Overview
EN ISO 8748:2007 is a European adoption of the international standard ISO 8748:2007, specifying the requirements for coiled, heavy duty spring-type straight pins. These pins are manufactured from steel or stainless steel (austenitic or martensitic) and have nominal diameters ranging from 1.5 mm to 20 mm. This standard ensures that these fasteners meet strict quality, dimensional, and mechanical property criteria essential for reliable industrial applications. It supersedes the earlier 1997 edition, reflecting updated material and testing requirements.
Key Topics
-
Scope and Dimensions
The standard defines precise dimensional tolerances for pin diameters and lengths, ensuring interchangeability and fitting accuracy. Dimensions include nominal diameters from 1.5 mm up to 20 mm, with detailed limits provided for pre- and post-mounting diameters, swaged chamfer ends, and lengths available in commercial increments. The recommended hole diameter for installation must match the pin’s nominal diameter with an H12 tolerance class in accordance with ISO 286-2.
-
Materials and Mechanical Properties
Pins covered by EN ISO 8748:2007 are constructed from carbon steel and stainless steels, including austenitic and martensitic grades. Chemical composition limits and hardness ranges are specified to guarantee mechanical performance:
- Steel pins are hardened and tempered to a Vickers hardness range of 420 HV to 545 HV.
- Martensitic stainless steel pins have a hardness range of 460 HV to 560 HV.
- Austenitic stainless pins are cold worked as per agreed specifications.
Mechanical testing such as shear strength must comply with ISO 8749.
-
Surface Treatment and Quality
The standard advises plain finish pins treated with protective lubricants unless coatings are specified. Due to the risk of hydrogen embrittlement, electroplating and phosphate coatings require careful process control, including mandatory baking after plating as per ISO 4042 guidelines. Workmanship requirements prevent burrs and defects on the pins to maintain performance and safety.
-
Testing and Acceptance
Acceptance inspection according to ISO 3269 ensures compliance with dimensional and mechanical standards. Shear testing per ISO 8749 evaluates pin strength, validating suitability for heavy-duty fastening applications.
-
Designation System
The standard provides a clear nomenclature for identifying pins by type, diameter, length, and material. For example:
- Steel pin with 6 mm diameter and 30 mm length: Spring pin ISO 8748 - 6 × 30 - St
- Austenitic stainless steel pin with the same size: Spring pin ISO 8748 - 6 × 30 - A
Applications
Coiled heavy duty spring-type straight pins specified by EN ISO 8748:2007 are widely used in mechanical assemblies requiring secure, resilient fastening under load and vibration conditions. Typical applications include:
- Automotive and aerospace components
- Machinery and equipment assembly
- Heavy-duty industrial and structural connections
- Precise alignment and shear load distribution in shafts and housings
- Equipment requiring corrosion resistance when using stainless steel variants
These pins provide durable, fatigue-resistant fastening solutions essential in demanding environments.
Related Standards
- ISO 8750: Spring-type straight pins - Coiled, standard duty
- ISO 8751: Spring-type straight pins - Coiled, light duty
- ISO 286-2: System of limits and fits - Tolerance grades and limit deviations for holes and shafts
- ISO 8749: Pins and grooved pins - Shear test
- ISO 3269: Fasteners - Acceptance inspection
- ISO 4042: Fasteners - Electroplated coatings
- ISO 6507-1: Metallic materials - Vickers hardness test - Test method
Understanding these related documents complements proper specification, testing, and application of spring-type straight pins, ensuring compliance and performance in engineering designs.
Keywords: EN ISO 8748:2007, spring-type straight pins, coiled heavy duty pins, steel pins, stainless steel pins, pin dimensions, shear strength, fasteners standard, ISO 8748, heavy duty spring pins, pin hardness, industrial fasteners, ISO fastener standards, hydrogen embrittlement prevention, pin designation.
