Fastener Technical Delivery Conditions, Standards and Quality Requirements
Technical delivery standards define the dimensional, mechanical, material, coating, inspection and quality requirements applicable to industrial fasteners. These standards ensure interchangeability, performance, reliability and safety across industries including automotive, electrical, construction, infrastructure, aerospace and general manufacturing. This guide provides a consolidated reference to the most important ISO standards governing fasteners.
Mechanical Properties
| Standard | Description | Applies To |
|---|---|---|
| ISO 898-1 | Mechanical properties of bolts, screws and studs | Carbon steel fasteners |
| ISO 898-2 | Mechanical properties of nuts with specified proof loads | Carbon steel nuts |
| ISO 898-6 | Fine thread nuts | Fine thread nuts |
| ISO 3506 | Stainless steel fasteners | Stainless fasteners |
| ISO 2702 | Heat-treated self-tapping screws | Self-tapping screws |
General Requirements
| Standard | Description |
|---|---|
| ISO 8992 | General technical delivery conditions |
| ISO 4753 | Thread end forms |
| ISO 225 | Terminology and dimension definitions |
Dimensional Tolerances
| Standard | Description |
|---|---|
| ISO 4759-1 | Dimensional tolerances |
| ISO 4759-3 | Washer tolerances |
Surface Discontinuities
| Standard | Description |
|---|---|
| ISO 6157-1 | Surface defects in threaded fasteners |
| ISO 6157-2 | Surface defects in nuts |
| ISO 6157-3 | Property class 12.9 and special applications |
Surface Coatings
| Standard | Description |
|---|---|
| ISO 4042 | Electroplating requirements |
| ISO 10683 | Zinc flake coatings |
| ISO 9227 | Salt spray testing |
Inspection and Quality Assurance
| Standard | Description |
|---|---|
| ISO 3269 | Sampling and inspection |
| ISO 16426 | Fastener quality management |
Hydrogen Embrittlement
| Standard | Description |
|---|---|
| ISO 4042 | Plated fasteners |
| ISO 15330 | Structural fasteners |
Fastener Specification Checklist
When specifying a fastener, define:
- Product standard
- Material
- Property class
- Surface finish
- Coating thickness
- Tolerance class
- Inspection requirements
- Certification requirements
- Packaging requirements
- Traceability requirements
Example:
M10 × 40 Hex Bolt, ISO 4017, Property Class 8.8, Zinc Plated ISO 4042, Acceptance Inspection ISO 3269.
Disclaimer
This page is intended as a technical reference guide only. Users should verify the latest editions of ISO, EN, DIN and BIS standards before specifying fasteners for safety-critical or regulated applications.
Frequently Asked Questions
What are general technical delivery standards for fasteners?
General technical delivery standards specify the requirements governing the manufacture, inspection, testing, acceptance, dimensions, mechanical properties, coatings, and quality assurance of industrial fasteners. These standards ensure consistency, interchangeability, reliability, and safety across different manufacturers and industries.
What is the difference between a product standard and a technical delivery standard?
A product standard defines the geometry and dimensions of a fastener, such as ISO 4017 for hex head screws or ISO 4032 for hex nuts. Technical delivery standards define the mechanical properties, tolerances, coatings, inspection procedures, and quality requirements applicable to those products.
Which standards govern the mechanical properties of carbon steel fasteners?
The primary international standards are:
ISO 898-1 for bolts, screws, and studs
ISO 898-2 for nuts
ISO 898-6 for fine pitch thread nuts
ISO 2702 for self-tapping screws
These standards define property classes such as 4.6, 8.8, 10.9, and 12.9.
Which standards govern stainless steel fasteners?
The mechanical properties of stainless steel fasteners are specified in the ISO 3506 series of standards, which classify fasteners according to stainless steel grades and strength classes such as A2-70, A4-70, and A4-80.
What is ISO 4759 used for?
ISO 4759 specifies dimensional tolerances for fasteners, including bolts, screws, nuts, and washers. It defines acceptable manufacturing variations to ensure interchangeability and proper assembly.
What is ISO 4042?
ISO 4042 specifies requirements for electroplated coatings applied to threaded fasteners, including coating thickness, corrosion protection, testing methods, and precautions relating to hydrogen embrittlement.
What is ISO 3269?
ISO 3269 establishes the acceptance inspection procedures and quality assurance requirements for fasteners, including sampling plans, inspection criteria, and lot acceptance requirements.
What is ISO 6157?
The ISO 6157 series defines permissible surface discontinuities and defects in bolts, screws, studs, and nuts, including cracks, laps, seams, folds, and other manufacturing imperfections
What standards apply to zinc plated fasteners?
Zinc plated fasteners are generally manufactured according to ISO 4042 for electroplating requirements, while their mechanical properties are specified by standards such as ISO 898 or ISO 3506, depending on the material.
What standards apply to zinc flake coated fasteners?
Zinc flake coatings used for high corrosion resistance applications are governed by ISO 10683, which specifies coating thickness, performance requirements, and testing procedures.
What is hydrogen embrittlement in fasteners?
Hydrogen embrittlement is a failure mechanism that can affect high-strength steel fasteners, particularly after electroplating processes. Standards such as ISO 4042 specify requirements for minimizing the risk of hydrogen embrittlement.
What standards govern fastener inspection and testing?
Fastener inspection and testing are primarily governed by:
ISO 3269 for acceptance inspection
ISO 898 series for mechanical testing
ISO 3506 for stainless steel testing
ISO 6157 for surface discontinuities
ISO 4759 for dimensional tolerances
What information should be specified when purchasing industrial fasteners?
A complete fastener specification should include:
Product standard
Nominal size and thread
Material grade
Property class
Surface finish or coating
Applicable technical delivery standards
Inspection requirements
Certification requirements
Packaging requirements
Why are technical delivery standards important?
Technical delivery standards ensure that fasteners supplied by different manufacturers maintain consistent dimensions, mechanical performance, corrosion resistance, and quality levels, thereby ensuring safety, reliability, and interchangeability.
Are ISO, DIN, and EN technical standards interchangeable?
Many DIN standards have been superseded by ISO or EN standards, but interchangeability depends on the specific standard. Engineers should always verify dimensions, tolerances, and performance requirements before substituting standards.
What standards should engineers specify for critical fastener applications?
For critical applications, engineers typically specify:
Product standard (ISO, DIN, or EN)
Mechanical property standard (ISO 898 or ISO 3506)
Dimensional tolerance standard (ISO 4759)
Coating standard (ISO 4042 or ISO 10683)
Inspection standard (ISO 3269)
Surface integrity standard (ISO 6157)
These requirements help ensure performance, safety, and traceability.