Eye Bolt

1. Industry Context

Eye bolts are load-bearing lifting and securing fasteners designed to create a controlled attachment point for lifting equipment, rigging assemblies, tension members, and restraint systems. Unlike conventional threaded fasteners whose primary role is clamping, eye bolts function as structural load interface components transmitting tensile, angular, and dynamic loads.

Across industrial sectors, eye bolts are classified as critical safety components, often governed by lifting regulations, inspection codes, and traceability requirements.

Primary Industrial Usage

Industry	Functional Role
Structural Steel	Temporary lifting points during erection
Oil & Gas	Equipment handling, valve lifting, skid installation
Power Generation	Turbine casing handling, maintenance lifting
Petrochemical	Reactor assembly lifting points
LNG & Offshore	Rigging under marine exposure
Heavy Engineering	Machinery transport & alignment
Shipbuilding	Deck lifting and mooring attachment
Railways & Infrastructure	Precast handling and maintenance lifting

SM Fasteners manufactures eye bolts suitable for static lifting, dynamic rigging, and permanent anchoring applications, supported by ISO 9001 certified production systems and globally compliant material traceability.

2. Technical Definition

An Eye Bolt is a threaded fastener featuring:

• A circular or forged eye forming a load connection point
• A threaded shank for anchoring into structures or equipment
• Load transmission primarily through axial tension

Functional Components

1. Eye Ring — Load interface
2. Shoulder (where applicable) — Supports angular loads
3. Shank — Transfers force into parent material
4. Thread — Provides mechanical engagement
5. Bearing Face — Distributes compressive load

3. Functional Role in Engineering Assemblies

Eye bolts perform three critical engineering functions:

3.1 Lifting Interface

• Connect hoists, chains, slings
• Transfer lifting loads safely

3.2 Restraint or Tie-Down Point

• Used in transport securing
• Structural bracing systems

3.3 Permanent Load Anchor

• Suspension systems
• Pipe support assemblies
• Cable routing supports

4. Load Mechanics & Force Behavior

Unlike standard bolts designed for preload and clamping, eye bolts experience direct load transfer.

4.1 Primary Load Types

Load Type	Description	Design Impact
Axial Tension	Vertical lifting	Maximum capacity
Angular Load	Off-axis lifting	Capacity reduction
Shear Load	Lateral force	Not recommended
Dynamic Load	Shock/vibration	Fatigue consideration
Cyclic Load	Repeated lifting	Requires fatigue resistance

4.2 Force Flow Path

Load transmission sequence:

Rigging → Eye → Transition Radius → Shank → Threads → Parent Material

Failure frequently occurs at:

• Eye-to-shank transition radius
• First engaged thread
• Improper angular loading

4.3 Angular Loading Reduction

Standard eye bolts are rated for vertical loading only unless shoulder design exists.

Lift Angle	Typical Capacity
0° (Vertical)	100%
30°	~65%
45°	~30–40%
90°	Not permitted

Shoulder eye bolts allow controlled angular loading when seated firmly against the mounting surface.

5. Joint Design Principles

Correct joint design governs safe lifting performance.

5.1 Thread Engagement Requirement

Minimum engagement:

Thread Engagement ≥ 1 × Nominal Diameter (steel)
Thread Engagement ≥ 1.5 × Diameter (aluminum)

5.2 Seating Requirements

• Shoulder must fully contact mounting surface
• No washers unless engineered
• Surface must be flat and perpendicular

5.3 Load Alignment Rule

Golden Engineering Rule:

Load centerline must pass through eye center.

Misalignment introduces bending stress → premature failure.

6. Preload & Installation Mechanics

Eye bolts are not torque-preloaded fasteners but must be installed with sufficient seating torque.

Typical seating torque:

T = K × D × F

Where:

• T = Torque
• K = Nut factor (~0.18–0.22)
• D = Nominal diameter
• F = Desired preload

Worked Example — Preload Calculation

Given:

• M20 Eye Bolt
• Desired preload = 45 kN
• K = 0.20

T = 0.20 × 0.020 × 45,000
T = 180 Nm

7. Mechanical Behavior

7.1 Stress Distribution

Critical stress concentration exists at:

• Eye curvature
• Thread root
• Shoulder transition

Forged eye bolts provide superior grain flow alignment compared to machined designs.

7.2 Torque–Tension Relationship

Approximate preload distribution:

Energy Usage	Percentage
Overcome thread friction	40%
Under-head friction	50%
Useful preload	~10%

Hence lubrication significantly affects performance.

8. Friction & Nut Factor Influence

Condition	Nut Factor (K)
Dry steel	0.22
Light oil	0.18
MoS₂ coated	0.14
PTFE coated	0.10–0.12

SM Fasteners provides coated eye bolts enabling predictable preload performance.

9. Failure Mechanisms

Eye bolts fail primarily due to improper application rather than material defects.

9.1 Fatigue Failure

• Cyclic lifting
• Shock loading
• Poor alignment

9.2 Shear Failure

Occurs when lateral loading replaces axial loading.

9.3 Thread Strip-Out

Caused by insufficient engagement length.

9.4 Hydrogen Embrittlement

Risk in high-strength plated bolts (>1000 MPa).

Mitigation:

• Controlled plating
• Post-bake hydrogen relief

9.5 Stress Corrosion Cracking

Occurs in:

• Chloride environments
• H₂S service
• High temperature exposure

SM Fasteners supports NACE MR0175 compliant material supply for sour environments.

10. Safety Factors

Typical design safety factors:

Application	Safety Factor
Static lift	5:1
Personnel lifting	10:1
Dynamic lifting	≥8:1
Offshore lifting	Project specified

11. Engineering Selection Criteria

Engineers must evaluate:

• Load magnitude
• Load direction
• Frequency of lifting
• Environmental exposure
• Installation material
• Inspection accessibility
• Regulatory compliance

12. Functional Advantages of Forged Eye Bolts

Compared to fabricated or bent versions:

Parameter	Forged Eye Bolt
Grain flow	Continuous
Fatigue life	High
Shock resistance	Superior
Certification	Easier compliance
Reliability	EPC-approved

SM Fasteners manufactures forged eye bolts under controlled forging and inspection workflows ensuring repeatable mechanical performance.

13. Eye Bolt Product Types & Engineering Variants

Eye bolts are engineered according to load direction, installation method, and service environment. Proper variant selection directly influences lifting safety, fatigue life, and compliance with international lifting standards.

SM Fasteners manufactures a complete range of standard and custom-engineered eye bolts, including exotic alloy and high-temperature materials aligned with global EPC specifications.

13.1 Shoulder Eye Bolt (Machinery Eye Bolt)

Primary industrial lifting configuration

Characteristics

• Forged shoulder below eye
• Supports angular lifting loads
• High fatigue resistance
• Controlled seating against surface

Typical Use

• Heavy equipment lifting
• Motor frames
• Pump assemblies
• Structural modules

Feature	Engineering Benefit
Shoulder contact	Prevents bending stress
Forged grain flow	Higher load capacity
Controlled alignment	Safer angular loading

13.2 Plain (Non-Shoulder) Eye Bolt

Designed strictly for vertical lifting only.

Limitations

• Cannot sustain side loading
• Susceptible to shank bending
• Used mainly for straight tensile applications

Applications

• Cable routing
• Static tie-down points
• Light assemblies

13.3 Dynamo Eye Bolt (DIN 580 Type)

One of the most globally standardized lifting eye designs.

Features:

• Fully forged body
• Wide bearing surface
• Defined Working Load Limit (WLL)
• Marked load rating

Commonly referenced standard:

DIN 580 – Lifting Eye Bolt

13.4 Eyebolt with Collared Shoulder

Used where:

• Rotational alignment required
• Repetitive lifting occurs

Advantages:

• Reduced localized stress
• Improved seating performance

13.5 Long Shank Eye Bolt

Used for:

• Thick wall installation
• Deep tapped holes
• Structural embedment

Industries:

• Bridge construction
• Offshore jackets
• Concrete anchoring

13.6 Swivel Lifting eye bolt

Advanced engineered lifting component.

Capabilities:

• 360° rotation
• Load alignment self-correction
• Reduced bending stress

Preferred in:

• Offshore lifting
• Heavy fabrication yards
• Turbine installation

13.7 Continuous Ring Eye Bolt

Used for permanent anchoring and rigging systems.

Applications:

• Marine rigging
• Fall protection
• Structural suspension

13.8 PEEK Eye Bolts (Specialized Applications)

SM Fasteners supplies PEEK polymer eye bolts for demanding environments where metallic fasteners are unsuitable.

Property	Engineering Advantage
Non-metallic	No galvanic corrosion
Chemical resistance	Aggressive media
Electrical insulation	HV applications
Lightweight	Aerospace assemblies
Temperature resistance	up to ~260°C

Industries:

• Semiconductor
• Chemical plants
• Medical equipment
• Electronics manufacturing

14. Dimensional Logic & Geometry Design

Eye bolt geometry is not arbitrary — dimensions are derived from stress distribution and lifting mechanics.

Critical Design Parameters

Parameter	Function
Eye internal diameter	Sling compatibility
Eye thickness	Shear strength
Transition radius	Fatigue life
Shoulder diameter	Load distribution
Thread length	Engagement strength
Shank diameter	Tensile capacity

14.1 Eye Geometry Principles

Engineering design ensures:

• Stress flow continuity
• Minimum stress concentration
• Adequate bending resistance
• Compliance with lifting regulations

Forged eye bolts maintain continuous grain orientation, significantly improving fatigue performance compared with machined rings.

15. Standard Dimensional Specification Table (DIN 580 Reference)

Metric Eye Bolt Dimensions

Thread Size	Pitch (mm)	Eye ID (mm)	Eye OD (mm)	Shoulder Dia (mm)	Thread Length (mm)	Overall Length (mm)
M6	1.0	20	36	20	13	45
M8	1.25	20	36	20	13	45
M10	1.5	25	45	25	17	53
M12	1.75	30	54	30	20	65
M16	2.0	35	63	35	24	72
M20	2.5	40	72	40	30	90
M24	3.0	50	90	50	36	109
M30	3.5	65	108	65	45	132
M36	4.0	75	126	75	54	150
M42	4.5	85	144	85	63	170
M48	5.0	95	166	95	72	190

(Values aligned with standard DIN lifting geometry; SM Fasteners customizes dimensions per project requirement.)

16. Working Load Limit (WLL) & Proof Load Table

Typical DIN 580 Load Capacity

Size	WLL Vertical (t)	Proof Load (kN)	Minimum Breaking Load (kN)
M8	0.14	4	8
M10	0.23	6.5	13
M12	0.34	9.5	19
M16	0.70	19	38
M20	1.20	33	66
M24	1.80	50	100
M30	3.20	90	180
M36	4.60	130	260
M42	6.30	180	360
M48	8.60	240	480

17. International Standards & Compliance

Eye bolts used in global EPC projects must comply with recognized standards.

17.1 Primary Standards

Standard	Description
DIN 580	Lifting Eye Bolts
DIN 582	Lifting Eye Nuts
ISO 3266	Mechanical properties
ISO 898-1	Carbon steel property classes
ASTM A489	Forged steel lifting eye bolts
ASTM A193	High-temp alloy bolts
ASTM F593	Stainless steel fasteners
BS 4278	Lifting eye specifications
ASME B30.26	Rigging hardware safety

SM Fasteners manufactures eye bolts aligned with these standards, supported by ISO 9001 certified quality systems and UKAF accreditation.

18. Property Class System (Metric)

Property Class	Yield Strength (MPa)	Tensile Strength (MPa)
4.6	240	400
5.6	300	500
8.8	640	800
10.9	940	1040
12.9	1100	1220

Lifting eye bolts typically use forged medium carbon steels equivalent to Class 8.8 or specialized lifting grades.

19. Thread Systems & Interchangeability

Eye bolts are manufactured across global thread systems.

Thread Standards & Tolerances

System	Standard	Typical Tolerance
Metric	ISO 261 / ISO 965	6g external
UNC	ASME B1.1	2A
UNF	ASME B1.1	2A
BSW	BS 84	Medium fit
BSF	BS 84	Fine pitch
NPT (special)	ANSI B1.20	Pressure applications

SM Fasteners supplies project-specific thread configurations ensuring interchangeability across international assemblies.

20. Thread Engagement Design Logic

Proper engagement prevents:

• Thread stripping
• Pull-out failure
• Localized yielding

Material	Minimum Engagement
Steel	1 × Diameter
Cast Iron	1.5 × Diameter
Aluminum	2 × Diameter
PEEK	2.5 × Diameter

21. Eye Orientation & Installation Geometry

Correct orientation ensures safe lifting.

Engineering requirements:

• Shoulder fully seated
• Eye aligned with lift direction
• No spacer stacking
• No partial thread engagement

Improper seating introduces bending moment exceeding design limits.

22. Weight Chart — SM Fasteners Reference

(Aligned with SM Fasteners production data for procurement estimation)

Size	Weight / Piece (kg)	Weight / 100 pcs (kg)
M8	0.05	5
M10	0.09	9
M12	0.16	16
M16	0.31	31
M20	0.56	56
M24	1.02	102
M30	1.85	185
M36	3.25	325
M42	5.20	520
M48	7.80	780

Weights support:

• EPC logistics planning
• Crane load calculations
• Export packing optimization

23. Engineering Selection Summary

Correct eye bolt selection requires evaluation of:

• Load direction
• Required WLL
• Material compatibility
• Environmental exposure
• Thread standard
• Inspection requirements
• Certification level

SM Fasteners provides custom engineering support, including special dimensions, exotic alloys, and PEEK lifting solutions tailored for global infrastructure and energy projects.

24. Material Engineering Philosophy for Eye Bolts

Eye bolts are categorized as safety-critical lifting fasteners, therefore material selection is governed not only by strength but also by:

• Fracture toughness
• Fatigue resistance
• Corrosion performance
• Temperature capability
• Hydrogen resistance
• Traceability compliance

SM Fasteners manufactures eye bolts using fully traceable raw materials, supported by EN 10204 3.1 certification, ensuring suitability for EPC, offshore, petrochemical, and infrastructure projects.

25. Industrial Material Grades Used for Eye Bolts

25.1 Carbon Steel Grades

Used for general lifting and structural applications.

Typical standards:

• ASTM A489 — Forged lifting eye bolts
• ASTM A36 / A105
• EN 10269
• ISO 898-1 Property Classes

Grade	Typical Property Class	Application
C15 / C20	4.6	Light duty lifting
C35 / C45	8.8 equivalent	Machinery lifting
EN8	8.8	Structural assemblies
EN19 / 4140	10.9	Heavy equipment

Advantages:

• High load capacity
• Good machinability
• Cost efficient

25.2 Alloy Steel Grades

Selected where higher strength and fatigue resistance are required.

Material	Standard	Key Use
ASTM A193 B7	High strength lifting
4140 / 42CrMo4	Offshore equipment
ASTM A320 L7	Low temperature service
AISI 4340	Heavy dynamic loading

Benefits:

• High yield strength
• Improved fatigue life
• Shock resistance

25.3 Stainless Steel Grades

Required where corrosion resistance dominates design selection.

Grade	Standard	Typical Environment
SS304	ASTM F593	Indoor industrial
SS316	ASTM F593	Marine exposure
SS316L	Low carbon	Chemical plants
SS321	Stabilized	High temperature
SS904L	Severe corrosion	Acidic environments

25.4 Duplex & Super Duplex Stainless Steel

Used in aggressive offshore and chloride environments.

Grade	PREN Value	Application
Duplex 2205	~35	Offshore structures
Super Duplex 2507	>40	Seawater service
Zeron 100	Extreme corrosion	Subsea equipment

25.5 Nickel & High Performance Alloys

SM Fasteners supplies eye bolts in advanced alloys for extreme environments.

Alloy	Service Capability
Inconel 625	High temperature + corrosion
Inconel 718	Aerospace lifting
Incoloy 825	Acid resistance
Hastelloy C276	Chemical processing
Monel 400	Marine corrosion
SMO 254	Chloride environments

25.6 PEEK Eye Bolts (Advanced Polymer Engineering)

For specialized industries.

Property	Value
Continuous temperature	~260°C
Chemical resistance	Excellent
Electrical insulation	High
Weight reduction	~70% vs steel

Applications:

• Semiconductor equipment
• MRI systems
• Electronics production
• Chemical handling systems

26. Material Comparison Table

Material	UTS (MPa)	Yield (MPa)	Corrosion Resistance	Relative Cost	Typical Application
Carbon Steel	400–800	240–640	Low	Low	Construction
Alloy Steel	900–1200	700–1000	Moderate	Medium	Heavy lifting
SS304	~520	~210	Good	Medium	General industry
SS316	~580	~290	Very good	Medium-High	Marine
Duplex 2205	~800	~550	Excellent	High	Offshore
Inconel 625	>900	>450	Exceptional	Very High	Chemical/LNG
PEEK	~100	~90	Excellent	High	Electronics

27. Mechanical Properties Table (Grade-Wise)

Property Class	Yield Strength (MPa)	Tensile Strength (MPa)	Hardness Range (HB)
4.6	240	400	120–170
5.6	300	500	150–200
8.8	640	800	250–320
10.9	940	1040	320–380
12.9	1100	1220	380–435

Lifting eye bolts typically utilize controlled hardness ranges to avoid brittle fracture.

28. Corrosion Resistance vs Environment

Environment	Carbon Steel	SS316	Duplex	Inconel	PEEK
Indoor Industrial	✓	✓	✓	✓	✓
Marine Atmosphere	✗	✓	✓✓	✓✓	✓
Seawater Immersion	✗	Limited	✓✓	✓✓	✓
Acidic Media	✗	Moderate	✓	✓✓	✓✓
H₂S Service	Limited	✓	✓✓	✓✓	✓
Chlorides	Poor	Good	Excellent	Excellent	Excellent

✓✓ = preferred material

SM Fasteners supplies materials compliant with NACE MR0175 / ISO 15156 for sour service projects.

29. Heat Treatment Processes

Heat treatment governs mechanical performance and safety reliability.

29.1 Normalizing

Purpose:

• Grain refinement
• Uniform microstructure

Applied to:

• Forged carbon steels

29.2 Quenching & Tempering (Q&T)

Most critical treatment for lifting eye bolts.

Process:

1. Austenitizing
2. Rapid quench
3. Controlled tempering

Benefits:

• High strength
• Improved toughness
• Controlled hardness

29.3 Solution Annealing (Stainless Steel)

Used for:

• SS304
• SS316
• Duplex alloys

Outcome:

• Restored corrosion resistance
• Removal of carbide precipitation

29.4 Stress Relieving

Applied after machining or welding.

Purpose:

• Reduce residual stresses
• Improve fatigue resistance

29.5 Hydrogen Relief Baking

Mandatory for plated high-strength bolts.

Typical requirement:

190–230°C for 2–24 hours

Prevents hydrogen embrittlement failures.

30. Hardness Limits for Critical Service

Service Condition	Maximum Hardness
General lifting	35 HRC
Offshore	32 HRC
NACE Sour Service	22 HRC

SM Fasteners strictly controls hardness to prevent sulfide stress cracking.

31. End-to-End Manufacturing Workflow (SM Fasteners)

Step 1 — Raw Material Verification

• Mill Test Certificate verification
• Chemical composition testing
• PMI validation (Positive Material Identification)

Step 2 — Cutting & Billet Preparation

• Controlled sawing
• Heat number traceability maintained

Step 3 — Closed Die Forging

Preferred method for lifting eye bolts.

Advantages:

• Continuous grain flow
• Higher fatigue strength
• Structural integrity

Step 4 — Flash Trimming & Calibration

Ensures dimensional accuracy before machining.

Step 5 — CNC Machining

Operations include:

• Thread preparation
• Shoulder finishing
• Eye calibration
• Bearing surface machining

Step 6 — Thread Formation

Thread Rolling (Preferred)

Advantage	Benefit
Cold working	Increased strength
Compressive stress	Fatigue resistance
Surface finish	Improved

Thread Cutting (Special cases)

Used for:

• Large diameters
• Exotic alloys
• Custom geometry

Step 7 — Heat Treatment

Performed in calibrated furnaces compliant with ISO 9001 control systems.

Step 8 — Surface Preparation

• Shot blasting
• Pickling
• Passivation

Step 9 — Coating Application

Performed according to customer specification.

Step 10 — Final Inspection & Marking

Each eye bolt receives:

• Size marking
• Material grade
• Heat number traceability
• WLL identification (when required)

32. Surface Finishing & Coatings

Surface engineering significantly impacts service life.

Surface Finish Comparison Table

Coating	Corrosion Resistance	Temperature Limit	Hydrogen Risk	Typical Use
Black Oxide	Low	120°C	None	Indoor
Zinc Plated	Moderate	120°C	Medium	General industry
Hot Dip Galvanized	High	200°C	Low	Structural outdoor
Mechanical Galvanized	Moderate	150°C	Low	Lifting hardware
PTFE / Xylan	Very High	260°C	None	Offshore
Dacromet / Geomet	High	300°C	Low	Automotive
Passivation (SS)	Excellent	High	None	Marine
Nickel Plating	High	400°C	Medium	Chemical plants

SM Fasteners provides coating systems aligned with project corrosion specifications.

33. Surface Treatment Selection Logic

Environment	Recommended Finish
Indoor dry	Black oxide
Outdoor construction	HDG
Offshore splash zone	Duplex SS + PTFE
Chemical plant	Inconel + passivation
Electrical insulation	PEEK

34. Hydrogen Embrittlement Control

Critical for high-strength eye bolts.

SM Fasteners applies:

• Controlled electroplating
• Immediate post-bake treatment
• Hardness monitoring
• Process validation under ISO 9001

35. Traceability & Identification System

Every production batch maintains:

• Heat number marking
• Material traceability
• Inspection linkage
• Manufacturing route record

Ensures audit compliance for global EPC projects.

36. Engineering Manufacturing Advantages — SM Fasteners

• ISO 9001 certified quality management
• UKAF accredited inspection control
• MSME registered manufacturing capability
• Forging + machining integration
• Exotic alloy manufacturing capability
• PEEK fastener engineering
• Project-based custom manufacturing

37. Inspection & Quality Control Philosophy

Eye bolts are classified as critical lifting safety components. Failure can result in catastrophic equipment damage, environmental risk, or personnel injury. Therefore, inspection programs must extend beyond dimensional verification into material integrity, mechanical validation, and traceability assurance.

SM Fasteners operates under an ISO 9001 certified Quality Management System, supported by UKAF-accredited processes, ensuring every eye bolt supplied for global EPC projects meets documented compliance requirements.

38. Incoming Raw Material Inspection

All production begins with controlled material verification.

Verification Activities

Inspection	Method	Purpose
Mill Test Certificate Review	EN 10204 3.1	Chemical & mechanical compliance
Chemical Analysis	Spectrometer	Grade confirmation
PMI Testing	XRF Analyzer	Alloy verification
Ultrasonic Testing	UT	Internal defect detection
Visual Inspection	ISO 2859	Surface integrity

Traceability is maintained from raw material heat number to finished product marking.

39. In-Process Manufacturing Inspection

Inspection checkpoints are integrated into the manufacturing workflow.

Process Stage	Inspection Control
Forging	Grain flow & crack inspection
Machining	Dimensional tolerance verification
Thread Rolling	Profile gauge validation
Heat Treatment	Furnace calibration records
Coating	Thickness measurement
Marking	Traceability confirmation

40. Final Inspection & Mechanical Testing

Mandatory Tests for Eye Bolts

Test	Standard	Purpose
Proof Load Test	DIN 580 / ASTM A489	Verify structural capacity
Tensile Test	ISO 898-1	Mechanical validation
Hardness Test	ASTM E18	Heat treatment confirmation
Magnetic Particle Testing	ASTM E709	Surface crack detection
Dye Penetrant Testing	ASTM E165	Non-magnetic alloys
Dimensional Inspection	ISO 2768	Geometry verification

Proof Load Testing Principle

Each eye bolt must sustain proof load without:

• Permanent deformation
• Thread damage
• Eye distortion

Typical requirement:

Proof Load = 2 × Working Load Limit (minimum)

41. Non-Destructive Testing (NDT)

NDT ensures safety integrity for lifting hardware.

Method	Detects	Application
MPI	Surface cracks	Carbon & alloy steel
PT	Micro surface flaws	Stainless alloys
UT	Internal defects	Large forgings
Radiography	Internal discontinuities	Critical applications

SM Fasteners supports third-party inspection agencies including EPC-approved inspectors.

42. Positive Material Identification (PMI)

Mandatory for:

• Oil & Gas
• LNG
• Offshore
• Chemical processing

PMI verifies alloy chemistry ensuring prevention of material mix-ups, one of the most common industrial failure causes.

43. Documentation & Certification Package

Each export supply may include:

Document	Description
EN 10204 3.1 MTC	Material traceability
Heat Treatment Report	Furnace cycle verification
Dimensional Report	Inspection records
Proof Load Certificate	Load validation
NDT Report	Crack inspection
Coating Report	Thickness confirmation
Certificate of Conformity	Compliance declaration
Packing List	Shipment traceability

3.2 certification available upon third-party witnessing.

44. Failure Prevention Engineering

Major Failure Modes & Mitigation

Failure Mode	Root Cause	Prevention
Eye deformation	Angular lifting	Use shoulder eye bolt
Thread pull-out	Insufficient engagement	Increase embed depth
Fatigue cracking	Cyclic loading	Forged construction
Hydrogen embrittlement	Improper plating	Controlled baking
SCC	Chloride/H₂S	Material upgrade

45. Industry Applications Mapping

45.1 Construction & Structural Steel

• Steel erection lifting points
• Precast concrete handling
• Bridge segment installation

Materials:

• HDG Carbon Steel
• Alloy Steel Q&T

45.2 Oil & Gas Industry

Upstream

• Wellhead equipment lifting
• Rig assemblies

Midstream

• Pipeline skid handling

Downstream

• Refinery maintenance lifting

Preferred materials:

• ASTM A193 B7
• Duplex Stainless Steel
• Inconel Alloys

Compliance:

• NACE MR0175 / ISO 15156

45.3 Power Generation

• Turbine housing lifting
• Generator transport
• Boiler maintenance

Temperature-resistant alloys often required.

45.4 Petrochemical & Chemical Processing

Key requirements:

• Corrosion resistance
• Chemical compatibility

Materials:

• SS316L
• Hastelloy C276
• SMO 254

45.5 LNG & Offshore Platforms

Critical challenges:

• Chloride attack
• Dynamic loading
• Low temperature

Preferred materials:

• Duplex 2205
• Super Duplex 2507
• ASTM A320 L7

45.6 Automotive & Heavy Equipment

• Engine lifting eyes
• Assembly fixtures
• Production handling

45.7 Railways & Infrastructure

• Maintenance lifting points
• Equipment installation
• Signal structure handling

45.8 Shipbuilding & Marine Engineering

• Deck lifting operations
• Mooring connections
• Marine rigging systems

45.9 PEEK Fastener Applications

Where metallic lifting hardware cannot be used:

• Semiconductor fabrication tools
• Cleanroom equipment
• MRI systems
• Electrically isolated lifting points

SM Fasteners supports engineered PEEK lifting solutions customized per OEM requirements.

46. Tightening Torque Chart

(Seating torque values — lubrication significantly influences results)

Size	Grade 8.8 Dry (Nm)	Grade 8.8 Lubricated (Nm)	Grade 10.9 Lubricated (Nm)
M8	25	18	26
M10	49	35	51
M12	86	60	88
M16	210	150	220
M20	410	290	420
M24	710	510	720
M30	1420	1010	1450
M36	2450	1750	2500
M42	4000	2850	4100
M48	6100	4350	6250

Torque ensures seating only — lifting capacity is independent of torque preload.

47. Proof Load & Tensile Strength Table (By Grade)

Size	Property Class	Proof Load (kN)	Ultimate Tensile Load (kN)
M12	8.8	52	65
M16	8.8	95	118
M20	8.8	148	185
M24	8.8	214	267
M30	10.9	353	441
M36	10.9	515	644
M42	10.9	713	892

48. Thread Standards & Tolerance Reference

Thread Type	Pitch Series	Fit Class	Application
Metric Coarse	ISO 261	6g	General industry
Metric Fine	ISO 965	6g	Precision equipment
UNC	ASME B1.1	2A	US equipment
UNF	ASME B1.1	2A	High vibration
BSW	BS 84	Medium	Legacy systems
BSF	BS 84	Fine	Machinery

49. Preload Calculation — Engineering Reference

Formula

Preload (F) = T / (K × D)

Where:

• T = Applied Torque
• K = Nut factor
• D = Nominal Diameter

Worked Example

Given:

• Torque = 300 Nm
• M20 Eye Bolt
• K = 0.18

F = 300 / (0.18 × 0.02)
F = 83,333 N ≈ 83 kN preload

50. Surface Finish Performance Comparison

Coating	Corrosion Life	Offshore Use	Maintenance
Zinc Plated	Medium	Limited	Moderate
Hot Dip Galvanized	High	Good	Low
PTFE/Xylan	Very High	Excellent	Minimal
Passivated SS	Excellent	Excellent	Low
Duplex Coating	Extreme	Preferred	Very Low

51. Weight Reference Table — SM Fasteners

Size	Weight / Piece (kg)	Weight / 100 pcs (kg)
M8	0.05	5
M10	0.09	9
M12	0.16	16
M16	0.31	31
M20	0.56	56
M24	1.02	102
M30	1.85	185
M36	3.25	325
M42	5.20	520
M48	7.80	780

Supports:

• EPC logistics planning
• Export container calculation
• Crane capacity verification

52. Export Packaging & Global Supply Capability

SM Fasteners supplies eye bolts worldwide with export-ready logistics systems.

Industrial Packaging

• VCI corrosion protection
• Thread caps & protectors
• Oil wrapping (when required)
• Batch identification labels

Export Crating

• ISPM-15 heat-treated wooden crates
• Steel pallet options
• Containerized bulk packaging
• Project-wise segregation

53. Global Procurement Readiness

SM Fasteners supports EPC and OEM procurement teams through:

• Custom engineering drawings
• Special material sourcing
• Fast-track manufacturing
• Batch traceability
• Third-party inspection coordination
• Multi-standard compliance

54. Quality System Integration — SM Fasteners

SM Fasteners manufacturing and supply systems demonstrate:

✅ ISO 9001 certified process control
✅ MSME recognized manufacturing entity
✅ UKAF quality system compliance
✅ Full material traceability
✅ Advanced alloy manufacturing capability
✅ PEEK fastener engineering expertise
✅ Inspection-ready documentation systems

55. Engineering Selection Checklist (Project Use)

Engineers should confirm:

• Required Working Load Limit
• Lift angle condition
• Installation material
• Thread compatibility
• Environmental exposure
• Required certification level
• Inspection requirements
• Coating specification
• Logistics constraints

56. Engineering Conclusion

Eye bolts are not general fasteners — they are engineered lifting interfaces whose reliability depends on metallurgy, forging integrity, correct geometry, installation discipline, and inspection control.

Through integrated forging, machining, material engineering, inspection, and export documentation capability, SM Fasteners provides eye bolt solutions suitable for:

• Global EPC Projects
• Offshore & Energy Infrastructure
• Heavy Engineering Manufacturing
• High-Reliability Industrial Applications

Manufactured under certified quality systems and supplied with full technical documentation, SM Fasteners eye bolts deliver strength, traceability, and global compliance readiness demanded by modern industrial projects.