange Nuts

Common grades:

• A2-70 / 304
• A4-80 / 316
• Duplex 2205
• Super Duplex 2507

Designed for:

• Offshore exposure
• Chemical processing
• Marine environments

11.7 PEEK Flange Nuts (Advanced Polymer Variant)

SM Fasteners supplies precision PEEK flange nuts where metal fasteners are unsuitable.

Advantages

• Electrically insulating
• Chemical resistant
• Lightweight
• Non-magnetic
• Radiation resistant

Typical Uses

• Semiconductor equipment
• Chemical plants
• Medical systems
• Electrical assemblies

12. Dimensional Logic and Engineering Geometry

The geometry of flange nuts is designed according to standardized proportional relationships ensuring predictable load transfer and compatibility.

12.1 Critical Dimensions

Symbol	Description
d	Thread diameter
P	Thread pitch
m	Nut height
s	Width across flats
dc	Flange diameter
k	Flange thickness
r	Fillet radius

12.2 Dimensional Specification Table — Metric Flange Nuts

(Typical ISO/DIN reference dimensions)

Size	Pitch (mm)	Height m (mm)	Across Flats s (mm)	Flange Dia dc (mm)	Weight/pc (g)
M5	0.8	5	8	11.8	1.1
M6	1.0	6	10	14.2	2.3
M8	1.25	8	13	17.9	5.0
M10	1.5	10	15	21.8	9.5
M12	1.75	12	18	26.0	16
M16	2.0	16	24	34.5	36
M20	2.5	20	30	43	75
M24	3.0	24	36	51	145

(Weights aligned with SM Fasteners manufacturing data ranges)

12.3 Weight Chart — Procurement Reference

Size	Weight / Piece (kg)	Weight / 100 pcs (kg)
M6	0.0023	0.23
M8	0.005	0.50
M10	0.0095	0.95
M12	0.016	1.60
M16	0.036	3.60
M20	0.075	7.50
M24	0.145	14.50

Used for:

• Freight estimation
• EPC BOQ calculations
• Export packing planning

13. Thread Geometry Engineering

13.1 Thread Form Standards

Standard	Included Angle	Application
ISO Metric	60°	Global industrial
UNC	60°	Structural
UNF	60°	Fatigue resistance
BSW	55°	Legacy systems
BSF	55°	Maintenance projects

13.2 Thread Tolerance Classes

System	External Thread	Internal Thread
ISO Metric	6g	6H
UNC/UNF	2A	2B
Precision Fit	3A	3B

Proper tolerance prevents:

• Galling
• Misalignment
• Preload scatter

14. Applicable International Standards

Flange nuts must comply with internationally recognized dimensional and mechanical standards.

14.1 ISO Standards

Standard	Scope
ISO 4161	Hexagon flange nuts
ISO 4032	Hex nuts reference
ISO 898-2	Mechanical properties
ISO 965	Thread tolerances
ISO 3506	Stainless steel fasteners

14.2 DIN Standards

Standard	Description
DIN 6923	Hex flange nuts
DIN 267	Mechanical requirements
DIN EN 10204	Inspection certification

14.3 ASTM Standards

Standard	Application
ASTM A563	Carbon steel nuts
ASTM A194	Pressure vessel nuts
ASTM F594	Stainless steel nuts
ASTM B637	Nickel alloy fasteners

14.4 British Standards (BS)

Standard	Description
BS 4190	Hexagon nuts
BS 3692	Metric precision
BS EN ISO equivalents	International harmonization

15. Property Class System (Mechanical Strength Classification)

Metric flange nuts follow ISO property class designation.

Property Class	Compatible Bolt	Typical Application
5	5.8 bolts	Light structures
8	8.8 bolts	General engineering
10	10.9 bolts	Heavy machinery
12	12.9 bolts	High-load systems

Rule:

Nut property class ≥ bolt property class

16. Interchangeability & Global Procurement Logic

EPC procurement requires interchangeability across standards.

Critical Factors

• Thread compatibility
• Height equivalence
• Bearing diameter
• Proof load compliance

SM Fasteners supports:

• Metric ↔ UNC conversions
• Project-specific drawings
• Custom flange geometry manufacturing

17. Engineering Geometry Impact on Performance

Larger Flange Diameter Results In:

✔ Reduced bearing pressure
✔ Improved fatigue resistance
✔ Higher vibration tolerance
✔ Better coating life

Flange Thickness Influence

Thickness	Effect
Thin	Lightweight assemblies
Medium	Standard industrial
Thick	Structural loading

18. Serration Geometry Considerations

Serration angle and depth determine locking performance.

Parameters include:

• Tooth pitch
• Penetration depth
• Surface hardness compatibility

Used where repeated loosening risk exists.

19. Design Compatibility with Automated Assembly

Flange nuts are optimized for:

• Robotic tightening
• High-speed assembly lines
• Torque-controlled tools
• Angle-controlled tightening systems

Integrated flange improves positional stability during installation.

20. Engineering Selection Matrix — Type vs Application

Application	Recommended Type
Structural steel	Plain flange
Automotive	Serrated flange
Offshore	Stainless flange
High temperature	Nickel alloy
Electrical isolation	PEEK flange nut
Chemical processing	Duplex/Super Duplex

21. Material Grades and Selection Criteria

Material selection is the most critical engineering decision affecting flange nut performance. The selected material must simultaneously satisfy:

• Mechanical strength requirements
• Corrosion resistance
• Temperature capability
• Hydrogen service compatibility
• Fabrication and coating suitability
• Lifecycle cost expectations

SM Fasteners manufactures flange nuts using certified raw materials supported by EN 10204 3.1 traceable Mill Test Certificates under ISO 9001 quality management systems.

21.1 Carbon Steel Flange Nuts

Carbon steel remains the most widely used material for structural and industrial assemblies.

Grade	Standard	Typical Property Class	Application
Low Carbon Steel	ISO / ASTM A563 A	Class 5	Light duty
Medium Carbon Steel	ASTM A563 DH	Class 8	Structural
Alloyed Carbon Steel	ASTM A563 DH3	Class 10	Heavy equipment
High Strength Alloy Steel	ISO 898-2	Class 12	High preload joints

Advantages

• High strength-to-cost ratio
• Excellent machinability
• Suitable for coating systems

21.2 Stainless Steel Flange Nuts

Used where corrosion resistance dominates design requirements.

Grade	ISO Class	Corrosion Resistance	Typical Industry
SS 304 (A2-70)	A2	Atmospheric	Construction
SS 316 (A4-80)	A4	Marine/chemical	Offshore
316L	A4	Chloride exposure	Petrochemical
321	Stabilized	High temperature	Exhaust systems

21.3 Duplex & Super Duplex Stainless Steel

Engineered for aggressive offshore and sour environments.

Material	Yield Strength	Corrosion Resistance	Service
Duplex 2205	High	Excellent	Offshore structures
Super Duplex 2507	Very High	Extreme	Seawater systems

Benefits:

• High resistance to pitting corrosion
• Excellent SCC resistance
• Lower weight vs carbon steel for equal strength

21.4 Nickel Alloy Flange Nuts

SM Fasteners supplies high-performance alloys for extreme environments.

Alloy	Temperature Limit	Key Resistance
Inconel 625	~1000°C	Oxidation
Inconel 718	~700°C	Creep strength
Hastelloy C276	Severe acids	Chemical resistance
Monel 400	Marine	Saltwater corrosion
Incoloy 825	Acidic service	SCC resistance
SMO 254	Chloride environments	Pitting resistance

21.5 PEEK Flange Nuts — Advanced Polymer Engineering

PEEK fasteners supplied by SM Fasteners address applications where metals fail.

Mechanical Characteristics

• Continuous service temperature: 250°C
• High dielectric strength
• Chemical inertness
• Radiation resistance

Applications

• Semiconductor processing
• Medical equipment
• Aerospace electronics
• Chemical dosing systems

22. Material Selection Criteria Matrix

Parameter	Carbon Steel	Stainless	Duplex	Nickel Alloy	PEEK
Strength	High	Medium	High	High	Low-Medium
Corrosion Resistance	Low	Good	Excellent	Extreme	Excellent
Temperature Range	300°C	600°C	300°C	1000°C	250°C
Cost	Low	Medium	High	Very High	High
Weight	Medium	Medium	Medium	High	Very Low
Typical Use	Structural	Marine	Offshore	Chemical/LNG	Electrical

23. Mechanical Properties by Property Class

Property Class	Proof Stress (MPa)	Tensile Strength (MPa)	Hardness (HV)
Class 5	500	500–600	150–200
Class 8	800	800–900	220–300
Class 10	1000	1000–1100	300–360
Class 12	1200	1200–1300	350–420

24. Heat Treatment Processes

Heat treatment determines final mechanical performance and reliability.

SM Fasteners controls heat treatment through validated furnace cycles and traceable batch processing.

24.1 Typical Heat Treatment Route

1. Forging
2. Normalizing
3. Quenching
4. Tempering
5. Stress relieving

24.2 Quenching & Tempering

Purpose:

• Increase tensile strength
• Improve fatigue resistance
• Stabilize microstructure

Typical Tempering Range:

Property Class	Tempering Temperature
Class 8	450–550°C
Class 10	400–500°C
Class 12	350–450°C

24.3 Case Hardening (Special Applications)

Applied when wear resistance is required without compromising core toughness.

Processes include:

• Carburizing
• Carbonitriding

24.4 Solution Annealing (Stainless & Nickel Alloys)

Ensures:

• Corrosion resistance restoration
• Carbide dissolution
• Uniform grain structure

24.5 Hydrogen Embrittlement Prevention

Mandatory for high-strength coated fasteners.

Process control:

• Controlled plating chemistry
• Post-plating baking (200°C / 4 hrs minimum)
• Hardness monitoring

24.6 Sour Service Requirements

For H₂S environments:

• Compliance with NACE MR0175 / ISO 15156
• Hardness limits typically ≤ 22 HRC

25. End-to-End Manufacturing Workflow

SM Fasteners follows a vertically controlled manufacturing sequence ensuring repeatable quality.

25.1 Raw Material Verification

Incoming inspection includes:

• Chemical composition verification
• PMI testing
• Mill Test Certificate review
• Heat number traceability

25.2 Forging Process

Hot forging is preferred for flange nuts.

Benefits

• Grain flow alignment
• Increased fatigue strength
• Reduced internal defects

Steps:

1. Bar cutting
2. Induction heating
3. Closed-die forging
4. Trimming

25.3 Machining Operations

Performed where precision tolerances are required:

• CNC turning
• Facing
• Flange profiling
• Serration machining

25.4 Thread Production

Thread Rolling (Preferred)

Advantages:

• Work hardening
• Improved fatigue life
• Smooth surface finish

Thread Cutting

Used for:

• Large diameters
• Exotic alloys
• Low production quantities

25.5 Deburring & Surface Preparation

Processes include:

• Vibratory finishing
• Shot blasting
• Cleaning & degreasing

Ensures coating adhesion and accurate torque behavior.

26. Surface Finishing & Coating Technologies

Surface engineering significantly influences corrosion resistance and tightening performance.

26.1 Coating Selection Philosophy

Coating must balance:

• Corrosion resistance
• Friction control
• Hydrogen embrittlement risk
• Environmental compliance

26.2 Surface Finish Comparison Table

Coating	Corrosion Resistance	Friction Stability	Temp Limit	Typical Use
Plain Oil	Low	Stable	150°C	Indoor
Zinc Plated	Medium	Good	120°C	General industry
Hot Dip Galvanized	High	Variable	450°C	Structural
Mechanical Galvanized	High	Uniform	300°C	Infrastructure
Zinc Flake	Very High	Excellent	300°C	Automotive
PTFE / Xylan	Excellent	Low friction	260°C	Chemical plants
Nickel Plating	High	Stable	400°C	Offshore
Passivation	Stainless protection	Stable	600°C	Marine

26.3 Corrosion Resistance vs Environment

Environment	Recommended Material/Coating
Marine atmosphere	SS316 / Duplex
Offshore splash zone	Super Duplex
Chemical acids	Hastelloy
LNG cryogenic	Nickel alloys
H₂S service	NACE compliant alloys
Electrical isolation	PEEK
Outdoor structural	HDG carbon steel

26.4 Coating Thickness Control

Typical ranges:

Coating	Thickness
Zinc plating	8–12 µm
HDG	45–85 µm
Zinc flake	10–20 µm
PTFE	20–40 µm

Thickness directly affects thread tolerance and assembly torque.

26.5 Galling Prevention

Particularly important for stainless steel flange nuts.

29. Incoming Material Inspection

Every manufacturing batch begins with validated raw material control.

Verification Activities

Inspection	Method	Objective
Chemical composition	Spectrometer / PMI	Alloy verification
Mill Test Certificate review	EN 10204	Traceability
Visual inspection	ISO 3269	Surface condition
Hardness check	Rockwell / Vickers	Heat condition validation
Ultrasonic inspection	Optional	Internal defect detection

Heat numbers remain traceable through forging, machining, coating, and packaging stages.

30. In-Process Dimensional Inspection

Critical dimensions controlled during production:

Inspection Tools

• GO / NO-GO gauges (ISO 1502)
• Optical comparators
• Digital calipers
• Coordinate Measuring Machines (CMM)

31. Mechanical Testing Requirements

Flange nuts must satisfy mechanical properties defined by international standards.

Mandatory Tests

Test	Standard	Purpose
Proof load test	ISO 898-2	Load capacity
Hardness test	ISO 6508	Heat treatment validation
Tensile compatibility	ISO 898	Bolt matching
Wedge loading test	ASTM F606	Thread integrity
Prevailing torque test	ISO 2320	Locking performance

32. Non-Destructive Testing (NDT)

Applied for critical applications including oil & gas, offshore, and pressure equipment.

Method	Detects
Magnetic Particle Testing	Surface cracks
Dye Penetrant Inspection	Micro defects
Ultrasonic Testing	Internal flaws
Eddy Current Testing	Material discontinuities

33. Positive Material Identification (PMI)

Essential for alloy and sour-service fasteners.

PMI ensures:

• Correct alloy supplied
• Prevention of material mix-up
• Compliance with project specifications

Used extensively for:

• Duplex
• Super Duplex
• Nickel alloys
• NACE service components

34. Certification & Documentation

SM Fasteners supplies complete documentation packages required for global EPC procurement.

Typical Documentation Set

Document	Purpose
EN 10204 3.1 MTC	Material traceability
3.2 Certification	Third-party validation
Heat Treatment Report	Mechanical assurance
Coating Certificate	Corrosion verification
Inspection Report	Dimensional compliance
Certificate of Conformity	Specification compliance
Packing List	Logistics control

35. Mechanical Properties Table (Grade-Wise)

Property Class	Proof Load (MPa)	Yield Equivalent (MPa)	Tensile Strength (MPa)
5	500	300	500–600
8	800	640	800–900
10	1000	900	1000–1100
12	1200	1080	1200–1300

36. Proof Load Capacity by Size (Typical Values)

Size	Proof Load Class 8 (kN)	Proof Load Class 10 (kN)
M8	18	23
M10	29	37
M12	42	54
M16	78	98
M20	122	153
M24	176	220

37. Tightening Torque Chart

(Typical engineering reference — lubricated condition)

Size	Class 8 Torque (Nm)	Class 10 Torque (Nm)
M6	10	13
M8	25	32
M10	50	63
M12	85	110
M16	210	270
M20	410	520
M24	710	900

Torque values depend on lubrication and coating friction coefficient.

38. Preload Calculation

Engineering Formula

$$F = \frac{T}{K \times D}$$

Where:

• F = Preload force
• T = Torque
• K = Nut factor
• D = Nominal diameter

Worked Example — M16 Flange Nut

Given:

• Torque = 210 Nm
• Nut factor = 0.15
• Diameter = 16 mm (0.016 m)

$$F = \frac{210}{0.15 \times 0.016}$$

$$F = 87,500 \text{ N}$$

Result:

≈ 87.5 kN clamping force

39. Thread Standards & Tolerances Table

Thread Type	Standard	Tolerance
Metric Coarse	ISO 261	6H
Metric Fine	ISO 965	6H
UNC	ASME B1.1	2B
UNF	ASME B1.1	2B
BSW	BS 84	Medium
BSF	BS 84	Close

40. Surface Finish Performance Comparison

Finish	Salt Spray Resistance	Friction Control	Maintenance Need
Plain	Low	Stable	High
Zinc Plated	72–120 hrs	Good	Medium
HDG	500+ hrs	Variable	Low
Zinc Flake	1000+ hrs	Excellent	Low
PTFE	Excellent	Very Low	Very Low
Passivated SS	Excellent	Stable	Very Low

41. Corrosion Resistance vs Environment

Environment	Recommended Material
Atmospheric exposure	Zinc plated carbon steel
Coastal / Marine	SS316 / Duplex
Offshore platform	Super Duplex
Acidic chemical plant	Hastelloy
LNG cryogenic	Inconel / Nickel alloys
H₂S sour service	NACE compliant alloy
Electrical systems	PEEK flange nuts

42. Weight Chart — Logistics & Procurement Reference

(Aligned with SM Fasteners manufacturing data)

Size	Weight/pc (kg)	Weight/100 pcs (kg)
M6	0.0023	0.23
M8	0.005	0.50
M10	0.0095	0.95
M12	0.016	1.60
M16	0.036	3.60
M20	0.075	7.50
M24	0.145	14.50

Used for:

• BOQ estimation
• Freight planning
• Container loading calculations

43. Industry Applications

Construction & Structural Steel

• Steel frame connections
• Bridge assemblies
• Pre-engineered buildings

Flange design prevents local crushing of coated structural members.

Oil & Gas (Upstream / Midstream / Downstream)

Applications include:

• Pipe supports
• Compressor skids
• Valve assemblies
• Pressure equipment supports

Materials supplied in accordance with NACE MR0175 / ISO 15156.

Power Generation

• Turbine enclosures
• Boiler systems
• Solar mounting structures
• Wind tower assemblies

Petrochemical & Chemical Processing

Requires:

• Chemical resistance
• Stable preload under temperature cycling

Nickel alloys and PTFE-coated flange nuts commonly used.

LNG & Offshore

Critical requirements:

• Anti-galling performance
• Corrosion resistance
• Cryogenic stability

Duplex and Inconel flange nuts widely specified.

Automotive & Heavy Equipment

• Suspension systems
• Engine mounts
• Axle assemblies

Serrated flange nuts enable high-speed automated assembly.

Railways & Infrastructure

• Track fastening systems
• Signaling structures
• Rolling stock equipment

Shipbuilding & Marine

• Deck equipment
• Structural panels
• Marine propulsion systems

PEEK Fastener Applications

Used where:

• Metal corrosion unacceptable
• Electrical isolation required
• Magnetic interference must be avoided

44. Failure Analysis & Reliability Engineering

Common field failures addressed through engineering control:

Failure Mode	Cause	Prevention
Self-loosening	Insufficient preload	Correct torque
Fatigue cracking	Cyclic loading	Proper grade selection
Galling	Stainless friction	Lubrication/coating
Hydrogen embrittlement	Improper plating	Post-bake treatment
Stress corrosion cracking	Chlorides/H₂S	Correct alloy

45. Industrial Packaging & Export Preparation

SM Fasteners prepares flange nuts for global shipment.

Packaging Methods

• VCI corrosion protection
• Moisture barrier packaging
• Thread protection systems
• Batch identification labeling

Export Crating

• ISPM-15 compliant wooden crates
• Palletized shipment
• Vacuum sealing (offshore projects)
• Container load optimization

46. Global Export Capability

SM Fasteners supports supply to:

• EPC contractors
• OEM manufacturers
• International distributors
• Oil & gas operators
• Infrastructure megaprojects

Supported Regions:

• Middle East
• Europe
• North America
• Southeast Asia
• Africa

47. SM FASTENERS — ENGINEERING POSITIONING

SM Fasteners demonstrates global supply readiness through:

• ISO 9001 certified manufacturing systems
• MSME registered industrial manufacturing
• UKAF accredited quality framework
• Advanced metallurgy capability
• Custom fastener engineering
• Capability in exotic alloys and PEEK materials
• Full inspection & certification packages

48. Engineering Selection Checklist

Before specifying a flange nut, engineers must confirm:

✔ Bolt property class compatibility
✔ Operating environment
✔ Required preload level
✔ Corrosion exposure
✔ Coating system
✔ Inspection requirement
✔ Certification level
✔ Installation method