Plain Washers

1. Industrial Context of Plain Washers

Plain washers are critical load-distribution elements within bolted assemblies. While geometrically simple, they perform essential mechanical functions influencing:

• Structural joint reliability
• Bolt preload retention
• Surface protection
• Fatigue life of assemblies
• Compliance with international structural standards

Across EPC projects, washers are mandatory engineered components, not accessories.

Industries relying heavily on precision washers include:

Industry	Functional Importance
Structural Steel Construction	Prevent embedment & plate deformation
Oil & Gas	Load control in flange joints
Power Plants	Vibration stability
Petrochemical Plants	Corrosion isolation
LNG & Offshore	Galling prevention
Heavy Equipment	Surface protection
Railways	Dynamic load resistance
Shipbuilding	Corrosion + vibration reliability

SM Fasteners manufactures washers aligned with global industrial procurement specifications, ensuring interchangeability with ISO, ASTM, DIN, and BS systems.

2. Technical Definition

A Plain Washer is a flat annular mechanical component placed between a fastener head/nut and the bearing surface to:

• Distribute compressive load
• Increase bearing area
• Prevent surface damage
• Reduce friction variation
• Improve preload consistency

Fundamental Geometry

• Outside Diameter (OD)
• Inside Diameter (ID)
• Thickness (t)
• Bearing Surface Area

Engineering definition:$$\text{Washer Bearing Area} = \frac{\pi}{4}(OD^2 – ID^2)$$

This directly influences stress distribution under preload.

3. Functional Role in Bolted Assemblies

Plain washers serve four primary engineering functions:

3.1 Load Distribution

Without a washer:

• High compressive stress develops beneath bolt head.
• Local yielding or indentation occurs.

With washer:

• Stress spreads uniformly across contact surface.
• Structural integrity preserved.

3.2 Preload Stabilization

Bolt preload depends strongly on friction conditions.

Washer provides:

• Consistent friction interface
• Reduced torque scatter
• Predictable clamp load

3.3 Surface Protection

Essential when assembling:

• Painted structures
• Coated steels
• Soft materials
• Composite plates
• Stainless steel joints

3.4 Alignment Compensation

Washers compensate for:

• Minor hole misalignment
• Surface irregularities
• Installation tolerances

4. Load Mechanics & Force Behaviour

4.1 Preload Concept

Bolt tightening creates tensile force:$$F_p = \frac{T}{K \times D}$$

Where:

• $F_p$​ = preload force
• $T$ = applied torque
• $K$ = nut factor
• $D$ = nominal diameter

Plain washers directly influence K-factor stability.

4.2 Compression Cone Theory

Load spreads through joint members forming a compression cone.

Washers:

• Expand cone base
• Reduce localized crushing
• Improve fatigue resistance

4.3 Friction Distribution

Typical torque breakdown:

Component	Torque Share
Thread friction	40%
Under-head friction	50%
Actual preload	10%

Washers control the largest torque variable — under-head friction.

4.4 Contact Stress Reduction

Contact pressure:$$\sigma = \frac{F}{A}$$

Increasing washer area reduces surface stress significantly.

5. Joint Design Principles

5.1 Washer Selection Philosophy

Engineers must evaluate:

• Bolt diameter
• Joint material hardness
• Coating system
• Temperature
• Corrosion exposure
• Dynamic loading

5.2 Hardness Compatibility Rule

General engineering rule:$$H_{washer} \geq H_{joint\ surface}$$

Prevents embedding loss.

5.3 Structural Steel Requirements

Standards often mandate washers:

• EN 14399
• AISC Steel Construction
• Eurocode 3

Used with:

• High-strength friction grip bolts
• Structural connections
• Slip-critical joints

5.4 Preload Retention & Relaxation

Washer improves resistance against:

• Embedment relaxation
• Thermal expansion cycles
• Creep deformation
• Vibration loosening

5.5 Failure Prevention Role

Plain washers mitigate:

Failure Mode	Washer Contribution
Fatigue cracking	Load distribution
Joint relaxation	Surface stabilization
Galling	Reduced friction
Surface indentation	Bearing enlargement
Coating damage	Protective interface

5.6 Washer Use in Critical Services

Mandatory in:

• Pressure vessel bolting
• Offshore flanges
• LNG cryogenic systems
• NACE MR0175 sour service
• High vibration machinery

6. Functional Behavior in Different Load Conditions

Load Type	Washer Role
Static Load	Bearing stabilization
Cyclic Load	Fatigue reduction
Impact Load	Stress dispersion
Thermal Cycling	Preload retention
Corrosive Exposure	Barrier protection

6.7 Washer Interaction with Fastener Systems

Compatible with:

• Bolts
• Screws
• Stud bolts
• Threaded rods
• PEEK fasteners (electrical isolation systems)

SM Fasteners provides washer solutions engineered alongside full fastener assemblies to ensure system-level reliability, not component-only supply.

7. Product Types & Engineering Variants of Plain Washers

Plain washers are manufactured in multiple engineered configurations designed to meet specific load distribution, tolerance control, and structural performance requirements.

SM Fasteners produces washers conforming to international dimensional systems ensuring interchangeability across global EPC projects.

7.1 Standard Plain Washers (Normal Series)

Typical Standards

• DIN 125
• ISO 7089
• ISO 7090
• BS 4320 Form A

Characteristics

• Standard OD-to-ID ratio
• General industrial usage
• Controlled bearing surface

Applications

• Machinery assembly
• Automotive components
• Equipment frames
• General bolting systems

7.2 Large OD Washers (Fender / Repair Series)

Standards

• DIN 9021
• ISO 7093
• BS 4320 Form G

Engineering Purpose

• Increased bearing area
• Suitable for soft materials

Applications

• Sheet metal structures
• Composite panels
• Insulation mounting
• Fabricated assemblies

7.3 Structural Washers (Heavy Duty)

Standards

• DIN 6916
• EN 14399-6
• ASTM F436

Design Features

• Increased thickness
• High hardness
• Structural bolt compatibility

Used in:

• Steel bridges
• High-strength friction grip joints
• Heavy infrastructure

7.4 Precision Ground Washers

Manufactured with tight flatness tolerances.

Used where:

• Alignment accuracy required
• Rotating machinery assemblies
• Bearing seating
• Aerospace equipment

7.5 Square & Plate Washers

Common in civil engineering:

• Timber structures
• Foundation anchoring
• Rail infrastructure

Provide large bearing surfaces for non-metal substrates.

7.6 PEEK Plain Washers (Advanced Polymer)

SM Fasteners supplies PEEK washers for specialized applications.

Properties:

• Electrical insulation
• Chemical resistance
• Non-magnetic
• Lightweight
• Temperature resistance up to ~260°C

Applications:

• Semiconductor plants
• Medical equipment
• Offshore instrumentation
• Hydrogen systems

8. Dimensional Logic & Geometry

Washer geometry directly controls contact stress distribution.

8.1 Fundamental Dimensional Parameters

Parameter	Symbol	Function
Nominal Bolt Size	d	Fit control
Inside Diameter	ID	Clearance
Outside Diameter	OD	Load distribution
Thickness	t	Bearing strength
Flatness	—	Preload stability

8.2 Clearance Design

Standard clearance:$$ID = Bolt\ Diameter + Clearance$$ID=Bolt Diameter+Clearance

Typical clearance:
0.2–1.0 mm depending on standard.

8.3 OD Selection Principle

Engineering guideline:

Joint Type	Recommended OD
Hard steel plates	Standard OD
Soft metals	Large OD
Composite materials	Extra large OD
Structural bolting	Heavy series

9. Dimensional Specification Table (Metric Series)

Standard Plain Washer Dimensions (ISO 7089 / DIN 125)

Bolt Size	ID (mm)	OD (mm)	Thickness (mm)
M3	3.2	7	0.5
M4	4.3	9	0.8
M5	5.3	10	1.0
M6	6.4	12	1.6
M8	8.4	16	1.6
M10	10.5	20	2.0
M12	13	24	2.5
M16	17	30	3.0
M20	21	37	3.0
M24	25	44	4.0
M30	31	56	4.0
M36	37	66	5.0

Manufactured under calibrated tooling systems within ISO dimensional tolerances.

10. Heavy Series Washer Dimensions (DIN 6916 / ASTM F436 Equivalent)

Bolt Size	ID	OD	Thickness
M12	13	24	4
M16	17	30	6
M20	21	37	6
M24	25	44	8
M27	28	50	8
M30	31	56	10
M36	37	66	12

Designed for high preload structural bolts class 8.8 / 10.9.

11. Dimensional Logic for Structural Engineering

Washer thickness must resist:$$t \geq \frac{F}{\pi(OD^2-ID^2)\sigma_{allowable}}$$

Ensures washer does not plastically deform under preload.

12. International Standards & Compliance

SM Fasteners manufactures washers fully compliant with globally accepted standards.

12.1 ISO Standards

Standard	Description
ISO 7089	Normal series washers
ISO 7090	Chamfered washers
ISO 7091	Product grade C
ISO 7093	Large OD washers
ISO 7094	Structural washers

12.2 DIN Standards

Standard	Application
DIN 125	Standard washer
DIN 126	Heavy washers
DIN 9021	Large OD washer
DIN 6916	Structural steel washer

12.3 ASTM Standards

Standard	Description
ASTM F844	General purpose washers
ASTM F436	Structural washers
ASTM A240	Stainless steel plate material
ASTM A193/A320	Stud bolt assemblies compatibility

12.4 British Standards (BS)

Standard	Description
BS 4320	Metric washer series
BS 3410	Structural assemblies
BS EN 14399	Preloaded structural bolting

13. Thread Standards & Tolerance Compatibility

Although washers are non-threaded, they must match bolt systems.

Thread Compatibility Table

System	Standard
Metric Coarse	ISO 261
Metric Fine	ISO 965
UNC	ASME B1.1
UNF	ASME B1.1
BSW	BS 84
BSF	BS 84

Washer clearance dimensions ensure compatibility across these systems.

14. Interchangeability Considerations

Global EPC procurement requires:

• Metric ↔ Imperial compatibility
• Standard OD equivalence
• Structural bolt system alignment
• Inspection acceptance by third-party auditors

SM Fasteners maintains dimensional equivalency allowing seamless replacement in international projects.

15. Geometry Influence on Performance

Geometry Parameter	Performance Effect
Larger OD	Lower contact stress
Greater thickness	Higher preload capacity
Flatness accuracy	Torque repeatability
Chamfered edge	Seating accuracy

16. Dimensional Inspection Parameters

Critical inspection characteristics:

• OD tolerance
• ID tolerance
• Parallelism
• Flatness
• Burr-free edges
• Surface finish Ra value

Inspection executed under ISO 9001 controlled systems.

Engineering Summary — Part 2

Plain washers must be selected not by availability but by:

• Load class
• Joint material
• Applicable international standard
• Preload level
• Environmental exposure

Correct dimensional selection directly governs joint reliability and lifecycle performance.

17. Materials Engineering for Plain Washers

Material selection is the primary determinant of washer performance, directly influencing:

• Load-bearing capacity
• Hardness compatibility
• Corrosion resistance
• Temperature tolerance
• Service life reliability

SM Fasteners manufactures washers across full industrial metallurgy ranges, supporting EPC, offshore, petrochemical, and high-performance engineering sectors.

17.1 Industrial Material Categories

Material Family	Typical Grades	Primary Use
Carbon Steel	IS 2062, ASTM A36	General engineering
Alloy Steel	EN 24, 4140, 4340	High strength joints
Stainless Steel	304, 316, 316L	Corrosion resistance
Duplex Stainless	2205	Offshore & chemical
Super Duplex	2507	Seawater service
Nickel Alloys	Inconel, Monel	High temperature
High Alloy	SMO 254	Chloride resistance
Exotic Alloys	Hastelloy C276	Acid environments
Engineering Polymer	PEEK	Electrical isolation

18. Mechanical Property Comparison Table

Material	Yield Strength (MPa)	UTS (MPa)	Temp Limit °C	Corrosion Resistance	Typical Application
Carbon Steel	250	400–550	300	Low	Structural steel
Alloy Steel QT	850	1000+	450	Moderate	Heavy machinery
SS 304	215	505	870	Good	Process plants
SS 316	205	515	870	Excellent	Marine
Duplex 2205	450	620	300	Very High	Offshore
Super Duplex 2507	550	800	300	Extreme	Seawater
Inconel 625	460	827	980	Exceptional	LNG & turbines
Hastelloy C276	355	790	1000	Acid resistant	Chemical plants
SMO 254	300	650	400	Chloride resistant	Desalination
PEEK	—	—	260	Chemical inert	Electrical isolation

19. Material Selection Criteria

Engineering selection must consider:

Mechanical Factors

• Bolt property class
• Preload magnitude
• Contact pressure
• Hardness compatibility

Environmental Factors

• Chloride exposure
• H₂S presence
• Acidic chemicals
• Temperature cycling

Regulatory Compliance

• NACE MR0175 / ISO 15156
• Pressure vessel codes
• Offshore standards

20. Corrosion Resistance vs Environment

Environment	Recommended Materials
Atmospheric	Carbon Steel + Zinc
Industrial Pollution	SS304
Marine	SS316 / Duplex
Seawater Immersion	Super Duplex
Chloride Chemical	SMO 254
Sour Gas (H₂S)	Duplex / Nickel Alloy
Strong Acids	Hastelloy
Cryogenic LNG	Inconel
Electrical Isolation	PEEK

SM Fasteners supports material traceability through EN 10204 certification.

21. Mechanical Property Classes (Steel Washers)

Washer hardness must support bolt preload without yielding.

Washer Class	Typical Hardness	Compatible Bolt Class
140 HV	Soft joints	≤ 5.8
200 HV	General engineering	8.8
300 HV	Structural	10.9
380 HV	Heavy duty	12.9

Structural washers (ASTM F436) typically ≥ 38 HRC equivalent.

22. Heat Treatment Processes

Heat treatment ensures washers achieve required hardness and mechanical stability.

22.1 Annealing

Purpose:

• Stress relief
• Improved machinability

Applied to:

• Stainless steels
• Nickel alloys

22.2 Quenching & Tempering (Q&T)

Process:

1. Austenitizing
2. Rapid quenching
3. Controlled tempering

Benefits:

• High strength
• Toughness balance
• Structural washer performance

22.3 Solution Annealing

Used for:

• Duplex
• Super Duplex
• Nickel alloys

Restores corrosion resistance.

22.4 Hardness Limits (Sour Service)

For NACE compliance:

• Maximum hardness typically ≤ 22 HRC
• Prevents sulphide stress cracking

23. End-to-End Manufacturing Workflow

SM Fasteners follows an ISO 9001 controlled production workflow.

23.1 Raw Material Verification

• Approved mills only
• Heat number traceability
• MTC verification
• PMI testing for alloy confirmation

23.2 Blanking / Forging

Stamping / Punching

• High production efficiency
• Tight dimensional control

Forged Washers

• Structural applications
• Improved grain flow

23.3 Machining (Precision Washers)

CNC turning used when:

• Tight tolerances required
• Exotic alloys used
• Custom geometries specified

23.4 Deburring & Edge Conditioning

Prevents:

• Coating damage
• Assembly scoring
• Stress concentration

23.5 Heat Treatment

Controlled atmosphere furnaces ensure:

• Uniform hardness
• Oxidation control
• Metallurgical consistency

23.6 Surface Preparation

Includes:

• Shot blasting
• Pickling
• Passivation
• Cleaning

24. Surface Finishing & Coatings

Surface engineering protects washers against corrosion and controls friction characteristics.

24.1 Surface Finish Comparison Table

Finish	Corrosion Resistance	Friction Control	Temperature Limit	Typical Use
Plain Oil	Low	Stable	120°C	Indoor machinery
Zinc Plated	Moderate	Good	200°C	Construction
Hot Dip Galvanized	High	Variable	450°C	Structural steel
Mechanical Galvanized	High	Uniform	300°C	Infrastructure
Black Oxide	Low	Excellent	400°C	Precision machinery
Phosphate	Moderate	Lubricity	300°C	Automotive
PTFE / Xylan	Very High	Excellent	260°C	Offshore
Passivated SS	Excellent	Stable	870°C	Chemical plants

24.2 Coating Selection Logic

Requirement	Recommended Finish
Low cost indoor	Zinc plated
Outdoor structural	HDG
Marine exposure	SS Passivated
Offshore oil & gas	PTFE
High temperature	Black oxide
Chemical plants	Nickel alloy base

25. Hydrogen Embrittlement Control

Critical for high-strength steel washers.

SM Fasteners applies:

• Controlled plating processes
• Post-bake de-embrittlement
• ASTM B850 compliance practices

26. Surface Engineering for Preload Accuracy

Coatings influence nut factor (K):

Surface Condition	Nut Factor
Dry steel	0.20–0.25
Zinc plated	0.18
Lubricated	0.12–0.16
PTFE coated	0.10

Stable friction improves torque reliability.

27. Manufacturing Traceability & Control

Each production batch includes:

• Heat number marking
• Batch identification
• Process documentation
• Inspection history
• Traceable packaging

Integrated within SM Fasteners ISO 9001 quality management system.

Engineering Summary — Part 3

Plain washer performance depends on correct integration of metallurgy, heat treatment, and surface engineering.

Failure to match washer material with bolt grade, environment, or coating system can result in:

• Embedment loss
• Corrosion failure
• Stress corrosion cracking
• Preload relaxation

SM Fasteners delivers washers engineered as load-bearing mechanical components, not commodity hardware.

28. Inspection & Quality Control Framework

Plain washers used in industrial assemblies are load-bearing engineered components requiring validated inspection under controlled quality systems.

SM Fasteners operates an ISO 9001 certified quality management system, integrating manufacturing, inspection, and documentation traceability aligned with EPC and global project procurement standards.

28.1 Incoming Raw Material Inspection

Verification performed prior to production:

• Mill Test Certificate (MTC) validation
• Chemical composition verification
• Heat number traceability
• Surface defect inspection
• Positive Material Identification (PMI) for alloy grades

Standards referenced:

• ASTM A751
• ISO 4042
• EN 10204

28.2 In-Process Dimensional Inspection

Critical dimensional checks:

Parameter	Inspection Method
Inside Diameter (ID)	Go/No-Go gauges
Outside Diameter (OD)	Digital calipers
Thickness	Micrometer
Flatness	Surface plate measurement
Parallelism	Comparator inspection
Burr condition	Visual & tactile inspection

Statistical Process Control (SPC) applied for batch stability.

28.3 Mechanical Testing

Test	Standard	Purpose
Hardness Test	ISO 6508	Verify property class
Compression Test	ASTM F606	Load capability
Microstructure Exam	ASTM E3	Heat treatment verification
Coating Thickness	ISO 1461 / ASTM B633	Corrosion protection
Salt Spray Test	ASTM B117	Coating performance

28.4 Non-Destructive Testing (NDT)

Applied for critical applications:

• Magnetic Particle Inspection (MPI)
• Dye Penetrant Testing (PT)
• Ultrasonic Examination (UT)
• Eddy Current Testing

28.5 Certification & Documentation

SM Fasteners provides:

• EN 10204 3.1 Material Certificates
• EN 10204 3.2 Third-Party Certification (when required)
• Heat Treatment Reports
• Dimensional Inspection Reports
• Coating Certificates
• Certificate of Conformity (CoC)

Suitable for international audit environments.

29. Failure Mechanisms & Engineering Prevention

29.1 Embedment Relaxation

Cause:

• Washer hardness too low

Solution:

• Structural grade washers

29.2 Fatigue Failure

Cause:

• Uneven load distribution

Mitigation:

• Proper washer OD selection

29.3 Hydrogen Embrittlement

Risk in plated high-strength steel.

Control:

• Post-bake treatment
• Controlled electroplating

29.4 Stress Corrosion Cracking

Occurs in:

• Chloride environments
• Sour gas service

Solution:

• Duplex / Nickel alloys
• NACE compliant hardness

30. Industrial Applications Mapping

30.1 Construction & Structural Steel

• Structural bolting assemblies
• Bridges & transmission towers
• Slip-critical joints

Standards: EN 14399 / ASTM F436.

30.2 Oil & Gas Industry

Upstream

• Wellhead equipment
• Pipeline supports

Midstream

• Pump stations
• Compressor skids

Downstream

• Refinery piping systems
• Pressure vessels

Materials:
Duplex, Super Duplex, Inconel.

30.3 Power Generation

• Steam turbine assemblies
• Boiler structures
• Nuclear auxiliary systems

Requirements:

• Preload stability
• High temperature resistance

30.4 Petrochemical & Chemical Processing

• Acid handling systems
• Reactors
• Heat exchangers

Materials:
Hastelloy, SMO 254, SS316L.

30.5 LNG & Offshore

Critical considerations:

• Cryogenic temperatures
• Saltwater exposure
• Dynamic vibration

Preferred materials:
Super Duplex / Nickel alloys.

30.6 Automotive & Heavy Equipment

• Chassis connections
• Suspension systems
• Engine assemblies

Washers prevent coating damage and embedment loss.

30.7 Railways & Infrastructure

• Track fastening systems
• Bridge anchor bolts
• Signaling equipment

Heavy structural washers widely used.

30.8 Shipbuilding

• Deck equipment mounting
• Marine propulsion systems
• Corrosion resistant assemblies

30.9 PEEK Washer Applications

• Electrical insulation
• Semiconductor processing
• Medical equipment
• Hydrogen energy systems

Advantages:

• Non-conductive
• Lightweight
• Chemical resistance

31. Export Capability & Global Supply Readiness

SM Fasteners supports international EPC procurement with controlled export logistics.

31.1 Industrial Packaging

Options include:

• VCI corrosion protection packaging
• Oil-coated packaging
• Heat-sealed poly bags
• Palletized bulk packing
• Barcode traceability labels

31.2 Export Crating

• ISPM-15 compliant fumigated wooden crates
• Shock-resistant packaging
• Moisture barrier systems
• Containerized shipment readiness

31.3 Documentation Package

Provided with shipments:

Document	Purpose
MTC (EN 10204 3.1/3.2)	Material traceability
Inspection Reports	QA validation
Heat Treatment Records	Mechanical verification
Coating Certificate	Surface compliance
Certificate of Conformity	Project approval
Packing List	Logistics tracking
Commercial Invoice	Export clearance

32. Engineering Tables — Complete Reference Section

32.1 Proof Load & Tensile Strength Compatibility

(Washer hardness must exceed joint bearing requirements)

Bolt Grade	Proof Strength MPa	Recommended Washer Hardness
4.6	240	140 HV
5.8	380	160 HV
8.8	640	200 HV
10.9	830	300 HV
12.9	970	≥380 HV

32.2 Tightening Torque Chart (Typical Steel Bolts)

Size	Grade 8.8 Dry (Nm)	Lubricated (Nm)
M6	10	7
M8	25	18
M10	49	35
M12	85	60
M16	210	150
M20	410	290
M24	710	500
M30	1400	1000

Washer surface finish directly influences torque repeatability.

32.3 Preload Calculation — Worked Example

Given:

• Bolt: M16 Grade 8.8
• Torque = 210 Nm
• Nut factor K = 0.20
• Diameter = 16 mm

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

$$F_p=\frac{210}{0.20 \times 0.016}$$

$$F_p=65,625\ N$$

Washer must withstand this compressive load without yielding.

32.4 Material Comparison Table

Material	Relative Cost	Strength	Corrosion Resistance	Typical Sector
Carbon Steel	Low	Medium	Low	Construction
Alloy Steel	Medium	High	Medium	Machinery
SS304	Medium	Medium	Good	Industrial
SS316	Higher	Medium	Excellent	Marine
Duplex	High	High	Very High	Offshore
Super Duplex	Very High	Very High	Extreme	LNG
Nickel Alloy	Premium	High	Exceptional	Chemical
PEEK	Premium	Moderate	Chemical inert	Electronics

32.5 Corrosion Resistance vs Environment

Environment	Carbon	SS304	SS316	Duplex	Nickel Alloy
Indoor	✓	✓	✓	✓	✓
Outdoor	△	✓	✓	✓	✓
Marine	✗	△	✓	✓✓	✓✓
Seawater	✗	✗	△	✓✓	✓✓
Acidic	✗	△	✓	✓	✓✓
H₂S Sour	✗	△	✓	✓✓	✓✓

✓✓ = Preferred

32.6 Surface Finish Performance Comparison

Coating	Corrosion Life	Friction Stability	Maintenance Need
Zinc Plated	Medium	Good	Medium
HDG	High	Variable	Low
Black Oxide	Low	Excellent	High
PTFE	Very High	Excellent	Very Low
Passivated SS	Excellent	Stable	Minimal

32.7 Thread Standards & Tolerance Compatibility

System	Standard	Usage Region
Metric	ISO 261 / ISO 965	Global
UNC	ASME B1.1	USA
UNF	ASME B1.1	Aerospace
BSW	BS 84	UK legacy
BSF	BS 84	Industrial legacy

32.8 Washer Weight Chart (Reference — SM Fasteners Manufacturing Data)

Size	Weight / Piece (kg)	Weight / 100 pcs (kg)
M6	0.002	0.20
M8	0.004	0.40
M10	0.007	0.70
M12	0.011	1.10
M16	0.020	2.00
M20	0.035	3.50
M24	0.060	6.00
M30	0.110	11.0
M36	0.180	18.0

Aligned with SM Fasteners production capability and export packing calculations.

33. Integrated Quality & Manufacturing Capability — SM FASTENERS

SM Fasteners demonstrates:

• ISO 9001 certified production systems
• MSME recognized manufacturing infrastructure
• UKAF accredited quality management
• Full traceability manufacturing
• Advanced alloy & PEEK fastener capability
• Custom washer engineering for EPC projects

Manufacturing philosophy:

Washers engineered as structural load components — not commodity items.

Engineering Summary — Plain Washers

Plain washers perform essential mechanical roles in bolted joint integrity:

• Control load distribution
• Stabilize preload
• Protect surfaces
• Improve fatigue life
• Ensure compliance with international standards

Correct washer selection integrates:

• Geometry
• Material metallurgy
• Heat treatment
• Surface engineering
• Inspection validation

Through certified quality systems, advanced materials capability, and export-ready documentation, SM Fasteners provides globally compliant plain washer solutions suitable for critical industrial, offshore, infrastructure, and energy sector applications.